HUMAN ANATOMY AND PHYSIOLOGY 241
INSTRUCTOR: METHEA SAPP
SPOKANE COMMUNITY COLLEGE
INSTRUCTOR: Methea Sapp
OFFICE/PHONE: Room #220, 533-7235
e-mail: msapp@scc.spokane.edu
Office hours: 7:30-8:30 Monday-Friday or by appointment
THIS LAB MANUAL BELONGS TO: ____________________________________
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NAME: _________________________ PHONE NUMBER: _____________________
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2
Table of Contents
GUIDELINES FOR DRAWINGS.......................................................................................... 4
TEN COMMANDMENTS OF MICROSCOPY ..................................................................... 5
MICROSCOPE STORAGE .................................................................................................. 6
MICROSCOPE USAGE ....................................................................................................... 6
MICROSCOPE .................................................................................................................... 8
TISSUES ............................................................................................................................ 10
INTEGUMENTARY HISTOLOGY...................................................................................... 18
CARE OF BONE SPECIMENS ..................................................................................... 21
AXIAL SKELETON ........................................................................................................ 22
APPENDICULAR SKELETON........................................................................................... 32
MUSCLE HISTOLOGY ...................................................................................................... 37
HUMAN SKELETAL MUSCLES ........................................................................................ 39
MUSCLES OF THE HEAD AND NECK .................................................................... 40
MUSCLES OF THE TRUNK ..................................................................................... 40
MUSCLES OF THE UPPER EXTREMITY ................................................................ 41
MUSCLES OF THE LOWER EXTREMITY ............................................................... 42
EXTERNAL ANATOMY OF THE FETAL PIG ................................................................... 45
MUSCLES OF THE FETAL PIG ........................................................................................ 46
ANATOMY & PHYSIOLOGY OF NEURONS, NERVES, AND THE SPINAL CORD ....... 50
REFLEXES ........................................................................................................................ 54
DEMONSTRATION OF A SOMATIC REFLEX: THE STRETCH REFLEX ...................... 54
DEMONSTRATION OF A VISCERAL REFLEX: THE SALIVARY REFLEX .................... 57
ANATOMY OF THE BRAIN AND CRANIAL NERVES...................................................... 58
AUDITORY & VISUAL REFLEXES & TASTE SENSATION ............................................. 63
THE EFFECT OF SMELL ON THE SENSE OF TASTE ................................................... 67
EYE ANATOMY & VISION PHYSIOLOGY........................................................................ 68
3
GUIDELINES FOR DRAWINGS
Properly made drawings are valuable means of recording observations and can provide a means
for reviewing materials observed in lab. Making a drawing of a specimen also forces the student
to make detailed observations and helps the student develop discipline and attention to detail.
1. Drawings should be made on plain white paper using a sharp hard lead pencil.
2. Drawings must be neat and large enough to show detail.
3. Lines used in drawing should be thin and continuous, not indistinct or “sketchy.” Stippling or
shading should be used to show contrast. Any erasures should be thorough.
4. Only what is actually observed should be drawn, but the view that is selected should be one
that shows a typical specimen.
5. Specific areas of the drawing should be labeled, preferably to the right of the drawing. Label
lines should be drawn with a straight edge or ruler and should run parallel to the top and
bottom margins of the page; the end of the line may be angled to avoid crowding. None of
the label lines should cross each other. The label line should touch the edge or the interior of
the structure indicated. Brackets may be used to enclose related labels. (Example: The parts
of the nucleus of a cell might be labeled separately and then bracketed with the general title
“nucleus.”)
6. A subtitle that identifies the specimen should be placed under the drawing. It should include
the name of the specimen, the degree of magnification of the drawing, and type of section:
x.s. (cross section), l.s. (longitudinal section), t.s. (tangential section), or w.m. (whole
mount).
F.Y.I The degree of magnification is calculated by dividing the dimension of the drawing by the
dimension of the specimen. (Example: A drawing is made of a cell whose actual diameter is 50
micrometers or 0.05 millimeters. The diameter of the drawn cell measures 5 cm or 50 mm. The
degree of magnification of this drawing would then be 50 mm divided by 0.05 mm = 1000X.)
Get off on the right foot and always be prepared to make the best study drawings possible.
Stock your backpack with…
Pencils and good erasers
Colored pencils if you don’t like our labs selection
A ruler
White out?
White blank paper will always be provided for you.
4
TEN COMMANDMENTS
OF MICROSCOPY
1. Place slide flat on stage, with corner firmly against
mechanical stage
2.
Adjust interpupillary distance to see one circle
3.
With new slide, start on scanning power
4.
If you can’t find anything, return to scanning power
5.
Before increasing magnification, focus sharp
6. Before increasing magnification, center specimen in
field
7.
On high power, NEVER use coarse focus
8.
When focused, adjust light with diaphragm
9. Draw from the highest magnification that shows area of
interest
10. To sharpen image & prevent eye fatigue adjust
eyepieces to match your individual eyes
5
MICROSCOPE STORAGE
1.
REMOVE SLIDE FROM STAGE. Remove immersion oil
from objective lens & slide if used.
2.
SCANNING POWER OBJECTIVE IN WORKING POSITION.
3.
RAISE STAGE TO STOPPING POINT
4.
CENTER MECHANICAL STAGE APPARATUS.
5.
TURN OFF THE LAMP.
6.
WRAP CORD NEATLY AROUND SCOPE.
7.
REPLACE PROTECTIVE COVER OVER SCOPE.
8.
CARRY WITH ONE HAND HOLDING ARM AND OTHER
HAND UNDER BASE.
9.
PLACE IN CABINET IN PROPERLY NUMBERED SPACE
WITH ARM FACING TOWARD YOU.
MICROSCOPE USAGE
1.
BRING ONLY ONE SLIDE BACK TO YOUR TABLE AT A
TIME. This makes more slides available to other
students and reduces the chance of breaking a slide by
accidentally knocking it off the table.
2.
PLUG IN ELECTRICAL CORD ON THE OPPOSITE SIDE
OF THE LAB TABLE, SO THAT THE CORD DOES NOT
HANG DOWN WHERE IT MAY CATCH ON ANYTHING.
6
Ocular lens = located next to your eye
Objective lens = located next to specimen
Revolving nosepiece = mount for objective lenses, allows for changing lens in working position
Stage = flat platform the slide rests on
Mechanical stage = spring-loaded clip that holds slide & two knobs located below stage which allow
the slide to be moved left or right and toward or away from you
Coarse focus knob = moves the stage up and down a relatively large distance for focusing
Fine focus knob = allows smaller, more precise movements of the stage for focusing
Illuminator = light source
Condenser = lens under stage which focuses light on the specimen
Diaphragm adjust lever= allows for adjusting the amount of light passing through the
specimen, & improving contrast
7
MICROSCOPE
1. Familiarize yourself with the following parts of the compound light microscope:
ocular or eyepiece
revolving nosepiece
objective lenses
scanning
low
high
oil immersion
stage
condenser
mechanical stage
coarse focus
fine focus
light
arm
base
2. Understand the following terms:





Field of view * = circle you see when looking through the microscope
Depth of field * = depth of the area in focus
Working distance * = distance between the end of objective lens and specimen
Light gathering ability * = amount of light entering the lens
Resolution or resolving power = distance apart two things must be to distinguish that
they are separate, so smaller distance equals better resolution. In practical terms this
represents the amount of detail you can see.
 Parfocal = when microscope is focused on one power (using one objective) it is also in
focus on the other powers (using other objectives). Your microscopes are close but not
perfectly parfocal.
* for these term; understand the effect of changing magnification (they all decrease as
magnification increases)
3. Multiply the ocular magnification times the objective magnification to calculate the total
magnification at each power and record below. Using a micrometer slide measure the
diameter of the field of view when using each objective lens and record your
measurements below.
OBJECTIVE
MAGNIFICATION
DIAMETER OF FIELD
Scanning power =
X
microns ()
Low power =
X
microns ()
High power =
X
microns ()
Oil immersion =
X
microns ()
8
4. Prepare a wet mount of the squamous epithelial cells lining your cheek.
1. Begin by scraping the inside of your cheek with the wide end of a toothpick to remove some
cells. Scrape firmly using the long side of the toothpick and then spread the cells onto a clean
slide.
2. Apply a drop of methylene blue stain, instead of the drop of water, followed by the cover
slip.
A wet mount slide can be prepared by placing your specimen in the middle of a clean glass slide and
adding a drop of water. Holding the cover slip at approximately a 45% angle to the slide, touch the lower
edge to the water and lower it slowly to prevent formation of air bubbles.
3. Starting on scanning power look over all the cells. If done properly you should have
hundreds of cells to choose from, although some will be in clumps or highly folded.
4. Try to find a well stained cell sitting alone and laying flat.
5. In the space below make a drawing of this cell from your observations on high power,
estimate the size of the cell and label the cell membrane, nucleus, nuclear membrane, and
cytoplasm.
6. Look for tiny, dark specks in/around any of the cells, these are bacteria which are normally
present.
Drawing of Cheek Cell
Point of interest: You should be able to see cells in your slide which represent 2 of the three
Domains of life. Domain Bacteria (consists of prokaryotes) and Domain Eukarya (consists of
the eukaryotes)
7. In your drawing above label a eukaryotic and prokaryotic cell.
8. Let slide dry
9. Put name on frosted tab of slide
10. File your slide in your lab sections slide box for future study and reference.
9
TISSUES
COMPLETED HISTOLOGY TABLE IS DUE AT THE END OF THIS TWO PART LAB
-20PTS Use pages 152-172 in Salidin to assist you with the following table and histology
exercise.
Background: Histology is the study of tissues; it is anatomy of the microscopic. Tissues are groups of
similar cells that have specialized function. Organs are formed of two or more types of tissues and carry
out a specific function. In histology you will concern yourself with how cells differ in shape and
function, how cells are organized within tissues and how tissues are organized within organs.
