Topic 7 Flashcards
(16 cards)
What are hormones?
Chemicals released into the blood that affect specific cells in certain organs.
What is a target organ?
The organ that hormones act on/ affects.
What is the endocrine gland?
Glands of the endocrine system that secrete hormones into the blood.
What are 3 differences between the endocrine and the nervous system?
-Endocrine is slow and nervous has quicker responses.
-Endocrine travels through the blood and nervous is electrical impulses.
-Endocrine affects multiple organs and nervous only affects one specific organ.
What does adrenaline do?
-Increase in heart rate and more blood is pumped each time.
-Increase in depth of breathing.
-Dilation (widening) of blood vessels.
-Increase blood glucose levels.
What is homeostasis?
Internal environment is kept constant.
What is thermoregulation?
Maintenance of heat.
What does the body do when it is too cold?
Shivering- muscle relax and contract rapidly so energy from cell respiration warms you up.
Hairs stand on end- erector muscles cause hairs to stand upright to trap a layer of heat to insulate the body.
Vasoconstriction- Thin blood vessels to less heat transferred to surrounding.
What does the body do when it is too hot?
Sweating- sweat spreads out over the skin and evaporates and therefore transfers energy from the skin to surroundings by heating.
Vasodilation- Hypothalamus causes small arteries to widen which increases blood flow and brings blood closer to the skin so energy transfer is dissipated to the surroundings causing cooling.
Skin hairs goes flat so no heat is trapped.
How does the body detects change in blood temperature?
Homeostasis controlled by the hypothalamus centre monitors blood temperature.
What happens when glucose levels are too high?
- Insulin is secreted by the pancreas into the blood.
- Insulin and the large amounts of glucose in the blood enters the liver.
- Insulin triggers glycogen synthesis so glucagon turns glucose into glycogen.
What happens when glucose levels are too low?
- Glucagon is secreted by pancreas.
- The small amounts of glucose in the blood and glucagon enter the liver.
- Glucagon turns glycogen into glucose .
What do the thyroid and pituitary gland do?
Thyroid- Produces thyroxine which regulates the rate of metabolism, heart rate and temperature.
Pituitary gland- Produces many hormones that cause other glands to release hormones that regulate body conditions.
What are the differences between hormones and neurons?
Neurons:
- Fast action.
- Act for a very short time.
- Act on precise area.
Hormones:
- Slow action.
- Act for a long period of time.
- Act in a general way.
What is negative feedback?
The body detects whether an amount of substance has gone above or below the normal level and acts correctly to get it back to normal.
What do the 4 hormones in the menstrual cycle do?
FSH- Causes a follicle in the ovaries to mature and stimulates oestrogen production.
Oestrogen- Causes uterus lining to thicken and grow and stimulate LH.
LH- Stimulates ovulation and the egg is released.
Progesterone- Maintains uterus lining and stops LH and FSH being produced.
