Nervous system and homeostasis

Things i just need to remember T-T

Hypothalamus

Regulates body temperature and water balance in the body

Medulla

Controls unconscious activities eg heart rate and breathing

Cerebellum

Controls balance, co-ordination of movement and muscular activity

Cerebrum

• Outer layer = cerebral cortex

• Controls intelligence, personality, conscious thought, and high level functions eg language/ memory

Motor neurones

Send electrical impulses to an effector

Effector

Produces a response to the stimulus

Stimulus

Change in environment

Sensory neurone

Sends electrical impulses to the relay neurone

Relay neurone

Located in the spinal chord, they connect the sensory and motor neurones

Synapse

• Spaces between neurones when the electrical impulses are turned into a chemical messengers

• they can ‘diffuse’ across the neurones and bind to the specific neurotransmitters

• these stimulate the next neurone to transmit the electrical impulse

Neurotransmitters

A chemical involved in passing nerve impulses from one nerve cell to the next (across a synapse)

Neurones bind to SPECIFIC neurotransmitters

Electrical stimulation

• A non invasive procedure, the brain is stimulated by a small electric current,

• depending on the patients response, scientists can locate which part of the brain was stimulated

• Eg. If the patient makes an involuntary movement, the motor area has been stimulated

• Done with EEGs

MRI (brain scan)

• Use strong magnetic fields and radio waves

• Shows details of brain structure and function

• If a person carries out tasks while under an MRI scan, scientists can see which parts of the brain are active as the task is carried out.

Risks of investigating and treating the brain

• some conditions, such as tumours, may require surgery, this could cause more damage/ side effects

• Risks need to be weighed against benefits in order for it to be ethical and practical

Cornea

Transparent and curved, lets light in and refracts it so that it is focused onto the retina

Iris

Controls how much light is let into the pupil, it is the coloured part of the eye that contains muscles that contract and relax

Pupil

Hole that lets in light

Sclera

Tough white outer layer that protects the eye

Lens

Sits behind pupil and focuses light onto the retina

Optic nerve

Nerve that carries impulses between the eye and the brain

Ciliary muscle and Suspensory ligament

Contracts and relaxes to change the shape of the lens