Lecture 28: Kidneys Flashcards
adrenal glands also called
suprarenal
outer part of kidney is
cortex
what is the medulla
cortex and pyramid
what separates diffferent pyramids
the columns
where do the artery vein and ureter meet
hillum
what does the ureter divide into
major and minor calyces
what is attached to each minor calyce
medullary pyramid (medulla delimited by extensions of cortex)
purpose of kidneys (basic)
filter blood and produce urine
three things urine formation involves
filtration, secretion, reabsorption of fluid by renal corpuscles and tubules
how much fluid filtered daily vs how much urine produces
180 L filtered, 1-2 liters of urine produced
function of kidneys (more specific)
1- remove metabolic waste products, foreign substances, and drugs.
2- regulate vol and composition of water and electrolytes in extracellular fluid
3- control acid base balance
what do kidneys synthesize
1) renine (regulation of arterial blood, ENDOCRINE)
2) erythropoietin (stim erythrocyte production in bone marrow ENDOCRINE)
3) convert vit D into active form for calcium balance
4) glucogenesis to make glucose from AA during starvation
what is a nephron
functional unit of kidney
how many nephrons per kidney
1 million
what is the nephron composed of
renal corpuscle, proximal convoluted tubule, loop of Henle, distal convoluted tubule
renal corpuscle
bowman’s capsule and glomerulus
bowman’s capsule
parietal layer, visceral layer (podocytes) and bowman’s/urinary space
glomerulus
tuft of capillaries supported by the mesangium (mesangial cells and ECM)
loop of henle
thick descending limb (of proximal tubule) + thin limbs + thick ascending limb (of distal tubule)
what does the nephron NOT include
collecting duct- different embryologic origin but functionally connected to nephron and VERY important
where do nephrons originate
cortex at the renal corpuscle
where is the thickest part of the ascending limb
macula densa (contact point of arterioles entering the flomerulus)
what do the connecting tubules connect to on both sides
distal convoluted tubule and collecting duct
what does the collecting duct do
transport urine to calyx
the visceral layer of bowmans is composed of
modified epithelial cells called podocytes
what vessel supplies the glomerulus and ddrains it
afferent glomerular arteriole and drained by efferent
describe the path into the kidney
renal artery to afferent arteriole to capillaries (located in glomerulus and surrounded by mesangium)
describe the path out of the kidney
capillaries to efferent arteriole to capillaries surrounding tubules OR vasa recta wrapping around loop of henle in medula to renal vein
what does podocyte cytoplasm contain
actin filaments, lysosomes, and microtubules because it has contractile and phagocytic functions
FORM PART OF GLOMELULAR BM
what do podocyte primary foot processes give rise to
secondary foot proesses that rest on GBM and form filtration slits
function of mesangium
mechanical support for glomelular capillaries
Structural relationship of mesangium and glomerular capillaries
The capillary wall is deficient in BM at the site of attachment to the measngium, and the endothelial cells lie directly on the masangium.
mesangial cells specific function
1) matrix production (support glomeular cap)
2) contractile (impact filtration)
3) vasoactive substance (endothelins induce constriction of afferent and efferent arterioles)
4) phagocytic (immune complex)
5) proliferative (in glomelular disease)
cells in PCT vs DCT (Shape)
both simple cuboidal but proximal has brush border and a ragged luminal border
LM cytoplasm and nuclei in PCT vs CT
PCT: cytoplasm is eosinophilic and nuclei is central or near base
DCT: cytoplasm is pale, nuclei is towards the lumen
LM nuclei number and cell border in PCT vs DCT
PCT = fewer nuclei per tubular XS and indictinct cell borders DCT = more nuclei per XS and cell borders are more distinct
what absorbs 80% of ultrafiltrate
apical surface microvilli
what do microvilli membranes do
transport proteins for transporting Na+, amino acids, and glucose into the cell
what do endocytic vesicles and lysosomes do
absorption and degratation of filtered proteins
what do BM plasma membranes do
Na K ATPase pump for active transport of sodium. AA and glucose also transported out of the cell
what do mitochondria do
energy production for active transport
function of BM plasma membrane infoldings in DCT
NA K ATPase pump for active transport of Na from tubular fluid to renal interstitium
what hormone mediates active transport of sodium
aldosterone secreted by adrenal cortex
what do thin limbs of loop do
generate potential to concentrate urine
what does vasa recta contain
blood that has been filtered through the glomerulus
what does the vasa recta do
provide nourishment and oxygen to medullary tissue
collecting duct function
reabsorption of water from the ducts - controlled by antidiuretic hormon (ADH, vasopressin) from posterior pituitary
justaglomeular apparatur is involved in
regulation of systemic blood pressure via renin-angiotensin-aldosterone system
JG apparatus composed of
macula densa of DCT
JG cells (renin producing, protease)
Extragolmerular mesangial cells (lacis cells)
where are JG cells found and what kind are they
modified smooth muscle in afferent arterioles containing renin but a few may be present in efferent
is kidney endocrine or exocrine
endocrine
exrectory passage
calyces, renal pelvis, ureter, urinary bladder, proximal urethera
urinary bladder function
conduit of urine
urinary bladder characteristics
impervious to water, resistant to bacteria, stretch to cover varying size of bladder (the cells do), there are plaques also btu we dont know why might just be for membrane strength and impermeability
