- Descending loop= simple squmous
- Thin ascending loop = simple squamous
- (impermeable to H2O)
- Thick ascending loop = simple cuboidal or columnar
- (short loop nefrons don't have thin ascending).
= where the ascending limb makes contact with the afferent arteriole serving the renal corpuscle - columnar tubule cells are crowded together
- smooth muscle fibers alongside the macula densa on the wall of the afferent arteriole. They secrete renin.
- juxtaglomerular apparatus - the macula densa and juxtaglomerular cells - regulates BP in the kidneys - regulates renin
output which controls H2
O, Na,& K through the renin/ angiotensin/ aldosterone pathway.