Endocrine system Flashcards
What are hormones?
Chemical molecules released directly into the blood for homeostasis.
Where are hormones secreted from?
Glands.
What does the pituitary gland do?
This produces hormones that act on glands to release hormones - ‘the master gland’.
What do the ovaries do?
These produce oestrogen for the menstrual cycle.
What do the testes do?
Produce testosterone for puberty and sperm production.
What does the pancreas do?
Produces insulin and regulates blood glucose levels.
What does the thyroid do?
Produces thyroxine which is involved in regulating the rate of metabolism, heart rate and temperature.
What does the adrenal gland do?
Releases adrenaline.
What is the difference between nerves and hormones?
Hormones are slower and act for a longer time in a more general way compared to the fast, short, precise nerves.
What happens if the blood glucose level is too high?
Insulin is secreted by the pancreas and the glucose is taken into the liver and turned into glycogen.
What happens if the blood glucose level is too low?
Glucagon is secreted by the pancreas to alert the liver and the liver turns the stored glycogen back into glucose.
What is type 1 diabetes?
When the pancreas produces very little insulin so the blood glucose levels are too high.
What is type 2 diabetes?
When someone becomes resistant to their own insulin and does not respond to it so there is too much glucose.
What is the job of the kidneys?
The kidneys filter the blood and make urine with unwanted substances in the blood.
What is inside urine?
Urea - made up of ammonia which is a waste product from deamination. Ions can be wrong for the body. Water - there can be too much so that is dealt with.
What is the concentration of urine controlled by?
A hormone called ADH monitors water content and uses negative feedback to say how much urine should be stored
What happens if the kidneys fail?
There will be many waste substances stored up and the levels of ion and water will build up causing death.
What does a kidney dialysis machine do?
It has a partially permeable membrane surrounded by dialysis fluid. Waste substances like ions and can go through but not big molecules. The dialysis fluid has the same levels of ions and glucose as blood so they will not diffuse over - only waste products diffuse across the barrier.
What are the disadvantages of kidney dialysis?
Three 3-4 hour sessions are needed a week and it is unpleasant as well as costing a lot. It can cause blood clots.
Talk about kidney transplants?
Can be rejected but are generally a cure - they have long waiting lists.
What are the key dates in the menstrual cycle?
Day 1 - the uterus lining breaks
Day 4-14 - uterus lining builds up again
Day 14- an egg is released from an ovary
Day 14-28 - The lining waits for a fertilized egg and if it does not arrive it starts again.
What does oestrogen do?
Causes the uterus lining to grow and stimulates LH and stops FSH
What does follicle stimulating hormone do?
Causes the egg to mature and stimulates ovaries to produce Oestrogen.
What does progesterone do?
Maintains lining of the uterus during the second half of the cycle. It inhibits LH and FSH
