B12 Homeostasis in action Flashcards
What happens to the blood flow to the skin when vasodilation takes place?
Increases, more energy transferred to the surroundings
In which two parts of the body would you find thermo-receptors?
Skin and hypothalamus
Which 4 response occur if we become too cold?
- Vasoconstriction of blood vessel
- No sweat is produced
- Shivering
- Hair stands up
Vasodilation of blood vessels
- capillaries get wider so a larger amount of blood can flow near the skin surface.
- heat is lost to the environment
Vasoconstriction of blood vessels
- capillaries get smaller so less blood can flow near the skin surface.
- heat is kept near to the body
Which waste products do we need to remove from our bodies?
Where do they come from?
How are they removed?
Carbon dioxide:
- produced by body cells during respiration
- removed through exhalation/ through the lungs
Urea:
- deamination in the liver forms ammonia (toxic) which is converted into urea
- filtered out the blood by the kidney and passed out the body in urine produced by the kidney
What happens if the concentration of carbon dioxide is too high?
It forms an acidic solution which could cause enzymes to denature
What happens if the concentration of urea is too high?
It is poisonous.
Function of the renal artery
Brings blood containing urea and other substances in solution to the kidney
Function of the renal vein
Carries blood away from the kidney, after urea and other substances have been removed from the blood
Explain how urea leaves the body.
- blood enters the kidney via the renal artery
- blood leaves the kidney via the renal vein
- the waste products gather
- the waste products leave via the ureter
Function of bladder
Stores urine
Function of ureter
Carries urine from the kidneys to the bladder
Function of the kidney
Filters the blood
Why do the red blood cells not get filtered out of the blood?
They are too large.
Why does urea need to be removed from the blood?
In high concentrations, it becomes poisonous.
Why do the kidneys have a large blood supply?
So that urea can be removed from all of the blood before the concentration builds up
How is glucose transported back into the blood?
Diffusion and active transport
Which reaction in the body produces water?
Respiration
The role of ADH (antidiuretic hormone) in water regulation - high/low ADH
High ADH - increases permeability of kidney tubule, more water reabsorbed by the kidneys, less urine
Less ADH - decreases permeability of kidney tubule, less water reabsorbed by the kidneys, more urine
What is ultrafiltration?
- The process in the kidney by which urea, salt and glucose etc. is extracted from the blood.
- When the blood passes through the top of the nephron, it enters the glomerulus, a network of tiny capillaries.
- This causes the pressure to increase and a fluid is pushed through the walls of the vessels. Blood cells and large proteins do not pass through the capillaries as they are too large. Most of the useful products enter the filtrate e.g. sodium, amino acids, glucose, so needs to be reabsorbed.
- This is a process called selective reabsorption.
Selective reabsorption
Sodium, amino acids and glucose (useful products) are reabsorbed from the filtrate back into the blood
Controlled and not controlled methods of maintaining water and mineral balance
NO CONTROL - water leaves the lungs and water, mineral ions, and urea lost by sweat
CONTROL - urea, excess water, and excess mineral ions removed via kidneys
Where is ADH produced?
Pituitary gland