Learning histology requires careful strategy. You will find the tissues that you are required to recognize
and understand on the following pages. The cells are found in the tissues and many are too difficult to see
clearly with the magnification levels available on our microscopes. You must begin on low power to get
an idea of the organization of the tissue. Move to higher and higher power only when you are
comfortable with your understanding of the tissue (use the reference books in lab and/or your text books
to get your bearings). This will become even more important later in the sequence of courses when we
study specific organs. If you can get an understanding of the basic tissue types and an appreciation for
how to study histology, you will find yourself in good stead in the future.
When looking at histological slides, it is important that you remember that you are looking at a single,
thin section of a three dimensional structure. Depending on how the specimen was sectioned, you may
get one of several different views. To illustrate this, think of sectioning a hard boiled egg. If we were to
take a cut through the top of the egg, you would see no yolk. If we cut through the egg lengthwise, but
off center, we would get very little yolk showing, but a lot of egg white. Cutting the egg transversely
through the center of the yolk would give us a lot of yolk, but little white showing. There are similar
problems when cutting through convoluted tubular structures. The key is to look at several examples of
the same structure and attempt to mentally recreate it in three dimensions. (See p.155 in Salidin for
illustration)
Many students get hung up on the color of the stains when first introduced to histology. Staining is a way
to show detail otherwise impossible to detect. There are a plethora of stains available for histo-technique
and you may see many examples of these. DO NOT learn things solely on the basis of color. It never
fails that a slide you see on an exam is stained differently then one you saw in class or in a textbook. Be
sure you concentrate on the morphology of the tissues and organs. Note the textures and opaqueness of
the structures and include this information in the column marked “description” in the tables you will find
in the lab manual.
Four Primary Tissue Types
1. Epithelial tissue: Epithelial tissues cover body surfaces, line body cavities and hollow organs, and
make up glandular tissues throughout the body. Depending on location, epithelial tissues derive from all
three primary germ layers: ectoderm (i.e. epidermis of skin), mesoderm (linings of blood vessels and
heart), and endoderm (mucosal layer of digestive tract). Epithelial tissues are composed of closely
packed cells, with little intercellular material, arranged in a continuous sheet. They are avascular (i.e.
contain no blood vessels) and obtain their nourishment through diffusion of substances from blood
vessels in the underlying connective tissue. It is supported atop a thin basement membrane which
separates it from the connective tissue below. Epithelial tissues are capable of rapid regeneration,
particularly in areas exposed to high abrasive forces. Since epithelial tissue always has one free surface, a
polarity is established between its free side (the apical surface) and the side adjacent the basement
membrane (basal surface). The plasma membranes that compose the two surfaces can possess very
different ingredients (e.g. receptors, microvilli) as warranted by the function of the particular tissue.
Epithelial tissues are classified based on the number of cell layers (simple or stratified) and the shape
(squamous, cuboidal, columnar, pseudostratified, transitional) of cell on the apical surface. (See Salidin
p.157 Fig. 5.3)
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2. Connective tissue: This is a very diverse group of tissues. All connective tissues have an abundant
extracellular matrix that surrounds relatively few cells. Connective tissues perform various functions
including: support, binding, storage, etc. Special cells, called fibroblast synthesize and release the various
fibers found in the matrix. Three specific fibers are recognized: collagenous fibers (abundant, strong,
inelastic, and made of protein collagen; occur in bundles), elastic fibers (long, threadlike, branching,
made of the protein elastin; they can stretch and return to their original length) and reticular fibers (short,
thin, branching; forming the internal framework (stroma) of glands. These fibers may only be visible
with certain stain techniques. Ground substance makes up the rest of the extracellular matrix and varies
from a fluid to a semi-solid gel. Connective tissues are classified according to the amount and
organization of the different fibers and ground substance. Although blood cells do not produce
intercellular substances, they are classified as connective tissues because they develop from mesoderm
like the other connective tissues.
3. Muscle tissue: These tissues are composed of cells elongated into tin fibers that are capable of
contraction when properly stimulated. All are richly supplied with blood vessels and nerves. Three
distinct types exist: smooth, cardiac, and skeletal. Virtually all muscle tissue is derived from mesoderm.
4. Nervous tissue: These tissues are composed of (1) highly specialized cells (neurons) with elongated
cytoplasmic processes (dendrites, axons) and (2) neuroglial cells that support and protect neurons.
Nervous tissue is capable of generating and conduction electrical signals for the purpose of information
relay. Nervous tissue is richly supplied with blood vessels and is derived from ectoderm.
Instructions for lab:
1. Find all of the following tissues and draw a representative group of several cells. (you may choose
to use blank paper or the following tables or any combination of the two….just be organized so
that you can rely on this information when you prepare for exams.
2. Label the drawing with the type of tissue and other details as listed (description, location, function)
3. Where specified; answer the questions and/or complete the given task(s)

Remember, take only ONE slide at a time back to your table.

Use your lab manual, textbook, and any additional materials as references.

Drawings should be on unlined paper, an appropriate size, clearly labeled, and arranged in an
orderly manner. Answers to questions, sizes, and locations should be grouped with each drawing.
These drawings will be your study tools for your lab exams so make sure they are accurate
and of a high quality.

Many slides contain several types of tissue, be careful to identify the correct tissue
Epithelial tissues are named by…
1) shape of the superficial layer of cells;
 Columnar = rectangular in cross section
 Cuboidal = square in cross section
 Squamous = flat in cross section
2) arrangement of cells;
 Simple = one layer of cells
 Stratified = two to many layers of cells
11
TISSUES
1. Simple squamous epithelium , H6004
This slide shows the squamous cells in cross section as the parietal portion of the glomerular
capsule in the kidneys. YOU MUST FIRST IDENTIFY THE CAPSULES USING
SCANNING POWER, then use high power to look at the capsular wall for examples of these
flat cells.
Task: Give another example of where this tissue is located in the body.
2.
Simple cuboidal epithelium H150
Surrounding the capsules are numerous tubules. Their walls are comprised of simple cuboidal
epithelium.
Task: Estimate the size of one cell and give another example of where this tissue is located.
3. Simple columnar epithelium H185 (tall), Do NOT use H180 (low)
Label:
apical end of columnar cells (on the surface)
basal end of columnar cells (connected to basal lamina)
goblet cells
Task: Measure the height and width of one columnar cell and give an example of where this tissue
is located.
4.a. Stratified squamous epithelium –Review Your Own Cheek Cell Slide
Review the following structures
Label:
cell membrane
nucleus
nuclear membrane
cytoplasm.
4. b. Stratified squamous epithelium (Esophagus, H7875)
Label: squamous cells
5. Transitional epithelium (Ureter, H8232)
Task: Give another example of where this tissue is located and describe the unique feature of this
epithelium.
6. Pseudostratified ciliated columnar epithelium H210
Task: First draw this tissue, then write a definition for this type of epithelium. Identify the
function of the cilia.
7. Areolar (loose) connective tissue H570
Label: elastic fibers (thin)
collagenous fibers (thick)
fibroblasts - it is difficult to see the cytoplasm of these cells, only the purple nuclei are
visible
12
8. Hyaline cartilage H6022
Label: lacunae
chondrocytes
intercellular matrix
9. Adipose tissue (Spleen, H2020)
ONLY USE SLIDES WITH AN ASTERISK (*) ON THE LABEL & LOOK AROUND THE
OUTSIDE OF THE SPLEEN FOR THE ADIPOSE TISSUE
Label: adipocytes
Estimate the size of one adipocyte.
10. Dense Regular
Label: collagen fibers
fibroblast nuclei
11. Fibrocartilage
Label: collagen fibers
condrocyte in lacuna
12. Blood
Label: red blood cell
white blood cell
platelets
13. Compact bone H782
Label: osteon or Haversian system
central (haversian) canal
lacunae
lamellae
osteocytes
canaliculi
intercellular matrix
14. a. Muscle, skeletal, teased individual fibers, A105-6
Observe this slide before the following (#14) slide, so that you can recognize individual fibers
b. Muscle, skeletal l.s. H6030 or Carolina #31-3256
Find an area of longitudinal fibers, (like Figure 26A, page 26 in Rust manual)
Label: nuclei
striations
15. Cardiac Muscle
Label: striations
intercalated discs
Question: What is the function of intercalated disks?
16. Smooth Muscle
Label: nucleus
17. Nervous (Spinal Cord H1550)
Label: neuron cell body
processes
nucleus
13
EPITHELIAL TISSUES
Tissue Type
Simple
Squamous
Epithelium
Description
Location
Simple Cuboidal
Epithelium
Simple
Columnar
Epithelium
Stratified
Squamous
Epithelium
Transitional
Epithelium
Pseudostratified
(Ciliated)
Columnar
Epithelium
14
Function
CONNECTIVE TISSUES
Tissue Type
Areolar
Connective
Tissue
Description
Location
Hyaline
Cartilage
Adipose Tissue
Dense Regular
Connective
Tissue
Reticular
Connective
Tissue
15
Function
CONNECTIVE TISSUES cont…..
Tissue Type
Fibrocartilage
Description
Location
Function
Location
Function
Blood
Compact
Bone
MUSCLE TISSUES
Tissue Type
Skeletal
Muscle
Tissue
Description
Cardiac
Muscle
Tissue
16
MUSCLE TISSUES CONTINUED…..
Smooth
Muscle
Tissue
NERVOUS/NEURAL TISSUE
Tissue Type
Nervous
Description
Location
17
Function
INTEGUMENTARY HISTOLOGY
DUE AT THE END OF LAB: TURN IN DRAWINGS COMPLETE WITH LABLED
STRUCTURES (SEE LIST BELOW) -10PTS
OBJECTIVE: Identify & be able to recognize the following structures from slides.
No one slide will have good examples of all the structures, so you will need to use several slides
to make a composite drawing that includes all of the following.
Use scanning power for most structures, going to high power for the strata of the epidermis or
when you have already identified a structure and then want more magnification.
Your textbook and lab manual are excellent references, so use them. Find as many pictures of
the structure of interest as possible BEFORE you try to find it on the slide. It is always much
easier to find something when you know what you are looking for. (See Salidin p. 188-203)
1.
