1
Q
cortex of the kidney
A
- outer layer
- filters the blood
- dense capillary network- carries blood from renal artery to nephrons
2
Q
medulla of kidney
A
- lighter
- contains tubules of the nephrons
- forms the pyramids + collecting duct of the kidney
3
Q
pelvis
A
- central chamber
- urine collects before passing out down the ureter
4
Q
bowman’s capsule
A
- cup-shaped structure
- contains glomerulus (tangle of capillaries)
- more blood goes into glomerulus than leaves bc of ultrafiltration.
5
Q
Proximal convoluted tubule
A
- first, coiled region of the tubule after the bowman’s capsule
- in cortex
- substances needed by body are reabsorbed
6
Q
Loop of Henle
A
- long loop of tubule
- creates region with high solute conc in TF in medulla.
- the descending loop runs down from cortex through the medulla to bend at the bottom of the loop
- ascending limb travels back up through the medulla to the cortex.
7
Q
distal convoluted tubule
A
- second twisted tubule
- fine tuning of water balance
- permeability of the walls to water sensitive to ADH in the blood
- ion balance and blood pH regulation .
8
Q
collecting duct
A
- urine passes down the CD through the medulla to the pelvis.
- more fine tuning of water balance (sensitive to ADH)
9
Q
describe ultrafiltration
A
- removal of nitrogenous waste
- osmoregulation in the blood
- glomerulus is supplied with blood from the wide afferent arteriole from the renal artery
- blood leaves through the narrower efferent arteriole
- high pressure in capillaries of glomerulus.
- blood is forced out of capillary wall
- fluid passes through basement membrane
- most of fluid can pass through
- blood cells and proteins with an RAM bigger than 69000 cannot pass due to their size.
- podocytes (wall of BC) act as an additional filter
- have extensions : pedicels.
- pedicels wrap around capillaries forming slits
- slits ensure any large cells, platelets or plasma proteins that made it past the epithelial cells/BM don’t get into the tubule
10
Q
what is the glomerular filtration rate
A
volume of blood filtered through the kidneys in a given time
11
Q
events in the PCT
A
- selective reabsorption
- of glucose and amino acids
- by active transport via co-transporter
- water follows via osmosis down CG
- conc of ions/urea inc
- walls PCT lined with epithelium
- epithelium have microvilli
- large SA for uptake
12
Q
events in the loop of henle
A
- filtrate entering DL is isotonic with the blood,
- water leaves by osmosis into conc tissue of medulla
- water into blood of capillaries down CG
- CG maintained along the DL
- concentrated solution at hairpin (hypertonic to blood)
- Bottom of AL perm to NaCl which diffuse out
- equilibrium is reached
- Na+ is actively pumped out
- Cl- follow down ECG
- walls of AL imperm to water
- water can’t follow by osmosis
- high conc of ions in TF of medulla
- filtrate is dilute and hypotonic to the blood
13
Q
events in DCT
A
- Perm of walls varies with ADH levels
- walls have a lot of mitochondria supplying ATP for AT
- Na+ AT if body lacks salt
- Cl- follow down ECG
- further concentrates the medulla
- water can osmote out
- conc the urine
- blood pH balanced
14
Q
events in the CD
A
- perm of CD controlled by ADH levels
- if ADH present water osmotes out into TF of renal medulla
- urine is more conc
- conc of Na in TF of medulla increases maintaining cg
- urine hypertonic to blood when needed to conserve water.
15
Q
what is fenestration
A
- gaps in capillary endothelial
- where water can be forced out .
16
Q
what is basement membrane made of
A
- collagen fibres
17
Q
how to calc net filtration pressure
A
blood pressure in glomelular - hydrostatic pressure in capsular.
18
Q
what receptor detech blood pressure
A
baroreceptor
19
Q
when your dehydrated how is the water content increased
A
- water potential drops
- detected by osmoreceptors in the hypothalamus
- posterior Pit gland stimulated to release ADH
- more ADH = DCT + CD are more perm
- more water reabsorbed into blood by osmosis
- small vol of highly conc urine
- less water is lost
20
Q
when you are hydrated how does water content reduce
A
- water potential rises
- detected by osmoreceptors in hypothalamus
- posterior PG releases less ADH
- less ADH = CD + DCT are less perm
- less water reabsorbed into the blood by osmosis
- large vol of dilute urine produced
- more water is lost.
21
Q
compare processes in DCT and PCT
A
- both involve co-transporters
- both use AT
- both involve selective reabsorption
- both use Na+
- DCT involves Ca2+
- co transport in DCT involves ions only/PCT uses glucose
- PCT involves ion and molecules (glucose)
