Session 2- Glomerulus Flashcards
Osmolality
Is solute per kg of solvent
OsmolaRity
Number of osmoles of solute per litRe
What is the average GFR
125 ml/min
RBF
Renal blood flow
Flow of blood through renal artery
RPF
RPF = RBF x (1- haemocrit)
How is GFR regulated
• Arterial smooth muscle responds to increases and decreases in vascular wall tension • It contributes to total auto- regulatory mechanism • It is a property predominantly of the preglomerular resistance vessels • Accurate • Interlobular • Afferent arteriole
FF
The filtration fraction - represents the proportion of the fluid reaching the kidneys that passses into the renal tubules
How can you distinguish between the PCT and DCT
PCT has debris within which is the brush border which is the main site of reabsorption
DCT has a large lumen no brush border
What 2 mechanisms are involved in auto regulation
Myogenic mechanism
Tubuloglomerular feedback
What is JXA
Juxtoglomerular apparatus which is the DCT nestled up with the glomerulus this allows the golmerulys to determine what’s going on in the DCT and respond accordingly
What are macular does a cells
Detect ow much NaCl is arriving in the cell
How does the afferent arteriolar respond to increase in BP
Vasoconstriction
This prevents the transmission of high BP to glomerular capillary and maintains normal glomerular capillary pressure which maintains GFR and RBF
How does the efferent arteriolar respond to blood pressure
If BP increases i vasoconstricts to increase GFR
Tubuloglomerular feedback mechanism- High Tubular flow
Macula dense cells of the DCT epithelium detect osmolality or the rate of movement of Na and Cl into the cells.
A signal is ent via the JGA cells triggered by an increase in NaCl conc of distal tubular fluid
ATP is released concerted to adenosine binds with A1 receptor o afferent arteriolar
Further vasoconstriction of th smooth muscle of the adjacent afferent arterioles and therefore decreased RPF which decreased GFR
Tubuloglomerular feedback mechanism - low BP
Release prostaglandins- attenuate constriction of afferent arteriolar
Renin released by JGA cells.
RENIN causes the release of angiotensin 2 which acts om efferent arteriole and causes vasoconstriction
what stimulates renin release
stimuli responsible for release -sympathetic nerve stimulation -decease stretch of afferent arteriolar -signals generated by macula densa cells in response to decrease in NaCl delivered