Scalp, Human Mallory l.s. H7456, NOTE: some slides are not stained with
Mallory stain. Be sure you look at both kinds.
Epidermis
 keratinized stratified squamous epithelium
 stratum corneum
 stratum granulosum
 stratum spinosum
 stratum basale (germinativum)
Dermis
 dermal papilla
 hair
 hair follicle
 piloerector muscle (arrector pili muscle)
 hair bulb with dermal papilla
 sebaceous gland
 suderiferous glands (Merocrine and Apocrine)
 areolar & dense connective tissue
Hypodermis
 adipose tissue
 blood vessel
18
2.
Scalp, Human c.s. H7450
 hair
 hair follicle
 sebaceous gland
3. Hair (pili)













shaft
root
medulla
cortex
cuticle
follicle
epithelial root sheath (internal root sheath)
connective tissue root sheath (external root sheath)
hair bulb
hair matrix
dermal papilla of hair root
Piloerector muscle (arrector pili)
sebaceous glands
4. Nail







nail body
nail bed
nail root
free edge
eponychium (cuticle)
lunule
nail matrix
19
THE SKELETON
Preliminary Study
Before beginning to study the bones that make up the skeleton, familiarize yourself with the
following terms. Look up the definition of each term in your text or other reference and write it
in the space provided. (See Salidin p. 244 Table 8.2)
crest:
condyle:
epicondyle:
facet:
fissure:
foramen:
fossa:
fovea:
head:
line:
meatus:
process:
spine:
sulcus:
trochanter:
tubercle:
tuberosity:
After this preliminary overview, you are ready to study individual bones and their markings.
Use figures to first locate all the markings of a bone, then progress to the actual bone. You will
be tested from the bones themselves (real-bone and plastic), therefore, do not attempt to learn the
bones and their markings solely from drawings and photographs. Examine several different realbone specimens of a bone as individual variations do exist. Be sure to look at the bones from all
angles and in their articulated and disarticulated states.
20
Use labeled figures of the entire skeleton and enlarged figures of the skull to initially locate all the bones you
are responsible for. (See Salidin p. 243-278 and Rust, pages 15-24.) Say their names out loud as you study
the figures.
Care of Bone Specimens
1. Handle all bone specimens with care, especially real-bone specimens, as they are irreplaceable. Please
treat real-bone specimens with respect; remember that they were once part of a human being.
2. Do not insert hard objects such as pens, pencils, dissecting needles, etc., into bone openings (foramina,
fissures, etc.) as erosion of the opening will result. Instead, use a pipe cleaner if you need to point out a
bone opening.
3. Do not pick up the fetal skeleton, the real-bone Beauchenne skull, or the display skulls. Study these
specimens at the materials tables where they are displayed. Other bone specimens may be moved from
the materials tables to your study area.
4. Put specimens away when you are finished with them:
a. Put bones back into their boxes. All boxes are labeled as to the bones they contain. Follow the
instructions on the boxes. DO NOT PUT OTHER BONES INTO THE BOX WITH THE
SAGITTALLY-SECTIONED SKULL!!
b.
Do not put plastic bone specimens on top of real-bone specimens in a box. Plastic specimens
are heavy and will crush real bone.
c. Slide the full, articulated skeletons back into their lockers and close the doors.
5.
Bone specimens may be moved from one life science lab to another as long as they are put away
when you are finished. DO NOT TAKE BONE SPECIMENS OUT OF THE SCIENCE
BUILDING!!
Instructions:
Use the following table in conjunction with the bone boxes, skeletons, and reference books to learn the
location/description/function of each of the bones and bone processes listed in the table. You may choose to
either fill in the table or use blank sheets of white paper for larger drawings.
21
Axial Skeleton
SKULL –Cranium Special Features
Sutures
Sagittal
Sketch
Description/Location/Function
Sketch
Description/Location/Function
Coronal
Squamous
Lambdoid
Sutural bones
Only in child skull
Anterior fontanel
Posterior (occipital)
fontanel
Sagittal suture
Squamous suture
22
Air Sinuses
Paranasal sinuses
Description/Function
Location
Frontal sinus
Sphenoid sinus
Ethmoidal sinus
Maxillary sinus
SKULL – Cranium Bones
Bone
Frontal Bone
Sketch
Description/Location/Function
Superciliary arch*
Glabella
Supraorbital margin
Supraorbital notch
(aka foramen)
Frontal sinuses
Parietal Bone
Occipital Bone
Foramen magnum
External occipital
protuberance
Hypoglossal canal
23
SKULL – Cranium Bones cont..…
Bone
Temporal Bone
Sketch
Description/Location/Function
Mastoid process
Styloid process
External acoustic (auditory)
meatus
Zygomatic process of the
temporal
Mandibular fossa*
Internal acoustic canal
Jugular foramen
Stylomastoid foramen
Carotid canal
Sphenoid Bone
Body
Sphenoid sinus
Greater wings
Lesser wings
Sella turcica
Optic foramen (canal)
Superior orbital fissure
Pterygoid processes
Foramen spinosum
Foramen ovale
Foramen rotundum
Ethmoid Bone
Cribriform plate
Crista galli
Perpendicular plate
Superior concha (turbinates)
Middle concha (turbinates)
24
SKULL – Facial Bones
Bone
Mandible Bone
Sketch
Description/Location/Function
Body
Angle
Ramus
Condyloid process
(aka Mandibular condyle)
Coronoid process
Mandibular notch
Mandibular foramen
Mental foramen
Maxillae Bone
Maxillary sinus
Palatine process
Infraorbital foramen
Lacrimal Bone
Palatine Bone
Horizontal plate
Inferior nasal conchae
25
SKULL – Facial Bones cont…
Bone
Nasal
Sketch
Description/Location/Function
Vomer
SKULL – MISCELLANEOUS BONES (See Salidin p. 600)
Bone
EAR OSSICLES
Malleus
Sketch
Description/Location/Function
Incus
Stapes
OTHER
Hyoid
26
Axial Skeleton
VERTEBRAL COLUMN
Bone
Description/Function
Location
Vertebra (general)
Centrum or body
Neural or Vertebral arch
(both pedicles & laminae)
Pedicles
Laminae
Vertebral foramen
Transverse process
Superior articular surface
Inferior articular surface
Spinous process
Vertebral foramen
27
VERTEBRAL COLUMN cont…..
Bone
Description/Function
Location
Cervical Vertebrae
Transverse foramen
Atlas
Superior articular surface
Inferior articular surface
Axis
Dens (aka Odontoid process)
28
Bone
Description/Function
Thoracic Vertebrae
Superior costal facet
Inferior costal facet
Transverse costal facet
Lumbar Vertebrae
Sacrum
Sacral promontory
Sacral foramina
Sacral Ala
Auricular surface
29
Location
THORACIC BONES
Bone
Description/Function
Location
Sternum
Manubrium
Body
Jugular notch
Xiphoid process
Ribs
Head
Neck
Tubercle
Shaft or Body
Costal groove
Costal cartilage
30
31
Appendicular Skeleton
PECTORAL (SHOULDER) GIRDLE
Bone
Clavicles
Sketch
Description/Location/Function
Sternal end
Acromial end
Scapula
Superior border
Medial border
Lateral border
Superior angle
Inferior angle
Subscapular fossa
Infraspinous fossa
Supraspinous fossa
Scapular spine
Acromion process
Coracoid process
UPPER EXTREMITY BONES
Bone
Sketch
Humerus
Description/Location/Function
Head
Anatomical neck
Surgical neck
Greater tubercle
Lesser tubercle
Intertubercular sulcus
Deltoid tuberosity
Capitulum
Trochlea
Medial epicondyle
Lateral epicondyle
Olecranon fossa
Coronoid fossa
Ulna
Olecranon process
Coronoid process
Trochlear notch
Radial notch of ulna
Proximal radioulnar
joint
Styloid process
32
UPPER EXTREMITY BONES cont….
Bone
Sketch
Radius
Description/Location/Function
Radial head
Radial tuberosity
Styloid process of
radius
Ulnar notch of radius
Carpal bones
Scaphoid
Lunate
Triquetrum
Pisiform
Trapezium
Trapeziod
Capitate
Hamate
Metacarplas
(numbered 1- 5; the
thumb is #1)
Phalanges
(numbered 1- 5; the
thumb is #1)
Proximal
Middle
Distal
33
PELVIC GIRDLE
Bone
Ilium
Sketch
Description/Location/Function
LOWER EXTREMITY BONES
Bone
Sketch
Femur
Description/Location/Function
Iliac crest
Anterior superior iliac spine
Anterior inferior iliac spine
Posterior superior iliac spine
Posterior inferior iliac spine
Greater sciatic notch
Acetabulum
Iliac fossa
Ischium
Ischial tuberosity
Ischial spine
Lesser sciatic notch
Pubis
Pubic symphysis
Superior ramus of pubis
Inferior ramus of pubis
Obturator foramen
Head
Neck
Greater trochanter
Lesser trochanter
Linea aspera
Lateral supracondylar line
Medial condyle
Lateral condyle
Intercondylar fossa
Lateral epicondyle
Medial epicondyle
34
LOWER EXTREMITY BONES cont…
Bone
Sketch
Patella
Description/Location/Function
Tibia
Medial condyle
Lateral condyle
Intercondylar eminence
Anterior crest (margin)
Tibial tuberosity
Medial malleolus
Proximal (superior) tibiofibular
joint
Distal (inferior) tibiofibular joint
Fibula
Lateral malleolus
Tarsal bones
Calcaneus
Talus
Navicular
Cuboid
Medial cuneiform
Intermediate cuneiform
Lateral cuneiform
Metatarsal bones
(Numbered 1-5; big toe is #1)
Phalanges
(toes numbered 1-5; big toe is #1)
Proximal
Middle
Distal
35
ARTICULATIONS
Joint
Knee
Sketch
Description/Location/Function
Fibular (lateral) collateral ligament
Tibial (medial) collateral ligament
Lateral meniscus (articular disc)
Medial meniscus (articular disc)
Anterior cruciate ligament
Posterior cruciate ligament
Patellar ligament
Hip
Ileofemoral ligament
Pubofemoral (pubocapsular)
ligament)
Ischiofemoral (ischiocapsular)
ligament)
Elbow
Anular ligament
Ulnar collateral ligament
Radial collateral ligament
36
MUSCLE HISTOLOGY
Background:
The major types of muscle are smooth, cardiac and skeletal. Although differing in location,
function, and nervous innervations all three types share the same molecular basis for
contractions.
