The Nervous System And Hormones Flashcards
What is a stimulus?
Anything we respond to e.g light
What do receptors do?
Detect stimuli
What do effectors do?
Respond to a stimulus e.g muscles or glands
What are the brain and spinal chords?
Coordinators
What is the function of the cornea?
Allows light to enter and causes some refraction
What part of the eye contains neurons to send information to the brain?
The optic nerve
What is the function of the vitreous humours?
To maintain the shape of the eye and keeps the retina against the wall of the eye
What is it called when the thickness of the lens can be adjusted to focus light rays of near/distant objects?
Accommodation
What is the ciliary body?
A ring of muscle surrounding the lens
Name the changes that occurs in the eye when focusing on near objects:
Ciliary muscle contracts to form a tight circle with a small diameter
Suspensory ligaments become slack
The lens springs back into its original thick shape
Name the changes that occur in the eye when focusing on distant objects:
The ciliary muscle relaxes and give a big diameter
Suspensory ligaments tighten and pull the lens
The lens becomes thinner
Name the three types of neuron:
Sensory
Association
Motor
Name the adaptions of neurons:
Branched ends to allow them to transmit impulses over a greater area
Long axon to transmit information from the CNS to the extremities of the body
Insulating myelin sheath - speeds up nerve impulses
What are synapses?
Gaps between neurones
Describe a transmission across a synapse:
Electrical impulse reaches end of axon
Causes neurotransmitter to be released
It diffuses across synapse to next neuron
If the concentration is high enough an impulse will be triggered in next neurone
