Topic 16: Urinary System

Question 1

List the structures of the urinary system:

Answer 1

o2 kidneys
o2 ureters
o 1 urinary badder
- 1 urethra

Question 2

What is the function of the urinary system

Answer 2

regulates: 
 blood volume
􏰁 blood pressure
􏰁 pH
􏰁 ion concentrations

eliminate waste; nitrogenous waste
e.g. urea, uric acid, hormones, drugs

Question 3

Describe the external anatomy of the kidney:

Answer 3

o retroperitoneal
o right lower than left
o supported & protected by 3 layers of CT
- renal hilus

Question 4

list the 3 layers of CT that support the kidney

Answer 4

a) fibrous capsule
b) perirenal fat capsule
c) renal fascia

Question 5

renal hilus (hilum):

Answer 5

􏰁 medial indentation
􏰁 entry point of:
o renal artery (superior) to
o renal vein (inferior) o ureter
o nerves

Question 6

describe the internal anatomy of the kidney

Answer 6

o renal cortex (superficial)
o renal medulla (middle and deep to the cortex)

• CREATIG URINE OCCURS HERE

Question 7

What does the renal medulla contain?

Answer 7

i. renal pyramids
􏰁 apex of pyramid = renal papilla

ii. renal columns
􏰁 separate pyramids
􏰁 contain blood vessels

Question 8

Nephron:

Answer 8

􏰁 functional unit of kidney (microscopic)

Question 9

What is the nephron composed of?

Answer 9

a) renal corpuscle

b) renal tubules

Question 10

renal corpuscle

Answer 10

􏰁 in cortex

􏰁 site of blood filtration (first step in urine formation)

Question 11

List the parts of the renal corpuscle

Answer 11

i. glomerulus
ii. Bowman’s capsule
iii. Filtration membrane

Question 12

glomerulus

Answer 12

= capillary bed

Question 13

Bowman’s capsule

Answer 13

􏰁 surrounds glomerulus
􏰁 collects filtrate from glomerulus
􏰁 2 layers:
􏰁 1) outer = simple squamous epithelium
􏰁 2) inner = podocytes 􏰣 wrapped around glomerular
capillaries

Question 14

Filtration Membrane

Answer 14

1. glomerular endothelium (capillaries)
   􏰁 simple squamous with pores (= fenestrations)
2. basement membranes
3. Podocytes (of Bowmans capsule)
   simple epi- projections cling to glomerulus

Question 15

List the parts of the renal tubules

Answer 15

i. Proximal Convoluted Tubule (PCT)
􏰁 in cortex

ii. Loop of Henle
􏰁 descending + ascending limbs
􏰁 in medulla

iii. Distal Convoluted Tubule(DCT) 􏰁 in cortex

iv. Collecting Ducts
􏰁 in cortex & medulla
􏰁 connect nephron to ureter (via calyces/renal pelvis)

Question 16

List the 2 types of nephrons and differences between the 2

Answer 16

a) Cortical (85%)
􏰁 renal corpuscles near kidney surface in cortex
􏰁 short Loop of Henle in outer medulla

b) Juxtamedullary (15%)
􏰁 renal corpuscles in cortex near medulla
􏰁 longs Loops
􏰕 penetrate deep into medulla
o allow concentration of urine depending on need

Question 17

Describe the kidney and nephron blood flow:

Answer 17

Aorta 
renal artery 
segmental artery 
interlobular artery 
arcuate artery 
cortical radiate artery 
afferent arteriole 
glomeruli 
efferent arteriole 
peritubular capillaries/ vasa recta 
cortical radiate vein 
arcuate vein 
interlobular veins 
renal vein 
inferior vena cava

Question 18

Juxtaglomerular complex:

Answer 18

􏰁 regulates filtrate formation

point of contact between end of ascending limb, afferent + efferent arterioles at renal corpuscle of same nephron

Question 19

Describe the parts of the Juxtaglomerular complex:

Answer 19

a) Tubular Portion
􏰁 modified (tall and narrow) ascending limb cells = macula densa

b) Arteriolar Portion
􏰁 afferent and efferent arteriolar portion = granular (juxtaglomerular cells) o monitor blood pressure
o contain renin (enzyme + hormone)

Question 20

Describe the histology of the ureters

Answer 20

a) Mucosa
􏰁 transitional epithelium

b) NO Submucosa
􏰁 lamina propria directly connected to muscularis externa

c) Muscularis externa
􏰁 smooth muscle (~ 3 layers)

d) Adventitia/Serosa
􏰁 retroperitoneal

Question 21

Describe the histology of the urinary bladder

Answer 21

a) Mucosa
􏰁 transitional epithelium with rugae

b) NO Submucosa
􏰁 lamina propria directly connected to muscularis externa

c) Muscularis externa
􏰁 = detrusor muscle - smooth muscle (~ 3 layers)

d) Adventitia/Serosa
􏰁 adventitia = anterior, posterior, and inferior 􏰁 serosa = superior

􏰁 internally:
o triangleof2ureters(posterior)+urethraopenings=trigone
􏰁 mucosa of trigone lacks rugae (smooth) 􏰕 allows openings to remain in fixed position

Question 22

Urethra histology

Answer 22

a) Mucosa
􏰁 transitional to stratified squamous epithelium

b) Muscularis externa
􏰁 smooth muscle

Question 23

Urethra

Answer 23

2 sphincters (both surround proximal end of urethra):
a) internal urethral sphincter (smooth muscle)
􏰁 thickening of detrusor muscle at base of bladder 

b) external urethral sphincter (skeletal muscle)
􏰁 in urogenital diaphragm

Question 24

urethra in males vs females

Answer 24

in females
􏰕 transports urine
in males
􏰕 transports urine + semen

Question 25

Describe the pathway of the filtrate

Answer 25

several DCT 
collecting ducts 
minor calyx 
major calyx 
renal pelvis 
ureters 
bladder 
urethra