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Glomerular Filtration - Coggle Diagram

- - - - wall consists of 3 layers:
        
        capillary endothelium
        
        basement membrane
        
        visceral epithelium
- - - - Glomerular filtration rate (GFR)
        
        Determined by:
        
        mean net filtration pressure
        
        affected by capillary hydrostatic pressure vs capillary oncotic pressure
        
        permeability of the filtration barrier
        
        selective permeabilty determined by:
        
        Molecurlar radius of substances
        
        Substances with molecular radius of 4nm or more are not filtered
        
        Net electrical charge of a molecule
        
        +vely charged are filtered more freely because attraction to -vely charged glycoproteins that incorporate glomerular basement membrane
        
        Shape and deformability of molecule
        
        long, flexible molecule enters easily
        
        surface area available for filtration
        
        mesangial cells contration reduces surface area
        
        regulated by:
        
        Renal factor
        
        Renal to system to renal
        
        Renin-Angiotensin-Aldosterone System
        
        AT II
        
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        Renin
        
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        Intrarenal
        
        Myogenic reflex
        
        if perfusion pressure is high, autoregulatory myogenic reflex reduces flow to glomerulus by constricting afferent arteriole and vice versa, allow maintenance of GFR despite marked changes on renal blood pressure
        
        Tubuloglomerular Feedback (TGF) involve in single nephron
        
        Involve juxtaglomerular apparatus
        
        Increased glomerular filtration, increased Na concentration in the tubule fluid at macula densa (due to increased tubule fluid flow, reduced NaCl reabsorption at ascending ascending limb, causing increased NaCl concentration available detected by macula densa), increased Na+ reuptake at apical via Na-K-2Cl transporter on macula densa cells, cells is depolarized, cause release of ATP at basolateral side
        
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        to prevent excessive reductions in single nephron GFR
        
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        Endothelium
        
        Releases potent vasoconstrictors and vasodilators
        
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        Systemic factor
        
        On blood volume
        
        Angiotensin II, Aldosterone and Vasopressin, all increase water and solute reabsorption
        
        Atrial natriuretic peptides (produced in cardiac atria) - causes natriuesis (sodium wasting) and diueresis (water wasting), thus reducing blood volume
        
        On vessel tone
        
        Vasopressin and catecholamines (adrenaline, noradrenaline) causes systemic vasoconstriction, increase BP
        
        Beta adrenergic stimulation can activate renin-angiotensin system
        
        Alpha adrenergic stimulation can cause renal vasoconstriction
        
        Vasoconstrictors may cause contraction of mesangial cells
        
        measured by:
        
        in clinical settings, using creatinine as they are freely filtered and not reabsorbed and secreted (at least not in dog) into the urine enabling accurate measurement
        
        Ccreatinine = (UcreatinineV)/Pcreatinine
        
        C is plasma clearance
        
        U is urine concentration
        
        V is volume of urine collected of period of time
        
        P is plasma concentration
        
        GFR are expressed on basis of body weight or body surface area