Physiology-Renal I

Question 0

2major regions of kidney anatomy

Answer 0

Outer cortex

Inner medulla

Question 1

Functions of kidney

Answer 1

Excretion of metabolic waste, foreign chemicals, drugs and hormone metabolites
Regulation of water and electrolyte balance
Regulation of arterial pressure
Regulation of acid-base balance
Regulation of erythrocyte production
Regulation of vitamin D production
Glucose synthesis

Question 2

How many pyramids in kidney

Answer 2

6-15

Question 3

Where does base of each pyramid sit

Answer 3

Corticomedullary junction

Question 4

Where does pyramid apex extend into?

Answer 4

Hilium; forms papilla

Question 5

Function of papilla

Answer 5

Delivers urine into minor calyces

Question 6

Where does urine flow from minor calyces

Answer 6

–> major calyces–> renal pelvis–> ureter

Question 7

Blood flow through kidney

Answer 7

Renal artery–> interlobular artery–> arcuate artery–> interlobular artery–> afferent arteriole–> glomerular capillaries–> efferent arteriole–> peritubular capillaries

Question 8

Two types of nephrons

Answer 8

Cortical

Juxtamedullary

Question 9

Cortical nephron

Answer 9

Glomeruli located in outer cortex
Sort loop of henle that penetrates only a short distance into medulla
Entire tubular system surrounded by network of peri tubular capillaries

Question 10

Juxtamedullary nephrons

Answer 10

Glomeruli lie deep in renal cortex near medulla
Long loop of henle deep in medulla
Long efferent arterioles extend from glomeruli down into outer medulla, then divide into two specialized capillaries called vasa recta

Question 11

Mesangial cells

Answer 11

• In glomerulus
• Have properties of smooth muscle cells
• In charge of constriction/dilation
• Synthesize prostaglandins and react to all
• Involved in immune-mediated glomerular diseases producing cytokines
• Participate in phagocytic functions to remove macromolecules that cannot pass thru basement membrane and remain in capillary wall

Question 12

Juxtaglomerular apparatus made up of

Answer 12

Macula densa
Mensagial cells
Granular cells

Question 13

Key function of glomerulus

Answer 13

Act as filtration barrier

-glomerular capillary wall restricts solute movement by using both size and charge selectivity

Question 14

Ultrafiltration

Answer 14

Passive movement of an essentially protein free fluid from the glomerular capillaries into bowman’s space

Question 15

Size selectivity maintained in glomerulus by

Answer 15

Basement membrane

Podocyte slit diaphragms

Question 16

Charge selectivity in glomerulus maintained by

Answer 16

Electrostatic repulsion created by a ionic sites in basement membrane and endothelial cell fenestrae

Question 17

3 basic processes of urine formation

Answer 17

Ultrafiltration of plasma by glomerulus
Reabsorption of water and salutes from ultrafiltrate
Secretion of solutes into tubular fluid

Question 18

Function of epithelial cells in glomerulus

Answer 18

Secrete hormones that influence vasomotor tone in renal circulation (endotheilin, prostacyclin, nitric oxide)

Question 19

3 major factors of autoregulation that modulate either afferent or efferent arteriolar tone

Answer 19

1. Myogenic reflex (afferent arteriole)
2. Tubuloglomerular feedback
3. Angiotensin II mediated vasoconstriction (efferent arteriole)

Question 20

Myogenic reflex

Answer 20

Myogenic stretch receptors in afferent arteriolar walls sense changes in arterial pressure
Increase in BP in afferent–> constriction of afferent arteriole
Decrease in BP of afferent–> dilation of afferent arteriole

Question 21

First line of defense against fluctuation in renal blood flow

Answer 21

Myogenic reflex

Question 22

Tubuloglomerular feedback

Answer 22

Links changes in NaCl concentration at macula densa with control of renal afferent arteriolar resistance
Increase in GFR–> increases NaCl concentration in loop of henle–> increase in NaCl sensed by macula densa–> macula densa signals to increase resistance of afferent arteriole (constriction)–> decreases glomerular filtration rate

Question 23

Ultrafiltration

Answer 23

Passive movement of an essentially protein free fluid from the glomerular capillaries into bowman’s space

Question 23

Angiotensin II mediated vasoconstriction of efferent arteriole

Answer 23

Decrease in renal blood flow causes JGA to release renin from granular cells
Renin–> catalyzes angiotensin–> angiotensin I–> angiotensin II–> vasoconstriction of afferent and efferent arterioles–> increased pressure in glomerular capsule, normalizing glomerular filtration rate

Question 24

Which arteriole is more sensitive to vasoconstriction?

Answer 24

Efferent

Question 25

What will a decrease in angiotensin II do to renal blood flow

Answer 25

Increase

Question 26

What will an increase in angiotensin II do to renal blood flow

Answer 26

Decrease

Question 27

Constriction of efferent arteriole will _____ glomerular hydrostatic pressure, and therefore______glomerular filtration rate

Answer 27

Increase; increase

Question 29

Constriction (increases/decreases) resistance

Answer 29

Increases

Question 30

Dilation (increases/decreases) resistance

Answer 30

Decreases

Question 31

How sympathetic nerves affect RBF and GFR

Answer 31

Innervate afferent and efferent arterioles
Norepinephrine and epinephrine cause vasoconstriction, which decreases GFR and RBF
-sympathetic tone is minimal when ECF is normal
-dehydration or strong emotional stimuli can activate sympathetic nerves

Question 32

How prostaglandins affect RBF and GFR

Answer 32

Increase RBF

• during certain conditions (hemorrhage, stress, dehydration) prostaglandins are released locally within kidneys–> increase RBF by dampening vasoconstrictor effects of sympathetic nerves and angiotensin II to prevent severe vasoconstriction/renal ischemia
• not much of an effect in healthy, resting subjects

Question 33

How nitric oxide affects RBF and GFR

Answer 33

Important vasodilator under basal conditions

Question 34

Creatinine

Answer 34

Byproduct of skeletal muscle creatine metabolism
Used to measure glomerular filtration
It is not secreted, reabsorbed, or metabolized by cells in nephron, so amount of creatinine excreted in urine = amount if creatinine filtered by glomerulus each minute