Sensory systems Flashcards
What is the pupil?
It is the opening in the middle of the eye which is often black. Light passes through this
What is the iris?
the visible coloured ring at the front of the eye
Why does the iris adjust?
To control the amount of light entering the eye through the pupil
What are tear glands?
AKA lacrimal glands
produce tears to clean and lubricate the front of the eye
What does the fluid found in tear glands contain?
Salt and natural antiseptic properties which defend against infection
What are aqueous and vitreous humours (fluids)?
Watery, jelly like fluids that fill the eye.
What do aqueous and vitreous humours do?
They keep the eye in shape and nourish it
What is the conjunctiva?
A thin membrane that protects the cornea
What is the cornea?
A transparent film through which light rays pass into the retina of the eye.
Where is the cornea found ?
At the front of the eye
What is the retina?
The inner lining of the eye which contains light sensitive cells called rods and cones
macula
Has a very high concentration of photoreceptor cells
What do macula detect?
It detects light and sends signals to the brain which interprets them as images.
What is the optic nerve?
It is where the nerve cells exit the eye.
Why is the optic nerve known as the blind spot?
Because there are no rods or cones
What is the ciliary muscle?
A muscle that enables the lens to change shape for focusing
How does the cilliary muscle stretch the lens?
By contracting
By contracting, what does the ciliary muscle become?
Flatter and thinner
What do suspensory ligaments do?
Attach the lens to the ciliary muscle