WHERE AM I?
Online Anatomy Module 1
INTRO & TERMS
CELL
EPITHELIUM
CONNECTIVE TISSUE
MUSCLE
NERVOUS SYSTEM
AXIAL SKELETON
APPENDICULAR SKELETON
MUSCLES
EMBRYOLOGY
Clicking out - X -will
take you back to ???
MICROANATOMY
This story of getting food to the mouth shows
working anatomy as parts of the body,
movements around joints, muscle actions, and
some underlying actions of bones of the
skeleton
Other stories of how the body
works make sense only in
terms of much smaller units
seen with the microscope,
down to the level of cells and
parts of cells - microscopic
anatomy or histology, for
example in the kidney and the
liver.
KIDNEY/RENAL HISTOLOGY
The kidney receives arterial blood,
processes it to produce urine, and
returns most blood via the renal vein
The working units are millions of tiny
coiled tubes (tubules) lined by cells
The production of urine is explained in
terms of how, from blood, fluid is
filtered into the start of the tubule, and
of how different cell types act on the
fluid as it flows along the tubule to be
collected
Other stories of how the body works make sense
only in terms of much smaller units seen with the
microscope, down to the level of cells and parts
of cells - microscopic anatomy or histology, for
example in the kidney and the liver.
Kidney tubule, starting at a renal corpuscle (for
blood filtration) and ending in a collecting duct
Renal
corpuscle
Arched
collecting
tubule
Distal
tubule
Proximal
tubule
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~
~
~
~
~
~
Thin
segment
Collecting
duct
~
~
~
~
~
~
Renal
corpuscle
The renal tubule is
lined by a single
layer of working
cells, changing as
one goes along
the tubule
Such a lining is a
tissue - an
EPITHELIUM
Arched
collecting
tubule
Distal
tubule
Proximal
tubule
~
~
Thin
segment
~
~
~
~
~
Collecting
duct
~
~
~
~
~
~
PROXIMAL TUBULE
DISTAL TUBULE
LIVER/HEPATIC HISTOLOGY
The liver receives venous blood, drained
mostly from the gut, processes it, and
sends it on to the heart, using a little to
produce bile. (A small amount of arterial
blood is needed.)
Unlike the kidney, there are no organized
tubules. Instead the action is biochemical,
and not reflected in much visible structure.
The three main interests are: the blood
flow, the bile collection & flow, and how
liver cells (hepatocytes) interact with blood
BLOOD FLOWS IN THE LIVER
SUBLOBULAR VEIN
6
5
Centripetal
blood flow in
sinusoids
INFERIOR VENA CAVA
7
HEPATIC VEIN
4
CENTRAL VEIN
For now, note only the
idea, not the details
3
Portal venule
2
Hepatic arteriole
1
PORTAL VEIN
Hepatic artery
BILE FLOW IN THE LIVER
Centrifugal flow of bile within
plates of hepatocytes in canaliculi
Bile ductule
HEPATIC DUCT
CELL TYPES & ARRANGEMENT OF LIVER
Endothelial cells
SINUSOID FOR BLOOD
Hepatocytes in plates
Principal liver cells
BLOOD
Bile canaliculus
(tiny channel)
HISTOLOGY TOPICS
TISSUE TYPES & WHAT THEY DO
CELL TYPES OF THE FOUR TISSUES
TYPICAL CELL: ITS STRUCTURES & THEIR FUNCTIONS
CELL ORGANELLES
ORGAN COMPOSITION & STRUCTURE
Which tissue types & how organized?
Which special cell types?
Which special structures? E.g., tubules
HISTOLOGY TOPICS: Plan
TISSUE TYPES & WHAT THEY DO
ORGAN COMPOSITION & STRUCTURE
Which tissue types & how organized?
Which special cell types?
Which special structures? E.g., tubules
Next, we’ll look at the four tissues in the context of
a typical tubular organ, then focus on the gut.
The four tissues - epithelia, connective tissue, muscle &
nervous tissue - are all present in such tubes, but
Epithelia will be considered in detail first, looking at all
types and why particular ones serve at specific body
sites.
