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Renal System - Coggle Diagram
Renal System
Components
Kidney
- renal cortex - granular, outer zone
- renal medulla - inner renal pyramids, zones
- parenchyma - pyramids and cortex between pyramids containing cortrical and juxtamedullary nephrons
- renal pelvis - funnel-shaped, continuous with ureter
Vascular Components
- abdominal aorta
- venal artery
- afferent arteriole
- glomerulus
- efferent arteriole
- peritubular capillaries
- renal vein
- inferior vena cava
Tubular Components
- renal corpuscle
- proximal convoluted tubule
- loop of Henle
- distal convoluted tubule
- collecting duct
Functions
Secondary Functions
- blood pressure maintenance
- anaemia correction (produce erythropoietin)
- calcium regulation
- protein catabolism
- detoxification
Primary Functions
- excretion
- acid base regulation
- osmoregulation - total water volume and concentration of solutes within water
- maintains ECF composition by regulating volume, electrolyte composition and osmolarity
Glomerular Filtration
Regulation of Glomerular Filtration
- increase in GFR increases urine concentration and decreases blood volume and pressure
Hormonal Regulation to increase Blood Pressure
- changes to GHP are detected by juxtaglomerular apparatus
- renin released to stimulate RAAS
- angiotensin II - vasoconstrictor, increases reabsorption of sodium and water, stimulates ADH and aldosterone production
- anti-diuretic hormone (ADH) - increases collecting duct permeability for water reabsorption
- aldosterone - activates potassium-sodium pump at distal convoluted tubule and collecting duct to retain more sodium
Hormonal Regulation to decrease Blood Pressure
- atrial natriuretic peptide (ANP) / brain natriuretic peptide (BNP)
- detected by stretch receptors in atria and ventricles
- inhibits ADH and aldosterone secretion
- increased excretion of sodium and water
- increased urine concentration and decreased blood pressure and volume
Autoregulation
- changes to GHP are detected by juxtaglomerular apparatus
- afferent arteriole vasodilation increases glomerular capillary pressure
Autonomic SNS Regulation
- vasoconstriction of afferent arterioles and increased fluid retention decrease GFR
Pressures Associated with Glomerular Filtration
- Glomerular Hydrostatic Pressure - pressure exerted in capillary walls by fluid, influenced by 1) arterial systematic blood pressure, and 2) vascular tone of afferent and efferent arterioles ~55mmHg (higher than other capillaries as afferent arteriole has greater diameter)
- Colloid Osmotic Pressure - pressure exerted by plasma proteins remaining within the blood, pulls fluid towards them ~30mmHg
- Capsular Hydrostatic Pressure - pressure exerted by fluid within Bowman's Capsule against Glomerulus ~inward pressure of 15mmHg
- Net Filtration Pressure = GHP - (COP + CHP) ~10mmHg
Glomerular Filtration Rate (GFR)
- dependent on net filtration pressure, glomerular SA and membrane permeability
GFR = U x V / P
- U = urine creatinine concentration
- V = urine flow rate (mL/min) ~90-120mL/min
- P = serum creatinine concentration
Urine Formation
Glomerular Filtration Rate
- water and solutes move from glomerulus into Bowman's Capsule; cells and proteins are not permeable
Tubular Reabsorption
- selective reabsorption of substances from filtrate into blood in proximal convoluted tubule
**carrier protein saturation causes temporary glycosuria
**90% obligatory water reabsorption and 10% facultative reabsorption when ADH is present
Tubular Secretion
- substances selectively move from peritubular capillaries into renal tubule (waste, drugs, hydrogen, ammonium)
Nephron Composition
- Bowman's Capsule undergoes Tubular Reabsorption; remaining substances move into efferent arteriole and return to renal vein
- blood moves through Nephron to excrete waste; multiple nephrons can drain into one collecting duct)
- afferent arterioles receive oxygenated blood from renal artery and delivers to glomerulus
Miturition
- process of urine expulsion from the body
Miturition Reflex
- filling of bladder - contraction of internal urethral sphincter and inhibiting detrusor muscle
- emptying bladder - contraction of detrusor muscle and relaxation of internal and external uretheral sphincters
Miturition Problems
- sphincter muscle tone loss; decreased prostate affects urinary retention
- decreased functional nephrons - decreased GFR, deteriorised filtration/reabsorption/endocrine functions, nephrons less sensitive to ADH
What is it
- urinary system
- produces, stores and eliminates urine
- composed of kidneys > ureters > bladder > sphincter > urethra
Path of Urine Flow
- urine drains out of pyramids
- minor calyces
- major calyces
- bladder - hollow muscular organ storing urine
detrusor muscle - involuntary longitudinal and circular layers under ANS control (relax for storage, contract for release)
internal urethral sphincter - involuntary ring of smooth muscle tissue at bladder neck maintaining urinary continence
- ureter - muscular tubes transporting urine from renal pelvis to urinary bladder via perastalsis
- renal pelvis
- urethra - urine passage, semen passage in men
- external urethral sphincter - voluntary striated muscle maintaining urinary continence and release
Urine Composition
- pH - 4.5-8
- osmolarity - 500-1200mosmol/day
- volume - 800-200mL/day
- colour - pale, clear yellow
- bacterial content - none
- protein - <25mg/day
- glucose - none