Homeostasis Flashcards
What factors need to be controlled in the body?
> PH
Body Temp
Blood glucose
W.P
What happens if PH isn’t controlled?
> Enzymes control reactions in cells if its too low of high the enzyme will denature
What happens if Body temperature isn’t controlled?
too low - kinetic energy for the E-s complexes, too high debature tertiary structure of AS
What happens if w,p isn’t controlled?
too high or low causes osmosis which causes cell to burst of shrivel
Filtrate =
the fluid that gets pushed out of the blood in the glomerulus into the Bowman’s capsule during ultrafiltration.
After the filtrate leaves the Bowman’s capsule, where does it go?
it travels into the PCT, where the body reclaims useful stuff.
What happens to the proteins that stayed in the blood during the formation of the glomerular filtrate?
Proteins just keep flowing in the blood and eventually rejoin circulation—nothing happens to them inside the nephron because they never left the bloodstream in the first place.
If proteins are found in the urine, it usually means
there’s a problem with the glomerulus—specifically, the filtration barrier is damaged.
how is water reabsorbed in the DCT?
> The filtrate arrives at the DCT from the loop of Henle -> has water in it (dilute)
As blood flows through the brain, the hypothalamus moniters water potential
if water content is to low, then ADH secreted from pituitary gland -> kidney then re-absorb more water
If converse then less ADH is released to ensure less water is reabsorbed
remaining water in the collecting duct becomes urine
How is the glomerlurar filtrate formed?
> Blood enters afferent arteriole -> efferent narrower -> lower hydrostatic pressure -> forces small things (e.g water + amino acids) out through Bowman’s capsule wall
Large things like proteins remain
How does reabsorption of glucose and water by PCT?
> AT transport of Sodium ions into blood, this lower concentration of Na+ in epithelial cells, allows Na+ ions to move from the lumen into epithelial cells by facilitated diffusion, joining with glucose to move through co-transporter proteins
Glucose and amino acids diffuses from epithelial cells into blood
W.p gradient created water diffuses in and diffuses across to the blood
How is the sodium ion gradient maintained in the Henle loop?
> ascending limb: This limb is impermeable to water
Na⁺ are actively pumped out into the surrounding medulla -> This makes the medulla salty.
This limb is permeable to water, lower water potential -> water leaves the descending limb by osmosis into the salty surroundings.
“Countercurrent” = flow in opposite directions.