Then, the main gut lining cell will be used to
present cell structure
SYSTEM ABBREVIATIONS
Worm Woman*/Tube man
Al
Re
cvl
U
0
Head modification of
body wall +
brain & special
senses + start
of two tubes
Soma - body
wall & the limbs
Viscera
tubes, modified
tubes, &
accessory
organs
Alimentary
Respiratory
Cardiovascular-lymphatic
Urinary
Reproductive
Re
Al
- - - -
cvl
- -
-
diaphragm
U
0
* See Worm powerpoint
Tubes are lined by
specific appropriate
EPITHELIA &
sometimes covered by a
slippery EPITHELIUM
Worm Woman*
Head modification of
body wall +
brain & special
senses + start
of two tubes
re
Al
Soma - body
wall & the limbs - - - Viscera
tubes, modified
o
tubes, &
accessory
organs
cvl
- -
-
diaphragm
u
* See Worm powerpoint
TYPICAL TUBULAR ORGAN
Many viscera are tubes or bags with a complicated wall
of layered tissues, & a space or lumen for the content
main working tissue Epithelium
inner service tissue Connective tissue
lumen &
content
motility tissue - Muscle
outer service tissue Connective tissue
TYPICAL TUBULAR ORGAN
together make
a MUCOSA
main working tissue - Epithelium
inner service tissue Connective tissue
lumen
motility (for movement)
tissue - Muscle
loose irregular ct
with vessels &
nerves
outer service tissue Connective tissue
TO MOVE FROM THE GENERAL TO
THE SPECIFIC - the GUT
The main working tissue has its
area for absorption of food
greatly increased by being on
finger-like projections - villi
There has to be a
membrane - mesentery
- fastened from the
body wall to the gut to
bring it its vessels &
nerves while it moves
lumen
motility tissue - Smooth
Muscle - is itself layered to
squeeze, churn & move food
outer service connective
tissue is covered by a
slippery layer of another
epithelium so that the gut
can slide against other
organs or itself
GUT PARTS
MUSCULARIS smooth muscle
suspensory MESENTERY
with blood vessels
VILLI covered
with simple
columnar
epithelium
GLANDS
SUBMUCOSA
connective tissue
covering SEROSA
with simple
squamous epithelium
GLANDULAR EPITHELIA
In several systems, the epithelial lining or covering for an
organ cannot produce all the working material needed, so
that other specialized epithelial cells have to be set aside
and grouped to produce the needed materials. These
collections of secretory cells are GLANDS.
GLANDS
GUT IN PLACE
non-stick surfaces needed
re
Al
o
cvl
MESENTERY
simple squamous epithelium mesothelium - lining
PERITONEAL (abdominal)
CAVITY
SEROSA with simple
squamous epithelium mesothelium
EPITHELIAL TISSUE TYPES : ROLES I
Very flattened cells with a central flat
nucleus, together like a low fried egg
Simple squamous
epithelium
ROLES: provides a selective lubricated
barrier that allows movement & diffusion
by convention shown diagrammatically from a side view
There is very little to a simple squamous epithelium
viewed from the side, even in electron microscopy (EM)
However, when viewed from on top with a silver
method to show cell boundaries, the cells are
more striking. If the specimen is mesentery there
are two epithelia at different focal planes.
Nuclei only seen if a
counter-stain is used
BODY CAVITIES LINED
BY MESOTHELIUM
non-stick surfaces needed
re
Al
cvl
A similar arrangement is used
for the slippery surface of the
heart in the pericardial cavity
A similar arrangement is used
for the slippery surface of the
lung in the pleural cavity
o
Also, for uterus in pelvic cavity
TUBE MAN’S EPITHELIA
Cavity
simple
squamous
Lung simple cuboidal
& simple squamous
re
Al
Viscera
- - - - - -
cvl
K-
u
o
Vessels simple squamous
The simple squamous epithelia
lining vessels and the smallest
air chambers of the lung are
primarily for a selective barrier
that permits diffusion, e.g., of
oxygen and carbon dioxide.
However, despite their small
size, these cells have many
other functions.
GUT PARTS
MUSCULARIS smooth muscle
suspensory MESENTERY
with blood vessels
VILLI covered
with simple
columnar
epithelium
GLANDS
SUBMUCOSA
connective tissue
covering SEROSA
with simple
squamous epithelium
TUBE MAN’S EPITHELIA
re
Al
Viscera
- - - - - -
cvl
K-
u
o
Stomach & Gut
simple columnar
EPITHELIAL TISSUE TYPES : ROLES I
Simple cuboidal
tightly sealed barrier of cells fat enough to have the
organelles to secrete into &/or transport from the lumen
(luminal) content
Simple columnar
a taller, more powerful version of simple cuboidal, and
providing a greater variety of cell types
by convention shown diagrammatically from a side view
Renal
corpuscle
The renal tubule is
lined by a single
layer of working
cells, changing as
one goes along
the tubule
Such a lining is a
tissue - an
EPITHELIUM. Here
simple cuboidal
Arched
collecting
tubule
Distal
tubule
Proximal
tubule
~
~
Thin
segment
~
~
~
~
~
Collecting
duct
~
~
~
~
~
~
PROXIMAL TUBULE
DISTAL TUBULE
EPITHELIAL TISSUE TYPES : ROLES I
Simple cuboidal
tightly sealed barrier of cells fat enough to have the
organelles to secrete into &/or transport from the lumen
(luminal) content
EPITHELIAL TISSUE TYPES : ROLES I
Simple squamous
selective lubricated barrier that allows movement & diffusion
Simple cuboidal
tightly sealed barrier of cells fat enough to have the
organelles to secrete into &/or transport from the lumen
(luminal) content
Simple columnar
a taller, more powerful version of simple cuboidal, and
providing greater variety of cell types
TUBE MAN’S EPITHELIA
Skin has Cornified stratified
squamous epithelium, well
attached to an underlying strong
flexible connective tissue - dermis
re
Al
Viscera
- - - - - -
cvl
K-
u
o
‘Cornified’ from a very protective
layer of dead superficial cells
This particular epithelium has
special name - Epidermis
Skin Cornified stratified squamous
EPIDERMIS: Layers & events
STRATUM CORNEUM of dead, but
attached, ‘hardened & wrapped‘ cells , will
slough off
S. GRANULOSUM multiple syntheses
to make cornified cells
}
}
S. SPINOSUM upward migration
of keratinocytes
S. BASALE
mitosis of stem cells
Keratinocytes - the principal epidermal cells differentiate (become specialized) after multiplying to
replace lost surface cells.
