lect 30 & 31: renal histology Flashcards
what type of epithelium is in the thick segments of the loop of henle
simple low cuboidal epithelium
what type of epithelium is in the thin segments of the loop of henle
simple squamous epithelium
describe the cells of the thick ascending limb
have no brush border and more basal vertical striations
what is the main function of the loop of henle
establish the counter-current exchange system which creates the osmotic conditions necessary to pull water out of the distal convoluted tubule and collecting duct in the presence of ADH
What does the ascending thin limb actively pump out and why
chloride ion allowing sodium ions to follow
what is the distal convoluted tubule lined with (epithelium)
simple cuboidal epithelium with smaller cells than those of prox conv tubule
when is the distal convoluted tubule permeable to water
when ADH is present
what is the function of ADH
reduces water loss
what type of epithelium is in the walls of the collecting duct
simple cuboidal epithelium
what are the 2 major specialized cell types associated with the collecting duct
principal cells and intercalated cells
what are the layers of the renal pelvis, ureter and urinary bladder
mucosa
submucosa
muscularis
adventitia
what are characteristics of the mucosa of the renal pelvis, ureter, and urinary bladder
transition epithelium
basement membrane
lamina propriar of FECT
some loose lymphoid tissue and a few smooth muscle cells
what forms the detrusor muscle
layers of smooth muscle in urinary bladder
what are characteristics of the prostatic urethra
secretion of urethra passing through prostate gland
mucosa lined with transitional epithelium
highly vascularized with veins with abundant elastic tissue
what are characteristics of membranous urethra
tall pseudostratified columnar cells but variable
extends through urogenital diaphragm and receives striated muscle cells forming the external sphincter of the bladder
what epithelium is in the cavernous urethra (male)
lined with pseudo stratified epithelium with patches of stratified squamous epithelium
what are lucanae of morgagni
glands in the male urethra that are invaginations of mucous membrane containing single or groups of intraepithelial mucous cells
what are glands of littre
branched tubular glands opening into the lacunae of morgagni
what epithelium lines the mucosa of the female urethra
primarily with stratified or pseudo stratified columnar epithelium with intraepithelial nests of mucous glands
where is angiotensin I primarily produced
in lungs
where does ACE come from
pulmonary and renal endothelium
what does the urinary system consist of
two kidneys and ureters
the urinary bladder and urethra
what is the medullary area divided into
outer medullary area deep to the juxtamedullary cortex
inner medullary area deep to the outer medullary area
what is the functional unit of the kidney
nephron
what is each nephron composed of
renal corpuscle & renal tubule
what is the renal corpuscle composed of
cup-shaped capsule (bowman’s capsule)
glomerulus
define glomerulus
capillary knot situated between 2 arterioles that lies within the indentation of the Bowman’s capsule
what is the renal tubule a continuation of
bowman’s capsule
where do nephrons empty into
collecting ducts
where do collecting ducts empty into
renal pelvis
where are the renal corpuscles of the cortical nephrons located
cortex
where do the glomeruli of the cortical nephrons empty into
capillary networks that surround the proximal and instal convoluted tubules of their nephrons and those of surrounding nephrons
what are the loops of henle like in cortical nephrons
short and do not extend deeply into the medulla
where are the renal corpuscles of the juxtamedullary nephrons located
in the cortex next to cortical-medullary junction
where do the glomeruli of juxtamedullary nephrons empty into
vasa recta consisting of long, straight arterioles and venues that run parallel to the loops of Henle and collecting ducts
what are the loops of Henle like in juxtamedullary nephrons
long and extend deeply into medulla
where is the glomerulus inserted
between afferent and efferent arterioles
where is a typical capillary bed inserted
between arteriole and venule
where does the efferent arteriole feed into
Either capillary loop (vasa recta) or capillary network (peritubular capillaries)
what do juxtaglomerular cells secrete
renin
what is renin
hypertensive factor
what type of muscle cells are at vascular pole of juxtaglomerular cell
circular smooth muscle cells
what is the outer layer of the bowman’s capsule and what type of epithelium is it
parietal layer: simple squamous epithelium
* squamous epithelium is continuous with the simple cuboidal epithelium of the proximal convoluted tubule
what is the inner layer of bowman’s capsule and what is it
visceral layer: inner layer of podocytes in contact with the endothelium of the glomerular capillaries
where is the bowman’s space and what is it continuous with
located between the parietal and visceral layers and is continuous with the lumen of the proximal convoluted tubule
what is the renal corpuscle involved in producing
a filtrate of blood
what are the three processes involved in the formation of urine and where do they occur
filtration (renal corpuscle)
reabsorption (renal tubule)
secretion (renal tubule)
what is the mesangium formed by
mesangial cells embedded in a mesangial matrix
where are intraglomerular mesangial cells located
located between nearby capillaries in the glomerulus and cover endothelium not covered by podocytes
where are extraglomerular mesangial cells located
between the afferent and efferent arterioles at the vascular pole and are associated with the juxtaglomerular apparatus
what are the functions of mesangial cells
contract, phagocytic, proliferative, synthesize, secrete, respond, provide mechanical support and regulate blood flow
how are mesangial cells contractile
utlize cytoskeletal contractile proteins to modify blood flow through glomerular capillaries
how are mesangium cells phagocytic
take up worn out glomerular basal lamina for recycling and also phagocytose immunoglobulins trapped in the basal lamina
what do mesangium cells synthesize
matrix and collagen
what do mesangium cells secrete
prostaglandins and endothelins
what do mesangium cells respond to
angiotensin II
what does endothelia do
causes vasoconstriction of the afferent and efferent glomerular arterioles.
what do cytoskeletal contractile proteins do
modify the blood flow through glomerular capillaries by contracting mesangial cells
what do cytokines induce
inflammatory reactions leading to occlusion of the capillary lumen
what are the components of the juxtaglomerular apparatu
macula densa
extraglomerular mesangial cells
juxtaglomerular cells
what does the macula densa respond to
responds to changes in sodium and chloride concentration in urine and hypotensin
what is the macular densa involved in regulating
involved in regulation of fluid-electrolyte balance and blood pressure regulation
define juxtaglomerular cells
modified smooth muscle cells associated with macula dense and afferent arteriole
what are juxtaglomerular cells innervated by
sympathetic nerve endings which increase renin release
what are the parts of the renal tubule
proximal convoluted tubule descending limb of henle loop of henle ascending limb of henle distal convoluted tubule
what is the distal convoluted tubule continuous with
collecting duct
what are the components of the renal filtration barrier
fenestrated endothelium of glomerular capillaries
fused basal laminae of endothelial cells and podocytes
filtration slits
what does the basal lamina contain
type 4 collagen, fibronectin, laminin, heparin sulfate
what are filtration slits created by
adjacent pedicels of podocytes
how are the pedicels of the filtration slits attached to the basal lamina
via alpha 3 beta 1 integrins
what can and cannot get through the renal filtration barrier
can: water, glucose, and most ions
cannot: proteins and negatively charged molecules
where does the proximal convoluted tubule extend
extends from urinary pole of the renal corpuscle to the beginning of the loop of henle
what type of epithelium is in the proximal convoluted tubule
simple cuboidal epithelium made up of truncated pyramidal cells
what does the proximal convoluted tubule remove
glucose and amino acids
what does the proximal convoluted tubule reabsorb
most of filtrate (including water), most sodium and chloride ions
