Lecture 1: Intro to Renal Physiology

Question 1

what contains nitrogen

Answer 1

proteins and nucleic acids

Question 2

what is azotemia

Answer 2

buildup of nitrogenous products

Question 3

mammals and many adult amphibians excrete

Answer 3

urea

Question 4

main function of kidney

Answer 4

excretion of metabolic waste products: endogenous organic compounds and exogenous compounds

Question 5

uremia

Answer 5

urine in blood

Question 6

accumulating urea spontaneously dissociates to form what

Answer 6

cyanate

Question 7

what occurs in the reaction of carbamylation

Answer 7

cyanate reacts irreversibly w/ proteins and free amino groups

Question 8

what is renal failure

Answer 8

reduction in filter capacity (GFR)
results in the accumulation of waste products in plasma (uremia, azotemia)

Question 9

functional unit of the kidney

Answer 9

nephron

Question 10

in what 3 ways does the kidney help remove metabolic waste products

Answer 10

filtration in glomerulus
secretion from blood into tubular lumen
reabsorption from tubular lumen back into blood

Question 11

where does reabsorption of 90% of HCO3 occur

Answer 11

proximal tubule

Question 12

active regulation of Ca excretion occurs where

Answer 12

distal tubule

Question 13

each nephron has a _____ and ______

Answer 13

glomerulus and tubulus system

Question 14

what arteriole carries blood to the glomerulus

Answer 14

afferent arteriole

Question 15

filtered blood leaves the glomerulus from the

Answer 15

efferent arteriole

Question 16

Modified smooth muscle cells that produce renin

Answer 16

granular cells

Question 17

water and solutes cross the glomerular capillary wall into _______ space, forming the glomerular filtrate

Answer 17

Bowman’s space

Question 18

what is glomerular filtration rate (GFR)

Answer 18

the volume of plasma filtered into Bowman’s space per unit of time (ml/min)

Question 19

what variables determine the amount of blood filtered by the glomerulus

Answer 19

• mean net filtration pressure
• area available for filtration
• permeability of the filtration barrier

Question 20

what forces favor glomerular filtration

Answer 20

• hydrostatic pressure of glomerular capillary (Pgc)
• oncotic pressure of filtrate in Bowman’s space

Question 21

what forces oppose glomerular filtration

Answer 21

• hydrostatic pressure of Bowman’s space
• oncotic pressure of blood

Question 22

when mesangial cells contract or relax, they affect…

Answer 22

capillary surface area and flow

Question 23

what type of substances regulate mesangial cell contraction/relaxation

Answer 23

vasoactive substances

Question 24

what does the filtration barrier consist of

Answer 24

• endothelial cells
• basilar (basement) membrane
• podocytes (visceral epithelium)

Question 25

what forms a filtration barrier

Answer 25

Bowman’s capsule

Question 26

why does the filtration barrier favor the filtration of positively charged molecules?

Answer 26

B/c filtration barrier is made of negatively charged laminin, fibronectin and peptidoglycans which favor positive charges

Question 27

the filtration barrier is ____ and ____ selective

Answer 27

charge and size-selective

Question 28

the glomerulus wall is permeable for molecules smaller than what size

Answer 28

4 nm

Question 29

85% of filtered water and solutes are reabsorbed by the _____ and _____

Answer 29

proximal tubule and loop of Henle

Question 30

what is Clearance (Cx)

Answer 30

the volume of plasma from which all of the substance x was removed and excreted in a given time

Question 31

if a substance is freely filtered, it will show in the ______ filtrate

Answer 31

primary

Question 32

when Cx = 0 ….

Answer 32

substance will not appear in the urine
(ex: glucose has a C of 0)

Question 33

what is the consequence of mesangial cell contraction on filtration? Wb relaxation?

Answer 33

contraction decreases SA+flow and decreases the filtration rate

relaxation increases SA+flow and increases the filtration rate

Question 34

what components of the filtration barrier are responsible for the favoring of filtration of positively charged molecules

Answer 34

laminin, fibronectin, and peptidoglycans

Question 35

what is canine nephrotoxic glomerulonephritis?

Answer 35

antibodies in the glomerular basement membrane damage the barrier –> acute glomerular injury

results in large molecules like proteins ending up in the urine

Question 36

modified smooth muscle cells that produces renin and are located outside of the afferent arteriole

Answer 36

granular cells

Question 37

explain the relationship b/w PG (glomerulus hydrostatic pressure) and glomerular filtration

Answer 37

PG is the most important driving force in filtration
- if pg decreases, so does GFR and vise versa

Question 38

what things alter PG

Answer 38

changes in the pressure and resistance in afferent / efferent arterioles

Question 39

what is oncotic pressure?

Answer 39

pressure from proteins, proteins pull fluid towards them

Question 40

what is the amount (mmHg) of O2 in the renal artery

Answer 40

100 mmHg

Question 41

what is the amount of (mmHg) of O2 in the renal vein

Answer 41

40 mmHg

Question 42

what are some endogenous organic compounds

Answer 42

urea, creatinine, indoles, phenols, bilirubin, hormones, enzymes, vitamins, etc

Question 43

what is the pathway of renal blood flow

Answer 43

renal a. → segmental → interlobar → arcuate → cortical radiate → afferent arteriole → glomerulus → efferent arteriole → peritubular capillaries → venules → cortical radiate vein → artcuate vein → interlobar vein → renal vein

Question 44

what part of the tubular system reabsorbs nearly all filtered glucose and amino acids

Answer 44

Proximal tubule

Question 45

what part of the tubular system is a major site of NH3 production

Answer 45

proximal tubule

Question 46

what part of the tubular system reabsorbs 90% of HCO3- (bicarbonate)

Answer 46

proximal tubule