Renal Histology I & II Flashcards
Juxtamedullary nephrons extend deep into the ____ and have long loops of henle
medulla
which are more numerous? cortical or juxtamedullary nephrons?
Cortical. Cortical have short loops of Henle and are found mainly in the cortex.
filtration occurs where?
in the Renal corpuscle only, also sometimes called Malpighian corpuscle.
the Bowmans capsule, also referred to as glomerular capsule has two layers… what are they?
visceral layer is attached to the capillary glomerulus & lined by podocyte cells
parietal layer is lined by simple squamous.
podocytes are flattened stellate cells that envelop capillaries. They have extensions that interdigitate with other podocytes called?
Pedicles
the parietal layer is lined by what kind of epithelium?
simple squamous ( this is continue with the simple cuboidal of the PCT)
twhat is the Bowmans space?
where does it exist>
the Bowmans or urinary space exists between visceral and parietal layer which contains the ultra filtrate.
the point where the urinary space is continuous with the lumen of the PCT is called
the urinary pole
the renal corpuscle contains other endothelia cells called?
mesangial cells
functions of mesangial cells are?
- Physical support of capillaries with in the glomerulus .
- Adjusted contractions in response to blood pressure changes , which help maintain an optimal filtration rate .
- Phagocytosis of protein aggregates adhering to the glomerular filter e.g. antigen – antibody complexes
- Secretion of several cytokines , prostaglandins and other factors important for immune defense and repair of glomerulus .
the area of the glomerulus from which both afferent and efferent arterioles arrive is called
the vascular pole
the glomerular filtration barrier consists of 3 layers, what are they?
fenestrated capillary endothelium
the basement membrane
the podocyte filtration slits
pores of the fenestrated capillaries are the first component of the filter. these are _____ in diameter and allow passes of all_____
70-90nm and move all non cellular formed elements of blood.
the basement membrane is juxtaposed between the ____ and the capillary endothelium. it is _____ thick and composed of type Iv collagen and laminin, etc.
between the pedicles and the capillaries.
0.1-0.5micrometers
the basement membrane is negatively charged which serves an ____ barrier preventing charged particles entering.
electrostatic
what is considered the glomerular ultra filter?
the basement membrane. Considered the primary filter. it contains the meshwork of basement membrane that allows passage of molecules like myoglobe (18kD) but NOT albumin (68kD)
the podocyte filtration slit are spaces ___ in diameter between interdicting pedicles
25nm
spanning adjacent pedicles and bridging the slit pores like a zipper is the
slit diaphragm,
the slit diaphragm is composed of _____ and other proteins, glycoproteins and proteoglycans.
nephrins
filtrate is considered….
blood plasma minus large molecules
in regard to renal disease, one of the earliest signs of diabetic nephropathy is_____ characterized by the presence of ______
proteinuria
albumin
a microscopic feature of renal disease is _______
Also called diabetic glomerularsclerosis
thickening of mesangia basement membrane, an increase in mesangial matrix
the PCT is lined with ______ epithelium. it contains an extensive ______
simple cuboidal
brush border
the function of the brush border is to ____
increase the absorptive surface, increases capacity of glomerular filtrate reabsorption
the cells in the PCT are very active and contain large amounts of ____ thus making it stain more intensely
mitochondria
why can the lateral edge of the PCT not be seen as clearly?
high degree of interdigitation between the cells
the functions of the PCT include
reabsorb glucose, 75% of water and NaCl in the filtrate
also secretes NH4+ ions in to the filtrate and indirectly absorbs most of the HCO3- from the filtrate
the NaCl, water and glucose reabsorption are all highly dependent on the
Na K+ atpase activity
where is the Na K ATPASE transporter located?
in the basolateral membra
where is the Na Glucose transporter located?
in the brush border membrane
HCO- is filtered at the ______
glomerulus (key word is filtered)
the HCO- filtration is dependent on the Na/H exchanger. The Na/H exchanger is present where?
What goes out of the tubule and what goes in?
in the brush border membrane
It uses Na gradient to drive H ions IN to the tubule, where it can combine with HCO- to form H2CO3
Carbonic anhydrase is also present where?
in the brush border membrane
the Na/NH4 exchanger is also located in the brush border membrane and uses the Na gradient to put NH4 ions where?
into the filtrate.
the straight proximal tubule is also known as the thick descending limb of the loop of henle. Its epithelium is continuous with the PCT so it is….
simple cuboidal et
what arises straight from the descending thick limb? and lies in the kidney’s outer____
descending thin limb
outer medulla
the thin descending limb along with the thin ascending limb are composed of _____ and have what kind of nuclei?
simple squamous epithelium
round bulging nuclei
they both are comparable to capillaries but can be distinguished by their lack of RBC and bulging nuclei
Then coursing back up is the thick ascending limb. What kind of epithelium would you expect it to have?
simple cuboidal ( just like the thick descending and the rest of the PCT prior to the thin limbs)
counter-current exchange is an important function along the entire PCT in providing______ urine
hypertonic
the descending thin limb has high permeability to _____ where as the thin ascending limb has high permeability to _____
tDLH-water
tALH-solutes
Under the effect of aldosterone, the DCT is impermeable to ____ but reabsorbs____
impermeable to Urea
reabsorbs NaCl
in the absence of ADH the fluid entering the collecting ducts is____ due to the fact that NaCl is reabsorbed without water
hypo osmotic with respect to plasma
the DCT is lined by _____ epithelium. The cells are ____ than the PCT cells and lack a _____
Simple cuboidal
shorter, lack brush border
these are modified cells of the DCT located adjacent to the renal corpuscle at the vascular pole
Macula Densa
Macula Densa cells are ______ cells and tightly packed. They have special ______ sensitive to Na levels of DCT filtrate
thin columnar
chemoreceptors
what provides the DCT with the means to reabsorb nearly all remaining NaCl filtrate
the Na/K ATPase activity
if the collecting tubule is a continuation of the DCT what kind of cells would you expect it to have?
simple cuboidal with NO brush border
Formed by the merging of the collecting tubules the collecting ducts converge to form parallel arrays that begin in the ____ and continue to the _____. These parallel bundles of ducts in the cortex are called_______
begin in the cortex
continue to medulla
medullary rays
two cell types are found in the cortical ducts what are they
principal cells(most abundant) intercalated cells*** only principal cells are seen in the medullary portion of the ducts
The role of principal cells is critical in water reabsorption from the filtrate. They can also reabsorb ___ & ____.
