Vision Flashcards
What are the four special senses?
Vision, hearing, taste and smell.
Outline what happens with the information the sensory organs recieve?
The sensory organs transmit information from the external environment to the CNS, so that the appropriate responses can be taken.
What are the functions of the eyelids?
Through blinking it keep the eyes lubricated and removes dust.
What are the funtions of the eyelashes?
The eyelashes prevent foreign materials from entering the eyes.
What is the iris?
This is the coloured area of the eye, which surrounds the pupil.
What is the pupil?
This is the dark circle in the centre of the eye, through which light passes.
What is the conjunctiva?
This is an epithelial layer which lines the inside of the eyelid and the outer surface of the eye
What is the role of the lacrimal glands?
These glands produce tears which keep the conjunctiva moist and clean.
The eyeball consist of two fluid filled sacs, what are they called?
Anterior and Posterior cavities
What structure separates these cavities?
The lens
How many layers does the eyeball contain?
3 Layers
Name the first layer and what it contains
Fibrous Tunic- protects the eye and contains muscles which help the eye to move, also contains the sclera (white part of the eye) and the cornea (transparent layer which covers the iris and pupil).
Name the second layer and what it contains
Vascular Tunic- contains blood vessels and smooth muscles. Consists of the iris (coloured part of the eye), the choroid (capillary networks) and the cilliary body (suspensory ligaments which holds the lens)
Name the third layer and what it contains
Neural Tunic- contains photoreceptors which respond to light called rods (numerous, respond to dim light) and cones (less numerous and require more light but allow colour vision. Also contains the retina
What is the retina?
This structure is the innermost layer of the eye, which has been specially adapted so that it can be stiumlated by light rays. It only contains nerve cell bodies and their fibres.
