Homeostasis Flashcards
How does the thermoregulatory centre (hypothalamus) control body temperature?
- the receptors in the brain detect temperature changes in the blood
- the receptors in the skin detect the change in skin temperature and send impulses to the brain
Explain why the
skin may appear red when the body temperature rises and the internal temperature rises above normal
The blood vessels on the surface of the skin get wider by vasodilation (opposite is vasoconstriction)
more blood on the surface of the skin so the skin appears red
More heat is lost by radiation so the body temperature returns back to normal
What is the importance of thermoregulation?
If the body temperature falls below normal, enzymes have less kinetic energy
this slows down reactions by enzymes and causes illness
what does the body do when the internal temperature falls below 37 degrees causing us to shiver?
The muscles CONTRACT at a higher rate so respiration occurs at a higher rate
more heat energy is released raising the body temperature back to normal
where are hormones produced?
endocrine glands
How does the pancreas control the blood glucose concentration on gluco regulation?
when the blood concentration level is too high
- the pancreas produces insulin that dissolves in blood plasma and travels to the liver
- glucose moves from the blood into the cells
- in the liver, excess glucose is converted to glycogen for storage
when the blood concentration level is too high
- the pancreas produces the hormone glucagon
- glucagon dissolves in plasma and travels to the liver
- glucose and released into the blood
Describe how the water and nitrogen content of the blood is controlled by osmoregulation
when the blood water content is too low
- more ADH is released into the blood
- kidney tubules absorb more water
- a more concentrated and smaller volume of urine produced
when the blood water content is too high
- less ADH released
- kidney tubules retain less water
- a more dilute and smaller volume of urine produced
what do the kidneys do?
- they maintain water balance in the body by filtering blood and producing urine
- They also filter glucose, mineral ions, and amino acids and selectively reabsorb them
- The blood cells and large proteins are trapped outside the kidney tissues
- produce urine and remove urea by ultrafiltration of the blood
what happens in ultrafiltration in the glomerulus of the nephron in the kidney?
- when particles that are smaller than urea are pushed out in the glomerulus, the nephron selectively reabsorbs all useful substances back into the blood such as glucose, amino acids and some water.
- the amount of water reabsorbed determines the amount of urine produced in the kidney
Explain how dialysis works
- blood passes our of artery via pump
- the blood thinners prevent clotting
- excess salt and urea are removed by diffusion in a dialysis membrane down a concentration gradient
- removes urea and maintain ion and glucose levels
- clean blood is returned to the vein of the patient
What are the effects of the adrenalin’s flight or fight response?
( adrenaline produced in adrenal gland)
- increases breathing/heart rate pumps more oxygen and glucose into muscle cells
- blood flow to muscles- more respiration and gas exchange
- convert glycogen to glucose
describe how the thyroxine hormone works
low levels of thyroxine detected by pituitary gland/brain/receptors/coordination
centre
thyroid stimulating hormone is released (by pituitary gland)
this causes thyroid gland to release thyroxine
as thyroxine levels rise the brain detects this change and reduces the TSH
production
How are Diabetes caused?
Type1- pancreas do not produce enough insulin and ruin blood glucose levels.
Type 2- caused by obesity as body cells no longer respond to insulin
