Renal Structure Flashcards
Renal capsule directly covers…
kidney
Renal capsule is composed of connective tissue that divides into 2 layers:
Fibroblast/collagen outer layer and myofibroblast inner layer
Renal cortex is mainly composed of…
fibroblast
Renal medullary is mainly composed of…
fibroblast,macrophages,pericysts and insterstitial cells
Renal medulla is composed of 8 to 10 coned shapped masses called…
Renal pyramids
The base of each pyramid originates at the border between …
cortex and medulla and terminates at the papilla (aka renal pelvis)
Renal blood supply starts with …
renal arteries
Renal circulation constitutes of two capillary beds…
what are those capillaries?
Glomerular and peritubular capillaries
Peritubular capillaries
-surround renal tubules
-have low hydrostatic pressure (fluid moves from the outside to inside capillary)
-favors reabsorption
Glomerular capillaries
-have high hydrostatic pressure
-fluid moves from the inside of capillary to the outside
-favors filtration
Nephron
functional unit of the kidney
Uriniferous tubule
highly convuluted structure that modifies the fluid passing to form urine
Nephron doesn’t include…
connecting duct
Nephron branches into…
renal corpuscle
proximal tubule
loop of henle
distal tubule
connecting tubule
connecting tubule
short minor part linking nephron to collecting duct
Filtration barrier mediates passage of…
proteins,molecules we don’t need
Basal lamina consists of 3 layers:
lamina rara externa
lamina densa(thick layer)(consists of collagen type IV)
lamina rara interna
Epithelial cells that become modified to perform filtering function are called
podocytes
Podocysts manufacture …
glomerular endothelial growth factor
Pedicels have a well developed glycocalyx composed of …
negatively charged sialoproteins, which form an electrostatic repulsion that contributes to the formation of the filtration barrier
alfa 3 and beta 1 intergrins in plasmalemma help them to …
adhere to the basal lamina
Filtration slits are..
are spaces that remain between adjacent pedicels after interdigitation
Filtration slits are covered with a thin…
flitration slit diaphragm
flitration slit diaphragm extend between neighboring pedicels and act as a …
filtration barrier
sllit diaphragm of two neighboring pedicels bind to each other via…
extracytoplasmic moieties of the transmembrane proteins nephrin
Slit diaphragm are important for maintaining..
glomerular permeability
If there is a genetic mutation of nephrin…
nephron syndrome is produced
Mesangial cells function is to …
provide support to the capillaries
There are 2 groups of mesangial cells:
-Extraglomerular mesangial cells(which are located in vascular pole)(outside glomerulus
-Intraglomerular mesangial cells (pericyte like cells, located within renal corpuscle) (inside glomerulus)
Intraglomerular mesangial cells function is…
phagocytic function
also collagen synthesis
important for contraction
provide physical support to capillaries of the glomerulus
Mesangial cells synthesize …
interleukin 1, endothelins,platelet derived growth factor,prostaglandins E2
Juxtaglomerular Apparatus has three components:
Macula densa (of the distal tubule)
Juxtaglomerular cells(of the afferent glomerular arteriole)
Extraglomerular mesangial cells
Function of juxtaglomerular cells is to…
secrete hormones (renin)
Macula densa function is to…
detect changes in Na+
utilizes feedback mechanisms to regulate glomerular filtration
Juxtaglomerular cells are…
smooth muscle cells located in tunica media of afferent glomerular arterioles which are richly innervated by sympathetic nerve fibers
What happens when there is a presence of high Na+?
macula densa detect the high NaCl concentration via apical Na+,K+ co transporter
Elevated filtration or reduced reabsorption of sodium and water equals…
higher Na at macula densa
Proximal tubule has 2 regions:
Proximal convoluted tubule and Pars recta of the proximal tubule
Bowman space drains into…
proximal tubule at the urinary pole
Function of the Proximal convoluted tubule…
-hydroxylation of vit D and release it to the capillaries
-fibroblastic interstitial cells near proximal tubules produce erythropoietin
Henle Loop divides into:
descending thin limb= highly permeable to water and moderately permeable to urea
ascending thick limb= not permeable to either water or urea(manufactures Tamm Horsfall protein uromodulin which impedes formation of kidney stones and decreases chances of urinary tract infections)
Distal convoluted tubule rate of Na+ reabsorption is regulated by…
Aldosterone from Adrenal glands
Distal convoluted tubule is impermeable to …
water and to urea
In response to hormone aldosteron, the distal convoluted tubule …
actively reabsorbs almost all of the remaining sodium from the lumen of the tubule into renal interstitium
K+ and hydrogen ions are actively secreted into the lumen thus…
controlling body’s extracellular fluid K+ levels and controlling the acidity of the urine
Distal convoluted tubules of several nephrons join to form…
short connecting tubule that eventually leads to form the collecting tubule
Cortical collecting tubules have 2 types of cuboidal cells…
principal cells(light cells)=site of action of the ADH (aka antidiuretic hormone)
intercalated cells(dark cells)= help maintain acid and base balance. Have type alfa cells and beta cells
type alfa cells = acidify urine
type beta cells= make urine less acidic
