Finals (1st year 1st sem)

• The kidneys regulate blood volume and composition, help regulate blood pressure, synthesize glucose, release erythropoietin, participate in vitamin D synthesis, and excrete wastes by forming urine.
• The ureters transport urine from the kidneys to the urinary bladder.
• The urinary bladder stores urine.
• The urethra discharges urine from the body.
• There are two types of acidosis: respiratory acidosis and metabolic acidosis.
• Acidosis occurs when pH of blood falls below 7.35.
• More H+ is secreted into urine when pH is decreasing and less H+ is secreted into urine when pH is increasing.
• Alkalosis occurs when pH of blood increases above 7.45.
• Kidneys secrete H+ into urine and directly regulate pH of body fluids.
• The kidneys are a major organ of the urinary system, bean-shaped and weigh 5 oz (bar of soap or size of fist), located between the 12th thoracic and 3rd lumbar vertebra, retroperitoneal and partially protected by the eleventh and twelfth pairs of ribs.
• The kidneys regulate blood ionic composition, which includes sodium ions (Na+), potassium ions (K+), calcium ions (Ca2+), chloride ions (Cl-), and phosphate ions (HPO42-).
• The kidneys regulate blood pH by secreting H+ and reabsorbing HCO3-.
• The kidneys regulate blood volume through the RAAS system.
• The kidneys regulate blood pressure through the RAAS system.
• The kidneys maintain blood osmolarity through water and electrolyte reabsorption.
• Filtration stops when hydrostatic pressure drops to 45.
• Three mechanisms that alter the GFR are Renal Autoregulation, Neural Regulation, and Hormonal Regulation.
• Renal Autoregulation involves two mechanisms: Myogenic mechanism and Tubuloglomerular Feedback.
• Angiotensin II constricts both the afferent and the efferent (reduces renal blood flow and GFR).
• Myogenic mechanism in Renal Autoregulation is when an increased blood pressure increases entry to the glomerulus, causing smooth fibers to stretch and triggering a contraction of the arteriole, narrowing the lumen and decreasing GFR.
• Tubuloglomerular feedback in Renal Autoregulation is mediated by the macula densa cells, providing feedback to the glomerulus.
• Increased blood pressure in Tubuloglomerular feedback leads to an increase in blood flow, allowing PCT to reabsorb essential materials (Na, Cl, water) before they reach the macula densa cells.
• Atrial Natriuretic Peptide (ANP) is released when the atrium is stretched, increasing GFR.
• Neural Regulation involves the kidneys being supplied with sympathetic ANS fibers that release norepinephrine, causing vasoconstriction in the afferent arteriole and decreased GFR.
• Glomerular Filtration Rate is the amount of blood filtered by the kidneys, measured in milliliters per minute.
• Even with an increased blood pressure, GFR and net filtration rises very little.
• Nearly constant at 80 – 180 mmHg.
• Hormonal Regulation involves two hormones: Angiotensin II and Atrial Natriuretic Peptide (ANP).
• Regulation of GFR involves adjusting blood flow into and out of the glomerulus and altering the glomerular capillary surface area available for filtration.
• The kidneys produce hormones such as Vitamin D and Erythropoietin.
• The kidneys regulate blood glucose level through gluconeogenesis and if glucose exceeds the renal threshold, it will begin to appear in the urine.
• The kidneys excrete wastes and foreign substances that have no useful function in the body, such as ammonia, urea, bilirubin in the form of urobilin, creatinine, uric acid.
• The kidneys have an external anatomy that includes a bean-shaped body that weighs 5 oz (bar of soap or size of fist), located between the 12th thoracic and 3rd lumbar vertebra, retroperitoneal and partially protected by the eleventh and twelfth pairs of ribs.
• The filtration membrane is leaky due to fenestrations (holes), containing mesangial cells, which are contractile cells that help regulate filtration.
• The kidneys have an internal anatomy that includes the renal cortex, which is superficial, light red, and the renal medulla, which is deep, darker reddish-brown.
• The collecting duct empties into calyces, carrying fluid from the cortex through the medulla.
• Glomerular Filtrate is the fluid that passes across the filtration membrane.
• Any change in the three pressures (Glomerular Hydrostatic Pressure, Capsular Hydrostatic Pressure, and Blood Colloid Osmotic Pressure) will affect GFR.
• The distal tubule is a structure between the Loop of Henle and the collecting duct.
• A decrease in oncotic pressure results in fluids escaping the capillaries, increased interstitial fluid, and EDEMA.