Renal Physiology Flashcards
Function of kidneys
To filter blood
Protective layers of kidney
Renal fasia, adipose capsule, renal capsule
What is in a lobe
One medullary pyramid, 2 halves of renal columns, and remaining cortex
Where are the papillary ducts and what as their function
Inner end of medullary pyramid. Drains urine into calyx
Location/function of maj/min calyces
Minor first, then major, drain urine from nephrons
Where can a nephron be found
Extending from cortex to medulla and back
Subsection of a lobe
lobules
Av amount of lobes in human kidney
8-12
Renal artery
Supplies
Renal vein
Drains
Visceral glomerus cells
Podocytes
What is inbetween visceral and parietal cells
Urinary space
Difference between proximal and distal convoluted tubule
Proximal takes urine from glomerus, distal provides feedback
Filtration layers between endothelial cells and poocytes
- Fenestrated endothelium
- Basal laminar
- Split membrane
Fenestrated endothelium blocks
RBCs
Basal laminar blocks
RBCs & Large proteins
Split membrane blocks
RBCs & Large & Medium proteins
What makes it through podocyte/endothelium barrier to urinary space
Small proteins
Renal blood pathway
Renal artery - segmental arteries - interlobar arteries - arcuate arteries - cortical radiate arteries - afferent arterioles - glomerular capillaries - efferent arterioles - peritubular capillaries - cortical radiate veins - arcuate veins - interlobar veins - renal veins
Formulae and units of osmolarity
Osmolarity = molarity x dissociation factor (mOsm/L)
150mM NaCl extracellular, 300mM urea intracellular… determine osmolarity
Isoosmotic
Hyper osmotic
Higher osmolarity than comparison
Iso osmotic
Same osmolarity than comparison
Hypo osmotic
Lower osmolarity than comparison
Outline tonicity
Movement of water due to osmolarity
70kg male fluid breakdown
60% mass is fluid (42l)
2/3 intracellular (28l)
1/3 extracellular (14l)
- 20% plasma (2.8l)
- 80% interstitial (11.2l)Excretion =
Filtration + secrection - reabsorption
Function of glomerulus
Filtration of small proteins out, rate of filtration
Change in blood pressure impacts kidneys how
Blood flow remains the same (arterioles) urine production does change
Constriction of glomerulus afferent arteriole
Increased resistance, decreased flow, decreased glomerulus pressure (less filtration)
Constriction of glomerulus efferent arterioles
Afferent arteriole fine, increased prssure prior to constriction (glomerulus) therefore more filtration
NFP=
GBHP - CHP - BCOP
Glomerulus filtration controlled how
BP and sympathetic control of arterioles, angiotensin ll vasoconstrictor, Atrial natriuretic peptide
Atrial natriuretic peptide
Relaxes mesangial cells, more Na+ out so more filtration
Macula cells
Found in ascending loop of henle (distal convoluted tubule) communicates rate of filtration by content of Na+
Compare juxtaglomemedullary and cortical nephrons
Cortical nephrons are in the cortex, juxtaglomemedullary nephrons extend from the cortex into the medullary pyramid
Role of proximal convoluted tubule
Most reabsorption of water and solutes here
60% of total volume
60% of all water and Na+
100% of glucose
Transport level of proximal convoluted tubule
Na+/Glucose symmporter brings both in, glucose diffuses out, Na+ pumped via Na/K atpase, movement of Na+ allows osmosis of water
Role of descending loop of henle
Low permeability to ions, high permeability to water
High osmolarity in interstitial space, water moves out
(300Osmol/L inside vs 1200 outside)
Role of ascending loop of henle
Impermeable to water Cl-, K+, Na+ actively reabsorped Na/K atpase pumps Na+ out Cl- diffuses out Very dilute solution now
Thin loop is _____ Thick loop is ______
Descending, ascending
Association of blood vessels to loop of henle
Descending loop associated with veins, which remove water, ascending loop associated with artery
Role of distal convoluted tubule & collecting duct
Continuation of Na+ & K+ reabsorption
Concentration of urine at bottom of loop of henle
1200mOsmol/L
ADH name and inhibitor
Anti-diuretic hormone, alcohol
Function of ADH
Water retention
Vassopresin
ADH
Function/location of osmoreceptors
Found in upper hypothalamus, tell hypothalamus to release ADH through Posterior pituitary
How does osmoreceptor activate
If blood pressure drops, [Na+] increases, or is osmolarity increases, the cell shrinks and causes an opening of Na+ channels to create AP to hypothalamus
Osmolarity required for release of ADH
280mOsmol/L
Osmolarity required for thirst stimulus
295mOsmol/L
Where does ADH act
Distal convoluted tubule and collecting duct
Pathway of ADH from blood
ADH binds to cell receptor of nephron, second messenger creates aquaporin 2 water pores which fuse to apical membrane allowing water reabsorption
Receptor input to hypothalamus
osmorecpetors and baroreceptors
X change in blood pressure required for ADH release
decrease of 10%
Role of renin angiotensin aldosterone system
salt retention
What do juztaglomerulus cells release
Renin
What causes renin release
Drop in afferent arteriole blood pressure, low NaCl conc, or decreased sympathetic activity
Function of renin
Rate limited step in production of ATll, converts angiotensin to ATl
Function of ATll
Aldosterone release
Vasoconstriction
Sodium and water reabsorption
Stimulate thirst, release ADH
Overall function/location of aldosterone
Sodium retention/reabsorption, comes from cortex of adrenal glands
How does aldosterone work
From adrenal cortex, transcription of Na+/K+ ATPase pumps in collecting duct
Upon haemorrhage…
Loss is isosmotic, so water retention and salt retention needed
Where in nephron is water reabsorbed
Proximal convoluted tubule, descending loop of henle, distal convoluted tubule, collecting ducts
Where is glucose reabsorbed/how
Proximal convoluted tubule, glucose sodium symporter
Where is Na reabsorbed/how
Proximal convoluted tubule, ascending loop of henle, distal CT and collecting tubule, Na+/K+ ATPase and Na+/K+/Cl- symporter in ascending tubule
Alcohol inhibits
ADH
Where is Cl- reabsorbed/how
Ascending loop of henle, Na+/K+/Cl- symporter
