Physiology 1 - Renal

• produces hormones for regulation of circulatory system, formation of RBC, and bone metabolism
• Maintenance:
• regulates composition and volume of body fluids
• adjust to continuously varying conditions by inc/dec/adjusting urine volume, concentration and composition to actual requirments
• only need 1/3 to be functional

• all intake through intestines
• (small amount from metabolic water (camels have a lot)
• somes leaves through lungs as vapor, evaporated off skin, most excreted by kidney

• intake = output
• 2.5 L in = 2.5 L out

• transplantaion
• peritoneal dialysis (inject lots of fluid into abdomen so that high wasteconcentration leaves the blood, fluid can then be drawn out of body)
• dialysis machine
• functions of kidneys becoem apperent when then fail

• accumulation of metabolites - urea, creatinine, uric acid, NH4+,
• disorder of water and electrolyte metabolism - hyperkalaemia (potassium, heart electrial system), hypernatraemia (Na, more in blood volume), hyermagnesaemia, hyerphosphataemia
• hypertension of arterial blood pressure - renin, angiotensin, aldosterone system(increase Na in blood)
• hormonal deficiency - anemia, erythropoietin(produced by kidneys

• retroperitoneal
• protected by layer of fat

triangle in shape

• no pelvis
• lobules

• basic unit for formation of urine
• each kidney contains ~ 1 million nephrons

renal artery - arcuate ateries (form boundary between cortex and medulla - interlobular arteries

• measures NaCl concentration to regulate tubular flow
• causes constriction
• part of DCT next to afferent arteriole
• "control center" - for urine flow and concentration

• 99% fluid filtered into bowmans capsule is reabsorbed by peritubular capillaries
• 1% remains and excreted as urine carrying waste

• 60 mmHg - glomerulus
• 13 mmHg - peritubular capillaries
• 15-25% - cardiac output flow through kidneys
• 1-2% - total renal blood flow through vasa recta

• 18 mmHg - Bowmans capsule
• 0 mmHg - at end of collecting duct

• humna - 180 L per day
• excret only 1 L

• visceral epi (podocytes)
• basement membrane
• capilary endothelium
• fenestrated channels - water passage and noncellular components
• 100 - 500 more permeable than other capillaries

• molecular weight of 5200 - filter like water, inulin
• proteins - almost impermeable
• pores are negatively charged (proteoglycans) reject negative proteins even if smaller diameter than pore
• positive > neutral > negative

• negative charge on membrane is neutralized
• increased protien found in urine
• clinically significant - use test strip to test for protein

• fluid is filtered from blood, processed in tubular system
• Flow speed - highly critical, saturable, directly depends on glomerular filtration rate
• increase speed, decrease amount of time for reabsorption (lost to urine)
• decrease speed, waste backup in blood

rate - fluid volume filtered per min from capillary blood into Bowman's capsule

• filtration rate - blood pressure, oncotic pressure, hydrostatic pressure, and oncotic pressure of ultrafiltrate(normally 0)
• net filtrate = (60-32)-(18-0) = 10 mmHg
• 60 = mean glomerular blood pressureof afferent and efferent arterioles

• increases resistance to blood = decreases blood pressure in glomerulus
• net = 5 mmHg
• decrease in net filtration pressure
• decrease consequently the filtration
• decrease hydrosatic pressure in capsule

• increase glomerular blood pressure
• increase in filtration
• net = 15 mmHg

• increases glomerular blood pressure
• decrease in blood flow
• decrease in filtration (less blood passes through per min)
• increase in blood oncotic pressure
• net = 5 mmHg

• decrease in tubular flow
• extends time for resorption
• increase reabsorption of wastes
• more NaCl causes vasodilation by Macula Densa to increase speed of blood flow

• increase speed of tubular fluid
• decrease time for reabsorption
• valuable nutrients are lost in urine
• Macula Densa senses NaCL and causes constriction to decrease speed by secretion of Renin

excess loss of solutes and water

of

increases retention of waste products

• myogenic reflex
• tubuloglomerular feedback

• increase in arterial pressure streches wall of arteriole b/c of to high of blood flow
• vessels constrict
• increased blood flow returns to normal

• afferent arteriolar vasodilation
• efferent arteriolar vasoconstriction
• juxtaglomerular complex

• when - decrease in tubular flow, NaCl - increase in absorption
• decease in concentration at Macula Densa -

• decrease in concentration
• dilation of afferent arteriole
• increase glomerular filtration pressure
• increase in fluid filtered
• increase in tubular fluid flow

• NaCl - increase in absorption, decease in concentration at Macula Densa
• release of Renin from Macula Densa
• Renin - angiotensin II - constrition of effernt arterioles
• increase in GFR

• short system - angiotensin increases systemic blood pressure (vasoconstrition)
• long system - aldosterone increases blood volume

• E2 and I2
• help maintain renal vascular resistance at normal levels by conteracting angiotensin II

• endothelin
• thromboxane A2
• Angiotensin II

• Nitric oxide
• prostaglandin E2 and I2