Skeletal muscle is innervated by axons of motor neurons belonging to the somatic division of
the nervous system (also called the voluntary nervous system). Upon entering a skeletal muscle,
axons of motor neurons branch and innervate from 5-200 individual muscle fibers. All the
muscle fibers innervated by a single motor neuron contract simultaneously and are termed a
motor unit.
In skeletal muscle, these muscle cells are elongated, cylinder-shaped cells that we call muscle
fiber or myofibers. They lie parallel to each other and contain smaller bundles of contractile
filaments. These bundles are called myofibrils. The contractile filaments are called
myofilaments and are arranged in such a way as to produce alternating light and dark bands
within the muscle fiber. Skeletal muscle appears striated because of these bands (crossstriations). Each skeletal muscle fiber possesses several nuclei which are found along the edges
of the muscle fibers. (See Salidin p. 404-408, fig. 11.1, 11.5 & 11.7a)
Individual skeletal muscle fibers are surrounded by a connective tissue sheath (endomysium).
These sheathed fibers are grouped together in bundles called fascicles which are bound by
connective tissue (perimysium). Fascicles are bound together by dense fibrous connective tissue
(epimysium) which also surrounds the entire organ. This organ is then surrounded by a sheet of
fibrous connective tissue (deep fascia). All of these connective tissue sheets are continuous with
each other and with the tendons that join the muscle to bone. (See Salidin p. 321 fig. 10.1)
Smooth (or visceral) muscle differs from skeletal muscle in structure, location, innervations and
physiological function. Smooth muscle fibers are not striated and are less cylindrical in shape
then skeletal muscle fibers. Smooth muscle fibers have a single nucleus which is found in the
center of the fiber. Smooth muscle is innervated by nerve fibers of the autonomic division of the
nervous system (also called the involuntary nervous system). By virtue of rhythmic contraction
and relaxation, smooth muscle in the walls of the gut, the urinary organs, and the reproductive
organs propels contents forward. Smooth muscle in the form of strong circular bands
(sphincters) controls the opening and closing of tubes or orifices. Generally speaking, skeletal
muscles adjust the organism to its external environment, while smooth muscles are concernments
of the gastrointestinal tract, constriction and dilation of blood vessels and emptying of the
urinary bladder.
Cardiac muscle is found only in the heart. It shares some properties with skeletal and some
with smooth muscle. The microscopic appearance of cardiac muscle fibers is similar to skeletal
muscle fibers (striated). In contrast to skeletal muscle, however cardiac muscle exhibits autorhythmicity and spontaneity. Cardiac muscle fibers branch and interconnect. The unique
junctions between cardiac muscle fibers (i.e., electric coupling) provide continuity in
transmission of excitation which allows the heart to pump blood into the arteries in a coordinated
manner. These junctions between cardiac muscle fibers are called intercalated discs and can
usually be seen under the microscope given the proper stain. Cardiac muscle fibers usually have
a single nucleus although they can have more. Cardiac muscle, like smooth muscle, receives
nervous input from the autonomic nervous system.
37
Instructions: Use a microscope and the prepared slides mentioned below to
answer the following questions and to complete any drawings that you may wish to
make for study aids.
Mammal Skeletal Muscle, #31-3256
Make note of the two orientations of muscle fibers on this slide. Some are sectioned
longitudinally so they appear as generally parallel lines. Others are cut in cross section so
bundles of fibers are apparent as generally rounded structures.
Questions:
In which perspective are striations visible?
Do you recognize the epithelial tissue that is also present on this slide?
Muscle Types, H1360 INSTRUCTOR WILL SET UP EXAMPLES OF THIS
SLIDE
This slide contains samples of three types of muscle. Using the clues listed below be able to
identify each type.
1) Skeletal = striations present, multinucleate cells (many nuclei visible)
2) Cardiac = striations present, single nucleus per cell (fewer nuclei visible)
3) Smooth = striations absent
Smooth Muscle, H6028
Note the smooth muscle that makes up the wall of the blood vessels as well as that surrounding
the vessels.
Smooth Muscle, t.s. H1250
This slide has smooth muscle fibers (cells) that have been teased apart (t.s. = teased section).
This allows observation of individual cells.
Question:
How does the basic shape of these smooth muscle cells differ from the shape of typical skeletal
muscle cells?
38
HUMAN SKELETAL MUSCLES
BE ABLE TO IDENTIFY ALL OF THE FOLLOWING MUSCLES FROM ANY
REASONABLE REPRESENTATION (model, cadaver photo, textbook figure,
drawing, or verbal description).
KNOW THE ACTION AND THE ORIGIN AND INSERTION OF ALL MUSCLES
MARKED WITH AN ASTERISK (*). (See following table)
IDENTIFY / RECOGNIZE THE FOLLOWING MOVEMENTS AT SYNOVIAL
JOINTS;
Flexion
Inversion
Plantar Flexion
Extension
Eversion
Supination
Hyperextension
Rotation
Pronation
Abduction
Circumduction
Elevation
Adduction
Dorsiflexion
Depression
39
MUSCLES OF THE HEAD AND NECK
Movements related to facial expression
Frontalis (or frontal belly of occipitofrontalis)
Orbicularis oris
Orbicularis oculi
Zygomaticus major * (actually #11, incorrectly identified as #13 on older torso model)
Levator labii superioris (#10 incorrectly identified on older torso model)
Depressor labii inferioris
Buccinator
Mentalis
Platysma
Risorius
Levator palpebrae superioris * (See Salidin p.615 & 616)
Movement of the eyeball (See Salidin p.615-616)
Superior rectus
Inferior rectus
Lateral rectus
Medial rectus
Superior oblique
Inferior oblique
Movement of mandible, tongue, pharynx
Masseter *
Temporalis
Medial (internal) pterygoid (See Salidin p.334)
Lateral (external) pterygoid (See Salidin p.334)
Genioglossus
Styloglossus
Hyoglossus
Movement of the head & neck
Sternocleidomastoid *
Semispinalis capitis
Splenius capitis (or just Splenius)
MUSCLES OF THE TRUNK
Breathing
Diaphragm
External intercostals
Internal intercostals
Abdominal wall
Rectus abdominis
External oblique
40
Internal oblique
Transversus abdominis (transversalis)
Muscles of pelvic floor & perineum (See Salidin p. 350)
Levator ani
Coccygeus
External anal sphincter
MUSCLES OF THE UPPER EXTREMITY
Movement of the shoulder & arm
Pectoralis minor
Serratus anterior
Trapezius
Levator scapulae
Rhomboideus major
Rhomboideus minor
Pectoralis major *
Latissimus dorsi *
Deltoid *
Teres major
Teres minor
Supraspinatus
Infraspinatus
Subscapularis
Coracobrachialis
Movement of the forearm
Biceps brachii *
Brachialis
Brachioradialis *
Triceps brachii *
Supinator
Pronator teres
Pronator quadratus
Movement of the hand & wrist
Flexor carpi radialis *
Flexor carpi ulnaris
Palmaris longus
Flexor digitorum superficialis
Extensor carpi radialis longus *
Extensor carpi ulnaris
Extensor digitorum *
Extensor digiti minimi
41
MUSCLES OF THE LOWER EXTREMITY
Movement of the thigh
Gluteus maximus *
Gluteus medius
Tensor fasciae latae *
Piriformis
Pectineus
Adductor longus *
Adductor magnus
Gracilis *
Iliopsoas: (iliacus & psoas major)
Movement of the leg & thigh
Quadriceps femoris * = The 4 muscles listed immediately below
Rectus femoris *
Vastus medialis *
Vastus lateralis *
Vastus intermedius *
Sartorius
Hamstring group
Biceps femoris *
Semitendinosus
Semimembranosus *
Movement of the leg & foot
Peroneus (Fibularis) longus
Tibialis anterior
Flexor Hallucis Longus
Gastrocnemius *
Soleus
Special Structures
Rectus sheath = aponeuroses of ext. & int. obliques and transversus abdominis, that enclose the rectus
abdominis
Linea alba = continuation of aponeuroses that meet at midline to form a fibrous band that extends from
xiphoid process to pubic symphysis
Galea aponeurotica (Epicranial aponeurosis) = sheet-like tendon that covers superior & lateral surfaces of
skull, connecting occipitalis and frontalis muscles
Iliotibial tract = tendons of gluteus maximus, tensor fasciae latae, & fascia lata (deep fascia of thigh) that
inserts into lateral condyle of tibia
42
MUSCLE
Adductor longus
ORIGIN
Body & inferior ramus of
pubis
INSERTION
Linea aspera of femur
Biceps brachii
above glenoid cavity on
scapula
radial tuberosity
Biceps femoris
coracoid process of scapula
ischial tuberosity of ischium
head of fibula
ACTION
Adducts & medially
rotates thigh & flexes
thigh at hip
flexes & supinates
forearm & flexes arm
flexes leg & extends
hip
linea aspera of femur
Brachioradialis
lateral epicondyle of
humerus
styloid process of radius
elevates trunk from
stooping posture
flexes elbow
Deltoid
acromial extremity of
clavicle & acromion &
spine of scapula
Lateral supracondylar ridge
of humerus
lateral epicondyle of
humerus
deltoid tuberosity of
humerus
abducts, flexes, &
extends arm
2nd metacarpal
Extends wrist
Dorsal surface of 2nd 5th phalanges
extends wrist &
phalanges
Flexor carpi radialis
medial epicondyle of
humerus
2nd and 3rd metacarpals
flexes wrist
Gastrocnemius
medial & lateral condyles of
femur
calcaneus via calcaneal
tendon
plantar flexes foot &
flexes knee
Gluteus maximus
iliac crest, sacrum & coccyx
gluteal tuberosity of
femur & iliotibial tract
extends thigh &
stabilizes femur on
tibia
Extensor carpi
radialis longus
Extensor digitorum
43
MUSCLE
Gracilis
ORIGIN
pubic symphysis & pubic
arch
INSERTION
medial surface of tibia
ACTION
flexes & medially
rotates tibia @ knee
Latissimus dorsi
Vertebrae T7- L5, crests
of sacrum & ilium
Lesser wing of sphenoid
intertubercular sulcus of
humerus
skin of upper eyelid
extends, & adducts
arm
elevates upper eyelid
zygomatic arch
angle & ramus of
mandible
elevates mandible
clavicle, sternum, &
cartilage of first six ribs
greater tubercle of
humerus
flexes, & adducts arm
anterior inferior iliac
spine & acetabulum
tibial tuberosity via
patellar tendon
Vastus lateralis
greater trochanter & linea
aspera of femur
tibial tuberosity via
patellar tendon
Vastus medialis
linea aspera of femur
tibial tuberosity via
patellar tendon
Vastus intermedius
anterior and lateral
surface of femur
tibial tuberosity via
patellar tendon
Semimemembranosus
ischial tuberosity
medial condyle of tibia
flexes leg & extends
thigh
Sternocleidomastoid
Manubrium of sternum
& clavicle
mastoid process of
temporal bone
Tensor fasciae latae
Iliac crest
Iliotibial tract
contraction of both
muscles flexes cervical
vertebral column,
singly each rotates
head to the opposite
side
Flexes thigh
Triceps brachii
infraglenoid tubercle of
scapula and posterior
surface of humerus
zygomatic bone
olecranon of ulna
extends forearm,
extends arm
skin & orbicularis at
angle of mouth
draws angle of mouth
up & out as in smiling
or laughing
Levator palpebrae
superioris
Masseter
Pectoralis major
Quadriceps femoris
Rectus femoris
Zygomaticus major
44
extends the knee,
rectus femoris also
flexes thigh
EXTERNAL ANATOMY OF THE FETAL PIG
1. Obtain a pig from the instructor. Examine for epitrichium, a layer of embryonic skin visibly peeling
off the surface. This skin is lost as the hair develops. It may be removed by rinsing the pig in tap
water. BE SURE TO DISCARD IT IN THE TISSUE DISCARD BIN; DO NOT LET IT PLUG
THE SINK DRAIN.
