Renal Histology Flashcards
What is the cortex of the kidney?
the outer granular part
What is the medulla of the kidney?
the inner striated part - comprised of pyramids
What vessels mark the boundary between the cortex and the medulla?
arcuate vessels
Where do the interlobular vessels project into?
the cortex
Where do the interlobar vessels project into?
the medulla
How many nephrons are there in the kidney?
0.5-1.5 million
What are the two types of nephrons in the kidney?
cortical and juxta-medullary
What are mesangial cells?
pericytes around capillaries in the kidney that support and control filtration
What are podocytes?
forms the inner layer of Bowman’s capsule that covers the surface of capillaries with interdigitating processes - visceral epithelial cells
What is special about the capillaries in the kidney?
they are fenestrated
What provides the filtration barrier?
thick basal lamina and a slit membrane between the foot processes of the podocytes
What is the histological structure of the proximal tubule?
simple cuboidal epithelium with a brush border and a folded basolateral membrane
What is the histological structure of the thin walled loop of Henle?
squamous epithelium
What is the histological structure of the distal tubule?
simple cuboidal epithelium with no brush border and even more mitochondria than the proximal tubule
Where are the macula densa?
on the distal tubule where it passes by the afferent and efferent arterioles
What does the macula densa look like histologically?
nuclei of the cells are very condensed and lined in a row
What is the histological structure of the collecting duct?
simple cuboidal epithelium that becomes columnar - not as convoluted as the tubules so can see a longer lumen on sections
What are the vasa recta?
capillaries that envelope the tubules
What is the structure of the ureter?
smooth muscle tube lined by transitional epithelium - lumen is usually unevenly shaped
What is the nerve control of peristalsis in the ureter?
autonomic
What is the structure of the bladder?
disorganised layers of smooth muscle around transitional epithelium
What is the nerve control of the smooth muscle in the bladder?
autonomic
What is the nerve control of the bladder sphincter?
voluntary
What is transitional epithelium?
It is stratified epithelium that looks either squamous (when bladder is full) or columnar (when bladder is empty)
What is inserted into the transitional epithelium in bladder distension?
membrane ‘plaques’
What is the permeability of the transitional epithelium?
non permeable - tightest junction of any epithelium in the body
What epithelium is in the urethra?
transitional epithelium and then stratified squamous
What type of muscle surrounds the urethra?
smooth muscle and striated muscle
