B1- The Nervous System Flashcards
What is the main job of the nervous system
React to surroundings and coordinate behaviour
What are the two nervous systems and what do they contain
Central nervous system and the peripheral nervous system. They contain receptors and neurones
What part of the nervous system detects changes in surroundings
Receptors
What are the bodies nerve endings and what do they detect
Light receptors in the eyes
Sounds receptors and balance receptors in the ears
Taste receptors on the tongue
Smell receptors in the nose
Touch,pressure and pain receptors in the skin.
What are neurones
Specially adapted cells that can carry a nerve impulse
What is a nerve impulse
Electrical messages that are carried along the axon
What are the three neurones
Sensory
Relay
Motor
What does the sensory neurone do
Carry nerve impulse from the receptors to your brain
What does the relay neurone do
Make connections been neurones in your brain and spinal cord
What does the motor neurones do
Carry nerve impulses from your brain to your muscles and glands
What are 3 properties of neurones and what are they for
Long shape of I make connections between parts of the body
Insulating sheath to speed up the nerve impulse
Dendrites or branched endings to allow a single neurone to act on many muscle fibres
What is a synapse
A small gap between neurones
How do synapses work
A transmitter substance diffuses the neurone across the synapse and then the transmitte binds with a receptor on the next neurone, causing the electrical impulse to be initiated in to that neurone
What are voluntary actions
Conscious decisions you make in response to a stimulus
What is the main job of the nervous system
React to surroundings and coordinate behaviour
What are the two nervous systems and what do they contain
Central nervous system and the peripheral nervous system. They contain receptors and neurones
What part of the nervous system detects changes in surroundings
Receptors
What are the bodies nerve endings and what do they detect
Light receptors in the eyes
Sounds receptors and balance receptors in the ears
Taste receptors on the tongue
Smell receptors in the nose
Touch,pressure and pain receptors in the skin.
What are neurones
Specially adapted cells that can carry a nerve impulse
What is a nerve impulse
Electrical messages that are carried along the axon
What are the three neurones
Sensory
Relay
Motor
What does the sensory neurone do
Carry nerve impulse from the receptors to your brain
What does the relay neurone do
Make connections been neurones in your brain and spinal cord
What does the motor neurones do
Carry nerve impulses from your brain to your muscles and glands
What are 3 properties of neurones and what are they for
Long shape of I make connections between parts of the body
Insulating sheath to speed up the nerve impulse
Dendrites or branched endings to allow a single neurone to act on many muscle fibres
What is a synapse
A small gap between neurones
How do synapses work
A transmitter substance diffuses the neurone across the synapse and then the transmitte binds with a receptor on the next neurone, causing the electrical impulse to be initiated in to that neurone
What are voluntary actions
Conscious decisions you make in response to a stimulus
What are reflex actions
Automatic responses to a stimulus to help protect your body from harm
Give an example of a reflex action and a voluntary action
Voluntary- spitting out food you don’t like
Reflex- taking the your hand off something hot to prevent getting burned
What are they iris,cornea,lens and optic nerve
The iris is the coloured bit of the eye and it controls how much light enters the eye. The cornea refracts the light and the lens focus uses light on to the retina so they Ray’s converge ( come together ) at a single point producing a clear image on your retina.the receptors on the retina cause nerve impulses to be sent to the brain
Why a re common eye defects
Long and short sightedness
Red- green colour blindness
What causes red green colour blindness
Specialised cells in the retina that detect red and green light are missing
What causes long and short sightedness
The lens being the wrong shape so the light rays can’t be focuses on the retina accurately
What ways can correct long or short sightedness and what lens is needed to correct each
Glasses, contact lenses or laser surgery.
Long sighted is corrected by. Convex lens, short sighted is corrected by a concave lens .
How does laser eye surgery work
A flap is cut into the cornea folding it back and the laser reshape the cornea.this means the light can focus on the retina properly
