5.2.4- Kidney Structure Flashcards
What is a nephron?
The functional unit of the kidney?
What is ultrafiltration?
Filtration of the blood at a molecular level under pressure
How are the kidneys supplied with blood?
Renal artery and is drained by renal vein
What is the structure of a Nephron and where is it found?
Starts in the cortex at a cup-shaped structure called the Bowmans Capusle. –> Remainder of the nephron is a coiled tubule that passes through the cortex –> forms a loop down into the medulla and back to the cortex before joining a collecting duct that passes back down into the medulla
What is the Glomerulus?
Knot of capillaries.
How is the blood supplied and filtered?
1) Renal artery splits to form many afferent arterioles leading to the glomerulus
2) Blood from glomerulus continues into an efferent (away from the centre) arteriole which carries blood to more capillaries surrounding the rest of the tubule.
3) These capillaries eventually flow together into the renal vein
What is the glomerulus surrounded by?
Bowman’s Capsule
The filter is the barrier between the blood in the capillary and the lumen of the bowman’s capsule. The barrier consists of three things to enable filtration, what are these three things?
1) The endothelium of the capillary
2) The basement membrane
3) The epithelial cells of the Bowman’s capsule
What is the endothelium of the capillary?
1) Narrow gaps between the cells of the endothelium of the capillary wall.
2) The cells of the endothelium also contains pores, called fenestrations.
3) The gaps allow blood plasma and the substances dissolved in it to pass out of the capillary
What are fenestrations?
Pores in the endothelium cells
What is the basement membrane?
1) Membrane consists of a fine mesh of collagen fibres and glycoproteins. –> This mesh acts as a filter to prevent the passage of molecules with a relative molecular mass of greater than 69,000
2) This means that most proteins (and all blood cells) are held in the capillaries of the glomerulus
What is the epithelial cells of the Bowman’s capsule?
1) Cells called podocytes, –> have a specialised shape -> Contain finger like projection called major processes.
2) On each major process are minor process/foot processes –> hold cells away from the endothelium of the capillary
3) These projection ensuer that there are gaps between the cells. Fluid from the blood in the glomerulus can pass between these cells into the lumen of the Bowman’s capsule
What are the three parts of the tubule that the Bowman’s capsule leads
1) Proximal convolutede tubule
2) Loop of Henle
3) Distal convoluted tubule
Where the fluid from the nephron go?
Collecting duct