2. Locate the mouth which is usually partially open, revealing the tongue. Note the snout which is used
for rooting in the soil for food. Note the two external nares (singular: naris) at the end of the snout.
3. The eyes are usually closed; gently pull the eyelids apart. Note the nictitating membrane in the
medial corner of the eye. This membrane can move across the eyeball to help keep it clean. Do
humans have this?
4. The opening into the ear is called the external auditory (acoustic) meatus (canal), and the flattened
flap of skin of the ear is called the auricle or pinna. The pinna and the external acoustic meatus make
up the external ear in the pig as well as in the human.
5. Note that the cervical region (neck) joins the thorax in front of the forelimbs. There is usually an
incision in the neck where blood has been withdrawn and red and blue latex injected to show blood
vessels.
6. The trunk is divided into two general regions, an anterior thorax and a posterior abdomen. Note that
the forelimbs are attached to the thorax.
7. Note that there are only four toes or digits on each limb as compared to five in humans. Examine the
limbs and note that they have the same general structure as those of humans, with some modifications.
Examine the posterior surface of one of the hind limbs and note the large protuberance about 5 cm
above the toes; this is the heel. Since the pig walks on the tips of the toes, the ankle and most of the
foot are elevated above the ground. Locate the ankle and the knee on the hindlimb; locate the wrist
and elbow on the forelimb.
8. Locate the mammary papillae which are present in a double row on the ventral side of the abdomen
in both sexes. They become functional only in the female.
9. Observe the umbilical cord located at the midline on the ventral surface of the abdomen. Using a
scalpel, make a transverse cut through the cord. Three openings should be visible on the freshly-cut
surface: one umbilical vein (injected with blue latex) and two umbilical arteries (red). Near the
umbilical arteries is a hard core of tissue called the allantoic stalk.
10. Locate the anus just ventral to the tail.
11. Determine the sex of your pig. In the female, locate the urogenital opening (common opening for
both the reproductive and urinary tracts) and the genital papilla adjacent to it. In the male, locate the
preputial orifice and the scrotum. The penis lies under the skin.
12. Return the pig to the drum of preservative when you are finished.
45
MUSCLES OF THE FETAL PIG
Before beginning the dissection of your fetal pig obtain two pieces of string each about two feet in
length. Tie one end of a string securely to the right front leg near the hoof and repeat for the right hind
leg. When working from the ventral side of the pig run each string under the dissecting tray and
temporarily tie the corresponding left leg by wrapping the string around the leg several times and securing
the remainder between the hooves. At the end of each lab period wrap the pig in cheesecloth and put it in
a tightly sealed plastic bag with a name tag attached. Put pig in locker labeled with your name. Always
clean your dissection tray and instruments, scrub down the desktop and put any tissue remnants in the
specially labeled can.
The proper dissection of muscles involves carefully separating one muscle from another so that they
can be identified. When dissecting think of your pig like a box of fine china, with each piece individually
wrapped and you must unwrap them very cautiously. Make incisions carefully and use a blunt probe as
often as possible for separating parts. Do less cutting and more dividing.
Listed below are the muscles each group should dissect and a diagram showing where to cut and
pull away the skin to expose the underlying muscles. Always start with a short, shallow incision using the
scalpel to determine the thickness of the skin then use scissors as much as possible to prevent cutting too
deep. Leave the skin attached and fold it back in place to cover the exposed muscles during storage.
Before attempting to identify any of the muscles, clean them off by removing loose connective tissue
(superficial fascia) and fat with the forceps. Observe the changes in the direction of muscle fibers which
will help you locate the muscle borders. Once you have identified these normal cleavage lines between
muscles use the blunt probe to separate one muscle from another. If the muscles separate as clean,
distinct bundles, your procedure is probably correct. If you observe a ragged or “chewed-up” appearance,
you are probably tearing a muscle apart rather than separating it from the adjacent muscles.
Use the references provided along with your lab manuals to identify the following muscles.
GROUP 1
sternohyoid
sternomastoid
mylohyoid
superficial pectoral
pectoralis profundus
posterior deep pectoral
anterior deep pectoral
46
GROUP 2
trapezius group
latissimus dorsi
biceps brachii
triceps brachii
deltoid
GROUP 3
rectus femoris
vastus medialis
semitendinosus
semimembranosus
adductor
pectineus
GROUP 4
tensor fasciae latae
vastus lateralis
gluteus medius
biceps femoris
gluteus maximus
47
48
49
ANATOMY & PHYSIOLOGY OF NEURONS, NERVES,
AND THE SPINAL CORD
Procedure:
You will find a series of lab stations set up around your lab. Some will have microscopes set up
while others will have charts or models for study. Go to each station and follow the appropriate
procedure in your manual. You can start at any station; you do not need to go in order. If there
are questions associated with a station, discuss them with your lab partners until you all
understand. Utilize your textbook, atlas, dictionary, classmates and instructor.
Station 1: Neurons
Study the model of the neuron and the slide showing neurons. Identify the structures listed
below.
A. Which parts of the neuron….
i) generate action potentials?
ii) conduct action potentials?
B. What cells form the myelin sheath in the PNS?
C. What cells form the myelin sheath in the CNS?
D. Does the function of myelination differ in the CNS and in the PNS? What is that function?
E. Sketch a neuron and label the following structures. Use a separate piece of paper for your
illustration.
Cell body (soma, perikaryon)
Nucleus
Nucleolus
Nissle bodies
Dendrite
Axon
Axon hillock
Axon terminal (synaptic knobs or buttons)
Telodendria
50
Station 2: Nodes of Ranvier
This slide show a “splayed” out piece of a nerve showing individual nerve fivers (i.e. axons)
wrapped with Schwann cells. Identify the Schwann cells and the nodes of Ranvier.
A. Why do these nodes exist?
B. Is the axon membrane beneath the myelin sheath depolarized when the action potential is
sent?
If NO, then where is the axon membrane depolarized?
C. How does the myelin sheath speed up action potential transmission?
D. Review with your lab partner(s) the formation and function of a node of Ranvier.
Station 3: CNS vs. PNS
There are two slides at this station. One is a cross section of a mammalian peripheral nerve
and the other is a section through a ganglion.
First look at the cross section of the mammalian nerve. Use the figure below to help you. Move
between 10X and 40X power to identify the following structures.
A. Sketch the nerve and label the following structures. Nerve H1580 (newer slides only)
Fascicle
Epineurium
Perineurium
Endoneurium
Blood vessels
51
B. Next look at the section through a ganglion. What is a ganglion? What is found in a
ganglion?
C. Are ganglion found in the CNS or the PNS?
D. Which of these slides shows myelination?
E. Where are the cell bodies located within the CNS?
Station 4: Spinal Cord (part I)
Study the spinal cord model and cross section on the scope.
A. How can you tell which side is dorsal and which side is ventral? Draw a picture of the spinal
cord and the roots to demonstrate. (Use the space provided below)
B. The structure of the spinal cord will become important when we study reflexes. Identify the
following structure on the spinal cord model. You may want to use a figure from your book as a
guide or make your own drawing.
Posterior funiculus
Lateral horn
Anterior funiculus
Anterior (ventral horn)
Lateral funiculus
White columns (white matter)
Dorsal root ganglion
Grey matter
Spinal nerve
Anterior median fissure
Dorsal root
Central canal
Ventral root
Arachnoid
Posterior median sulcus Pia mater
Gray commissure
Dura mater
Posterior (dorsal) horn
Spinal meninges
C. What are the fundamental differences between white and gray matter?
52
Station 5: Spinal Cord (part II)
This is another cross-section of a mammalian spinal cord.
