14. Coordination and Response Flashcards
What travels along neurones?
electrical impulses
What two systems comprise the mammalian nervous system?
central nervous system (CNS)
peripheral nervous system (PNS)
What does the CNS consist of?
brain and spinal cord
What does the PNS consist of?
nerves outside of brain and spinal cord
What is a nerve?
tissue made of many different neurones
What is the role of the nervous system?
coordination and regulation of body functions
What is the order of the reflex arc?
receptor, sensory neurone, relay neurone, motor neurone, effector
What does a sensory neurone do?
receives electrical impulses from a receptor and sends it to a relay neurone (towards CNS)
What are some different types of receptors?
visual
olphatory
auditory
touch
taste
What does a relay neurone do?
receives electrical impulses from a sensory neurone, sends it to a motor neurone.
information received is processed in the brain for an appropriate response.
What does a motor neurone do?
receives electrical impulses from a relay neurone (from the CNS) and sends it to effectors
Where are effectors found?
muscles and glands
What is the structure of a sensory neurone, simply?
cell body in the middle, long
What is the structure of a relay neurone, simply?
cell body at the top, short, no myelin sheath
What is the structure of a motor neurone, simply?
cell body at the top, long
Which neurone(s) do(es) not contain myelin sheath?
relay neurone
What are dendrites?
extension of cell membrane that captures electrical impulses
What is an axon?
extension of cell membrane that conducts the electrical impulse
What are synaptic ends?
branches of the axon that will connect to another neurone
What is a myelin sheath?
fat layer that insulates the axon
What is the role of the myelin sheath?
allows a faster electrical impulse by insulation the axon
Define the term ‘reflex action’.
a means of automatically and rapidly reacting to stimuli by coordinating our effectors (muscles/glands)
or
autonomic/involuntary reaction of the body against dangerous situations
What is a synapse?
a junction between two neurones
Describe the events at a synapse.
- impulse stimulates release of neurotransmitters from vesicles into synaptic gap
- neurotransmitters diffuse across synaptic gap
- neurotransmitters bind to receptor proteins on postsynaptic neurone
- impulse stimulated in postsynaptic neurone
What happens to neurotransmitters once an impulse is sent?
they are recycled or destroyed
What do synapses ensure?
impulses flow in one direction only
What does a sense organ consist of?
a group of receptor cells that respond to specific stimuli
What is the function of the cornea?
refracts light
What is the function of the iris?
controls how much light enters the pupil
What is the function of the lens?
focuses light onto the retina
What is the function of the retina?
contains light receptors, some sensitive to light levels, some to light of different colours
What is the function of the optic nerve?
carries impulses to the brain
What does the iris consist of?
radial and circular muscles
What happens to your iris when exposed to bright light?
circular muscles contract
radial muscles relax
What happens to your iris when exposed to dim light?
radial muscles contract
circular muscles relax
What correlation do radial and circular muscles have?
they are antagonistic
How does light from far away objects enter the eye?
in almost parallel lines
How does light from near objects enter the eye?
diverging lines
What happens to ciliary muscles when seeing far away objects?
relax
What happens to the tension in the suspensory ligaments when seeing far away objects?
increases