Year 9 Science – Homeostasis & Endocrine System Study Notes

Homeostasis

The maintenance of a constant internal environment despite changes to the external environment

photoreceptors

colour and light

mechanoreceptors

sound and pressure

Chemoreceptors

Chemical change

Nociceptors

Pain receptors

Thermoreceptor

heat or temperature change

Hormones

-Protine molecules

-Produced in glands in small amounts

-travel in the blood

-travel slower than nervouse impulses

-Travel through all parts of the body(because they travel in the blood stream)

-Co-ordiate long term process such as growth and sexual development

-connect specifically to their targets(receptors) like ‘lock & key’

Pituitary Gland

ADH(Antidiuretic hormone), FHS (Follicle Stimulating Hormone), LH(Luteinizing Hormone), GH(growth Hormone), TSH(Thyroid Stimulating Hormone),

Thyroid Gland

Thyroxine

Pancreas

Insulin, Glucagon

Adrenal Gland

Adrenalin

Testes

Tesostrone

Ovaries

Progesterone, Oestrogen

ADH(Antidiuretic hormone)

Water absorption in your kidneys

FSH (Follicle Stimulating Hormone)

Causes follicles in the ovaries to develop and secrate oestrogen

LH (Luteinizing Hormone)

Causes ovulation

GH (growth)

bone and muscle growth

TSH(Thyroid Stimulating Hormone)

Stimulates the thyroid gland to release its hormones

Thyroxine

regulates the rate of cell metabolism

Insulin

lowers glucose but turning it into glycogen to be stored in the liver

glucagon

increases glucose in the blood and controls the transformation of glycogen to glucose in the liver

adrenalin

causes the flight or fight instinct and all symptoms related

Testosterone

promotes development of male secondary sexual characteristics

Progesterone

thickens uterine wall and prevents contraction until the baby is born

oestrogen

controls development of female secondary sexual characteristics and regulates menstruation.