The Special Senses Flashcards
Where are the special senses processed?
In the CNS
What are the sensory systems?
Somatosensory system (pressure,warmth, vibration, limb position)
Sight (visual)
Hearing (auditory)
Taste (gustatory)
Smell (olfactory system)
What are the accessory structures of the eye?
Eyebrows
Eyelids or palpabrae
Eyelashes
Conjunctiva
Lacrimal apparatus
Extrinsic eye muscle
What are the characteristics of the conjunctiva?
Transparent mucous membrane
Important for lubrication and protection
What are the structures of the lacrimal apparatus?
Lacrimal gland (responsible for tears)
Nasolarimal duct (goes to nasal cavity)
What are the three layers of the eye wall?
Fibrous layer
Vascular layer
Nervous tissue layer
What is contained within the fibrous layer?
Sclera (white of the eye)
Cornea (front of the eye)
What is contained within the vascular layer?
Choroid (melanin containing cells)
Ciliary body (ciliary muscles change the thickness of the lens)
Iris (coloured part of the eye)
What is contained within the nervous tissue layer?
Retina
-outer= pigmented retina scatters light
-inner= sensory retina
What is the path of vision in the eye?
Iris allows light into the eye
Focused by the cornea, ,SNS, and humours onto the retina
The lights tricking the retina produces action potential that are relayed to the brain via the optic nerve
What are the two chambers of the eye?
Anterior segment (front of lens)
Posterior segment (behind the lens)
What is contained within the anterior segment of the eye?
Anterior chambers (between cornea and iris)
Posterior chambers (between iris and lens)
Aqueous humour (fills anterior segment) (maintains pressure, refracts light)
What is contained within the posterior segment?
Vitreous chamber
Vitreous humour
What are the two layers of the retina?
Outer thin pigmented layer (melanocytes)
Inner thicker neural layer (contain three types of neurones)
What neurones are contained within the inner thicker neural layer of the retina?
Photoreceptors
Bipolar cells
Ganglion cells
What are the regions of the (posterior) retina?
Macula (high res colour vision)
Optic disc (blood vessels enter eye, no photo receptors)
What is the process of light passage through the eye?
Light passes through anterior cavity
Focused by lens
Passes through vitreous humour
Pass between axons, ganglion cells and bipolar cells
Reach photoreceptors next to pigmented layer
What is the direction of travel of neuronal signal in the eye?
Photoreceptors synapse with bipolar cells
These synapse with ganglion cells
These run on internal surface and converge at posterior of the eye
These forms optic nerves which exits the eye