(The grubiness inside used clothes is mostly rubbed-off skin cells.)
EPITHELIAL TISSUE TYPES : ROLES II
Stratified squamous
very protective barrier,
needing glandular
lubrication from slimy
mucus
Stratified squamous,
keratinized
highly protective against
abrasion, dehydration, &
microorganisms
piled-up, tightly
attached, & internally
reinforced cells
death
modification
cell
migration
differentiation
proliferation
WORM WOMAN’S EPITHELIA
Oral & Esophagus stratified squamous
re
Al
Viscera
- - - - - -
cvl
K-
u
o
diaphragm
Reproductive most types, e.g.,
Vagina stratified squamous
TUBE MAN’S EPITHELIA
Airway
pseudostratified columnar
re
Al
Viscera
- - - - - -
cvl
K-
diaphragm
u
o
Urinary tract transitional
EPITHELIAL TISSUE TYPES: ROLES III
Surface cells have a
special thick urineresistant membrane
Transitional/
urothelium
specialized chemical
protection, with an ability to be
stretched
muco-ciliary escalator
to rid airway of particles,
also provides reflexes &
immune defense
Pseudostratified columnar ciliated
EPITHELIAL TISSUE TYPES III
Why the name ‘Pseudostratified columnar ciliated’?
A major division among the Epithelia is between
SIMPLE, with a single layer of cells, and STRATIFIED,
where the cells are in two or more layers.
Pseudostratified falls in between: its nuclei give the
appearance of layering, but all cells extend down to
fasten to the supporting basement membrane/lamina
‘Columnar’ because
most cells are tall
Cilia are fine beating
hairs sticking out at the
top
nuclei at different
levels, but cells all
touch basal lamina
EPITHELIAL TISSUE TYPES: ROLES III
Pseudostratified columnar ciliated
muco-ciliary escalator
to rid airway of particles,
also provides reflexes &
immune defense
Has different cell types
Ciliated cells have long protruding
hairs that beat forcibly in unison in
one direction to push along the
mucus coating
Mucus cells that liberate slimy mucus
onto the surface to trap particles
The muco-ciliary escalator rids airway of
particles, by finally swallowing or spitting
EPITHELIAL TISSUE TYPES : ROLES II
Stratified squamous
very protective barrier,
needing glandular
lubrication
Stratified squamous,
keratinized
highly protective against
abrasion, dehydration, &
microorganisms
piled-up, tightly
attached, & internally
reinforced cells
death
modification
cell
migration
differentiation
proliferation
TUBE MAN’S EPITHELIA
Oral & Esophagus stratified squamous
Cavity
simple
squamous
Airway
pseudostratified columnar
re
Al
Viscera
- - - - - -
Lung simple cuboidal &
simple squamous
cvl
Vessels simple squamous
K-
u
o
diaphragm
Stomach & Gut
simple columnar
Kidney simple cuboidal
Urinary tract transitional
Reproductive most types
Skin Cornified stratified squamous
GLANDULAR EPITHELIA
In several systems, the epithelial lining or covering for an
organ cannot produce all the working material needed, so
that other specialized epithelial cells have to be set aside
and grouped to produce the needed materials. These
collections of secretory cells are GLANDS.
Extra mucus
Airway glands, Duodenal & Salivary
glands
Digestion
Gastric glands, Pancreas
Blood processing
Hormones
Milk
Liver
Endocrine glands
Mammary glands
GLANDULAR EPITHELIA
Although cells in covering and lining epithelia secrete, they are limited
in number. To get more secreting power, and sometimes to focus it
differently, e.g. to interact with blood, rather than dump into a principal
tube, epithelial cells can build glands
ENDOCRINE GLAND
EXOCRINE/DUCTED GLAND
basal
lamina
Duct lined by
cuboidal cells
control
hormone
Capillary
Nerve
Secretory unit lined by “cuboidal” cells
Clumps of endocrine cells
GLANDULAR EPITHELIA: Products & Roles
Extra mucus
Extra defense
Airway glands, Duodenal & Salivary
glands
Airway glands
Digestion
Gastric glands, Pancreas
Blood processing
Hormones
Liver
Endocrine glands
Milk
Mammary glands
Sweat
Sweat glands
Grease
Sebaceous glands
Special genito-urinary functions
WHERE AM I?
Online Anatomy Module 1
ORIENTATION
CELL
EPITHELIUM
CONNECTIVE TISSUE
MUSCLE
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