Glomerular perfusion Flashcards
Define renal corpuscle?
Glomerular tuft and Bowmans capsule
Define glomerular tuft?
Convoluted, interconnected glomerular capillaries that protruding into Bowman’s capsule
Where is renal curpuscle?
Kidney
What cells present in renal corpuscle?
Mesangial cells- specialised pericytes
Where are mesangial cells found?
Renal corpuscle
State 4 functions of renal corpuscle?
1) Structural support for capillary
2) Production of extracellular matrix protein
3) Contraction; regulates flow and filtration
tubuloglomerular feedback
4) Phagocytosis of breakdown products
What is bowmans capsule?
What is continuous with it?
Encase glomerulus
Proximal convoluted tubule
What is total glomerular SA?
1m2
Are membranes fenestrated or unfenestrated?
Negative or positive charge?
Fenestrated
Negative charged
Where does filtrate collect?
Bowmans space
What are 2 layers in Bowmans capsule?
Basement membrane
Parietal epithelium cells
What are 3 layers of glomerulus?
Endothelial cells
Basement membrane
Podocytes
What is layer adjacent to capillaries?
Adapted?
Endothelial cells
Fenestrated
Single cell
What sites on top endothelial?
Basement membrane
Fusion 2 bm
Capillary and podocyte BM
Negative charged
What sits on top BM?
Podocytes
Single cell
Foot processes- act filtrate barrier
Function of podocytes?
Act filtrate barrier
Explain myogenic autoregulation?
Location?
Smooth muscle contraction response external stretching force
Occurs capillary walls
What are 2 types autoregulation?
Myogenic
Tubuloglomerular feedback
Explain tubuloglomerular feedback?
Respond sodium chloride conc
High conc NaCl- afferent arteriole constricts- lower
- red BF
Low conc NaCl- afferent arteriole dilates- higher
- build pres
Efferent- after
Afferent- before
Constriction or dilation in response to high NaCl?
What?
Constriction of afferent arteriole
What illicits fast response of tubuloglomerular feedback?
GFR
What illicits slow response of tuboglomerular feedback?
RAAS
What senses Na+ conc lvls?
Macula densa cells
Function of macula densa cells?
Detect Na+ conc lvls
Through NKCC2 transported
Explain process tuboglomerular feedmack?
1) Macula densa cells detect Na+ concentration levels
through NKCC2 transporter
2) Signals through adenosine and nitric oxide to walls of
arterioles, afferent main effected
3) Flow rate high (high Na+)- constriction of afferent
arteriole
- causes GFR to fall
Flow rate low (low Na+)- dilation of afferent arteriole
- causes GFR to rise
4) Reduced GFR and renal blood flow (RBF) increases
sympathetic activity- causes vasoconstriction
5) Increases HR, BP, and CO- shunt blood to muscles
Label
Explain what occurs if high GFR?
1) High GFR- high NaCl load
2) Macula densa detect and secrete ATP
3) Mesangial cells metabolise ATP to adenosine
4) Adenosine stimulate granular cells
5) Afferent arteriole constricts
6) Reduced GFR
Decreased GFR- what occurs afferent arteriole?
Dilate- GFR rises
Increased GFR- what occurs afferent arteriole?
Constrict- GFR falls
What are Na+ conc lvls detected through?
Macula densa cells
NKCC2 transportes
What ns does tubuloglomerular impact?
Sympathetic
What occurs if reduced GFR and RBF? (SYMP)
Sympathetic activity increased
Vasodilation afferent
Increase HR, BP, CO
Shunt blood muscles
What is afferent arteriole?
Function?
Part renal artery
Carry oxygenated blood into glomerulus
What is efferent arteriole?
Function?
Part renal artery
Carry deoxygenated blood, waste
BP- How to increase GFR?
What happens efferent and afferent arteriole?
Efferent- constrict
Afferent- dilate
BP- How to decrease GFR?
What happens efferent and afferent arteriole?
Efferent- Dilate (allow blood escape)
Afferent- Constrict (reduce blood flow)
When does renal perfusion fail?
Above 200mmHg
Below 80mm Hg
To increase GFR?
Afferent and efferent
Constrict the efferent arteriole (build up pressure before)
Dilate the afferent arteriole (builds up pressure after)
