Lesson 2 part 1 Flashcards
What are the 5 special senses?
1.) Olfaction
2.) Gustation
3.) Vision
4.) Equilibrium
5.) Hearing
what is Gustation?
sensory perception of molecules dissolved in water (tasting)
- gustation chemical stimulants are tastants; which are detected by gustatory receptor cells (sensory cells) that are clustered in 4,000 taste buds
what are Lingual papillae?
visible bumps on the tongue
- there are 4 types, three of which are taste buds
what are the 4 types of Lingual papillae?
1.) Filiform papillae
2.) Foliate papillae
3.) Fungiform papillae
4.) Vallate papillae
Definition of Filiform papillae?
small spikes with no taste buds
- sense food texture (mouthfeel)
- provides friction
Definition of Foliate papillae?
Form parallel ridges along sides of posterior two-thirds of tongue
- taste buds that mostly degenerate by age 3
Definition of Fungiform papillae?
Shaped like mushroom, at tips and side of tongue
- each has about three taste buds
Definition of Vallate papillae?
Large papillae arranged in a V at rear of tongue
- contains up to one-half of all taste buds
what are Gustatory receptor cells?
they are the sensory cells that detect tastants.
what are taste buds comprised of?
- Clusters of 50-100 taste cells
- supporting cells
- Basal cells
what are Basal cells?
stem cells that replace taste cells every 7 to 10 days
What are the 5 primary taste sensations?
1.) Salty
2.) Sour
3.) Sweet
4.) Bitter
5.) Umami
what does the taste Salty come from?
produced by metal ions
- Sodium and Potassium
what does the taste Sour come from?
acids such as in citrus fruits (H+ ions)
what does the taste sweet come from?
associated with carbohydrates and other foods of high caloric value
where does the taste Bitter come from?
spoiled foods and alkaloids such as nicotine, caffeine, and quinine
where does the taste Umami come from?
meaty of savory taste of amino acids (Glutamate) in chicken or beef broth. receptor sensitive to amino acids, small peptides and nucleotides.
what is Oleogustus?
a newly found primary taste
- is the taste of fats
- receptors detects long chains of fatty acids
Which three cranial nerves carry taste information?
- Facial Nerve 7 anterior two-thirds of tongue
- Glossopharyngeal Nerve 9 posterior one-third of tongue
- Vagus Nerve 10 palate, pharynx, and epiglottis
where do the three cranial nerves synapse onto?
They synapse onto neurons located in the medulla oblongata
- This is where the second-order neuron takes over
What happens once the second-order neuron takes over at the medulla oblongata?
- Hypothalamus and amygdala= activate reflexes for salivation, gagging, and vomiting
- Thalamus, which relays to primary gustatory cortex in Insula for perception of taste
- Thalamus also relays to orbitofrontal cortex from overall impression of flavor, palatability of the food
what is Olfactory Mucosa?
Patch of epithelium in roof of nasal cavity that houses receptor cells.
- contains 10s of millions olfactory cells, epithelial supporting cells, and basal stem cells
what is Lamina propria?
Superior to mucosa, contains areolar connective tissue, blood vessels, nerves, and olfactory glands
what are Olfactory cells?
They are located in the olfactory mucosa
- Neurons
- have 10s of millions immobile cilia (olfactory hair)
what do olfactory glands produce?
produce mucus to coat the olfactory organs
what is the definition of Hearing?
response to vibrating air molecules
- pressure waves in air
what is the definition of Equilibrium?
sense of motion, body orientation, and balance
what is the definition of sound?
any audible vibration of molecules
what is the definition of pitch?
whether a sound is high (treble) or low (bass)
What is pitch determined by?
Frequency of vibration (hertz, Hz)
What frequency can humans hear?
20 to 20,000 Hz
Outer (external) ear?
Funnel for conducting airborne vibrations to the eardrum.
