Hormones, Adrenalin Flashcards
Hormones are chemical messengers that target organs in the body.
Hormones are produced by endocrine glands and released into the blood.
They travel around their body until they reach their target organs
Remember
Endocrine glands release hormones into the blood until they reach their target organs
Each hormone causes its target organ to respond e.g by releasing another hormone
Which hormones are released by the pituitary and the hypothalamus
Both are in the brain
PITUITARY- secretes TSH, ADH, FSH and LH
Hypothalamus- produces TRH and CRH
Thyroid gland secretes ….
(Neck piece)
Pancreas secretes ….
Adrenal gland secretes ….
Thyroid gland secretes thyroxine
Pancreas secretes insulin and glucagon
Adrenal glands secrete adrenaline
The production of thyroxine is an example of negative feedback
Explain how the production of thyroxine is controlled by negative feedback
- when the conc of thyroxine is too low in the blood, negative feedback stimulates a correct mechanism
- hypothalamus stimulates more TRH and the pituitary produces more TSH
- thyroxine conc is too high. This inhibits TRH production by the hypothalamus, so less thyroxine is produced
Thyroxine. What is it?
A hormone that controls metabolic rate
This is the rate at which cells respire
Effects of adrenaline:
It has many target organs liver, the heart and blood vessels
- Increases heart rate
- Constricts blood vessels to make blood pressure higher
- dilates blood vessels to increase blood flow to muscles
- causes the liver to convert glycogen to glucose , which is released into the blood
The menstrual cycle process …
1-5 days is the breakdown of the uterus lining (menstruation)
During second week - uterus lining gradually builds up
Day 14- OVULATION the release of an egg from an ovary
Days14-16 - FERTILISATION
Weeks3-4- uterus lining builds up
Week 4- if fertilisation does occur , menstruation stops
What is a hormonal contraceptive way
Hormone pills, implants or injections and works by releasing hormones to prevent ovulation and thickens mucus at cervix to block sperm from passing
Barrier methods include:
Condoms, the diaphragm, caps, sponges.
Work by stopping sperm from reaching the egg
Start of menstrual cycle
22222 fsh LH oestrogen ,…
High levels of oestrogen stimulate release of more LH
Low levels of progesterone allow FSH to be released
FSH stimulates growth and maturation of follicles
LH drop at start will trigger ovulation
Maturing follicles stimulate…
Oestrogen production. Maturing follicles stimulate oestrogen
Increasing oestrogen causes thickening of the wall.
Falling oestrogen and progesterone can trigger menstruation in first 5 days
Falling oestrogen and progesterone levels will cause what
Menstruation.( the lining breaks down)
