Urinary system

Question 1

sources of heat gain during exercise

Answer 1

convection, conduction, thermal radiation, solar radiation, metabolic heat production

Question 2

heat loss during exercise

Answer 2

convection, respiratory evaporation, radiation, sweat evaporation, conduction

Question 3

main role of kidneys

Answer 3

conserve body water and electrolytes during periods of increased loss
they process the plasma portion of the blood by removing and adding substances from it

Question 4

roles of kidney

Answer 4

removes waste products, eg urea and foreign chemicals
Regulate total body water, salts and acid base balance . excrete just enough water and salts to maintain homeostasis
* Involved in gluconeogenesis (e.g. during fasting, the kidneys
produce glucose from amino acids that is released into the blood)
* Release hormones that regulate blood pressure (e.g. renin) and
EPO (increases number of red cells)
* Produce an active from of Vitamin D that influences calcium
balance and promotes strong, healthy bone

Question 5

what are the 2 types of nephron

Answer 5

Juxtamedullary
cortical

Question 6

cortical nephron

Answer 6

primarily in renal cortex
These represent the majority of the kidney nephrons
Corpuscle located in outer cortex
Henle’s loops do not plunge deep into the medullar

Question 7

Juxtamedullary nephron

Answer 7

spans renal cortex and medulla
fewer
Renal corpuscle close to cortical-medullary junction
Henle’s loops plunge deep into the medullar
Generate osmotic gradient for water reabsorption

Question 8

2 main components of nephron

Answer 8

renal corpuscle (glomerulus and bowmans capsule)
tubule

Question 9

sequence through the nephron

Answer 9

afferent arteriole–>renal corpuscle–>efferent arteriole–>proximal convoluted tubule–>proximal straight tubule–>descending limb of loop of henle–>thin segment of ascending limb–>thick segment–>distal convoluted tubule–>cortical collecting duct–>medullary collecting duct–>renal pelvis

Question 10

components of glomerulus

Answer 10

glomerular capillaries surrounded by visceral layer of bowmans capsule (podocytes)

Question 11

components of podocytes

Answer 11

filtration slits
fenestrae
extensions

Question 12

Blood in the glomerular is separated from fluid in Bowman’s space by a filtration
barrier consisting of three layers

Answer 12

Single cell lining of the capillary endothelium
Non-cellular protein-rich layer of basement membrane
Single cell lining of the Bowman’s capsule

Question 13

peritubular capillaries

Answer 13

supply nephron with its own blood
form veins for blood to leave kidney

Question 14

macular densa

Answer 14

component of distal convoluted tubule
contains sensors that detect changes in blood composition at renal corpuscle

Question 15

Juxtaglomerular cells

Answer 15

in afferent arteriole they function as baroreceptors
component of distal convoluted tubule
secrete renin which influences the formation of ANGIOTENSIN 2 which is a hormone that controls blood pressure (vasoconstriction and sodium/water retention)

Question 16

renal control of blood pressure (increase)

Answer 16

stimuli to kidney to release renin
liver produces angiotensinogen
renin (enzyme) converts angiotensinogen into angiotensin 1 and angiotensin converting enzyme converts this inactive form into angiotensin 2
which causes vasoconstriction and causes release of aldosterone which causes Na+ and H2O retention, both leading to an increase in blood pressure

Question 17

3 distinct
inputs to juxtaglomerular cells
that increase renin secretion

Answer 17

Renal sympathetic nerves (increase activity when low plasma volume)
intrarenal baroreceptors (decrease in pressure)
Macula densa (decrease in glomerular filtration rate, decrease NaCl delivery to macula densa)

Question 18

hypotonic solution

Answer 18

lower concentration of non-penetrating solute compared to normal extracellular fluid

Question 19

hypertonic solution

Answer 19

have a higher
concentration of nonpenetrating
solutes compared to normal
extracellular fluid.

Question 20

osmotic regulation with vasopressin, eg excess water ingested

Answer 20

decrease in body fluid osmolarity, decrease in firing my hypothalamic osmoreceptors, decrease in vasopressin secretion, decrease in plasma vasopressin, decrease in tubular permeability of collecting ducts to water, decrease in water reabsorption, increase in water excretion

Question 21

volume regulation with vasopressin, eg decrease in plasma volume

Answer 21

decrease in pressure (of arteries, veins, atrius), increase in vasopressin secretion

Question 22

glomerular filtration

Answer 22

filtration of
plasma from glomerular capillaries into the
Bowman’s space
glomerular filtrate)
The filtrate is cell free and, except for
large proteins, contains all the substance
in virtually the same concentrations as in
plasma – “ultra-filtrate”

Question 23

forces involved in glomerular filtration

Answer 23

glomerular capillary blood pressure (favours)
fluid pressure in bowmans space (oppose)
osmotic force due to proteins in plasma (oppose)

Question 24

decrease GFR

Answer 24

dilate efferent arteriole
or
constrict afferent arteriole
(controlled by neural and hormonal input)