Nervous System Flashcards
What does the human nervous system consist of
The central nervous system (CNS) and peripheral nervous system (PNS)
What is the CNS?
The brain and spinal chord
What is the PNS?
Nerve cells that carry information from or to the CNS
What is information carried by?
Nerves which are bundles of neurons
What are neurons?
Long cells that carry electrical signals
What’s the gap called where neurons meet?
The synapse
How do signals pass the synapse?
Chemically to the next neuron, where the electrical pulse continues
What is a receptor
A sense organ
What is an effector
A muscle or gland
What is the coordinator
The brain or spinal chord
How does information flow form receptors to effectors
From the receptor, via sensory neurons, to the coordinator, and then through motor neurons to the effector
What are the changes in the world around us to our nervous system
Stimuli
What do sense organs contain
Specialised cells called receptor cells
What are reflex actions?
A protective and automatic response to a stimulus
How are reflex actions different to normal ones?
They bypass the brain, and are coordinated by the spinal chord
What is the name for the nerve pathway in a reflex action?
A reflex arc
What is involved in a reflex arc?
stimulus → receptor → sensory neurone → relay neurone → motor neurone → effector → response
What is the eye?
A sensory organ controlled by light
Sorry can you try and memorize this :D
Cornea
Clear area of the sclera, it refracts light - bends it as it enters the eye.
Iris
Muscles which alter the size of the pupil, controlling the amount of light entering the eye.
Lens
Focuses light onto the retina.
Retina
Contains the light receptor cells.
Optic nerve
Carries impulses between the retina and the brain.
Sclera
White, tough outer layer.
Choroid
Pigmented middle layer with many blood vessels. It absorbs light to avoid reflection and nourishes the retina.
Blind spot
Where the optic nerve leaves the retina so lacks receptor cells.
Pupil
Small hole at the centre of the iris through which light enters the eye.
How does information flow from receptors to effectors?
- Stimulus
- Receptor
- Sensory neuron
- Relay neuron
- Motor neuron
- Efector
- Response
