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: ____________________________________ IF FOUND PLEASE RETURN TO: ____________________________ OR CALL:_________________________ STUDY PARTNERS/LAB AND LECTURE CONTACT(S) NAME: _________________________ PHONE NUMBER: _____________________ NAME: _________________________ PHONE NUMBER: _____________________ NAME: _________________________ PHONE NUMBER: _____________________ 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) 10 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