Kidney Histology Flashcards
what is the function of the urinary system
- Regulation of blood composition, pressure and volume
- EPO – produced red blood cells
- Electrolyte and acid base balance
- RAAS – pressure and volume of blood
what are the components of the urinary system
- Kidneys
1. Renal parenchyma (nephorns)
2. Passageways for urine calyx – renal pelvis - Ureter
- bladder – reservoir and pump
- Urethra – removes urine
what is the nephron
a funnel shaped epithelial structure where a blood filtrate is processed ultimately leaving urine
what makes up the nephron
= Bowman’s capsule and renal tubule these make up the nephron
describe the structure of the bowman capsule
- it has a parietal wall - this is made out of simple squamous epithelium
- has a visceral wall - this is close to the glomerular and contains podcytes
what cells support the bowman capsule
supported by mesangial cells and their extracellular matrix- mesangium
what are the two poles of the bowman capsule
vascular pole
urinary pole
describe the vascular pole and the urinary pole of the bowman capsule
vascular pole where the site of afferent and efferent arterioles enter
urinary pole- opposite side where the proximal convoluted tubule begins
what makes up the renal corpuscle
• Bowman’s capsule with its glomerulus (tuft of capillary loops) supported by mesangial cells and their extracellular matrix- mesangium
- globular capillaries
what is the function of the renal corpuscle
- ultra-filtration of blood
describe how substances are inhibited from crossing the bowman capsule
- too large - podocytes have spaces between there foot processes, 60,000
- podocytes have a negative charge therefore if the molecule such as protein is negatively charged then it is inhibited from getting through -
in what circumstance can albumin go through the kidney
if it is albumin, if there is damaged to the glomerulus it becomes leaky and the podocyte charges are missing then albumin can filter into the lumen and is lost therefore the patient has oedema as not enough reabsorption into the blood back from the interstitial tissue
what is the function of the mesagnial cells
- produce the mesnaignal matrix
- have immuoreactivity
- cytokines are released by the mesaingal cells
- angiotensin II bindings to the receptors and stimulates mesangial cell contraction
- interacts with the juxtaglomerular system
name the three things that the globular filtration barrier is made out of
- Fenestrated capillary endothelium
- Basement membrane
- Podocyte layer of Bowman’s capsule – end feet that stick down on the basement membrane, between the podocyte process they have membranes and proteins that can regulate and charge
what is the function of the proximal convoluted tubule
reabsorption
- this is facilitated by sodium potassium ATPase in the basolateral membrane - produces a concentration gradient
what does the proximal convoluted tubule reabsorb
- 70-80% of the water, Na+ and Cl-
- ~100% of amino acids and glucose
- some bicarbonate reabsorbed/ H+ secreted
- larger proteins, carbohydrates - endocytosis