A. Where do you think you can find a motor neuron cell body? Find one and sketch it under
40X power. Use the space below for your drawing. Return the scope to an unfocussed state
when you are finished
B. Where can you find a sensory neuron cell body? Find one and sketch it under 40X power.
Use the space below for your drawing. Return the scope to an unfocussed state when you are
finished
53
REFLEXES
Reflexes are predictable, involuntary motor responses to various stimuli. They are usually rapid
responses and are usually protective in nature. The neural pathway involved in a reflex is called
a reflex arc. There are five components to any reflex arc:
1.
2.
3.
4.
5.
receptor – responds to the stimulus, generating a nerve impulse
sensory neuron – conducts the nerve impulse to CNS
integration center – one or more synapses in CNS
motor neuron – conducts the nerve impulse from CNS to the effector
effector – responds to the efferent nerve impulse
Somatic reflexes involve the somatic nervous system, and the effector in a somatic reflex is
skeletal muscle. In contrast, visceral reflexes involve the autonomic nervous system; effectors
include smooth muscle, cardiac muscle, and glands (secretory cells).
DEMONSTRATION OF A SOMATIC REFLEX: THE
STRETCH REFLEX
In the stretch reflex, the receptor is a muscle spindle which, when stretched, initiates a reflex
arc that results in the contraction of the muscle in which the muscle spindle is embedded.
Stretch reflexes prevent overstretching of muscles. This exercise demonstrates two stretch
reflexes: the patellar reflex and the Achilles reflex.
Materials: reflex hammer
A.
PATELLAR REFLEX
Procedure:
1. The subject should be seated comfortably, with the legs hanging free. Eyes of the subject
should be
closed. Using the rubber reflex hammer, sharply tap the patellar ligament just below the
patella. Test
both the right and the left legs. Record the response below:
Right leg:
Left leg:
Which muscles contracted?
54
In order for these muscles to contract, which muscles had to be inhibited from contracting?
What is the minimum number of neurons involved in this reflex arc? What functional types of
neurons are they?
Identify the five components of this reflex arc:
receptor:
sensory neuron (give the name of the nerve):
integration center:
motor neuron (give the name of the nerve):
effector:
Could the subject feel and locate the site of the tap of the reflex hammer?
Where in CNS is this sensation perceived?
2. Test the effect that mental distraction has on the subject’s response by having the subject
add a column of six 4-digit numbers (without the aid of a calculator) while you test the reflex a
second time in both legs. Was the response greater or less than the original response?
What conclusions can you draw regarding cerebral cortex involvement in the patellar reflex?
55
B. ACHILLES REFLEX
Procedure:
1. Have the subject kneel on a chair or stool with the feet dangling in a relaxed manner over the
edge of the seat. Grasp the subject’s foot firmly and slightly dorsiflex the foot. Sharply tap
the Achilles (calcaneal) tendon with the reflex hammer. Test both legs. Record the results:
Right leg:
Left leg:
If little or no response occurs, mentally distract the subject as was done in Step 2 in the patellar
reflex procedure above and repeat the test.
Which muscles contracted?
56
DEMONSTRATION OF A VISCERAL REFLEX: THE
SALIVARY REFLEX
Materials: 2 graduated cylinders, lemon juice, pH paper, gloves, bin of 10 % chlorine bleach disinfectant
NOTE: Wear gloves when handling saliva-contaminated materials.
1. Have the subject refrain from swallowing for 2 minutes. The subject should then spit the accumulated
saliva into the graduated cylinder. Record the volume of saliva (measure only the liquid saliva, not
any foam.) Using pH paper, determine the pH of the saliva; record below.
Volume:
pH:
2. Place 2 or 3 drops of lemon juice on the subject’s tongue. Wait 5 to 10 seconds, then determine the
pH of the subject’s saliva by touching a fresh piece of pH paper to the tip of the tongue. Record the
pH value below.
pH:
Once again, the subject is to refrain from swallowing for 2 minutes. After the two-minute period is
over, collect the saliva in a clean graduated cylinder; measure the volume and the pH; record results
below.
Volume after the 2-minute lemon juice treatment:
pH after the 2-minute lemon juice treatment:
3. Was the volume of saliva produced after lemon juice treatment less than, greater than, or the same as
the original volume produced?
_________________________________
4. Summarize the pH changes that occurred during this experiment:
__________________________________________________________________________________
5. What function does the salivary reflex serve in this situation?
__________________________________________________________________________________
6. Name the receptor and the effector in the salivary reflex:
Receptor:
Effector:
NOTE: Dispose of saliva-contaminated glassware in a bin of 10 % chlorine bleach. Dispose of
contaminated pH paper in a biohazard bag. Wipe down the table top with 10 % chlorine bleach when you
are finished.
57
ANATOMY OF THE BRAIN AND CRANIAL NERVES
Procedure:
In today’s lab you will be dissection sheep brain to learn the anatomy of the brain and its associated nerves
called cranial nerves. Remember, although the brain is in the central nervous system (CNS), the cranial
nerves are part of the peripheral nervous system (PNS). You should work in groups of four on this
exercise.
The sheep brains are stored in a substance that is toxic if ingested. You should wear gloves and lab coats
for this dissection. Also be sure to tie back long hair and roll up your sleeves.
Dissection pans are available at the front of the room. Be VERY careful with the scalpels as they can be
surprisingly sharp. Most of the sheep brains will be saved after sue so make sure you dispose of them as
indicated by your instructor. DO NOT DISPOSE OF ANY BRAIN TISSUE IN THE GARBAGE OR
SINK. Also be sure to scrub your dissection pans out and completely wash and rinse your dissecting tools
as well.
Before cutting anything, examine the sheep brain carefully. Use your lab atlas to help you determine
which side is dorsal and which side is ventral. Figure out which side is toward the front of the head, or
rostral, and which is caudal. (Because the brain call all be considered “cranial”, the term rostral is usually
used instead.) To get your bearings, identify the cerebral hemispheres, cerebellum, and brain stem. At
the rostral end of the brain, you may notice some “extra” tissue that does not appear in your atlas. This
tissue was left on by the biological supply house to protect the olfactory bulbs, which are easily damaged.
Similarly, the tissue on the ventral side of the brain has been left on to protect the pituitary gland, which
is easily lost otherwise. DRAW and label what you see.
The brains should still be encased in the dura mater (the outer protective covering of the brain), so your
next step will be to carefully remove this covering. The dura mater can be removed by carefully cutting
alongside the longitudinal fissure and the lateral edges of the cerebrum. At this point to no remove the
dura mater from the ventral region of the brain or from the brain stem. If the tissue encasing the olfactory
bulbs comes off easily and is in your way, you may remove the tissue. If possible, you might want to
leave it on for protection of the olfactory bulbs until you are ready to study them. Note how tough the
dura mater is. The dura mater is the outer of three layers making up the meninges. The inner two layers,
the arachnoid mater and the pia mater, more closely follow the contours of the brain. You may not be
able to separate these two layers.
Once you have removed most of the dura mater, you can begin to see the structure of the cerebral
hemispheres more clearly. You will see the raised ridges, or gyri, and grooves between them, called sulci.
The deeper grooves are called fissures; you cut down the longitudinal fissure, and the transverse fissure
separates the cerebrum from the cerebellum. Using your atlas at your lab station, identify the frontal,
parietal, temporal, and occipital lobes. DRAW and label what you see.
Move on to observe the cerebellum. Find the cerebellar hemispheres, and note that they are separated
by an additional cerebellar lobe, the vermis, rather then by a fissure as in the cerebrum. DRAW and
label what you see.
Use your blunt probe to gently pull apart the two hemispheres at the top. If you look down into the
longitudinal fissure, you can see light colored tissue holding the hemispheres together. Do not pull the
hemispheres completely apart at this time. The tissue holding them together is called the corpus
callosum. The corpus callosum is made up of bundles of neural fibers connecting the two hemispheres.
58
Next, carefully spread the cerebellum back from the cerebrum. When you pull the cerebellum back, you
should be able to see the corpora quadrigemina region of the midbrain. Find the superior and inferior
colliculi. While still spreading the cerebellum back from the cerebrum, gently part the cerebral
hemispheres slightly to see the pineal body, also called the pineal gland. DRAW and label what you see.
Turn the sheep brain so that you are looking at the ventral side. Very carefully begin to remove the
remaining dura mater from the ventral area. These next few steps will take a steady hand and some
patients. It will be very difficult to remove the dura mater from around the optic chiasma, but you should
be able to identity this structure even with the dura mater present. Be especially careful removing the dura
mater from the region around the brain stem, since you want to leave the cranial nerves as intact as
possible. Looking at the ventral side you should be able to easily find the olfactory bulbs, olfactory
tract, optic nerve, optic chiasma, optic tract, infundibulum, pituitary gland, (hypophysis),
mammillary body, pons, medulla oblongata, and pyramids. DRAW and label what you see.
Next locate as many of the cranial nerves as possible. You may not have all the cranial nerves still on
your specimen, but someone else in your class may have an example of the nerves you are missing. Look
for them! The first three cranial nerves (olfactory, optic, and oculomotor) are generally easy to find.
The next five or six (4-trochlear, 5-trigeminal etc. ) will likely be on all the sheep brain specimens.
Some of the cranial nerves may be difficult to positively identify if earlier nerves are missing. Do your
best to find as many as possible. DRAW and label what you see.
The next step is to make a sagittal section through the midline of the brain. For this cut you many want to
use a long knife. It is more difficult to see everything if you must use a scalpel. It is important to make a
single cut through the whole brain; do not “saw: back and forth through the brain tissue or you will have
trouble identifying the interior structures. Make the cut along the longitudinal fissure between the cerebral
hemispheres. Once you have made this cut, you should be able to identify the arbor vitae (“tree of life”),
the branching structure forming the cerebellum. The “branches” of this tree are formed by cerebellar
white matter, while the “leaves” are formed by cerebellar gray matter. To find the peduncles of the
cerebellum, cut off one of the “trees” near the base of its “trunk.” The three “stumps” which remain are
the superior, middle, and inferior peduncles. DRAW and label what you see.
