Co-ordination and Response in Humans Flashcards
what is the central nervous system made up of?
the central nervous system consists of the brain and the spinal cord
what is a sensory neurone?
transmits nerve impulses from the sense organs or receptors to the central nervous system
what is a relay neurone?
transmits nerve impulses from the sensory neurone to the motor neurone.
where is a relay neurone found?
they are found within the central nervous system
what is a motor neurone?
transmits nerve impulses from the central nervous system to the effectors
how does a nerve impulse get transmitted from a neurone to another neurone?
nerve impulses are transmitted across a synapse via neurotransmitters from the (___ neurone) to the (___ neurone)
what is the reflex action?
it is a involuntary action, an immediate response to a specific stimulus without conscious control
what is the reflex arc?
a reflex arc is the shortest pathway which nerve impulses travel from the receptor to the effector in a reflex action
describe the pathway taken when a person moves his arm reflectively away from a source of pain.
- [receptors] in the skin detect the** [pain >stimulus],** and a nerve impulse is generated
- the nerve impulse impulse is transmitted by a [sensory] neurone to the spinal cord to a** [relay]** neurone via neurotransmitters across a synapse
- the relay neurone transmits the nerve impulse to a [motor] neurone via neurotransmitters across a synapse
- the motor neurone transmits the nerve impulse to an [effector>arm muscle] via the ventral root
- the muscle **[reaction>contracts **]and moves the arm away
S,R,S,R,M,E,R
what is the choroid?
contains a lot of blood capillaries, supplies nutrients to cells in the eye
- there is a layer of pigment(melanin) between the retina and choroid that absorbs light, to prevent reflection of light within the eye.
function of the cornea?
it refracts or bend light rays into the eye
what are the 2 kinds of photoreceptors in the retina?
rod cells and cone cells
what are rod cells?
rod cells are photoreceptors in the retina, that detect light (black and white visions)
- they are present throughout the retina EXCEPT the fovea and the blind spot
what are cone cells?
cone cells are photoreceptors in the retina, that detect light (red/green/blue)
- present at highest concentration at the fovea, absent at the blind spot
pupillary reflex (when it is bright, what happens to the eye?)
Circular muscles of the iris > contracts
Radial muscles of the iris> relax
pupils> constrict
amount of light entering the eye> reduced