Aneq 305 final exam

• the function of the excretory system is the maintenance of proper internal levels of inorganic solutes, maintenance of proper plasma water, removal of waste, and maintenance of osmotic balance
• the four excretory organ systems that are involved in homestasis are respiratory systems, digestive system, integument and glands, and renal organs
• the renal organs filter body fluids and regulate water ions and many organic substance, selectively reabsorb and secret these molecules, output of the renal organ is called urine
• the kidney is where the urine is produced and it has many functional components
• ureters facilitate the movement and passage of urine, it carries urine from the kidneys to the bladder
• bladder is temporary storage site of urine
• urethra provides route for urine excretion, and it carries urine from the bladder to the outside.
• the kidneys are the urine-forming organ, the blood is supplied by renal artery and exits via the renal vein
• urine drains into urinary bladder and the bladder empties to the outside through the urethra
• the kidney filters blood, produces erythropoietin and activates vitamin D
• the kidney filters blood by maintaining H2O balance, maintains blood osmolality, regulates ion concentration, maintain plasma volume, contributes to acid-base balance, eliminates metabolic waste production eliminates foreign compounds
• the nephron is the smallest functional unit of the kidney, it is abundant and it consist of vascular and tubule component
• afferent arteriole carriers blood to the glomerulus
• glomerulus is a ball-shaped knot of capillaries site of filtration of the blood
• peritubular capillaries surround the tubules it supplies the renal tissue with the.blood and exchange materials with tubular fluid
• the tubular components of the nephron are the bowman's capsule, the proximal tubule, loop of henle, and distal tubule and collecting duct
• the bowman's capsule collects glomerular filtrate
• proximal tubule is the uncontrolled re-absorbtion and recreation of selected substances
• the loop of henle establishes osmotic gradient in renal medulla, the defending limb plunges into the medulla, ascending limb returns to cortex
• the distal tubule and collecting duct is fluid leaving is urine which enters the renal pelvis
• the juxtaglomerular apparatus is located where the distal tubule passes through fork formed by afferent and efferent arteriole
• granular cells are specialized vascular cells
• macula densa specialized tubular cellular
• granular cells of juxtaglomerular apparatus secrete the hormone renin into the blood in response to fall in Na+, EcF volume or blood pressure
• Renin- angiotensin- aldosterone system (RAAs) is the regulation of plasma Na+ is important for blood pressure regulation , the reabsorption of filtered Na+ is subject to normal control in the nephron
• too much Na+ decrease Na+ reabsorption
• too little Na+ increase reabsorption
• granular cells JGA secrete renin
• renin secretion is increased when granular cells sense a decreased in blood pressure changes within the afferent arteriole, macula dense cells sense a fall in NaCl,
• granular cells are innervated by the sympathetic nervous system; decreased in blood pressure -> increased in sympathetic activity -> more renin released
• once renin is released into the blood it acts as an enzyme
• in blood renin catalyzes conversion of anglotensinogen a circulating protein into anglotensin 1
• angiotensin 1 is converted into angiotensin 2 by angiotensin- converting enzyme (ACE) in the pulmonary circulation
• angiotensin 2 is the primary stimulus for aldosterone recreation from the adrenal cortex
• RAAS stimulates Na+ reabsorption in distal tubules and collecting ducts, elevates blood pressure, stimulates thirst and salt hunger
• the effects of aldosterone is that it increases Na+ reabsorption by the distal tubules and collecting ducts, stimulates secretion of vasopressin which promotes water retention by the kidneys, potent constrictor of systemic arterioles directly increasing blood pressure
• effects of the RAAS is Na+ reabsorption, water retention, vasoconstriction, thirst and salt hunger
• Na + reabsorption is aldosterone increases Na+ reabsorption in the distal tubules and collecting ducts more Na+ in tubules -> Cl- follows passively -> H2O follows by osmosis -> raising blood pressure
• water retention is angiotensin 2 stimulates vasopressin release from hypothalamus and release from posterior -> increase H2O reabsorption by kidney tubules -> increase in blood pressure
• vasoconstriction is angiotensin 2 constricts arterioles -> increase blood pressure