The sagittal section also allows you to find the intermediate mass of the thalamus. This is a circular
structure which has a slightly different texture than the areas surrounding it; usually it appears paler in
color and smoother in texture then the surrounding tissues. The hypothalamus is located in the region
below the thalamus, toward the medulla oblongata.
The hypothalamus forms the walls of the third ventricle. The regions of the brain are connected by a
system of ventricles which are derived from the embryonic neural tube. The lateral ventricles are visible
just ventral from the corpus callosum. The lateral ventricles are connected to the third ventricle by the
interventricular foramen, which you can find using your blunt probe. Carefully push the probe into the
third ventricle, and you should be able to make the end of it come out into the lateral ventricle.
The final section you need to make is through the cerebrum. Make a transverse cut though on of the brain
halves going through the cerebrum and the optic chiasma. This will allow you to see the cerebral cortex,
composed of gray matter, and cerebral white matter.
Study the preserved human brains, human brain models for further clarification and comparison.
59
Brain Structures
 Cerebral hemispheres
 Sulcus (pl. sulci)
 Gyrus (pl. gyri)
 Longitudinal fissure
 Transverse fissure
 Cerebral cortex
 Cerebral white matter
 Corpus callosum
 Frontal lobe
 Parietal lobe
 Temporal lobe
 Occipital lobe
 Central sulcus
 Precentral gyrus
Human brain only
 Postcentral gyrus
 Lateral sulcus
 Diencephalon
 Thalamus
 Intermediate mass (may not be visible in sheep brain)
 Hypothalamus
 Mammillary bodies
 Infundibulum
 Pituitary gland (hypophysis)
 Pineal body (pineal gland)
 Cerebellum
 Cerebellar hemispheres
 Vermis
 Superior peduncle
 Inferior peduncle
 Middle peduncle
 Arbor vitae
 Cerebellar white matter
 Cerebellar gray matter
 Brain stem
 Mid brain
 Corpora quadrigemina
 Superior colliculus
 Inferior colliculus
 Pons
 Medulla oblongata
60
Brain structures cont…..
 Ventricles
 Lateral ventricles
 Third ventricle
 Interventricular foramen
 Meninges
 Dura mater
 Arachnoid mater
 Pia mater
 Cranial nerves
 I: Olfactory
 olfactory tract
 olfactory bulb
 II: Optic
 Optic chiasma
 Optic tract
 III: Oculomotor
 IV: Trochlear
 V: Trigeminal
 VI: Abducens
 VII: Facial
 VIII: Vestibulocochlear
 IX: Glossopharyngeal
 X: Vagus
 XI: Accessory
 XII: Hypoglossal
61
62
AUDITORY & VISUAL REFLEXES & TASTE
SENSATION
ANATOMY OF THE EAR
Materials: Models of the human ear, sets of auditory ossicles, sectioned demonstration human
skull. Read the information on ear anatomy in your text and study the figures there.
Procedure:
1. Examine the models of the human ear for the following structures:
Outer ear:
Pinna (auricle)
External auditory (acoustic) meatus (canal)
Middle ear:
Tympanic membrane (Is missing on the older model but the tympanic ring is present.)
Auditory ossicles: (See also a set of these bones.)
Malleus
Incus
Stapes (Is missing on the newer model.)
Middle ear cavity
Opening of the Eustachian tube (auditory tube)
Oval window (Note that the footplate of the stapes fits over this hole.)
Round window
Inner ear:
Cochlea
Vestibule
Semi-circular canals:
Posterior
Lateral
Superior (anterior) (Has been sectioned in the newer model to show the semicircular duct within.)
Ampulla of each semi-circular canal
Internal auditory meatus
Vestibulocochlear nerve
2. When you have finished with the models, reassemble them and return them to the supply
table.
63
HEARING TESTS
In both of these tests, strike the tines of the tuning fork with the rubber reflex hammer to set the
fork to vibrating. Do not strike the tuning fork against a hard object such as the edge of the
table. Conduct the Rinne test first to determine if there is conductive or nerve (sensory)
deafness present, then conduct the Weber test. Conductive hearing loss is due to damage to
the tympanic membrane or the auditory ossicles, in other words, the pathway that conducts
sound waves to the cochlea. It can usually be remedied by surgery or hearing aids. Nerve or
sensory hearing loss is usually due to damage to the hair cells of the cochlea or the nerves
themselves; damage to these structures cannot be corrected.
Materials: Tuning fork, rubber reflex hammer, cotton
A.
RINNE TEST
Procedure:
Plug one ear with cotton. Strike a tuning fork and hold the vibrating tines of the fork 3 to 6
inches away from the opening of the external auditory meatus of the unplugged ear. The
subject should indicate whether or not he or she can hear the sound of the tuning fork. As soon
as the subject indicates that he or she can no longer hear the sound, place the stem of the still
vibrating fork on the subject’s mastoid process. Have the subject indicate if he or she can once
again hear the sound.
Results:
Interpretation:
No Hearing Loss:
*Can hear the tuning fork near pinna; when sound disappears,
*cannot hear the fork when it is placed on mastoid process.
Conductive Hearing Loss:
*Cannot hear tuning fork near pinna.
*Can hear tuning fork when placed on mastoid process.
Sensory Hearing Loss (Nerve Deafness):
*Cannot hear tuning fork near pinna.
*Cannot hear tuning fork when placed on mastoid process.
Repeat the test in the other ear.
64
B.
WEBER TEST
Procedure:
Strike the tuning fork with the reflex hammer and place the stem of the vibrating tuning fork
against the center of the forehead. Record whether the subject can hear the sound of the fork
better in one ear than another or if the sound is heard equally in both ears.
Results:
Interpretation:
(1)
If the subject has normal hearing, the sound will be heard equally in both ears.
(2)
If the subject has conductive deafness in one ear, the sound will be heard louder
in the deaf ear than in the normal ear. (The reason for this is that the deaf ear is not normally
activated by sound waves through the air and is therefore more acutely attuned to sound waves
being conducted to the cochlea through the bone.)
(3)
If the subject has nerve deafness in one ear, the sound will be heard louder in the
normal ear than in the deaf ear.
65
OLFACTORY ADAPTATION
Materials: absorbent cotton, two different aromatic oils (such as oil of wintergreen, peppermint,
cloves, etc.)
Procedure:
1. Plug one nostril with absorbent cotton. Hold the bottle of aromatic oil under the open nostril
at a distance where the subject can first detect the odor and note the time. Breathe by
inhaling through the open nostril and exhaling through the mouth. Notice when the odor
disappears and note the time. Record how long it took for olfactory adaptation to occur:
_________________________
2. Repeat the entire experiment with the other nostril. Record the time:
_________________________
3. Immediately test a different oil with the nostril that has just experienced olfactory adaptation.
What are the results?
_________________________________________________________________________
_________________________________________________________________________
What conclusions can you draw?
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
NOTE: Dispose of cotton in the autoclave bag provided.
66
THE EFFECT OF SMELL ON THE SENSE OF TASTE
Materials: Absorbent cotton, biohazard bag, toothpicks, cubes of apple, potato, carrot, turnip,
or other vegetables of similar texture
Procedure:
1. Work in pairs. One student should plug both nostrils with absorbent cotton and sit with eyes
closed.
2. Using a toothpick to transfer a cube of food, the other student should place the cube of food
in the subject’s mouth and ask him/her to identify the food. Use the following sequence of
activities:
First:
Second:
Third:
Fourth:
Allow the food to rest on the mouth without manipulation.
Manipulate the food with the tongue.
Remove the cotton plugs and allow the food to rest on the tongue.
With the cotton plugs removed, manipulate the food with the tongue.
At no time should the subject be allowed to see the food being tested.
3. Repeat Step 2, using a different food. Continue in this manner until several different foods
have been tested. Record results in the table below. Discard the used cotton plugs in the
biohazard bag when finished.
4. The students should switch roles and repeat the exercise.
Results:
WITH NOSE CLOSED
FOOD
AT REST
WITH MANIPULATION
Apple
Potato
Carrot
Turnip
What conclusions can you draw from these results?
67
WITH NOSE OPEN
AT REST
WITH MANIPULATION
EYE ANATOMY & VISION PHYSIOLOGY
DISSECTION OF PRESERVED EYE
Materials: Preserved sheep or cow eye, dissecting pan, gloves, scissors, scalpel, blunt probe,
penlight. Saladin p. 613, 615, and 616
Procedure:
1. Obtain a preserved eye and place it on a dissecting pan. Examine the external surface.
Remnants of the extrinsic eye muscles may be present and can be identified by their tan
color and skeletal muscle structure. There may be an appreciable amount of fat attached to
the eye as well; it will be white in color. Part of the conjunctiva may also be present as a
membrane over the anterior surface of the sclera. Using scissors, clip away excessive
amounts of muscle and fat so that you can locate the stump of the optic nerve. It can be
found on the posterior surface and will be visible as a small (2 – 3 mm in diameter) round
structure embedded in fat. Its color and texture will be different from the surrounding fat.
Run your fingers over the posterior surface of the eye; you may be able to locate it better by
touch than by sight.
2. Return to the anterior surface of the eye. Note that the cornea, which is normally
transparent and colorless, is cloudy in this specimen. The cloudy appearance is due to the
action of the preservative on this tissue. The color of the cornea in your specimen is not due
to the cornea itself but to the appearance of the colored iris seen through the cornea. Notice
the tough membrane that covers the anterior surface of the eye except for the cornea; this is
part of the conjunctiva. In reality, the conjunctiva lines the inner surface of the eyelids too,
forming a continuous membrane between the anterior surface of the eye and the eyelids.
The white surface of the eye is the sclera, which is a tough coat that makes up the bulk of
the wall of the eyeball.
