Urinary System And The Adrenal Flashcards
(50 cards)
How many lobes does a rat kidney have
1 - they are Unilobar
How many lobes does a human kidney have
8 - it is multilobar
Describe the lobar structure of the human kidney
It becomes indistinct on the surface at birth
Describe the kidney cortex
Has a profuse blood supply and contains units where ultrafiltration occurs
This is where the majority of reabsorption takes place
What are the units of the kidney cortex where ultrafiltration takes place
Malpighian/ renal corpuscles
Describe the renal medulla
Has a poorer blood supply that the cortex and contains tubules and blood vessels running in parallel bands
The medulla tapers down from the cortex to end in a blunt pyramid (the papilla)
True or false:
The number of cortical nephrons is much greater than that if juxtamedullary nephrons
True
How many nephrons are in the human kidney
1 million
What does each renal corpuscle consist of
A glomerulus and Bowman’s capsule
What does Bowman’s capsule consist of
2 epithelial layers with Bowman’s space between them
The inner epithelium is in close association with the glomerular capillaries and reflects at the vascular pole to form the parietal layer, which is continuous with the PCT
What forms the visceral layer of Bowman’s capsule
What about the parietal layer?
Podocytes
Squamous epithelium
Describe the podocytes of the inner epithelium of Bowman’s capsule
They have long cytoplasmic extensions (primary processes) that give rise to secondary foot processes, both of which embrace the capillary loops
What is the vascular pile of the renal corpuscle
Where the blood supply enters and leaves the glomerulus
What is the urinary pole
Where the PCT joins Bowman’s capsule
It is opposite the vascular pole
What distinguishes the PCT
A brush border
What is the macula densa
What does it look like in a LM
A distinct epithelial region found at the junction of the thick ascending limb and the DCT, closely opposing the glomerular vascular pole
Look for a distal tubule touching the outer glomerulus, showing many nuclei side by side or even overlapping
Which cells are the macula densa cells in contact with at the glomerular vascular pole
The extra glomerular mesangial cells
What does the macula densa do
Monitors the change in [NaCl] in tubular fluid
Mediates renin release by juxtaglomerular cells
What does the Mesangium consist of
Mesangial cells and mesangial matrix interposed between glomerular capillaries
The extra- and intraglomerular mesangial cells are continuous
What do mesangial cells do (5)
Produce mesangial matrix
They have contractile properties
provide structural support to the capillary network
Play an indirect role in glomerular filtration by regulating blood flow via endothelins
They are phagocytic and remove trapped residues and aggregated protein from capillary basement membrane to keep the filter free of debris
What is characteristic about where the renal papilla projects into the calyx
The presence of a high cuboidal epithelium, with no brush border and the lateral cells are distinctly visible with LM
What are the only tubules between the papillary ducts
Thin limbs of loops of Henle and capillaries
What does the glomerular barrier through which plasma is filtered consist of
Fenestrated capillary endothelium
A basement membrane
Podocyte layer
Describe the fenestrated layer of the filtration barrier of the glomerulus
Contains numerous fenestrations of ~50 -100nm in diameter
