excretion Flashcards
excretion
.removing metabolic waste from cells
break down of amino acids in the liver
.amine groups are removed from amino acids
.producing toxic ammonia and organic acids
.ammonia combines with CO2 to form urea via the ornithine cycle
.urea is excreated from liver cells, enters bloodstream and is filtered out the body via the kidneys as part of urine
break down of alcohol in the liver
.alcohol dehydrogenase breaks down ethanol to ethanal
.ethanal is converted into ethanoate
break down of hydrogen peroxide in liver
.catalase splits hydrogen peroxide into oxygen and water
function of liver in regulating blood glucose
.converts glucose into glycogen
.stores glycogen granules in its cells
.releases glucose into the bloodstream
structure of liver
.hepatic artery = supplies oxygenated blood
.hepatic vein = carries away deoxygenated blood towards heart
.hepatic portal vein = brings nutrient-rich blood from intestines
.bile duct transport bile to the gallbladder
kidney structure
fibrous capsule- outer membrane that surrounds and protects the kidney
.renal cortex- outer region that contain bowmans capsule, convoluted tubules and blood vessels
.renal medulla- inner region that contain loops of henle collecting ducts and blood vessels
.renal pelvis - cavity that collects urine into the ureters
ultrafiltration
.blood enters glomerulus via afferent arteriole
.blood leaves the glomerulus via smaller efferent arteriole maintaining high hydrostatic pressure
.high pressure forces water and small solutes out of the blood through pores in the capillary endothelium
.the molecules move through basement membrane which has collagen fibres that prevent large molecules and blood from passing into Bowmans capsule
.molecules move through bowmans capsule epithelium and is collected in the bowmans capsule
what is in the glomerular filtrate
water
salt
glucose
urea
adaptations of the PCT
.microvili to increase SA for reabsorption
.many mito to provide ATP
reabsorption in the PCT
.reabsorbs most glucose, amino acids, ion and 85% of water
.sodium ions are activetly transported into blood capillaries reducing sodium ion conc in epithelial cells in PCT
.sodium ions move from PCT lumen to the epithelial cells down the conc gradient
.sodium ions are co-transported with glucose and amino acids into epithelial cells
.the reabsorbed molecules the diffuse into the blood capillaries
reabsoption in the DCT
.reabsorption of any remaining substances via active transport
.DCT membrane permeability changes to regulate further reabsorption of water and solutes
.regulation of blood pH via selectively reabsorbing certain ions
descending limb vs ascending limb
.descending is permeable to water
.ascending limb is permeable to ions
water reabsoprtion in the loop of Henle
.water leaves the filtrate at the descending limb via osmosis into the interstitial space
.lowest WP of filtrate at the bottom
.water that is lost is reabsorbed into the blood via surrounding capillaries by osmosis
.sodium and chloride ions leave at the ascending limb into the interstitial space at the bottom due to low WP
.conc of ions in interstitial space increase making WP in low
.ions are actively transported out the top of the ascending limb as their conc in filtrate decreases as you go up
.this creates a water potential gradient in the interstitial space
ADH action
.ADH attaches to receptors on the surface of the cells in the DCT
.triggers activation of cAMP which initiates a series of reactions that lead to the phosphorylation of aquapotins
.aquaporin vesicles merge with the plasma membrane
.water moves through aquaporins by osmosis from DCT into interstitial space
.water is reabsorbed into surrounding blood vessels
