9.9 osmoregulation and temperature regulation Flashcards
what is deamination?
the removal of the amino group from excess amino acids that is converted into ammonia and then urine
where does deamination take place?
in the liver
why can we not store ammonia?
very toxic and highly soluble
what are the two main functons of the osmoregulatory role of the kidney?
- ultrafiltration
-selective reabsorption
what are the tubules in kidneys called?
nephrons
where does ultrafiltration take place?
glomerous and Bowman’s capsule
how is high pressure created in the glomerous?
same volume of blood passes through the afferent and efferent arterioles that have different size lumens
what happens during ultrafiltration?
1- under high pressure, plasma and much od it’s content is forced out of the endothelium of the glomerous
2- it passes through a basement membrane which filters out molecules based on size and charge
3- basement membrane is made of collagen and glycoproteins
what are podocytes?
specialised cells of the Bowman’s capsule that have projections that wrap around the glomerolous, between projections are filtrations slits which allow more filtrate to pass
what three layers does the filtrate have to pass through to get to the nephron?
- endothemium of the glomerous
- basement membrane (filter)
- the epithelium of the podocyte
what does the filtrate contain?
- water
- salts (Na,Cl,K)
- small amino acids
- glucose
- urea
what does not pass into the filtrate?
- blood cells
- large plamsa proteins
- polypeptides
what does the proximal convulated tubule selectively reabsorb?
- most of the water
- some of the salts
- all the glucose and amino acids
what are the adaptations of the proximalk convulated tubule?
-thin walls
- microvilli
- abundance of mitochondria
- tight junctions
how does selective reabsorbtion in the proximal convulated tubule happen?
1- sodium-potassium pumps in the basal membrane moves sodium ions out of the epithelial cells and into the blood
2- this lowers sodium concentration in epithelial cells, causing others in the filtrate to difuse down the concentration gradient through co-transporter proteins
3- these proteins transport a sodium ion and another solute (glucose or amino acid) this is secondary active transport
3- water moves by osmosis from the filtrate to the blood due to lower water potential
5- a few proteins are taken back into the blood by pinocytosis
what occurs in the loop of Henle?
osmoregulation