Physiology-Renal I Flashcards Preview

Physiology > Physiology-Renal I > Flashcards

Flashcards in Physiology-Renal I Deck (35):
0

Functions of kidney

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

1

2major regions of kidney anatomy

Outer cortex
Inner medulla

2

How many pyramids in kidney

6-15

3

Where does base of each pyramid sit

Corticomedullary junction

4

Where does pyramid apex extend into?

Hilium; forms papilla

5

Function of papilla

Delivers urine into minor calyces

6

Where does urine flow from minor calyces

--> major calyces--> renal pelvis--> ureter

7

Blood flow through kidney

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

8

Two types of nephrons

Cortical
Juxtamedullary

9

Cortical nephron

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

10

Juxtamedullary nephrons

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

11

Mesangial cells

-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

12

Juxtaglomerular apparatus made up of

Macula densa
Mensagial cells
Granular cells

13

Key function of glomerulus

Act as filtration barrier
-glomerular capillary wall restricts solute movement by using both size and charge selectivity

14

Ultrafiltration

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

15

Size selectivity maintained in glomerulus by

Basement membrane
Podocyte slit diaphragms

16

Charge selectivity in glomerulus maintained by

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

17

3 basic processes of urine formation

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

18

Function of epithelial cells in glomerulus

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

19

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

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

20

Myogenic reflex

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

21

First line of defense against fluctuation in renal blood flow

Myogenic reflex

22

Tubuloglomerular feedback

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

23

Ultrafiltration

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

23

Angiotensin II mediated vasoconstriction of efferent arteriole

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

24

Which arteriole is more sensitive to vasoconstriction?

Efferent

25

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

Increase

26

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

Decrease

27

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

Increase; increase

29

Constriction (increases/decreases) resistance

Increases

30

Dilation (increases/decreases) resistance

Decreases

31

How sympathetic nerves affect RBF and GFR

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

32

How prostaglandins affect RBF and GFR

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

33

How nitric oxide affects RBF and GFR

Important vasodilator under basal conditions

34

Creatinine

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