Physiology 2

Question 1

What are the functions of the kidneys

Answer 1

water balance 
salt balance 
maintenance of plasma volume 
maintenance of plasma osmolarity 
acid-base balance 
excretion of metabolic waste products 
excretion of exogenous waste products 
excretion of exogenous foreign compounds 
secretion of renin 
secretion of erythropoietin 
conversion of vitamin D into active form (calcitriol)

Question 2

what is secreted by the kidneys

Answer 2

renin (to control arterial BP)

erythropoietin (RBC production)

Question 3

what is the PRIMARY function of the kidneys

Answer 3

to regulate the volume, composition and osmolarity of the body fluids via the controlled excretion of electrolytes and other substances

Question 4

what are the 2 main parts of the kidney

Answer 4

cortex

medulla

Question 5

what is the nephron

Answer 5

functional unit of the kidney (smallest structural compartment that can perform all the primary functions)

Question 6

what are the functions of the nephron

Answer 6

filtration
reabsorption
secretion

Question 7

what is the firs place the blood is filtered in the nephron

Answer 7

bowman’s capsule

Question 8

how does blood enter the bowman’s capsule

Answer 8

it goes through an afferent arterial which drains into a glomerular capillary

Question 9

where does the blood drain after the glomerulus

Answer 9

the blood that did not go through the filter continues through the efferent tubule into the PERITUBULAR CAPILLARIES

Question 10

how thick are the renal tubules

Answer 10

1 cell thick - single layer of epithelial cells

Question 11

where do the peritubular capillaries drain into

Answer 11

a venule and then a vein

Question 12

what is the function of the peritubular capillaries

Answer 12

supply tubular cells with nutrients as well as receive any substances reabsorbed from the tubular fluid

Question 13

what are the 4 different segments of the nephron

Answer 13

Bowman’s capsule
Proximal tubule
Loop of Henle
Distal tubule

Question 14

where does the distal tubule empty into

Answer 14

into collecting ducts

originates in cortex but travels down into the medulla where it empties into the renal pelvis

Question 15

what do you call the fluid in the renal tubules

Answer 15

tubular fluid

Question 16

what do you call the fluid in the collecting duct

Answer 16

urine

Question 17

what are the 2 types of nephron

Answer 17

cortical

juxtamedullary

Question 18

how does the juxtamedullary nephron differ from the cortical nephron

Answer 18

Much longer loop of Henle
Has a single capillary instead of a network following the tubule
produces more concentrated urine

Question 19

what is the tubular capillary in the juxtamedullary nephron called

Answer 19

vasa recta

Question 20

how are nephrons arranges in the kidney

Answer 20

in a radial fashion with the loops of Henle pointing down into the medulla giving its striated appearance

Question 21

the diameter of the efferent arterial is wider than that of the afferent true/false

Answer 21

false

the afferent arteriole is wider than the efferent - this is so more blood can come in and be held in the glomerulus to create

if there is contraction of the afferent arteriole there is a change in blood volume in the glomerulus

relaxation of the afferent arteriole increases blood flow into the glomerulus

Question 22

what 3 layers does blood have to pass through to get from the glomerular capillary into the tubular fluid

Answer 22

Capillary endothelial cells
Basement membrane
Podocyte cells

Question 23

what are the 3 layers collectively called (in the bowman’s capsule)

Answer 23

the glomerular membrane

Question 24

what does the glomerular membrane do

Answer 24

works as a molecular sieve letting small molecules through and preventing large ones going through (RBCs and proteins)

Question 25

what is the juxtaglomerular apparatus

Answer 25

specialised cells in the part of the distal tubule where it passes between the afferent and efferent arterioles

Question 26

what specialised cells are found in the juxtaglomerular apparatus and what do they do

Answer 26

granular cells - produce and secrete renin to initiate RAS

Macula dena cells - monitor the amount of salt in tubular fluid as it passes this region

Question 27

what is urine

Answer 27

notified filtrate of blood

Question 28

what are the 3 main processes done to the blood by the kidney to make urine

Answer 28

glomerular filtration
tubular reabsorption
tubular secretion

Question 29

what is tubular secretion

Answer 29

substances being secreted from the peritubular capillaries into the tubule

Question 30

what is reabsorption

Answer 30

molecules going back into the peritubular capillaries from the tubular fluid

Question 31

how do you calculate the rate of excretion

Answer 31

rate of excretion = rate of filtration + rate of secretion - rate of reabsorption

Question 32

what is GFR

Answer 32

glomerular filtration rate

Question 33

how do you calculate the rate of filtration of a substance

Answer 33

rate of filtration = plasma concentration of substance x GFR

Question 34

how do you calculate the rate of excretion of a substance

Answer 34

rate of excretion = concentration of substance in urine x urine production

Question 35

how do you calculate the rate of reabsorption of a substance

Answer 35

reabsorption = rate of filtration - rate of excretion

Question 36

what does it mean if rate of filtration > rate of excretion

Answer 36

a net reabsorption of the substance has occurred

Question 37

what does it mean is the rate of filtration < rate of excretion

Answer 37

a net secretion of a substance has occurred

Question 38

how do you calculate the rate of secretion of a substance

Answer 38

secretion = rate of excretion - rate of filtration

Question 39

what is a normal GFR

Answer 39

125 mms/m