Special senses - Sight and Sound Flashcards
Which of the five senses is NOT a special sense?
TOUCH
The rest of the senses have a specialized organ that detects the stimuli, but touch is not specialized because there are touch receptors everywhere!!
What is the sense organ for sight?
Eyes
What is the sensory layer for sight?
Retina
What is the stimulus for sight?
Photons
What are the receptor cells for sight?
Photoreceptors
Where does photoreception occur?
Retina
Describe the structural components of the eye?
Anterior cavity
Aqueous humour
Posterior cavity
Vitreous humour
Cornea
Lens
Retina
Where is the anterior cavity of the eye and which humour does it contain?
Between lens and cornea
- containing aqueous humour
Where is the posterior cavity of the eye and which humour does it contain?
Between lens and the back of the eye
- containing vitreous humour
Compare aqueous humour to vitreous humour
Aqueous humour is more fluid-like, a salt solution
Vitreous humour is gel-like, more solid
The both o them are responsible for maintaining the shape of the eye, cushioning
What are some accessory structures in the eye?
- eyelashes
- eyelid
- pupil
- iris
How do accessory structures in the eye participate in physical protection?
- protect the eyes
- keep it lubricated
- keeps out foreign substances
How do accessory structures in the eye participate in controlling access of light?
- iris plays a significant role in controlling access of light
- can dilate or constrict to allow more or less light into the eye
in darkness, dilator layer causes pupil dilation (widens to allow more light)
in light, sphincter layer constricts pupil (allows less light into the eye)
What is the iris and its functions?
An accessory structure(?) of the eye that consists of two smooth muscle components
- controls access of light
- has a radial pattern in the muscle that contracts in darkness to open up pupil
Dilator layer = pupil dilation
Sphincter layer = pupil constriction
What is the cornea?
A special fibrous layer of connective tissue
What is the retina?
The sensory layer of the eye found at the back
What is the pupil?
A hole
- absence of the iris muscle
- allows light to come in to the sensory layer
How is light brought to a focal point?
Via the LENS
- the lens refracts light and brings light into focus
- changing the shape of the lens changes how we can bend light coming into our eyes
What is acommodation?
the bending of light/changing the shape of the lens to reach the focal point
What is the ciliary body?
Two smooth muscle layers that is connected to the lens via connective tissue
What is the function of the ciliary body?
Participate in accommodation - changing the distance focal point by controlling the shape of the lens
For close vision: What kind of accommodation is required?
Ciliary muscle contraction
= lens ROUNDED
For distant vision: What kind of accommodation is required?
Ciliary muscle relaxed
= lens FLATTENED
Describe the layers of the retina?
The retina is a multi-layered sheet of neurons