Urinary System

Question 1

What are the structures of the urinary system?

Answer 1

2 kidneys
2 ureters
1 urinary bladder
1 urethra

Question 2

What are the functions of the urinary system?

Answer 2

regulates:
- blood volume
- blood pressure
- pH
- ion concentrations
eliminates waste
- ex: urea, uric acid, hormones, drugs

Question 3

What is the functional unit of the kidney called?

Answer 3

nephron

Question 4

What does it mean for the kidneys to be retroperitoneal?

Answer 4

they lay behind to peritoneum

Question 5

Which kidney is lower?

Answer 5

right is lower than left

Question 6

What are the 3 layer of CT that support and protect the kidneys called?

Answer 6

fibrous capsule
perirenal fat capsule
renal fascia

Question 7

What is the medial indentation of the kidney called?

Answer 7

The renal hilus or just hilum

Question 8

What is the hilum entry points for?

Answer 8

• renal artery (superior)
• renal vein (inferior)
• ureter
• nerves

Question 9

What is the difference between the renal cortex and renal medulla?

Answer 9

cortex: outer (superficial) part of kidney
medulla: inner (deep) part of kidney

Question 10

What is the apex of the renal pyramid called?

Answer 10

renal papilla

Question 11

What separates the renal pyramids and contains blood vessels?

Answer 11

renal columns

Question 12

Where are renal corpuscles located? What do they do?

Answer 12

• located in the renal cortex of the kidney
• their function is to filter blood which is the first step in urine formation

Question 13

What is the glomerulus? Where is it located?

Answer 13

a capillary bed located in the renal corpuscle

Question 14

What is the Bowman’s capsule? Where is it located?

Answer 14

• collects filtrates from the glomerulus
• has 2 layers
  - outer/parietal: simple squamous epithelium
  - inner/visceral: podocytes (modified simple squamous epithelium) wrap around glomerular capillaries/endothelium

Question 15

What is the filtration membrane of the renal corpuscles?

Answer 15

consists of:
- glomerular endothelium (capillaries), simple squamous epithelium with pore (fenestrations)
- basement membranes
- podocytes (of bowman’s capsule), simple epithelium projections cling to glomerulus

Question 16

What makes up renal corpuscles? Where are they located?

Answer 16

located in the cortex of the kidney
- glomerulus
- bowman’s capsule

Question 17

What are the 4 renal tubes? Where are they located?

Answer 17

• proximal convoluted tubule: in cortex, closest to renal corpuscle
• loop of henle: in medulla, ascending and descending limbs
• distal convoluting tubule: in cortex
• collecting ducts: in cortex and medulla, connects nephron to ureter

Question 18

What are the 2 types of nephrons? What percentage of each?

Answer 18

• cortical: 85%
• juxtamedullary: 15%

Question 19

Which type of nephron is closer to the surface in the cortex?

Answer 19

cortical

Question 20

Which nephron type has shorter vs longer henle loops? What does this change?

Answer 20

cortical nephrons have short henle loops in the outer medulla, while juxtamedullar nephrons have longer henle loops penetrating deep into the medulla which allow concentration of urine depending on need

Question 21

What does the juxtaglomerular complex do?

Answer 21

regulates filtrate formation

Question 22

Describe the tubular portion of the juxtaglomerular complex

Answer 22

called the macula densa, made up of modified (tall and narrow) ascending limb cells

Question 23

Describe the arteriolar portion of the juxtaglomerular complex

Answer 23

juxtaglomerular (granular) cells make up afferent and efferent arteriolar portion. They monitor blood pressure

Question 24

Describe the histology of the ureter

Answer 24

• mucosa: transitional epithelium
• no submucosa: (lamina propria of mucosa is connected directly to muscularis externa)
• muscularis externa: 3 smooth muscle layers
• serosa/adventitia: retroperitoneal

Question 25

Describe the histology of the urinary bladder

Answer 25

• mucosa: transitional epithelium with rugae
• no submucosa: (lamina propria of mucosa is connected directly to muscularis externa)
• muscularis externa: ~3 layers of smooth muscle form detrusor muscle
• serosa/adventitia:
  - adventitia: inferior, anterior, and posterior
  - serosa: superior

Question 26

What is the difference between serosa and adventitia?

Answer 26

serosa has a layer of areolar CT and epithelium while adventitia only has areolar CT

Question 27

What is a trigone?

Answer 27

• triangle of 2 ureters (posterior) and urethra openings
• mucosa of trigone lacks rugae (smooth) - allows openings to remain in fixed position

Question 28

Describe the histology of the urethra

Answer 28

• mucosa: transitional to stratified squamous epithelium
• muscularis externa: smooth muscle

Question 29

What are the 2 sphincters of the urethra?

Answer 29

• both surround proximal end of urethra
  a) internal urethra sphincter (smooth muscle): thickening of detrusor muscle at base of bladder
  b) external urethra sphincter (skeletal muscle): in urogenital diaphragm