RP2: The Urinary System: Functional Anatomy and Urine Formation by the Kidneys

Question 1

What is the pattern of urine flow through the kidney?

Answer 1

MinorCalyx ➔ Major Calyx ➔Renal
Pelvis ➔ Ureter ➔ Urinary
Bladder ➔ Micturition Reflex

Question 2

What do parasympathetics and sympathetics do for peristalsis in the ureter?

Answer 2

• Parasympathetic enhances
  peristalsis
• Sympathetic decreases
  peristalsis.

Question 3

What prevents the backflow of urine from the bladder into the ureters?

Answer 3

Muscle tone compresses ureter and prevents black flow of urine during micturition

Question 4

What is the vesicoureteral reflux?

Answer 4

• Backflow of urine into ureter
• Enlargement of ureters
• Increase pressure and damage to renal pelvis

Question 5

What is the ureterorenal reflex?

Answer 5

• Ureters blocked (ex. Ureteral stone)
• Reflex to reduce RBF and urine formation
• Protective

Question 6

What neurons detect degree of bladder stretch?

Answer 6

Visceral sensory

Question 7

What neurons stimulate contraction of detrusor muscle and relaxation of Internal Sphincter?

Answer 7

Parasympathetic

Question 8

What nerve provides somatic motor neurons controlling External Sphincter?

Answer 8

Pudendal nerve

Question 9

What neurons control bladder blood vessels?

Answer 9

Sympathetic

Question 10

What is the micturition reflex?

Answer 10

• stretch reflex
• contraction of the detrusor smooth muscle

Question 11

Where is the brain center for the micturition reflex?

Answer 11

pons and cerebral cortex

Question 12

What is the function of the micturition reflex?

Answer 12

1. Keep reflex partially inhibited except when desired to urinate
2. Prevent relaxation of external urethral sphincter even though micturition reflex is occurring so can wait until convenient
3. Help initiate reflex and inhibit external urethral sphincter when desired to urinate.

Question 13

What percent of cardiac output goes to the kidneys?

Answer 13

20%

Question 14

What is the unique microcirculation of the kidney?

Answer 14

Afferent Arteriole ➔ Glomerular Capillaries ➔ Efferent Arteriole ➔
Peritubular Capillaries ➔ Venules

Question 15

Which capillary bed in the renal microcirculation is meant for filtration and which is meant for secretion/reabsorption?

Answer 15

• glomerular = high pressure; filtration
• peritubular = low pressure; secretion and reabsorption

Question 16

What is the path through the nephron?

Answer 16

proximal convoluted tubule
descending limb of loop of henle
thin segment of ascending loop of henle
thick segment of ascending loop of henle
distal convoluted tubule
collecting duct

Question 17

What are the two types of nephrons?

Answer 17

1. Cortical
   ➢ 70-80% of nephrons
   ➢ Glomerulus in outer cortex
   ➢ Short loops of Henle
   ➢ Peritubular Capillaries
2. Juxtamedullary
   ➢ 20-30% of nephrons
   ➢ Glomerulus near cortex/medulla border
   ➢ Long Loop of Henle (extends deep into medulla)
   ➢ Vasa Recta
   ➢ Play role in concentrating
   urine

Question 18

Why do we filter so much and then expend so much energy to return greater than 99% back into the ECF?

Answer 18

because some waste products can only be removed by the kidneys

Question 19

What is the equation for a substance that undergoes all for handling processes?

Answer 19

Ex = Fx – Rx + Sx