Special Senses Flashcards
Types of cells within a taste bud
Sensory cells/taste receptor cell, supporting/sustenitacular cells and basal cells
Taste receptor cells
Apical microvilli with chemoreceptors at the apical pore
Sustentactular cells
Supporting sensory cells
May also be a stage in the development of the sensory cells
Basal cells of the taste bud
Act a stem cells
What happens when an appropriate chemical enters the taste pore
It binds and its receptor causes a release of a neurotransmitter from the sensory cells that stimulate sensory nerve endings
5 different tastes
Sweet, sour, bitter, salty and umani
Olfactory epithelium
Pseudostratified columnar epithelium
Cell types of olfactory epithelium
Olfactory receptor cells, support cells, receptor cells and basal cells
Olfactory receptor cells
Bipolar neurones and their nuclei are typically in the middle
Support cells of olfactory epithelium
Provide mechanical and metabolic support to the neurones
Nuclei in the basal part of epithelium
Basal cells of olfactory epithelium
Act as stem cells
Nuclei in the basal part of the epithelium
Receptor cells of olfactory epithelium
Have an olfactory vesicle that extends above the epithelium with non-motile cilia attached
Receptors on the cilia respond to odorants that we can detect and depolarise the cell, producing an action potential
Path of axons from olfactory receptor cells
Out of epithelium in bundles, through the cribriform plate of the ethmoid bone and into the olfactory bulb
What do the olfactory support cells secrete
Odorant binding proteins and enzymes that have a role in deactivating odorants to terminate their effect
What does the olfactory mucosa consist of
Olfactory epithelium and the underlying lamina propria
Lamina propria of olfactory mucosa
Contains connective tissue, blood vessels for warming the air, Bowman’s glands and bundles of axons
Function of Bowman’s glands
Produce a serous secretion that is released at the surface via ducts and dissolves odorants
Type of gland of Bowman’s gland
Tuboalveolar gland
What is the pinna of the ear and external auditory meautus covered by
Epidermis
Characteristic of ear canal
Hairy skin with sebaceous glands and modified apocrine sweat glands
Name of modified sweat glands in the ear canal
Cervminous glands
What do the cervminous glands produce
Cervmin - a yellowish waxy substance
Layers of the tympanic membrane
Outer layer of thin epidermis, middle layer of collagenous connective tissue and an inner layer of simple cuboidal epithelium
How many turns does the cochlea undergo
2.5
Name for the centre of the cochlea
Modiolus
Ganglion in the cochlea
Spiral ganglion - made of bipolar nerve cell bodies
Three compartments of the cochlea
Scala vestibule, cochlear duct and scala tympani
Name for the very tip of cochlea and what communicates here
Helicotrema and the scala vestibule and scala tympani
What does sound transduce through
Hair cells within the organ of Corti
What does the organ of corti sit on
The basilar membrane
Are high or low frequencies responded to at the tip of the cochlea
Low
Sets of hair cells
3-5 rows of outer hair cells
1 row of inner hair cells
What are the support cell of the hair cells called
Phalangeal cells
What do vibrations in the basilar membrane cause
Specialised stereocilia on the apical ends of the hair cells to move against the overlying tectorial membrane
What does deformation of the stereocilia on the hair cells cause
Opening of ion channels that depolarise the hair cell which causes the release of neurotransmitters that cause action potentials in the spiral ganglion
What are the main hair receptors
Inner hair cells
How is position and motion of the head determined
Through the hair cells in the utricle, saccule and semicircular canals
The utricle and saccule determine
Head position
The semicircular canals determine
Head movement
Swelling within the semicircular ducts
Ampulla
What is within the ampulla
A sensory organ called the crista ampullaris
Structure of the crista ampullaris
Core of connective tissue bulging into the lumen with a covering of epithelium containing hair cells with stereocilia
What are the stereocilia of the CA embedded in
A dome of gelatinous material called copula
What is contained within the hair cells of the vestibular system
Cilium in addition to the stereocilia
Stereocilia + cilium =
Kinocilium
What are the utricle and saccule
Two swellings in the vestibule
What lines the utricle and saccule
Simple cuboidal epithelium with a small patch of sensory epithelium called the macule
What are the stereocilia of the saccule and utricle embedded in
Gelatinous layer which has crystals of calcium carbonate and protein called otoconia
