Excretory System Flashcards
urinary artery vs vein:
Artery: blood supply to kidney
Vein: blood supply away
Functional unit of the kidney
Nephron
part of the nephron located in the renal cortex:
What is its role?
Renal corpuscle
- filters blood from afferent arterial, diffusion to glomerular capillaries of bowman’s capsule
- Reabsorb substances back into peritubular capillary
- Secrete substances back into corpuscle
- Out towards` urinary excretion
Part of nephron located partially in cortex and medulla:
- how does it extend
Renal tubule: cortex, deep into medulla, back up into cortex
- Filtrate travels through until reaching the collecting duct for drainage
Pathway of urine:
- renal corpuscle > renal tubule > collecting duct > medullary pyramids > minor and. Major calyx > renal pelvis > ureter > urethra
Control of urine release from the body:
Internal and external urethral sphincters
- internal: smooth, autonomic control
- external: skeletal, voluntary control
What soluble mixture is called and includes and occurs by:
Filtrate
- water, salt, vitamins, glucose, amino acids
NOT: proteins, blood cells
Occurs via hydrostatic pressure
Parts of the renal tubule
Proximal convoluted tubule (PCT): reabsorb small nutrients, glucose in large quantities (virtually all)
Loop of Henle: descending and ascending > retention of water and solutes (sodium)
- reduce volume of urine without change concentration
Distal
Overall:
- adjust volume filtrate, reabsorbs valuable nutrients, expels waste
What is hypertonicity? And what part of the nephron is hypertonic?
Solute rich: more concentrated?
- Medulla > cortex hypertonicity
- mostly Sodium
Descending vs Ascending loop of Henle:
Descending: permeable to water but not ions
- water down concentration gradient > vasa recta
Bottom of loop: very concentrated
Ascending: permeable to ions (na/K) - but now after
- ions out to vasa recta
- active transport required the higher up the ascending limb
opposite direction of filtrate and blood in loop of henle is defined as:
- what direction is each
Countercurrent multiplier system
- filtrate down loop of henle
- blood up the vasa recta
Part of the nephron where ADH works to reabsorb what?
Collecting duct, promote water reabsorption
Ions, urea, and water are reabsorbed in this part of the nephron:
- this effectively does what
Collecting duct: reduces filtrate volume and increases osmolarity
This hormone acts on what part of the nephron(s) to promote reabsorption of sodium?
Aldosterone:
- acts on collecting duct and DTC
This hormone works to reabsorb calcium in what part of the nephron?
PTH in the DTC
How does ADH influence osmolarity?
- works on collecting duct
- promotes aquaporin insertion to reabsorb water
- Thus promotes water retention > reduce osmolarity
Osmolarity = solute (ions) / solvent
- incr solvent without changing solute reabsorption will decr osmolarity
How does excretory system regulate blood pH?
- reabsorb/excrete H+ protons in the urine
- Sodium proton exchanger
What is the structure of urea? How is urea created?
(NH2)2C=O
- carbo containing carrier of excess amine groups
- Ammonia is byproduct of protein breakdown > liver convert ammonia to urea
Kidney failure during severe dehydration is most likely due to:
Inadequate blood volume for effective filtration
- Dehydration reduces filtrate through nephrons of kidney
- fluid volume drastically reduced, kidney unable to effectively do job of filtering and maintaining homeostasis and bodily fluids
In the tropics, someone without sweat glands is more likely due die of heat stroke. What about vasodilation might cause this?
- Rely solely on vasodilation, radiation of heat, to respond to elevated external temperatures
- radiation alone is ineffective
- may actually gain heat by absorbing radiation from the sun, leading to further elevation in body temp
What will osmolarity look like if someone is dehydrated?
Blood and urine osmolarity would be similar
