Lab 40.
Urinary Anatomy and Kidney
Dissection
Urinary Anatomy
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Kidneys: filters blood, produces urine
Ureters: convey urine to bladder
Bladder: holding tank
Urethra: carries urine to the outside for
elimination
Kidneys
• One on each side, between T12 and L3
• Left sits higher than right (due to ?)
• Retroperitoneal: behind the peritoneal
cavity (so has no serous membranes)
– Between peritoneum and dorsal body wall
Nephrons
• Kidney cells called nephrons filter the
blood
• Each consists of:
– renal corpuscle
• Bowman’s Capsule
• glomerulus
– renal tubule (PCT, DCT, loop of Henle)
Renal Corpuscle
• Glomerulus = tangled mass of 50 or so
fenestrated capillaries that receive blood from an
afferent vessel.
• Bowman’s capsule: kind of like a really tiny
pericardium for the glomerulus
• Capsular space: like pericardial space, between
glomerulus and Bowman’s capsule
• Fluid is squeezed out of glomerular caps into the
capular space, then enters the tubule
Renal Corpuscle
Renal Histology
• Bowman’s capsule:
– Parietal epithelium (tissue type?)
– Visceral epithelium (continuous with parietal
at vessel points)
43.2 - Kidney Section
• Examine the slide on low power. Try to identify
by sight: capsule, renal cortex, glomeruli and
tubules. On medium or high power, draw and
clearly label a portion of the renal cortex that
includes a glomerulus. In your drawing, include
and label: glomerulus, Bowman’s capsule, renal
corpuscle, parietal layer of Bowman’s capsule
(type of epithelium here), capsular space, and
tubules. Indicate the type of epithelia found in
the tubules and the type of epithelia that lines
the capsular space (same as above, in the
parietal layer).
43.3 – Urinary Tract
• Ureter  bladder  urethra
• Mucosa lined with a transitional epithelium
(almost everywhere). Why mucosa?
• Lamina propria
• (Smooth) muscle layer
• Outer connective tissue layer
Ureter
• Ureter has two layers of smooth muscle:
concentric and longitudinal
A. Ureter
• Start by looking at the slide on low power.
At medium power, draw and label: the
lumen, epithelial layer (indicate the type),
lamina propria, smooth muscle layer and
outer connective tissue layer (if present).
• Using the high power objective, take a
good look at the epithelial layer of the
ureter. Rhetorical question- Could you tell
this apart from stratified squamous; how?
Bladder
• Mucosa of bladder has rugae
• Bladder muscle layers = detrussor muscle,
which contracts to force urine into the
urethra
B. Urinary Bladder
• Draw and clearly label the urinary bladder.
In your sketch, include the following:
epithelia (and the type!), lamina propria,
detrusor muscle. I recommend using the
medium power, but you can choose.
Urethra
• Males have longer urethras that carry semen as well as
urine. The female urethra is only about 2 inches long and
carries urine only.
• Both have external urethral sphincter made of skeletal
muscle, allowing for conscious control of urination
• Urethral lining is transitional at neck, stratified columnar
in the middle, and stratified squamous near the external
orifice
• Lamina propria is very elastic, mucin secreting cells in
the pockets of longitudinal folds
• Males: mucous glands extend into lamina propria
• Females: lamina propria has lots of veins and is
surrounded by layers of concentric smooth muscle
C. Urethra (female)
• On medium power, draw and clearly label the
urethra. In your sketch, include: epithelia (type),
lamina propria and muscle (is this smooth
muscle or skeletal, or both?)
• Be sure to take a close look at the epithelial
layer. NOTE: The urethral lining consists of a
stratified epithelium that varies from: transitional
at the neck of the bladder to stratified squamous
near the external urethral orifice (in females). If
this is the case, where are you in the urethra?
Kidneys
External anatomy
• Connective tissue layers
– Renal capsule (inner layer): collagen fibers
– Adipose capsule: thick layer of adipose
around renal capsule
– Renal fascia: Dense irregular CT, penetrates
down to renal capsule
• Hilum: medial surface indentation;
entry/exit point of blood vessels, lymph,
nerves, ureter
Internal Anatomy
• Renal cortex: Outer layer just under
caspule, reddish brown.
• Renal medulla:
– 6 to 18 renal pyramids (point toward hilum)
• Tips are called renal papilla
• Pyramids separated by renal columns
• “Renal lobe” = one pyramid, overlying cortex and
adjacent renal columns
Interlobar
arteries
Internal Anatomy – urine flow
• Renal papilla in each pyramid contain
ducts that drain into a minor calyx
• 4 - 5 minor calyces combine to form a
major calyx
• 2 - 3 major calyces combine to form the
renal pelvis, a funnel-shaped chamber
found at the hilum.
• Renal pelvis is connected to ureter
Kidney Dissection
• Working in groups of two or three, examine the
kidney. Locate the hilum. What major ‘pipes’
enter and exit the kidney here? Can you see the
adipose capsule and the renal capsule?
• Follow the procedures in your lab notebook. Be
sure to look for: the cortex, medulla, renal
columns, renal pyramids, renal papilla, minor
and major calyces, renal pelvis and interlobar
arteries.
Dissection
• Glove up
• Get tools, kidney and rinse it off
• Look at external anatomy: hilum, connective
tissue layers
• Cut in half longitudinally (into ant/post halves)
• Internal anatomy: cortex, medulla, renal
columns, renal pyramids, renal papilla, minor
and major calyces, renal pelvis and interlobar
arteries.
To turn in:
• Four drawings
• Review Sheet 40
• Due next Thurs