- Begins with cartilaginous auricle (pinna) on side of head
What is the auditory canal (external acoustic meatus)?
slightly curved passage 3 cm long leading through temporal bone to eardrum.
What is the Tympanic membrane innervated by?
- Vagues nerve 10
- Trigeminal nerve 5
this makes the tympanic membrane very sensitive
What is the Tympanic cavity?
air-filled space between the outer and inner ear
how does air get into the tympanic cavity?
air enters through the auditory tube
- which is a passageway to nasopharynx, normally the passage is closed (flattened) but opens when swallowing and yawning.
what are the Auditory ossicles?
- the three smallest bones of the body
- connect tympanic membrane to inner ear
- Malleus
- Incus
- Stapes
definition of Malleus?
has a long handle attached to inner surface of tympanic membrane and a head that articulates with incus.
definition of Incus?
has triangular body that articulates with malleus and long limb articulates with stapes.
definition of stapes?
shaped like a stirrup; base (footplate) held in an opening called the oval window, where the inner ear begins.
what is the oval window?
where the inner ear begins
what is Stapedius?
muscle that attaches to stapes
- contraction reduces vibration of stapes on oval window
what is Tensor tympani?
muscle attaches to tympanic membrane
- loud noise causes tensor tympani to contract tensing the eardrum
what is tympanic reflex?
the stepedius and tensor tympani muscles reflexively contract to protect the inner ear from loud sounds.
Inner (internal) ear?
Portion of ear housed within a maze of temporal bone passages.
what is the bony Labyrinth?
internal passages in temporal bone
- inner ear
what is the Membranous labyrinth?
fleshy tubes suspended within bony labyrinth
- tube-within-a-tube structure
What is Perilymph?
fluid between bony and membranous labyrinth; similar in composition to intracellular fluid
what is Endolymph?
fluid within membranous labyrinth; labyrinth; similar in composition to intracellular fluid
what is vestibule?
chamber where the labyrinths begin
- contains organs of equilibrium
what is the cochlea?
coild organ used in hearing
- has three fluid-filled chambers separated by membranes
which part of the basilar membrane makes high pitch sounds?
the basal end near oval window because it is stiff and moves with high frequency waves
which part of the basilar membrane makes low-pitched signals?
the Apex of the basilar membrane because it is more flexible and moves more with low frequency waves
what are the reasons older people lose hearing?
- tympanic membrane becoming less flexible
- ariculations between ossicles stiffen
- round window begins to ossify
Conductive Deafness?
conditions interfere with transmission of vibrations to inner ear
- damaged tympanic membrane, otitis media, blockage of auditory canal, and otosclerosis (fusion of ossicles that prevents free movement
Sensorineural (nerve) deafness?
death of hair cells or any nervous system elements concerned with hearing
- musicians and people normally exposed to loud sounds
what is equilibrium?
sense of body orientation, movement and balance
what is vestibular apparatus?
contains receptors for equilibrium
what is static equilibrium?
perception of orientation of head in space; detected by saccule and utricle
what is dynamic equilibrium?
perception of motion or acceleration
Linear acceleration?
change in velocity in a straight line; detected by saccule and utricle
- dynamic equilibrium
Angular acceleration?
change in rate of rotation; detected by semicircular ducts
- dynamic equilibrium
what is Macula sacculi
lies vertically on wall of saccule
what is macula utriculi
lies horizontally on floor of uticle
Which areas do the vestibular nuclei relay information to? 5 areas.
1.) Cerebellum= integrates vestibular info into controls of head and eye movement, muscle tone and posture
2.) Reticular formation of the brain stem= thought to adjust blood circulation and breathing
3.) Spinal cord= descend through two vestibulospinal tracts of SC, and innervate extensor antigravity muscles
4.) Thalamus= relay to cerebral cortex for awareness of position and motor control of head and body
5.) Nuclei of oculomotor, trochlear, and abducens nerves (3, 4, 6)
