Ch. 21 Special Senses Flashcards
Olfaction
- olfactory epithelium
- 3 kinds of cells: olfactory receptor cells, supporting cells-door binding proteins, basal cells
- olfactory (Bowman’s) glands: mucous producing glands to moisten epithelial surface and dissolve the ordinary molecules
Olfactory Pathway
olfactory receptors- olfactory nerves- olfactory bulbs- olfactory tract- cerebral cortex-
primary olfactory area (temporal lobe)- perception of smell
limbic system and hypothalamus- behavioural responses
orbitofrontal areas (frontal lobe)- odor identification
Gustation
5 primary tastes
- all other tastes are combined of these five
Anatomy of Gustation Receptors
- receptors for taste are located in the taste buds
- number of taste buds declines with age
- each taste bud consists of three kinds of epithelial cells: supporting cells, gustatory receptor cells, basal cells
- supporting cells contain microvilli and surround gustatory receptor cells: gustatory microvilli (hairs)
Taste Buds
- found in elevations on the tongue called papillae
- circular vallate papillae: form an inverted V-shaped row at back of tongue
- fungiform papillae: mushroom-shaped elevations scattered over entire surface of tongue that contain about five taste buds each
- foliate papillae: located in small trenches on the lateral margins of the tongue, most degenerate in early childhood
- filiform papillae: contain tactile receptors but no taste buds; increase friction between the tongue and food, making it easier for the tongue to move food in oral cavity
Gustatory Pathway
gustatory receptor- CN VII and XI- taste buds- gustatory nucleus-
thalamus- parietal lobe- primary gustatory area- perception of taste
- limbic system and hypothalamus- behavioural responses
Vision (eyelids)
- palpebrea
- levator palpebrae superioris muscle
- palpebral fissure
- lateral commissure and medial commissure
- lacrimal caruncle
- tarsal plate
- tarsal glands (Meibomian glands)
- Chalazion= a tumor or cyst in tarsal glands
- conjunctiva
- palpebral conjunctiva
- bulbar conjunctiva
- sebaceous ciliary glands
- eyebrows and eyelashes
Lacrimal Apparatus
- lacrimal apparatus produces and drains lacrimal fluid or tears
- lacrimal ducts
- lacrimal puncta
- lacrimal canaliculi lead into the lacrimal sac and the nasolacrimal duct
Anatomy of the Eyeball
Fibrous Tunic: sclera, cornea, scleral venous sinus
Vascular Tunic: choroid, ciliary body/process, iris, pupil, lens
Retina
Retina
- optic disc
- central retinal artery and central retinal vein
- pigmented layer: melanin in pigmental layer of retina helps absorb light rays
- neural sensory layer
- 3 layers of retinal neutrons: photoreceptor, bipolar and ganglion layer
- cells present in bipolar layer: horizontal and amercing cells
- rods and cones
- photopigment molecules
Anterior and Posterior Chambers of the Eye
- anterior cavity
- aqueous humor
- anterior and posterior chambers
- vitreous chamber
- vitreous body
- vitreal floaters
Visual Pathway
bipolar cells- optic nerve- optic chiasm- optic tracts- lateral geniculate nucleus- primary visual areas of occipital lobes- superior colliculi-visual reflexes- pretectal nuclei-accomodation of reflexes
Ear (external)
- collects sound waves
- auricle
- external auditory canal: ceruminous glands
- tympanic membrane: umbo and malleus
Middle Ear
- transmit sound waves to oval window
- auditory ossicles: malleus, incus, stapes
- head of malleus articulates with incus; articulates with stapes and the footplate of the stapes fits into the oval window
- tensor tympani muscle
- stapedius muscle
- auditory tube “eustachian tube”
Internal Ear
- labyrinth
- 2 main divisions: outer bony labyrinth encloses an inner membraneous labyrinth; perilymph; endolymph (houses receptors for equilibrium and hearing)
- 3 main areas on bony labyrinth
1. semicircular canalds= circular motion
2. vestibule= utricle and sacculae- linear motion
3. cochlea= organ of corti
