Urinary

Question 1

Functions of Urinary System (3)

Answer 1

1) Regulate volume, composition, pH of body fluids
2) Eliminate drugs/food additives/urea
3) Endocrine ( release of compounds into blood to regulate Ca++ absorbtion, blood pressure, RBC formation)

Question 2

Kidney Facts

Answer 2

-1/5 of blood flow to kidney

• Reconditions blood to return to system, removes waste
• Hard capsule surrounding kidney prevents overfilling
• 750mL of urine produced daily
• smallest functional unit = nephron

Question 3

What percent of nephrons are Cortical?

Main function?

Answer 3

85%

-Re-absorption of “good” blood components

Question 4

What percent of nephrons are juxtamedullary?

Main function?

Answer 4

15%

-H2O reabsorption

Question 5

Body produces how many liters of filtrate per day?

Answer 5

80 LITERS!!!!!!!!!!!!!!!!

Question 6

PCT Function

Answer 6

Reclaims “good” blood components and about 65% of H2O follows

• Including 100% of GLUCOSE
• Pumps solutes and H2O follows

Question 7

Filtration system of Bowman’s Capsule/glomerulus

Answer 7

Fluid is driven into the capsule via net pressure of 10mmHg outward from the glomerulus (125mL per min moved)

Question 8

Brush Border

Answer 8

Cilia on inside of PCT to increase SA for reabsorption.

Question 9

Is there a high or low mitochondria concentration in PCT cells?

Answer 9

HIGH

Question 10

Descending Loop Permeability

Answer 10

Very H2O permeable

NOT permeable to Na+ or Cl-

Question 11

Ascending Loop Permeability

Answer 11

Not H2O permeable

-Cells actively pump Na+ out

Question 12

Concentration of solutes at top of loop of henle?

Concentration of solutes on bottom of loop of henle?

Answer 12

300mmHG

1200mmHg

Question 13

Aldosterone

Answer 13

• Adrenal cortex steroid
• Causes increased Na+ reabsorption = increased H2O retention (activates additional sodium pumps)
• Causes DCT to become H2O permeable

Question 14

Juxta-Glomerular Apparatas

Answer 14

Maintains/regulates pressure within glomerulus via JG cells and the Macula Densa

Question 15

JG cell

Answer 15

“Juxta Medullary Cell”

• stimulated when BP in glomerulus is too low
• Releases rennin into blood

Question 16

Macula Densa

Answer 16

• Activated when blood pressure in glomerulus is too HIGH
• Causes paracrine secretion, which stimulates SM cells on afferent arteriole to contract, reducing flow = reduced pressure

Question 17

Rennin/Angiotensin Activation

Answer 17

Rennin is released by JG cells when glomerulus BP is too low.

• Rennin is enzyme that is released to blood stream where Angoiotensin is present (INACTIVE)
• Rennin activates angiotensin to become Angiotensin 1
• When Angiotensin 1 reaches lungs, ACE enzyme converts Angiotensin 1 to Angiotensin 2 (MOST POTENT VASOCONSTRICTOR)

Question 18

Angiotensin 2 Effects

Answer 18

• ADH release causing “thirstyness” (causes fluid retention = increased BP)
• Vasoconstriction of vessels
• AT KIDNEY, afferent & efferent arterioles constricted.

Question 19

External sphinctor of urethra becomes controllable at what age?

Answer 19

2

Question 20

Micturation

Answer 20

Urination

Question 21

Sphinctors of Urethra

Answer 21

Internal = SM = autonomic
External = skeletal muscle = voluntary