coordination and response and the eye Flashcards
how does the nervous system work
a receptor receives a stimuli, which then sends a message to the control centre which then in turn sends a message to an effector
what are types of receptors
thermoreceptors, auditory receptors, olfactory receptors, photoreceptors, peripheral chemoreceptors(chemical changes in the blood) and nociceptors(detecting and responding to pain), baroreceptors(pressure)
what are examples of effectors
muscles and glands
what sense organ contains photoreceptors
eyes light is its stimulus and the function of it is sight
what sense organ contains baroreceptors
ears its stimulus is air vibrations and its function is to hear
what sense organ contains chemoreceptors
nose its stimulus being chemicals and its function being to smell
what sense organ contains chemoreceptors
tongue its stimulus being chemicals and its function being to taste
what sense organ contain thermoreceptors and mechanoreceptors
skin its stimulus being heat pressure and its function being to touch
what is the function of a sensory neurone
transporting the message from the stimulus to the CNS
what is the function of a relay neurone
In CNS
Message from sensory neurone passed to motor neurone
what is the function of a motor neurone
Comes from CNS
Message ends with EFFECTOR
what is a synapse
Where the electrical impulse passes from one neurone to the next
what is the iris
the coloured part of the eye which can expand and contract to control the amount of light that enters the eye.
what is the ciliary muscle
changes the shape of the lens for focusing
what is the pupil
the circular opening which lets light into the eye. It appears black because the choroid is visible through it.
what is the cornea
a transparent layer responsible for most of the refraction (bending) of light rays that enter the eye.
what is the retina
contains the light-sensitive cells, the rods and cones.
what is the yellow spot
this area has the highest density of cones and thus offers maximum sharpness but only works at full efficiency in bright light.
what is the vitreous humor
a jelly-like substance which helps to keep the shape of the eyeball, supports the lens and keeps the retina in place at the back of the eye.
what is the aqueous humor
watery fluid which supports the cornea and the front chamber of the eye.
what is the suspension ligament
attaches ciliary muscles to the lens
what is the function of the lens
helps to focus
what is the chloroid
a darkly coloured layer which reduces reflections inside the eye and contains blood vessels which help to nourish the cells of the retina.
what is the sclera
the tough outer coat which protects the eye against damage. The muscles that move the eye in its socket attach to the sclera.
what is the optic nerve
composed of sensory neurones which carry nerve impulses to the visual centre at the rear of the brain.
what is the blind spot
at the exit point of the optic nerve. There are no light-sensitive cells here so light falling on this region cannot be detected.
what is a rod light receptor
Sensitive to low light intensities – enable us to see in black and white
what is a cone light receptor
Sensitive to high light intensities– enable us to see in colour
