Topic 7 Flashcards
What is the Pituitary gland?
The master gland
Secretes hormones into the blood to have an effect on the body or stimulate other gland to produce different hormones
What is the pancreas
Secretes insulin
Controls blood glucose level
Thyroid, what is it
Secretes thyroxine
Controls metabolic rate, heart rate temperature
Adrenal gland
Secretes adrenaline
Involved in the “fight” or “flight” response (the body’s response to stressful situations)
Ovary
Secretes oestrogen
Involved in the menstrual cycle and the developing of female secondary sexual characteristics
Testes
Secretes testosterone
Is involved in the production of sperm and the development of male secondary sexual characteristics
Nervous systems vs hormonal
Blood transports hormone to a target organ vs electrical impluses
Nervous system acts quicker but hormonal systems acts for longer
What is adrenaline?
Adrenaline is a hormone produce by the adrenal glands to prepare the body for a flight or fight response. (Dangerous situation)
Outline effects of adrenaline
Increased heart rate and blood pressure : this allows oxygen to reach the muscles quicker, so we can move out of the path of danger.
Increase blood flow to muscles: blood vessels dilate to allow more blood to reach the muscles. Allowing them to have more oxygen for respiration.
Increase blood sugar levels: the liver is stimulated to break down glycogen into glucose, which muscles use in respiration.
Thyroxine
Thyroxine is a hormone that regulates metabolic rate (how quickly reactions occur).
Thyroxine: Low levels
Low levels of thyroxine stimulate production TRH in hypothalamus
TRH causes the release of TSH from pituitary gland
TSH acts on the thyroid to produce thyroxine
When thyroxine levels have reached the normal level, thyroxine inhibits the release of TRH, which stops the production of TSH
Thyroxine: High levels
Controlled by negative feedback:
When the levels increase, it is detected by receptors in the brain (hypothalamus)
This inhibits the release of TSH
This inhibits the release of thyroxine, so levels of thyroxine fall
Menstrual cycle: FSH
Follicle stimulating hormone (FSH) causes the maturation of an egg in ovary, within a structure called a follicle
Produced in the pituitary gland
Stimulates the ovaries to produce oestrogen
Menstrual cycle: oestrogen
Oestrogen causes the lining of uterus to grow again
Produced in the ovaries
Secretion as stimulated of FSH
Stimulates the production of LH and inhibits the secretion of more FSH
Luteinising hormone: Menstrual cycle
Produced in the pituitary gland
Produced as a result of hormone oestrogen
It releases results in ovulation
Progesterone: Menstrual Cycle
Produced in the ovaries and secreted from the egg follicle
Maintains the lining of uterus, and supports a pregnancy if the eggs is fertilised
Inhibits the release of both FSH and LH
Contraceptive Pill and contraceptive patch : Mixed Pill (oestrogen and Progesterone)
Means oestrogen levels are constantly high, inhibiting FSH so no mature eggs
The lining also stops developing and the mucus in the cervix become thick so sperm cannot move through