Name______________________________
FUNCTION AND STRUCTURE OF URINARY SYSTEM LAB
(Adapted from Murray Jensen at UMN http://faculty.matcmadison.edu/cshuster/ap2/Kidney_Dissection.pdf)
The human urinary system has two basic functions, both of which occur in the kidneys. The first
function is to remove nitrogenous wastes (such as creatine, urea, and uric acid) from the body. The
second function is to maintain the electrolyte, acid-base, and fluid balances of the blood.
In this lab exercise, you will explore the macro and microanatomy of the urinary system and relate
these structures to the function of the kidney.
Part 1. Microscopic kidney anatomy
1. View slides of kidney structures available today, or use Histology Index or other online
resources.
2. Find the magnification that shows the overall nephron or other structures as directed.
3. Sketch and label structures.
Labeled sketch(es) of kidney slide(s):
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Part 2. Macroscopic kidney anatomy
There are four primary components to a kidney:
1. Renal Capsule: A smooth semitransparent membrane that adheres tightly to the outer
surface of the kidney.
2. Renal Cortex: The region of the kidney just below the capsule. When your kidney is
dissected then you should be able to see blue and red specks scattered through the cortex.
These are specks of injected latex that illustrate the rich vascular supply of the cortex.
3. Medullary Region (renal medulla): The region just deep to the cortex that is segregated into
triangular and columnar regions. The triangular regions are the renal pyramids, which
should be striated (or striped) in appearance due to the collecting ducts running through
them. The columnar regions between the pyramids are the renal columns. These renal
columns are where the interlobar arteries are located.
4. Renal Pelvis: A cavity within the kidney that is continuous with the ureter, which exits from
the hilus. The pelvis has portions that extend towards the apexes of the renal pyramids. The
primary (large) extensions are the major calyces and the smaller extensions are the minor
calyces.
Procedure for dissection
1. Collect your dissecting tools and tray. Obtain a preserved kidney.
2. Examine the external anatomy. You should notice adipose tissue (remnants of the adipose
capsule) clinging to the renal capsule (Figure 1). Notice a “pinched-in” area where the renal
blood vessels and ureter are attached to the kidney. This is the renal hilus.
Figure 1
Figure 2
3. Remove the renal capsule (Figure 2).
4. Once the renal capsule is removed, you will be looking at the renal cortex (if you would
remove the renal cortex, you would see the renal medulla).
5. Separate the renal blood vessels from one another and from the ureter. Generally, the tube
with the most adipose around it is the ureter.
6. Notice the histological differences (and similarities) between the renal arteries, renal veins,
and ureter.
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7. Make a frontal (coronal) section through the kidney (Figures 3 & 4).
Figure 3
Figure 4
8. Identify the renal pyramids (and parts of the pyramids), the renal columns, the renal pelvis,
renal cortex, ureter, and any blood vessels that are present (figure 4).
9. Check off the kidney structures you identified.
o
o
o
o
o
o
o
o
o
o
o
o
o
calyx (calyces)
adipose tissue
hilus
renal arteries
renal medulla
renal capsule
renal columns
renal cortex
renal papilla
renal pelvis
renal pyramids
renal veins
ureter (if present)
5. Describe the location of the kidneys in terms of the thoracic and lumbar vertebrae
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6. What is the function of the fat surrounding the kidneys? What can occur if this fat dwindles?
7. What portion of the kidney contains the renal pyramids?
8. What blood vessels function to carry blood from the aorta to the renal arteries?
9. What is the smooth semitransparent membrane that adheres tightly to the outer surface of
the kidney?
10. When you remove this membrane from a kidney, what portion of the kidney becomes
clearly visible?
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11. What structures allow urine to move from the kidneys to the urinary bladder?
12. What is the smooth muscular layer of the renal artery called?
13. What region of the kidney is between the capsule and the medulla?
14. What are the areas between the renal pyramids?
15. What is the cavity within the kidney that is continuous with the ureter?
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16. What is the area of the kidney where the renal blood vessels and ureter are attached to the
kidney?
17. What type of tissue composes the loops of Henle? Where in the body is this tissue also
found (see page 90 in the text).
Part 3. Functions of kidney
Each kidney contains over a million tiny structures called nephrons. Nephrons are the structural
and functional units of the kidney. Each kidney is composed of two main structures, a glomerulus
and a renal tubule. The closed end of the renal tubule is enlarged and cup-shaped and completely
surrounds the glomerulus. This is called the glomerular capsule. The inner layer is composed of
cells called podocyes that have long branching foot processes (“pods”), which intertwine with each
other and cling to the glomerulus. Podocytes form a sieve-like membrane around the glomerulus.
The rest of the tubule extends from the glomerular capsule and twists into a hairpin loop called the
loop of Henle and then coils and twists into the collecting duct, giving the body opportunities for
filtering blood and maintaining solute and water balance.
1. What are the two primary functions of the urinary system?
2. During micturition, urine moves out of the urinary bladder via what structure?
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3. Name four abnormal urinary components and their possible causes.
4. Referring to your textbook, name and describe the three processes involved in urine
formation.
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5. What is diffusion? Give an example of diffusion in the human body besides in the urinary
system.
6. What is active transport? Give an example of active transport besides in the urinary system.
7. What is osmosis? Give an example of osmosis besides in the urinary system.
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8. Complete this chart referring to your textbook or Figure 5.16.
More
salt
inside
Less
salt
inside
More
salt
outside
Less
salt
outside
Process is called
Cells shrink & shrivel
Cells swell & burst
9. In the bathtub without bubbles your skin gets “pruny.” What is happening in terms of
osmosis?
10. I suggest that people gargle with salt water when they have a sore throat. How does this
help?
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11. Label the arrows in this diagram.
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