B3 - Controlling internal Flashcards
What’s homeostasis
Keeping the conditions within a narrow range constant
In the body what must be kept constant
Temperature Water Ions Waste levels Blood Glucose
What are the waste products that need to be removed from the body?
Urea
Excess water
Carbon dioxide
How is urea made
Produced in the liver from the breakdown of amino acids, temporarily stored in the bladder and filtrated by the kidneys and passed trough urine
What exactly do the kidneys do?
Filter the blood
Reabsorb ALL the glucose
Reabsorbing needed ions
Reabsorbing needed water
Releases urea (picked up along the way) excess ions and water
What is dialysis
A replacement for kidneys
Blood passes through tubes and passes dialysis liquid through a partially permeable membrane and absorbs the waste.
Advantages and disadvantages of dialysis
A - Better than death
D - Regular hospital trips (3 times a week) Could be for life
Why might the body reject a kidney?
There lie antigens on the surface of the cells which can be seen as foreign so the recipients body attacks them thinking they’re dangerous.
What are immunosuppressant drugs
Drugs to prevent rejection
Why must body temperature be kept the same?
At 37 degrees so that enzymes can work efficiently and not denature
How does the body regulate temperature in the body?
In the thermoregulatory centre in the brain
Receptor cells detect the blood temperature flowing through the brain
Skin receptors also send signals to the centre to tell the temperature and whether to increase or reduce blood flow
How does sweating cool the body
More water is lost from the body when it’s hot due to increase rate of evaporation.
If core temperature rises what does the brain do
- Blood vessels dilate allowing more blood to flow through, more energy is radiated away
- Sweat glands produce more sweat
- Body hair lies flat
If core temperature falls what does the brain do
- Blood vessels constricts so blood flow decreases, less energy is radiated
- No sweat is produced
- Body hair stands erect and traps a layer of insulating air
- When we shiver our muscles contract and this requires energy so our blood warms
Name 5 things doctors have to consider when prescribing different treatments
General health Length the patient has been on dialysis Costs Risks of infection Ethical issues such as the waiting list and whether the wealthy can get to the front
What monitors our blood glucose and how
The pancreas
If there is too much glucose in our blood the pancreas produces insulin which causes the glucose to move from the blood to the cells
In the liver what happens to excess glucose?
Converted to glycogen for storage
Why do children and the elderly have to be considered for temperature change
Children have a large sa to volume so they release a lot of energy and dehydrate quickly when it’s hot which means enzymes denature
The elderly die from hypothermia because they do not move, muscle contract and cant release energy
What if no, or little levels of insulin are created?
Blood glucose levels become too high and this is known as type 1 diabetes
What happens when insulin is released
Causes the blood glucose level to fall
If it gets too low receptors in the pancreas detect it. So, the pancreas releases glucagon which causes the stored glycogen to change back into glucose.
How is type 1 diabetes treated
Genetically engineered bacteria with human insulin which must be injected before every meal for the rest of their life
Name some new methods created that can help cure type 1 diabetes
Pancreas transplants
Embryonic stem cells
