W4 - Upper Urinary System Flashcards
Unfiltered blood flows into the kidney through the ??? and filtered blood flows out via the ???
Renal artery, renal vein
The capsule is made of connective tissue and is supported by underlying stromal cells ((myo)fibroblasts), what does the capsule do?
PReserves hydrostatic pressure for filtrations
What can the stomal cells do within the kidney?
Repair it if injured
The cortex is directly underlying the capsule, what filtration units are found in the cortex?
Renal corpuscle of the nephron
What is the typical pathway of a nephron?
Begin in cortex, and convolute through medulla and end in papilla
What is the functional unit of the kidney and does it have simple/stratified epithelium throughout the entirety of it?
Nephron, all simple epithelium
What makes up the renal corpuscle?
Glomerular capillaries surrounded by Bowman’s capsule
What process occurs in the renal corpuscle and where is it always located?
Ultrafiltration and located in the cortex
What 5 structures are found in the renal tubule?
PCT, LoH, DCT and collecting tubule/ducts
Where are the PCT+DCT found, where are the LoH and collecting tubules/ducts found?
PCT + DCT - cortex, LoH - mostly medulla, Collecting tubules/ducts - medulla
There are different types of nephron that originate in different parts of the cortex, what are these characterised by and what are they called?
Length of LoH, long - juxtamedullary, short - cortical loop, intermediate - midcortical
What is wider, the diameter of the afferent or efferent arteriole in the glomerulus?
Afferent is wider than efferent (therefore more pressure in efferent than afferent)
What types of cells line the glomerulus?
Endothelial cells in capillaries
The Bowman’s capsule is double walled, outer parietal and inner visceral layers, what type of epithelium/cells make these up?
Outer parietal - simple squamous, inner visceral - podocytes
What is it called where afferent arterioles become efferent arterioles?
Vascular pole
What is it called where the ultrafiltrate exits the Bowman’s capsule once collected in the space between the glomerulus and BC and enters the PCT?
Urinary pole
What is it called where the capillaries enter and leave the corpuscle?
Arteriole pole
Mesangial cells are structural and phagocytic cells that sit amongst the capillaries, how do they generally function?
Keep the space clear of unwanted objects and bacteria
What type of pressure forces molecules between podocytes into the Bowman’s space?
High osmotic pressure
Fenestrae are holes between the endothelial cells, what do they/do they not allow through?
Yes - water, ions No - RBCs and large proteins
A glycocalyx surrounds the luminal surface of endo cells and it consists of -vely charged glycosaminoglycans, what does this therefore stop the diffusion of?
-vely charged molecules
The glomerular BM has 3 layers, what are they called from internal to external and what do they prevent from crossing?
Lamina - rara interna, densa and rara externa, they help to limit filtration of intermediate/large solutes
Podocytes interdigitate to form filtration slits, these slits are bridged by a slit diaphragm which contains pores, what does this prevent from crossing?
Large proteins
A glycocalyx covers the podocytes, what does this restrict the filtration of?
LArge anions
What is the Macula densa and lacis cells (part of juxtaglomerular apparatus)?
The part of the DCT that touch the glomerulus and is responsible for sensing sodium
The main function of the LoH is to create a conc grad in the medulla, what system does this use?
Counter-current multiplier system by reabsorbing water, sodium and chloride ions
The LoH has thick/thin descending limbs and thick/thin ascending limbs, but what are their epithelium types?
Both thick are simple cuboidal, both thin are simple squamous
The LoH uses Na+ pumps to create a high conc of Na+ deep in the medulla near the CD, where does the water therefore move passively from and to down it’s conc grad?
From CD into medulla (creates conc urine)
The DCT has less mitochondria, is shorter and less convoluted than the PCT, they are both lined with simple cuboidal epithelium but how are they different in DCT to the PCT? (3 factors)
DCT simple cuboidal cells are smaller and have no brush border, leading to a larger lumen
DCT are impermeable to water, what is it’s role?
Absorption of NaCl and Ca2+
Because the PCT has more mitochondria than the DCT, which one is more eosinophilic?
PCT
Many CTs extend from a nephron and several join to form CDs, what do many CDs join to form and where does this structure deliver the urine to?
PApillae, delivers urine to minor calyx
There are 2 cell types in the CDs, principal (predominant) and intercalated (fewer) cells, what are principal cells rich in and what do intercalated cells do?
Principal - lots of aquaporins, intercalated - maintain blood acid-base balance by secreting H+ or HCO3-
What does the epithelium become in the renal papillae?
Transitional epithelium
