Urinary tract

Question 1

which organs are part of the upper urinary tract and the lower urinary tract?

Answer 1

• Kidneys
• Ureters (connects the kidneys to the urinary bladder)
• Urinary bladder (stores urine)
• Urethra (collect & drain urine from the body)

Question 2

What is the functional organ of the urinary system?

Answer 2

Kidneys:
1. Nitrogenous waste disposal
2. Filters blood
3. Volume/blood pressure regulation
4. Ionic balance
- Located high in the abdomen
- At the level of the thoracolumbar junction

Question 3

which kidney is more cranial

Answer 3

The right kidney is more cranial
- Its cranial end is embedded in the renal impression of the caudate lobe of the liver (except in pig)
- Pigs: both kidneys are at the same level

Question 4

what are the kidney shape in the different species?

Answer 4

• Bean-shaped:
  a. carnivores, small ruminants, pigs, and the horse’s left kidney
• Heart-shaped and smooth:
  b. horse’s right kidney
• Lobated: cattle

Question 5

what is the different in lobation (fused/not fused, cortex/medulla) in the different species?

Answer 5

• Carnivores:
  o Smooth kidneys: complete fusion of the kidney cortical tissue
  o Capsular veins: normal, distinct veins under the capsule of the cat’s kidney
• Pig:
  o smooth kidney due to fused cortical tissue but has unfused medullary tissue resulting in papillae within a smooth kidney
  o No renal crest
• Lobated kidneys: found in the ox
  o Results from incomplete fusion of kidney lobes
  o It has calyces and papillae, but no renal pelvis
• Horses:
  o have glands in the wall of the renal pelvis
  o Terminal recesses
  Long tube-like extensions that collect and carry
  urine from the kidney poles to the small renal
  pelvis
  o Secretes mucus which gives the urine a turbid appearance

Question 6

is glomeruli are found in the cortex or the medulla

Answer 6

cortex

Question 7

what is the functional unit of the kidney is and its 4 functional regions. Know the features of these structures.

Answer 7

Functional unit of the kidney: nephron

1.Renal corpuscle
a. Site of initial filtration
b. Actual site of urine production
c. Consists of the glomerulus and the glomerular
capsule
d. “Malpighian Body”
2.Proximal convoluted tubule
a. Resorption of water, glucose, proteins, and
sodium from filtrate
b. 99% recovery
3. Loop of Henle
a.Countercurrent exchange of ions
b. Concentrates salt in the interstitium
4.Distal convoluted tubule
a. Active transport of sodium
b. secretion

-(Collecting duct)
o Final concentration of urine

Question 8

what is the differences between the afferent arteriole and the efferent arteriole

Answer 8

Afferent arteriole: the vessel that enters the glomerulus

Efferent arteriole: the vessel that leaves the glomerulus
a. Slightly narrower than the afferent

Question 9

what are the 3 barriers to filtration in the glomerulus

Answer 9

Glomerular capsule (aka Bowman’s capsule):

• Double-walled, expanded end of the renal tubule
  surrounding the glomerulus
• Has a visceral layer (surrounding the glomerulus)
• Parietal layer (surrounding the urinary space)

Question 10

what kind of epithelium is in the proximal and distal convoluted tubules

Answer 10

Proximal convoluted tubule: simple cuboidal epithelium
- The longest part of the nephron
- Microvillous brush border
- 99% of the ultrafiltrate is reabsorbed here

Distal convoluted tubule: simple cuboidal epithelium
- Lacks a brush border
- Function is active transport of sodium to the
interstitial space
- Has a special region near the corpuscle and afferent
arteriole = macula densa

Question 11

which portion of the nephron recovers 99% of the initial urine filtrate

Answer 11

Proximal convoluted tubule

Question 12

what is the macula densa is and what its function is

Answer 12

Macula Densa: chief cells within the kidney

• Associated with a single corpuscle
• One component of the juxtaglomerular apparatus
• Associated cells of uncertain function
• Special region of distal tubule
• One component of the juxtaglomerular apparatus
• Extra space is filled with mesangial cells
• detects sodium concentration in the tubular fluid

Question 13

which cells produce the hormone renin

Answer 13

juxtaglomerular cells in arterioles are secretory and produce the hormone of renin

Question 14

Know whether renin is released in response to high or low blood pressure

Answer 14

Drop in (low) blood pressure triggers a response of renin to be released

Question 15

what branch of the aorta supplies blood to the kidneys

Answer 15

Renal artery is the branch of the abdominal aorta

Question 16

what is the function of the rete mirabile?

Answer 16

“Wondrous net”

• Extensive plexus of capillaries and veins formed
  after blood has passed out of the glomerulus
• Surrounds the loop of Henle
• Controls the sodium gradient within the interstitium