B10 Nervous Control In Humans Flashcards
Stimuli
Changes in the environment
Examples of sense organs
Ears, eyes, skin etc.
The types of skin receptors
1) touch corpuscle
2) free nerve ending (pain)
3) pressure corpuscle
4) cold receptor
5) heat receptor
Central nervous system
AKA the CNS. Formed by the brain and the spinal cord. It is for processing information
The peripheral nervous system
AKA the PNS. Formed by many different kinds of nerves and extends throughout the body. It is for movement and senses.
Sensory neurone
The cell that connects the receptor to the CNS
Co-ordinator
What brings about a response (usually the brain) in a message
Motor neurone
The cell that connects the CNS to the effector
The effector
The organ, muscle or gland that starts a response
Flow chart of how a response is produced
Receptor to sensory neurone to co-ordinator to motor neurone to effector
Relay neurone
Connects the sensory neurone to the motor neurone. They look like a smaller version if the motor neurone. It bypasses the brain so the body can react faster*
A message is STILL sent to the brain so you register the sensation (e.g pain)
Receptors and where they are found
Groups of specialized cells that detect stimuli and turn them into electrical impulses. They are often located in the sense organs. Each organ has receptors sensitive to particular kinds of stimulus
Features of a motor neurone
Very long axons- allows it to transmit nerve impulses over long distances
Has many branches- so it can receive signals from all directions
Axon surrounded by fatty myelin sheath- acts as insulation, prevents electrical impulses from leaking out of the neuron
Nerve fibres
Strands of cytoplasm. What dendrites and axons are made up of
Difference between nerve and neurone
Nerve- compromised of a bundle of nerve fibres wrapped in connective tissue
Neurone- a specialised cell with a cell body, dendrites and axon
Synapse
The gap where two neurones meet.
Neurotransmitters
The chemicals that cross the synapse and pass the message on.
Change in pupil size in dim, bright and normal lighting
Dim- large, to absorb more light
Bright- small, to minimize damage to eye
Normal- medium/ normal sized
Iris
What controls the amount of light entering the eye
Pupil
The space that allows light to enter
Choroid layer
The black layer of the eye containing blood vessels that stops light being reflected around inside the eye. It absorbs light
Scleroid layer
AKA the scelera. Tough, white and protective layer around the pupil.
Fovea
The most sensitive part of the retina. Yellow in color
Cornea
Lets light enter the eye. Transparent
