SB7 Flashcards
Hormonal system
Uses chemical messengers called hormones to cause responses in the body
What is a hormone?
Chemical messenger
What are the endocrine glands?
Pituitary
Thyroid
Adrenals
Ovaries
Testes
Pancreas
What hormones does the pituitary gland produce?
ACTH
FSH
LH
Growth hormones
What hormone does the thyroid gland produce?
Thyroxine
What hormones do the pancreas produce?
Insulin and glucagon
What hormones do the ovaries produce?
Oestrogen and progesterone
What hormone does the adrenal gland produce?
Adrenalin
What hormone does the testes produce?
Testosterone
What is the organ that is affected by the hormone?
Target organ
How does the hormone affect the organ?
It changes what the organ is doing
Metabolic rate
The rate at which the energy stored in your food is transferred by all the reactions that take place in your body
Resting metabolic rate
Measured with the body at rest, in a warm room, and a long time after the person last ate
What hormone affects metabolic rate?
Thyroxine
Where is thyroxine excreted from
Thyroid gland
What are the effects of thyroxine?
Causes heart cells to contract more rapidly
Increases the rate that proteins and carbohydrates are broken down in the cells
What is the control of thyroxine concentration an example of?
Negative feedback
What 2 hormones control the amount of thyroxine produced?
TRH
TSH
Where is TRH secreted from?
Hypothalamus
Where is TSH secreted from ?
Pituitary
Explain negative feedback in terms of thyroxine concentration
An increase in thyroxine concentration inhibits the release of the hormones that control the release of thyroxine, therefore creating less thyroxine produced in the blood, and vice versa
Where is adrenalin secreted from
Adrenal glands
How much Adrenalin is secreted in normal conditions?
Very little
What happens to the amount of Adrenalin released when a situation is frightening?
An increase of impulses reaches the adrenal glands and triggers a lot of adrenaline to be released into the blood
What are the target organs affected by Adrenalin
Heart
Liver
What happens when Adrenalin affects the liver
It causes the breakdown of glycogen which promotes glucose molecules being released into the blood which means more respiration can take place.
What happens when adrenaline affect the heart
Heart muscle cells contract quicker which means the heart rate is higher and they contract stronger which means there’s more blood pressure
What happens to the blood vessels when adrenaline affects them
The diameter of blood vessels widens which means there is more blood flow to the muscles and the diameter of blood vessels that lead to different organs narrows which means there is less blood flow to those organs which also increases blood pressure
Describe the different stages of the menstrual cycle
The first stage of the menstrual cycle is menstruation when you have your period and the lining breaks down
The second stage is after the period the uterus lining starts to thicken again
The third stage happens around day 14 which is ovulation which is when the egg is released
Stage four is when the uterus lining thickens and the last stage is when the egg cell travels along the oviduct to the uterus, where it can be fertilised and grow into an embryo
What hormones control the menstrual cycle
FSH, LH, oestrogen and progesterone
When is oestrogen at its peak
During ovulation