Histology Flashcards
(53 cards)
Medulla has no what
renal corpuscles
how are tubules oriented
Tubules are orientated radially, pointing from the cortex to the medulla
Whats in the medulla
There are no glomeruli in the medulla - just tubes & blood vessels
What tubular structures are in the medulla
Tubular structures; tubules of the loop of henle (A), tubules of the collecting duct (CT) & blood vessels
What happens in the pelvis
The space that urine drains into - its continuous with the collecting ductsproximallyand the uretersdistally
What is the pelvis lined by
Lined by transitional epithelium (the same that is in the bladder)
What points into the renal pelvis
The tips of the medullary pyramids project into the renal pelvis - at this point the pyramids are composed purely of collecting ducts
Cells of the glomerulus
Most of the cells that can be seen are mesangial cells and capillary endothelial cells
What stain to distinguish mesangial cells
periodic acid shift (PAS)
How does PAS distinguish mesangial cells
PAS stains glycoproteins in the glomerulus basement membrane - highlighting capillaries and allowing you to see the mesangial cells in-between
What are the 3main functions of the mesangial cell’s smooth muscle
- Structural support for the capillary and production of extracellular matrix protein
- Contraction of these muscles in the glomerulus tightens the capillaries and reduces the glomerular filtration rate (GFR) - this is important in tubuloglomerular feedback - where chemical changes in the tubules feedback to alter the GFR
- Involved in the phagocytosis of the glomerular filtration membrane breakdown products
2 components of the juxtaglomerular apparatus
afferent arteriole & distal convoluted tubule
Endothelium f the afferent arteriole
The endothelium of the afferent arteriole is expanded to form a mass of cells called GRANULAR CELLS which are able to DETECT BLOOD PRESSURE and secrete renin in response to a reduction in blood pressure
Epithelium of proximal convoluted tubule
CUBOIDAL EPITHELIUM
Why does the surface of the proximal convoluted tubule look fuzzy
Cells have microvilli that increase the surface area of the cell - why the surface looks FUZZY
why do the cells of the proximal convoluted tubule have lots of mitochondria
The cells of the proximal convoluted tubule have lots of mitochondria because they actively transportions from the glomerular filtrate including TWO THIRDS of the sodium & potassium
what does PCT reabsorb
NaCl, proteins, polypeptides, amino acids & glucose
These of the PCT cells also absorb the small protein molecules that got through the glomerulus
What do the lysosomes of the PCT do
Lysosomes are present which are involved in the degradation of small protein molecules that are reabsorbed from the urinary space
NOTE: there are more lysosomes in the proximal convoluted tubule that in the distal
What do the lysosomes of the PCT do
black dots
Thin segment of loop of henle`
simple squamous
Thick segment of loop of henle
low cuboidal
what supplies the loop of the henle
rich vasa recta
What passes out of the thin descending limb
Water but NOTionspassivelyflow out of the thin descending limb into the high osmolarity interstitium - thereby concentrating the urine
The ions the body wants back are then actively pumped out of the ascending limb - leaving water & waste products
how is the distal convoluted tubule recognised
Can be recognised since its cells DO NOT HAVE MICROVILLI meaning no “fuzzy” brush border is present
