The kidney Flashcards
(30 cards)
What artery supplies the kidney with blood to be filtered?
The renal artery
What vein carries the filters blood away from the kidneys?
The renal vein
What is the cortex?
This id the dark outer layer which contains many capillary networks
What is the medulla?
Contains nephrons
What is the pelvis?
Where the urine collects before travelling to the ureter
What ia the nephron?
structures within the kidney where the blood is filtered and useful substances are reabsorbed into the blood
What is the glomerulus?
When the renal artery splits to form many different arteries leading to a knit of capillaries called the glomerulus
how does fluid enter the bowmans capsule?
fluid pushed into the bowmans capsule because afferent arteriole is wider than efferent arteriole so high hydrostatic pressure pushed fluid from blood into bowmans capsule
What is the filter?
The barrier between blood in the capillary and lumen of the bowmans capsule
Describe the endothelium of the capillary
has narrow gaps between cells of endothelium which allows blood plasma and substances dissolved in it to pass out of the capillary
Describe the basement membrane
this is a fine. mesh of collagen and glycoproteins which act as a filter to prebent the passage of molecules or a relative molecular mass grater than 69000
Describe the epithelial cells of the bowmans capsule
these contain podocytes which have finger like projections which create gaps between cells so fluid from the blood in the glomerulus can pass between these cells into the lumen of the bowmans capsule
Describe ultrafiltration
- blood enters through the afferent arterioles
- high hydrostatic pressure ,mans that water and small molecules are forced out of the capillaries and form the glomerulus filtrate
- once it exits the capillary it passes through the basement membrane which acts as a sieve pre-empting large proteins and blood cells passing through the gaps in the capillary endothelium
Where does selective reabsorption occur?
in the proximal convoluted tube
Summarise selective reabsorption
- sodium ions are actively pumped out of cells lining the proximal convoluted tubule
- concentration of sodium ions in cell decreases creating a concentration gradient
- sodium ions diffuse down gradient from lumen into cells via a cotranporter protein which also carries glucose or amino acids at the same time
- water moves in via osmosis
- glucose and amino acids diffuse into the blood so are reabsorbed
What is osmoregulation?
the control of the water potential in the body
where is the changes in water potential detected/
osmorecpetors found in the hypothalamus
What happens if you need to conserve less water?
the walls of the collecting duct become less permeable so less water is reabsorbed and a greater volume of urine is produced
What happens if you need to conserve more water?
the walls of the collecting duct become more permeable so more water can be reabsorbed into the blood and produces a smaller volume of urine
What happens when there is a decrease in the water potential of the blood?
this is detected by osmorecpetors in the hypothalamus which asues more ADH to be released from the posterior pituitary, this is detected by cell surface receptors and makes the collecting duct walls more permeable so more water is reabsorbed into the blood which creates less urine and increases the water potentialw
what happens when there is an increase in the water potential of the blood?
the osmoreceptors in the hypothalamus detect this and causes less ADH to be released so that the walls of the collecting duct are less permeable therefore less eater is reabsorbed and more urine is produced which will reduce the water potential
What is kidney failure?
this is when the kidneys are unable to regulate levels of water and electrolytes in the body or unable to remove waste products
how is kidney function assessed?
assessed by estimating gate glomerulus filtration rate and also by analysing the urine for substances such as proteins which would indicate that the filtration mechanism is damaged
What does dialysis do?
This artificially regulates the concentrations of solutes in the blood
