Endocrine System and Hormones (Menstrual Cycle (Day 1: New period starts,…
Endocrine System and Hormones
Rate of metabolism, regulates heart rate and temperature
Lots of hormones
Regulate body condition
Puberty and sperm production
Prepares body for fight or flight
Regulate blood glucose level
Hormones and Negative Feedback
Hormones: Chemicals released directly into the blood, they are carried to other parts of the body but only affect particular cells and organs known as target organs. They are produced in glands which make up our Endocrine system.
Negative Feedback: control levels of hormones in blood using negative feedback systems. The body detects level of a substance has gone above or below the normal level, by triggering a response to bring the level back to normal.
Released by pituitary gland, causes follicle to mature in ovaries and stimulates Oestrogen production
Released by ovaries, causes the lining of the uterus to thicken and grow, high level stimulates LH surge
Released by pituitary gland, stimulates ovulation at day 14, the follicle ruptures and egg is released, stimulates the remains of follicle to develop into structure called corpus luteum which secretes Progesterone.
Released by corpus luteum after ovulation, maintains the lining of the uterus, inhibits release of LH and FSH, when level of Progesterone there's a low level of Oestrogen, the lining of the uterus breaks down. Low Progesterone allows FSH to increase and then the whole cycle starts again.
Day 1: New period starts
Day 10: Progesterone is released, this maintains the lining of the uterus.
Day 7: Oestrogen is produced by the ovaries, this starts building the lining of the uterus
Day 13: LH, made in the pituitary gland is released.
Day 5: Period is complete
Day 14: Egg is released
Day 15: Oestrogen levels drop
Day 16: FSH production begins in the pituitary gland, this starts preparing the next egg
Day 20: Egg travels down towards the uterus
Day 28: No implantation so progesterone and oestrogen levels fall rapidly
Adrenaline and Thyroxine
Released by Adrenal Glands
-increased heart rate
-increased blood pressure
-increased blood flow to the muscles
-raised blood sugar levels by stimulating the liver to change glycogen into glucose
Released by Thyroid Glands
-Regulates metabolic rates
-Low levels of thyroxine stimulates production of TRH in hypothalamus this causes release of TSH from the pituitary gland
-TSH acts on the thyroid to produce thyroxine
-When thyroxine levels are normal thyroxine inhibits the release of TRH and the production of TSH