Na & K
What hormone released from the pituitary gland controls the principal cells water permeability?
ADH
what stimulates ADH release?
dehydration. it causes increases permeability of collecting ducts to water leading to conservation of water and forming a HYPERtonic urine.
without ADH the collecting tubules remain impermeable to ___ and large amount of _____ urine are produced
water, hypotonic
the intercalated cells have _____ and abundant ______.
apical microvilli
abundant mitochondria
what do intercalated cells secrete? ( they regulate acid base balance)
H+ or HCO-
these are large(100-200micrometers) straight collecting ducts in the inner medulla, each formed by several smaller collecting ducts
Papillary ducts of Bellini
papillary ducts empty into…
minor calyces
an_______ is present on each renal papilla and consists of about 25 pores that represent the ends of the papillary ducts
area cribrosa
describe the flow of filtrate/production of urine
affarent arteriole»glomerulus> PCT>descending limb> ascending limb> DCT> collecting tubules> collecting duct> papillary duct> minor calyx>major calyx>penal pelvis>ureter….. PEE!! urine my thoughts <3
the Juxtaglomerular Apparatus JGA is made up of what two things ?
the Affarent arteriole
a portion of the DCT
The JGA is responsible for regulating blood pressure. It does this by the help of what cells found within the JGA
Juxtaglomerular cells(contain mechanoreceptors sensing pressure near the arteriole)
Macula Densa cells(contain chemoreceptors that are sensitive to Na+ concentration)
the Juxtaglomerular cells are surrounded around the affarent arteriole and possess what two things?
Renin & Mechanoreceptors
the macula dense cells are found within the DCT at the vascular pole. They are ____ cells and have what property
thin columnar cells
chemoreceptors sensitive to Na level of the filtrate.
there is one other cell type found within the JGA in addition to JG cells and macula densa cells. What kind of cells are they and what is their function
Extraglomerular mesangial cells. These lie between the macula dense and Bowmans capsule.
They function the same as other mesangial cells and provide supportive, contractile, defensive functions.
How is blood pressure changes sensed?
decrease in BP is sensed by :
macula densa cells which sense the drop in Na+
JG cells sensing pressure changes in the affarent arteriole
how is blood pressure regulated?
drop in BP>JG cells release renin> Renin acts on plasma globulin>angiotensinogen>angiotensin I
there are other molecules responsible for regulating BP. What does ACE do?
Angiotensin converting enzyme- enzyme in the blood secreted by pulmonary endothelial cells. angiotensin I»angiotensinII.
what is angiotensin II
a powerful vasoconstrictor which increases BP.
also stimulates release of aldosterone from adrenal cortex resulting in the reabsorption of Na+ in the DCT.. water follows…increasing volume.. increasing BP
the blood supply of the kidney is (starting with the renal artery at the hilum of kidneys)
renal a>segmental a.>interlobar a.>arcuate a>interlobular a.>affarent arteriolies.
what arteries travel up renal columns between pyramids?
interlobar arteries
what arteries are formed of interlobar arteries at the corticomedullar junction
arcuate arteries
efferent arterioles exiting each renal corpuscle differ depending of its a cortical nephron or Juxtamedullary. what are the main differences
Cortical nephron efferent arterioles are smaller in diaper and give rise to peritubular capillary network.
Juxtamedullary nephron efferent arterioles are larger and give rise to the vasa recta.
the descending portion of the vasa recta is ____ & the ascending side is…
arterial
venous.. much larger diameter with fenestrations.
The ureter is composed of the first layer of mucosa with contains ______ epithelium lining the lumen surface. the lamina propria is composed of ______ connective tissue
transitional epithelium
dense irregular fibroelastic CT
the Next layer, the muscular is composed of 2 smooth muscle layers in the _____
& 3 layers near the _____
proximal 2/3
near the bladder
the undistended bladder has transitional epithelium that is ____ layers thick, while the distended full bladder the cell become flat and epithelium appears____
5-6 layers
3-4 layers thick
what special feature does the bladder contain that protect the transitional epithelium from damage when they flatten?
plaques, composed of uroplakin.
the bladder has an osmotic barrier which is found there
between urine and tissue fluids ( plaques are part of th cosmetic barrier because tehey are impermeable to salt and water)
the bladder rests on lamina propria and deep to this is the ____ of the bladder
muscular coat
muscle fibers run in various directions without easily distinguishable layers except at the _____ where a thick middle _____ layer is sandwiched between two longitudinal layers
neck
circular
the outer covering adventitia is dense irregular _____connective
collagenous
name all the parts of the male urethra
prostatic ( transitional et)
membranous (stratified squamous or pseudo stratified columnar epithelium )
Spongiosum(stratified squamous epithelium with patches of pseudo stratified columnar epithelium)
the female urethra is made of ____ epitherlium
stratified squamous with patches of pseudo stratified columnar.
