Year 9 Science – Exam rev

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.

Endocrine system

A collection of glands that make and release chemical messengers Called hormones which help regulate body functions to maintain homeostasis

Gland orders top to bottom

Hypothalamus, pituitary gland, thyroid gland, thymus, Adrenal gland, pancreas, ovaries, tests

Cell structure top to bottom

Dendrites, nucleus, cell body, axon, Mylons seath, axon terminal

S.R.C.E.R

stimulus, response, control centre, effector, response

Stimulus

Something in the internal or external environment that excites a receptor

Receptors

A cell containing a high concentration of sensitive nerves

Control center

The part of the body that receives impulses from receptors to decide our reactions

Effector

Communicates directly to the brain, muscles or glands

Voluntary

A response to a stimulus that you can control and think about

Involuntary

A response to a stimulus that you can not control or think about

Positive feedback

Acts in the direction of the stimulus to maintain stable environment e.g. lactation, contractions

Negative feedback

Opposes the direction of the stimulus to maintain stable environment e.g. temp change, glucose regulation, water regulation

Temp decrease nervous system

Thermo receptors, hypothalamus, blood vessels & muscles, vasoconstriction & shivering

Temp increase nervous system

Thermo receptors, hypothalamus, sweat glands & blood vessels, sweating, vasoconstriction

Temp decrease endocrine system

Thermo receptors in hypothalamus , hypothalamus, pituitary gland increase TSH and thyroxine levels

Temp increase endocrine system

Thermo receptors in hypothalamus , hypothalamus, pituitary gland decrease TSH and thyroxine levels

Too much glucose

Blood thickens, damages blood vessels and can lead to stroke or heart disease

Not enough glucose

Dizziness, fatigue, unconsciousness and death

Glycogen

Form in which glucose is stored in the liver

Glucose management system

Glucose is turned into glycogen to store, glycogen is turned to glucose by glucagon to use

High glucose

Pancreas, pancreas, insulin

Low glucose

Pancreas, pancreas, release glucagon

Low water nervous system

Hypothalamus manages blood and water osmolarity

Low water endocrine system

Hypothalamus, hypothalamus, pituitary gland, increase ADH produced to stop water loss to urine

High water endocrine system

Hypothalamus, hypothalamus, pituitary gland, decrease ADH production to allow water to leave the body

Ionic bonding

When one atom usually a metal gives up a valence electron to another atom usually a non metal

Electrostatic force

The attraction between negative and positive ions which creates a 3D lattice structure

Ployatomic ions

Chemically bonded atoms with an overall charge

Ide, ate, it’s

IDE - on periodic table, neg charge

Ate - more oxygen ions not on periodic table

Ite - not on periodic table

Average speed

Speed = d/t

Speed = Vav

Average velocity

Average velocity = displacement/time

Change in velocity

Final velocity - initial velocity

Acceleration

Acceleration = change in velocity/time

Types of force

Friction, applied, drag(air resistance ), magnetic, electric, normal(stable), spring, gravity

Force due to gravity

Fg =m x g

g = 9.8 N

unit = N/kg