3. Hold the eye firmly on the dissecting pan, anterior side up. Using a scalpel, make an incision
about 1 cm long, 5 to 6 mm from the edge of the cornea. (NOTE: Do not hold the eye in
your hand when making this incision; hold the eye firmly on the pan surface.) Using scissors
continue this incision all around the perimeter of the cornea, keeping about 5 to 6 mm from
the edge of the cornea. Carefully lift the anterior part of the eye away from the posterior part.
When you remove the anterior portion of the eye, a watery fluid should run out of the eye;
this is the aqueous humor, and it fills the anterior chamber and the posterior chamber of
the anterior cavity. (See Figure 96a in Rust for a view of these two chambers.)
4. Examine closely the interior of the anterior part of the eye. Note the black-colored iris and
the opening in its center which is the pupil. Run a blunt probe under the iris to demonstrate
the presence of the anterior chamber of the anterior cavity. Surrounding the iris is a ring of
black-colored tissue, the ciliary body. Notice the fibers that are arranged in a radial pattern
in the ciliary body; these fibers are the smooth muscle fibers of the ciliary muscle. Use a
penlight to illuminate the iris and the ciliary body to better see these two structures. (See the
lower left eye in Figure 95a in Rust for comparison.)
5. Turn your attention to the posterior portion of the eye. Observe the convex lens which is
normally clear, colorless, and elastic, but which will be white, cloudy, and hard in your
specimen due to the preservative. Notice the tiny black lines that are found around the
68
circumference of the lens. These are the suspensory ligaments that attach the lens to the
ciliary body. They normally break when the eye is dissected open. Remove the lens and
notice the thick vitreous humor that fills the posterior cavity of the eye. Gently remove the
vitreous humor to expose the whitish-colored retina. Gently lift the retina with the blunt
probe. It is very delicate and will disintegrate readily with rough handling. Notice that the
retina is attached at only one place in the eye, the optic disk (blind spot). Find this point of
attachment and place the blunt probe on it. Now turn the eye over to the posterior side and
locate the optic nerve. Notice that the optic nerve corresponds to the location of the optic
disk. Return to the interior of the posterior part of the eye. Notice the black-colored layer of
tissue under the retina. This is the choroid. Run a probe along its edge and detach it from
the outer sclera. Notice that the posterior part of the eye is made of three tunics: the outer
sclera, the middle choroid, and the inner retina.
6. Examine the choroid for the presence of the tapetum lucidum, a multi-colored, iridescent
area. The tapetum lucidum functions to reflect light out of the eye; it is not present in
humans.
7. When you are finished, discard all tissue in the Tissue Discard Bin. Wash and dry your
instruments. Wash off the dissecting pan and return it to the stack on the supply table. Wipe
off the table with 10 % chlorine bleach disinfectant.
69
VISUAL TESTS
Working with your lab partner, do all of the following tests. Some require the use of special
materials available only in lab; others can be done at home. If you are pressed for time, do
those tests that require special materials first; then, if you have time, do the remaining tests. If
you cannot complete all the tests during the lab period, finish the remaining tests outside of lab.
Even though you are working with your lab partner, each of you should play the subject in each
of the tests.
A. DEMONSTRATION OF BLIND SPOT
Materials: Meter/yard stick, figure shown below
Procedure:
1. Hold the figure below about 18 inches from your eyes. Close your left eye and focus your
right eye on the X, which should be positioned so that it is directly in line with your right eye.
Move the figure slowly toward your face, keeping your right eye focused on the X. When the
light rays from the dot are focused onto the blind spot of your eye, the dot will disappear from
your vision.
X
2. Repeat the test using the left eye. Close the right eye and, this time, focus the left eye on
the dot, not on the X. Move the figure slowly toward your face, keeping your left eye focused
on the dot. Eventually the X will disappear.
Why did the object (X or dot) disappear?
_________________________________________________________________________
_________________________________________________________________________
B. VISUAL ACUITY
Visual acuity is sharpness of vision. It can be tested with the use of a Snellen eye chart. Each
line of letters in the Snellen eye chart is marked with the distance at which the normal, or
emmetropic eye can clearly see the letters in that line.
Materials: Snellen eye chart, meter/yard stick
Procedure:
70
1. If you wear glasses, test each eye with glasses and also without glasses. (If you wear
contact lenses, leave your lenses in place; do not remove them.) Stand 20 feet from the
posted Snellen eye chart; have your lab partner stand next to the eye chart. Cover one eye
and read aloud the letters of the smallest line on the chart that you can see. Have your
partner check the accuracy of your reading. Record the value of this line below. Move the
cover to your other eye and test that eye in a similar manner. Record results below.
Record your results as a common fraction, with 20 as the numerator; the denominator of the
fraction will be the number of the smallest line you were able to read. A person with normal
vision will have a visual acuity of 20/20. A person with myopia or nearsightedness, will have
a denominator greater than 20. For example, if a myopic eye has a visual acuity of 20/40,
that means the eye can see at 20 feet what the normal eye can see at 40 feet.
WITHOUT GLASSES
WITH GLASSES
Visual acuity of right eye:
Visual acuity of left eye:
C. NEAR-POINT ACCOMMODATION
The ability of the lens to focus light rays onto the retina to form a clear image is primarily due to
the ability to change the shape of the lens. Changing the shape of the lens is a function of the
elasticity of the lens itself. As humans age, the elasticity of the lens decreases, resulting in an
inability to focus on objects close to the eye. This condition is known as presbyopia. Lens
elasticity can be tested by measuring the near point of accommodation (the closest distance
at which the eye can focus on an object).
Materials: Ruler or meter/yard stick
Procedure:
1. Cover one eye. Hold this page in front of the uncovered eye at arm’s length. Focus on the
letter “P” in the word “procedure” at the beginning of this exercise. Slowly move the page
toward your eye until the letter becomes blurred. Then move the page back until the letter is
once again in focus. Have your lab partner measure the distance between your eye and the
page at this position. Record this distance below.
2. Repeat the procedure with the other eye. Record results below.
Near-point for right eye: _________________________
Near-point for left eye: _________________________
71
3. Compare your results with the information in the following table:
AGE IN YEARS
NEAR-POINT OF ACCOMMODATION
10
7.5 cm or 3 inches
20
9 cm or 3.5 inches
40
17 cm or 6.75 inches
60
83 cm or 33 inches
D. TEST FOR ASTIGMATISM
If there are uneven refractive areas of the cornea and/or lens, uneven bending of the light rays
will occur. This condition is known as astigmatism.
Materials: Astigmatism test chart, meter/yard stick
Procedure:
1. Stand in front of the posted astigmatism test chart, at a distance of 10 feet. If you wear
glasses, test your eyes without your glasses as well as with your glasses on. Cover one eye
and look at the center of the chart. If all the radiating lines appear to be equally dark and
distinct, then there is no distortion of the lens or cornea. If some of the lines are blurred or
appear lighter than others, then some degree of astigmatism exists. Test the other eye in a
similar manner. Record results below.
Right eye: _____________________________________________
Left eye: _____________________________________________
E. COLORBLINDNESS
Defects in color vision can be detected by the use of pseudoisochromatic plates. These plates
are used primarily for screening for colorblindness; precise diagnosis of a color vision defect
requires more sophisticated testing.
Materials: Standard Pseudoisochromatic Plates
Procedure:
1. Obtain a set of Standard Pseudoisochromatic Plates. Read the information on pages 6-7 in
the set of plates pertaining to the care of the plates and their use. Sit about 30 inches away
from the plates in natural light conditions. Have your lab partner show you each plate for a
maximum of 3 seconds exposure; record on a separate piece of paper the number that is
72
visible to you when you look at each plate. Compare your results to the score sheets in the
back of the book of plates. Note that Plates 1-4 are demonstration plates; plates for testing
begin at Plate 5. Record the interpretation of your results below:
F. PHOTOPUPILLARY REFLEX
Exposure to a bright light causes a change in the diameter of the pupil.
Materials: Penlight, metric ruler
Procedure:
1. Have the subject sit comfortably in a dimly-lit room. Place a book or some other barrier
between the eyes. Hold the millimeter ruler under the subject’s right pupil. While watching
the pupils closely, briefly shine the bright penlight into the right eye of the subject. Observe
the change in diameter of the right pupil. Record if the pupil increased or decreased in
diameter and by how many millimeters. Was there any change in the diameter of the left
pupil? Record results below.
2. Repeat the exercise with the left eye. Record results below.
CHANGE IN PUPIL DIAMETER
EYE ILLUMINATED
RIGHT PUPIL
LEFT PUPIL
Right
Left
3. What can you deduce about the neural pathways involved in this reflex?
_________________________________________________________________________
_________________________________________________________________________
4. What is the function of the photopupillary reflex?
_________________________________________________________________________
_________________________________________________________________________
G. ACCOMMODATION REFLEX
Materials: metric ruler
73
Procedure:
1. Have the subject gaze for 1 minute at a distant object (but do not have the subject gaze at a
light source or window). Hold the metric ruler under the pupil of the right eye so that you can
measure the diameter of the pupil.
2. While still observing the right pupil, have the subject look at a sheet of printed material held
6-10 inches from his or her face. Measure the diameter of the pupil. Record results below.
3. Repeat the exercise measuring the left pupil. Record results.
DIAMETER OF PUPIL IN MILLIMETERS
DISTANT FOCUSING
CLOSE FOCUSING
Right pupil
Left pupil
4. What is the response of the iris to a change from distant focusing to close focusing?
_________________________________________________________________________
_________________________________________________________________________
5. What is the value of this reflex?
_________________________________________________________________________
H. CONVERGENCE REFLEX
Procedure:
1. Have the subject focus at a distant object for 1 minute then hold a pen or pencil in front of
the subject, 6 to 10 inches from his or her face. Observe the position of the subject’s
eyeballs when the change is made from distant focusing to close focusing on a small object.
Record your observations below:
_________________________________________________________________________
2. What muscles are involved in this response?
_________________________________________________________________________
3. What function does this reflex serve?
_________________________________________________________________________
74