renal physiology

• regulate composition of most of the ECF and plasma ions
• maintain water balance 
• maintain acid-base balance,pH
• excretion of metabolism products/blood born chemicals/foreign compounds 
• production of hormones = erythropoietin(red blood cells) and renin(modulates blood pressure)
• converts vitamin D into its active form 
• regulates calcium and phosphate ions concentration 

• GLOMELUR FILTRATION 
• TUBULAR REABSORPTION 
• TUBULAR SECRETION 
• URINE EXCRETION 

• inferior vena cava 
• abdominal aorta 
• ureter tube collecting urine from the kidneys to the bladder 

• functional unit of the kidney 
•  made of bowmans capsule,proximal tubule, loop of henle, distal tubule, collecting duct 
• vascular compoonent - afferent arteriole,glomerulus,efferent arteriole,peritobular capillaries 

progressive/irreversible loss of kidney structure and function, symptoms only appear after disease becomes well advanced,

symptoms include; dehydration, lack of erythropoietin secretion(RBC),anemia,weakened bones due to lack of vitamin D conversion 

HAEMODIALYSIS 

• blood cleaning outside the body 
• blood reinjected 
• fresh solution constantly being put in 

PERITONEAL DIALYSIS 

• peritoneral cavity space between abdomen wall and abdominal organs 
• artificial kidney used but inside the body 

• afferent arteriole carries plasma to the capillaries of the glomerulus( cluster of nerve endings and vessels at the end of the tubule)
• increase in pressure forces plasma from the capillaries to the bowmans capsule
• filtered plasma enters the proximal tubule 

• liquid substance goes through luminal membrane of the kidney tubular cells 
• liq crosses cytosol of tubular cells 
• crosses basolateral membrane of tubular cells
• crosses interstitial fluid through diffusion 
• goes through peritubular capillaries 

1) PASSIVE 

• follows osmotic gradient, no ATP required 
• Cl, urea 

2)ACTIVE 

• moves against conc gradient, uses ATP
• Na,glucose 

• doesnt occur in descendling limb of loope of henle 
• distial tubule/collecting duct reabsorption depends on hormonal control 
• active sodium reabsorption depends on Na/K ATPase located in the basolateral membrane of tubular cells 
• low intracellular Na and high Na in lateral space maintained 
• too much sodium= no reabsorption= excreted in urine / too little sodium=most/all Na is reabsorbed 
• lack of this system would lead to blood poisining due to accumulation of waste products 

• diabetic disorder 
• kidneys collecting duct dont show increase in water permeability in response to vassopressin causine dilute urine to be excreted 

• average urine made 1.25ml/min
• no water intake=dehydration=dec ECF volume= dec blood pressure 
• too much water intake= excess water = inc ECF volume = inc blood pressure 
• too much salt= hypertension 
• vertical osmotic gradient in the renal medulla enables kidneys to produce urine at a conc of 100-1200 mOsm/litre 
• ascending loop is not permeable to water but reabsorbs Na/Cl
• descending limb permeable to water but no sodium reabsorption 

• hypothalamus, secreted by posterior pituitary 
• when vassopressin reaches capillaries surrounding the nephron 
• binding to vassopressin receptor on collecting duct membrane 
• more water taken in by tubule through water channels on the tubular membrane 
• reabsorption of water into the body
• vassopressin constantly produced producing an isotonic urine of 300mOsm/litre 
• the more hydrated, the less vassopressin produced 

• alcohol inhibits vassopressin production 
• meaning the distial tubule/collecting duct are impermeable to water and its not reabsorbed 
• very dilute urine/dehydration