Compendium 7 Flashcards

Question

Functions of renal system

Answer 1

``` Excretion Regulate blood volume and pressure Solute concentration of blood Extracellular pH Red blood synthesis Vitamin D synthesis ```

Answer 2

Filtration Tubular reabsorption Tubular secretion

Answer 3

Movement of fluid derived from blood flowing through glomerulus and filtration membrane Substances moved across membrane into bowmans capsule to be filtered and fluid is now called filtrate Filtrate contains: water, glucose, amino acids, urea, irate ions, creatinine, some ions Driven by pressure

Answer 4

The part of cardiac output that passes through the kidneys | Varies from 20-30% in a healthy resting adult

Answer 5

Amount of filtrate produced each minute (~180L/day) 99% filtrate reabsorbed Filtration membrane so important as it allows vital molecules (red blood cells, large molecules) can stay in body transport O2 and toxins can be removed

Answer 6

Smooth muscle cells of wall of afferent arteriole are called juxtaglomerular cells Specialised tubule cells form distal convoluted tubule called MACULA DENSA These secrete RENIN that can travel through blood to act on proteins and organs to reduce urine volume

Answer 7

Return of water, small molecules and ions into blood (amino acids, ions, sugar) - most reabsorption Occurs in renal tubules Low pressure in capillaries allows for flow of substances from tubules (high to low pressure) to capillaries then into renal vein for circulation Contains 2 surfaces: Apical- out of nephron lumen Basal- into blood

Answer 8

SYMPORT- active movement Na across basal membrane linked to reabsorption of most solutes Basal membrane = potassium sodium pumps that move Na so it has high conc. in filtrate and now conc. in nephron cell Na wants to move from high to low, so will move across apical surface Glucose piggybacks and comes in with Na (symport) and is moving up its conc gradient from low conc. in filtrate to high in nephron cell Glucose now high conc in cell and wants to move to low conc. so binds to specific carrier molecules so it can cross basal surface via facilitated diffusion into interstitial fluid whereby it is picked up by capillaries to be returned to blood

Answer 9

Example: movement Na with Ca - they move in opposite directions Na with conc. gradient, Ca against conc. gradient

Answer 10

Proximal convoluted tubule

Answer 11

Reabsorption water and some solutes Reduces filtrate down to 20% Thickness/thinness and osmotic gradient of tube determines what transport mode

Answer 12

Little reabsorption as under normal control by anti-diuretic hormone ADH makes walls more permeable to water so water moves out of filtrate back in to body = small amount of concentrated urine Reabsorption water via osmosis Sometimes ion reabsorption via active transport and symport Coffee and alcohol are diuretics so urine is passed more frequently as less water reabsorbed by kidneys --> too much leads to dehydration as more water lost than what is being taken in

Answer 13

Movement of non filtered substances, toxin by products of metabolism, drugs or molecules not normally produced by body into nephron for excretion Occurs mainly in distal convulted tubule Can be active or passive Ammonia, penicillin, H, K often secreted

Answer 14

1% filtrate becomes urine , 1-2 L per day Dilute or concentrated depending on body's needs (ADH or renin) 95% water, 5% wastes (urea, ammonia, uric acid, H, K, creatinine, bile, drugs, toxins) Hydrated body = small amount concentrated urine Very hydrated = produces large amounts of dilute urine

Answer 15

Bladder capacity is 1L Elimination of urine Full bladder activates receptors in smooth muscle which sends message to CNS Brain voluntarily controls external urinary sphincter When sphincter relaxes = urination