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B11 - Hormonal coordination - Coggle Diagram
B11 - Hormonal coordination
Principles of hormonal control
Compared with the nervous system, the effects of hormones' are slower but longer lasting.
The pituitary gland is the master gland that secrets several hormones into the blood in response to body conditions.
The blood carries the hormone to a target organ where it produces an effect.
Some of the hormones act on other glands and stimulate them to release hormones to bring special effects.
The endocrine system is composed of glands that secrete chemicals called hormones directly into the bloodstream.
Key endocrine gland are the pituitary gland, thyroid gland, pancreas, adrenal glands, ovaries and testes.
Pituitary gland
FSH stimulate ovaries to secret oestrogen
TSH stimulates thyroid gland to secret thyroxine.
ADH affect amount of urine produced.
The control of blood glucose levels
Type 1 diabetes, blood glucose may rise to high levels because pancreases doesn't secrete enough insulin.
Type 2, body stops responding to own insulin - causes obesity
Pancreas produces insulin, which allows glucose to move from the blood into cells and stored as glycogen in the liver and muscles.
Blood glucose is monitored and controlled by the pancreas.
Treating diabetes
Type 2
Carbohydrate-controlled diet and taking more exercise.
Or drugs
Type 1
Controlled by injecting insulin to replace hormone.
New methods - pancreas transplants, pancreas cell transplant
Artificial control of fertility
Contraceptive methods
Oral contraceptives, hormonal injections, implants and patches, barriers methods - condom and diaphragm, intrauterine devices, spermicidal agents, abstinence, and surgical sterilisation.
Can be controlled by hormonal and non-hormonal methods.
Human reproduction
Oestrogen is the main female reproductive hormone produced by the ovary.
Testosterone is the main male reproductive hormone produced by the testes. Stimulates sperm production.
During puberty reproductive hormones cause secondary sexual characteristics to develop.
Menstrual cycle
FSH, LH, oestrogen and progesterone
Each month - eggs mature & thick lining in uterus - 28 days egg released from ovary (ovulation) - if not fertilised lining and egg are shed.
At puberty eggs begin to mature in the ovary and one is released every 28 days.