General senses
somatic & visceral
Special senses
smell, taste, vision, hearing & equilibrium
Olfaction
sense of smell
olfactory epithelium consists of olfactory receptors, supporting & basal cells
Olfaction
(3) cells in olfactory epithelium
1) olfactory receptor - bipolar neuron with cilia (olfactory hairs) that respond to odorants
2) supporting cells- support & nourishment
3) basal cells - replace olfactory receptors
Physiology of Olfaction
Odorant binds to receptor of olfactory hair→ G-protein activation→
activation of adenylate cyclase→ production of cAMP→ opening of Na+ channels→ inflow of Na+ →generator potential→ nerve impulse through olfactory nerves → bulbs →tract →primary olfactory area
Gustation
taste buds -found in papillae - (vallate, fungiform, foliate)
- made up of (3) cells: supporting, basal cells, gustatory receptor cells (50 per taste bud)
each gustatory receptor cell has a gustatory hair that projects through taste pore
Physiology of gustation
5 types of taste: sour, sweet, bitter, salty & umami
Tastant dissolves in saliva → PM of gustatory hair→ receptor potential→ nerve impulse via cranial nerves VII, IX & X→ medulla→ thalamus→ primary gustatory area of cerebral cortex.
Lacrimal Apparatus of Eye
group of structures that produces & drains lacrimal fluid (tears)
Lacrimal Apparatus
production & pathway of tears
Tears from the lacrimal apparatus- lacrimal glands→ excretory lacrimal ducts→ lacrimal puncta→ lacrimal canals→ nasolacrimal sac→ nasolacrimal duct
Wall of eyeball
(3) layers
1) fibrous tunic
2) vascular tunic
retina
(3) layers of wall of eyeball
1) fibrous tunic
2) vascular tunic (uvea)
retina
1) OUTER
sclera - white of eye
cornea - transparent coat covering iris
2) choroid - lines internal surface of sclera
becomes ciliary body consists of ciliary processes & ciliary muscle
Iris
3) Optic Disk - blind spot, where optic (II) nerve exits
Macula lutea - fovea centralis: area of highest visual acuity
