Hormones Flashcards
What are hormones? What are they released by? How does it travel? How is it triggered? Speed of response Length of response
Hormones are chemical messenger which control different body functions
They are released by endocrine glands (a type of effector organ). These glands do not have ducts (tubes) to carry the hormones away so the hormones are released directly into the bloodstream where they travel to the target organ. Although, they can occasionally act fast, the effects of hormones are mostly slow and long lasting.
Adrenaline
Produced by which gland?
Target organ?
Effect
It’s produced by adrenal glands
It’s target organ is the heart
It prepares the body for fight or flight response
ADH
Produced by which gland?
Target organ?
Effect?
It’s produced by the pituitary glands
It’s target organ is the kidneys
It controls the water balance by triggering the uptake of water in kidneys
Insulin
Produced by which gland?
Target organ?
Effect?
Produced by the Pancreas
It’s target organ is the liver
It decreases blood sugar levels by causing the liver to convert glucose to glycogen
Testosterone
Produced by which gland?
Target organ?
Effect?
It’s produced by the testes
It’s target organ is the male reproductive organs
It controls puberty in males and controls sperm production
What is the menstrual cycle and what happens during it (3 things)? How long is average cycle?
The menstrual cycle in women is a recurring process during which:
- A mature egg is released
- The lining of the womb is prepared for pregnancy
- The uterus lining and egg are shed during menstruation (period) if the egg is not fertilised
The average cycle is 28 days long, but may vary significantly from woman to woman
How the thickness of the womb lining changes during the menstrual cycle? Days: 0-5 6-12 14 15-25 28-30
Days 0-5: The old egg leaves body in menstruation (bleeding as uterus lining is shed).
Days 6-12: New egg id maturing in the ovary
Day 14: Egg released (ovulation)
Days 15-25: Womb lining thick and spongy ready to receive new egg
Days 28-30: Egg not fertilised so womb lining breaks down
Which hormones control the menstrual cycle?
Oestrogen and progesterone which are produced by the ovaries
FSH and LH which are produced by the pituitary gland
Days 1-5 of the menstrual cycle
The first day of menstrual cycle is day 1-5 of the menstrual cycle. The uterus lining breaks down and is expelled from the body along with an unfertilised egg. Oestrogen levels are low
What happens after days 1-5? What is the effect of this hormone? How is it released?
Follicle stimulating hormone (FSH) starts to be released by the pituitary gland in the brain. The hormone travels in the blood to the ovaries. The FSH triggers the development of the eggs in the ovary and they start to mature. It also stimulates the ovaries to produce oestrogen which causes the uterus lining to repair itself and build up again after menstruation.
What happens after the FSH being released and has stimulated the ovaries? Days 12-15
The ovaries produce so much oestrogen that it is detected by the pituitary gland in the brain and causes the gland to stop producing FSH. Instead the pituitary gland starts to produce another hormone called luteinising hormone (LH).
What happens after the LH is produced? Day 14
LH reaches a peak and triggers ovulation - the release of a mature egg
What happens after ovulation is triggered? Days 14-21
Progesterone is released by the empty follicle in the ovary. This maintains the uterus lining in anticipation of a fertilised egg. Progesterone also stops the production of FSH and LH.
What happens if a woman becomes pregnant after the production of FSH and LH stops?
The follicle continues to produce progesterone and the uterus lining remains thick.
What happens if pregnancy doesnt occur after the production of FSH and LH stops?
If pregnancy doesnt occur, then the levels of progesterone and oestrogen falls. Towards the end of the menstrual cycle, the lining breaks down and a period occurs. The cycle starts again.
