Control and Coordination Flashcards
What are hormones?
Chemical messengers that target organs in the body
How are hormones and nerves different?
Hormones have long-lived effects while nerves have short-term effects, nerve impulses work quickly while hormones take longer to work
What does the hypothalamus produce?
TRH and CRH which target the pituitary gland
What does the pituitary gland secrete?
TSH, LH, FSH and ADH, TSH targets the thyroid gland, ADH targets the kidneys, LH and FSH target the ovaries
What does the thyroid gland secrete?
Thyroxine which controls metabolic rate
What does the pancreas secrete?
Insulin and glucagon which target the liver, muscle and adipose tissue
What does the adrenal gland secrete?
Adrenaline which targets various organs eg. heart, liver, skin
What do the testis secrete?
Testosterone which targets the male reproductive organs
What do the ovaries secrete?
Oestrogen and progesterone, progesterone targets the uterus, oestrogen targets the ovaries, uterus and the pituitary gland
What is negative feedback?
When a factor rises below or above normal level a corrective mechanism happens to bring the factor back to normal level, production of thyroxine is an example of negative feedback
What does adrenaline do?
Bring about the ‘flight or fight’ response due to sudden stress
What are the effects of adrenaline?
- Increases heart rate
- Constricts some blood vessels to make blood pressure higher
- Dilates other blood vessels to increase blood flow to muscles
- Causes the liver to convert glycogen into glucose which is released into the blood
Which hormones are involved in the menstrual cycle?
Oestrogen, progesterone, FSH and LH
What is menstruation?
The breakdown of the uterus lining, it begins on day 1 and last for about 5 days
What happens in the second week of the menstrual cycle?
The uterus lining is gradually built up
What is ovulation?
The release of an egg, it takes place around day 14
When is fertilisation most likely to take place?
In days 14-16 of the menstrual cycle
What happens in weeks 3 and 4 of the menstrual cycle?
The uterus lining continues to build up
What happens if fertilisation does occur?
The uterus lining is maintained and menstruation doesn’t occur at the beginning of the next menstrual cycle
Give some examples of hormonal contraception
Pills, implants and injections
Give some examples of barrier methods
Male and female condoms, caps, sponges
What does FSH do?
Causes a follicle in the ovary to mature
What do high levels of oestrogen stimulate the release of?
LH
What does progesterone inhibit the release of?
LH and FSH
What does an LH surge cause?
Ovulation
What do maturing follicles stimulate?
Oestrogen production
What does increasing oestrogen cause?
Thickening of uterus lining
What do falling oestrogen and progesterone levels trigger?
Menstruation