urinary system part 2

18問 • 1年前

問題一覧

What 2 types of cells are found in the DCT and functions of each ?

principle cells- have receptors for both antidiuretic hormone (ADH) and aldosterone (to increase blood pressure; part of renin-angiotensin-aldosterone system), intercalated cells- play a role in homeostasis of blood pH

Define glomerular filtration, tubular reabsorption, tubular secretion

glomerular filtration- water and solutes in blood plasma move across wall of glomerular capillaries where they are filtered and move into glomerular capsule and then into renal tubule, tubular reabsorption- the process of returning important substances from the filtrate back to the body (blood), tubular secretion- the movement of waste materials from the body to the filtrate

The body’s entire extracellular fluid volume is filtered how many times per day ?

Describe the filtration membrane

glomerular capillaries and podocytes completely encircle the capillaries to form a leaky barrier

What 3 barriers are present in the filtration membrane ?

glomerular endothelial layer, basal lamina, filtration slit formed by podocyte

What is the main force that “pushes” water and solutes through the filtration membrane ?

glomerular blood hydrostatic pressure (GBHP)

The pressure drives or promotes the process of filtration for GBHP ?

promotes filtration

What 2 forces oppose filtration ?

capsular hydrostatic pressure (CHP), blood colloid osmotic pressure (BCOP)

What is net filtration pressure ?

total pressure that promotes filtration

What happens if the GFR is too high or too low ?

if too high, needed substances may pass too quickly through renal tubules and are not reabsorbed and lost in urine instead, if too low, nearly all filtrate may be reabsorbed and waste products may not be adequately excreted

How is glomerular filtration rate regulated ?

by adjusting blood flow into and out of glomerulus, by altering glomerular capillary surface area available for filtration

Describe obligatory reabsorption

occurs when it is obliged to follow the solutes as they are reabsorbed (L to H), 90% of reabsorption of water filtered by kidneys, occurs in PCT and descending limb

Describe facultative reabsorption

describes variable water reabsorption, adapted to specific needs, remaining 10% of water is reabsorbed this way, regulated by effects of anti-diuretic hormone and aldosterone on the principle cells of the renal tubules and collecting ducts

Explain the sodium-glucose symporter in the PCT

2 Na+ and 1 mol of glucose attach to symporter protein, carries them from tubular fluid into tubule cell, glucose then exits basolaterial membrane and diffuse into peritubular capillaries

Explain the sodium-hydrogen antiporter

carries filtered Na+ down it’s concentration gradient into PCT cell as H+ is moved from cytosol into lumen

Explain bicarbonate buffer

HCO3- is reabsorbed, thereby safeguarding supply of buffer, after H+ is secreted into fluid within lumen of PCT, it reacts with filtered HCO3- to form H2CO3 which readily dissociates into CO2 and H2O

PCTWhich part of the nephron serves as the major site where parathyroid hormone stimulates reabsorption of Ca2+?

PCT

Explain the Na+, 2Cl-, K+ symporter

Na+ actively transported into interstitial fluid at the base and diffuses into vasa recta via sodium potassium pump, 2Cl moves through leakage channels on basolateral membrane into the interstitial fluid and then into vasa recta, K+ is brought in by symporters moves down its concentration gradient back into lumen

lymphatic system part 2

ユーザ名非公開 · 29問 · 1年前

lymphatic system part 2