B12 - Homeostasis Flashcards
What temperature is the body’s temperature kept at
37 degrees
Where is the body’s temperature monitored
The thermoregulatory centre in the brain
What happens when the body’s temperature rises
The blood vessels that supply your surface skin capillaries dilate allowing more blood to flow through the skin capillaries. Energy is transferred by radiation to the environment and the skin cools.
Sweat glands produce more sweat.
What happens when the body’s temperature falls
The blood vessels that supply your surface skin capillaries constrict and less blood flows through the skin capillaries.
Sweating stops.
You shiver - your muscles contract and relax quickly. This requires a greater rate of respiration which transfers more heat to the blood.
What is excretion
The process of removing waste matter
How is carbon dioxide removed from the body
It is produced by cells during respiration
It needs to be removed as it forms an acidic solution
It is diffused out of cells into the blood and out of the blood into the alveoli and then out the lungs
How is Urea removed from the body
It is produced from nitrogenous, which is from the break down of amino acids in the liver
Deamination is the removal of the amino group from amino acids which forms ammonia
The rest of the amino acid is used in respiration
The ammonia is converted to urea and is excreted out the body
It travels from the liver cells to the blood and then through the kidneys and out through the urine
How is water and mineral ions balanced
Water enters the body through drinking
Water is also produced in our body during respiration
Water is lost in 2 ways, controlled and not controlled
The uncontrolled ways are water getting out the lungs when you exhale and through sweat
The controlled ways is via the kidneys and excreted in the urine
What are the functions of the kidneys
They are important in homeostasis in the water balance of your body
If you are short of water then the kidneys conserve it
How does the kidneys work
They work as a filter for your blood
The blood cells and large proteins are too big to got into the kidney tissues
The smaller molecules such as glucose, mineral ions urea and water move through the kidney
All the glucose is reabsorbed into the blood
However the amount of water and mineral ions that are reabsorbed varies
This is known as selective reabsorption
What is ADH
Antidiurectic Hormone
ADH controls the levels of water in the body which acts on the kidney tubules
What happens when there is too little water
More ADH is released from the pituitary gland into the blood
ADH causes the kidney tubules to reabsorb more water
A more concentrated urine is produced and the water levels are restored
What happens when there this too much water
Less ADH is released from the pituitary gland which causes the kidney tubules to reabsorb less water
What is Dialysis
Dialysis is when the function of the kidneys is carried out artificially by the dialysis machine
During dialysis, the person’s blood flows out their body and in between partially permeable membranes and on the other side is the dialysis fluid
The dialysis fluid is the perfect concentration for diffusion to happen where the buildup of urea and mineral ions are diffused out the blood
Dialysis requires a controlled diet and weekly appointments for a few hours
What are the advantages of Diaylsis
Available to all kidney patients
Saves the patients life
What are the disadvantages of Diaylsis
A careful controlled diet is needed (water, protein, salt intake)
In between dialysis sessions, ions and water can build up causing damage to cells
Dialysis is usually needed 3-4 times a week for up to 4 hours
The average cost of dialysis is £31,000 per patient per year
Blood thinners are used during dialysis as there is a risk of blood clots
Skin is repeatedly punctured
What are kidney transplants
People can survive on just 1 kidney which means healthy people can give one of their kidneys away
The donor kidney is joined to the blood vessels in the groin
If the treatment is successful then the kidney will function properly and no other treatment is needed
The risk of rejection is the biggest and this risk is reduced by the donor being close genetically and the recipient is given drugs to suppress immune responses
What are the advantages of Kidney transplant
Transplanted kidney works like a normal kidney so no diet restrictions
Lasts 10-12 years
What are the disadvantages of Kidney transplants
Immunosuppressants need to be taken for life
Shortages of organ donors
Major surgery required so risk of infection and anaesthetic
Doesn’t last forever
The cost of a transplant is £17,000 per patient per transplant
Around £5,000 per year for medication
