Special Senses 1 Flashcards
Name the 4 types of papillae
- Filiform
- Fungiform
- Foliate
- Circumvallate
Which papillae do not contain taste buds
Filiform
Roughly how many taste buds exist in the oral cavity
3000
What is at the surface of a taste bud
An apical taste pore
Name the 3 cell types within a taste bud
- Sensory cells or taste receptor cells
- Support cells
- Basal cells
What do the sensory cells contain
Apical microvilli with chemical receptors at the apical pore
What is the lifespan of the sensory and support cells
Around 10-14 days
What are the 5 principal tastes
- Sweet
- Sour
- Bitter
- Salty
- Umami
What happens when an appropriate chemical enters the taste pore and binds to a receptor
It releases neurotransmitters from the receptor cell (which are epithelial), that stimulate sensory nerve endings
Describe the olfactory epithelium
Pseudostratified columnar (lacks goblet cells)
What grows out from the olfactory bulb
Olfactor nerves, which dive down through the cribriform plate
Name the 3 cells of the olfactory epithelium
- Olfactory receptor cells
- Support cells (or sustentacular cells)
- Basal cells
What extends above the olfactory epithelial layer, coming from the olfactory receptor cells
Olfactory vesicle with 10-20 long non-motile cilia attached
What type of epithelium is the olfactory mucosa
Neuroepithelium
Roughly how many odorants can our bodies detect
Around 10,000
What do the olfactory support cells secrete
Odorant binding proteins
What is the lifespan of an olfactory receptor cell
Around a month
What do Bowman’s glands help to do in the nasal cavity
Solubilise the odorant, allowing it to interact better with the neuroepithelium
What layers does the olfactory mucosa consist of
- Olfactory epithelium
2. Lamina propria (underneath)
What does the lamina propria contain
- Connective tissue
- Blood vessels (warm the air)
- Bowman’s glands
- Bundles of axons (from receptor cells)
What glands exist within the ear canal (external auditory meatus)
- Sebaceous
2. Ceruminous glands
What do the ceruminous glands produce
Cerumin, a yellowish waxy substance
How many layers does the tympanic membrane have; and describe them
Three layers
- Outer layer of thin epidermis
- Middle layer of collagenous connective tissue
- Inner layer of simple cuboidal
What does the round window allow
Allows for pressure changes to move through the cochlea
How many spirals exist in the cochlea
2.5 turns
Name the membranes that separate the scala vestibuli and scala tympani
- Basilar membrane
2. Vestibular membrane
What is the function of the organ of Corti
Changes the vibrations into electrical impulses that are then sent to the brain
Name the central core of the cochlea
The modiolus
Name the three compartments of the cochlea
- Scala vestibuli
- Scala tympani
- Cochlear duct between them
Where do the scala tympani and scala vestibuli communicate with each other
At the very tip of the cochlea, at the Helicotrema
What structures detect sound on the organ of Corti
Stereocilia:
- Inner
- Outer
What row of stereocilia do we hear with
One row of inner stereocilia
What do the stereocilia move against to allow us to hear
The tectorial membrane
How many semicircular canals are located within each inner ear
Three:
- Anterior
- Posterior
- Lateral
What do the hair cells in the utricle and saccule detect
Head position
What do the hair cells in the semicircular canals detect
Movement
What exists within the ampulla of each semicircular canal
A sensory organ called the crista ampullaris
What does the crista ampullaris consist of
A core of connective tissue bulging into the lumen with a covering of epithelium containing hair cells with stereocilia
Where are the stereocilia located
Embedded within a dome called the cupola
What happens to the cupola when the head turns
The movement of the fluid bows the cupola, and in turns bends the stereocilia
What is the small patch of sensory epithelium in the vestibule of the semicircular canals
Macula
What do the stereocilia contain on their surface
Crystals of calcium carbonate and protein, called otoconia
Why do the otoconia move under gravity
They are denser than the surrounding endolymph fluid; thus under gravity, they will get misplaced
