B3.3 Homeostasis Flashcards
How is urea made?
The break down of amino acids
What’s homeostasis?
Maintaining a constant internal environment
How is water lost?
Sweating
Urine
Breathing
How are ions lost?
Sweating
Urine
Why does water and ion level have to be controlled?
If it’s wrong water will move into or out of the cell by osmosis and damage the cell
What temperature should the body be and why?
37
For enzymes to work properly
What’s the thermoregulatory centre?
In the brain
Monitors and controls temperature
Has receptors sensitive to temperature
What happens if your temperature is too high?
Wider capillaries
More blood near surface
Heat is lost
More sweat (which evaporates to cool you)
What happens if your too cold?
Smaller capillaries
Less heat loss
Shiver which is a contraction of muscles which releases energy from respiration as heat
What temperature is hypothermia?
35
What hormones control sugar level?
Insulin
Glucagon
What happens if there is too much sugar in the blood?
Insulin released
Liver converts glucose to glycogen for storage
So insulin allows glucose to move from the blood to body cells
Sugar levels drop
What happens if there is too little sugar in the blood?
Glucagon released
Liver converts glycogen to glucose for respiration
What’s diabetes?
Don’t produce insulin
Need injections
Test blood with blood usage testing strips
What are the parts of the urinary system?
Kidney
Ureter
Bladder
Urethra
What ultrafiltration?
In the bowmans capsule in the nephron
Filtering the blood
Gets rid of large molecules like cells or proteins
What’s selective reabsorption?
Reabsorbing the sugar, ion and water needed (down an osmotic concentration gradient)
What’s in urine?
Urea and excess water and ions
Where do kidneys in kidney transplants come from?
Living related, living unrelated or cadaver donors ( brain dead)
Why can it be hard to find a donor?
Long waiting lists
Tissue typing
Shortage of donors
What’s kidney failure?
Where the kidneys don’t work properly
Symptoms of kidney failure?
Confusion Fatigue Nausea Blood in urine Abnormal heart rhyme
What’s dialysis?
A procedure where patients are connected to a machine which acts as a kidney for them
How does dialysis work?
Blood is mixed with thinners to avoid clots them it’s removed and pumped opposite to the dialysis fluid so exchanges can occur
What is dialysis fluid?
Similar levels of glucose so it doesn’t move
Similar levels of ions so it will only move if there isn’t enough ions in the blood
No urea so there’s a large concentration gradient so it diffuses from the blood
How often do patients need to use a dialysis machine?
2-3 times a week for 4-6 hours
Advantages and disadvantages of kidney transplants?
Cheaper for NHS, normal life after
Need immunosuppressant drugs, shortage of kidneys, it needs an operation, only lasts 8-9 years
Advantages and disadvantages of kidney dialysis?
No storage or need for drugs
Expensive for NHS, regular sessions, have to change your diet
How is a kidney transplant done?
Cut Kidney in and old one out Blood vessels attached Ureter connected to the bladder Closed up
What is organ rejection?
If the antigens are different the body can create antibodies to kill the new organ
How can they reduce organ rejection?
Tissue typing Immunosuppressant drugs (but then there's more chance of infection and they have to be taken for life)
What’s a urinary tract infection and how is it treated?
A bacteria infection of the urinary system where protein is present in urine
Treated with antibiotics
What’s renal failure and how is it treated?
Kidneys can’t filter the blood
Dialysis or transplant
What does high blood pressure do?
It forces large molecules out of the blood into the filtrate
Can cause permanent damage
