Chapter 16/17 Special Senses Flashcards
What is sensation?
The conscious or subconscious awareness of change in the external or internal environment
What is perception?
The conscious interpretation of sensations performed mainly by the cerebral cortex
What is a sensory modality?
each type of sensation.
1. touch
2. pain
3. vision
4. hearing
Sensory modalities are grouped into what?
Either general senses or special senses
What are general senses?
Somatic or visceral
What are somatic senses?
Tactile, thermal or proprioceptive
What are visceral senses?
Pressure, chemicals, stretch, nausea, hunger, temperature
What are some of the special senses?
Smell, taste, vision, hearing, and equilibrium
Different types of what are used in the different senses?
Sensory receptors
What kind of sense is smell?
Chemical sense
The human nose contains how many receptors for smell
10 to 100 million
Where is the sense of smell located?
Olfactory epithelium of the superior part of the nasal cavity
The olfactory epithelium covers what surface?
The inferior surface of the cribriform plate (of the ethmoid bone of the skull) and extends along the superior nasal concha
What are the 3 types of olfactory cells?
- Olfactory receptor cells
- Supporting cells
- Basal cells
What are the supporting cells (columnar epithelium) in the nose?
Located in the mucous membrane lining the nose and used for physical support, nourishment and electrical insulation of olfactory receptor cells
What do basal stem cells do?
They undergo mitosis to replace olfactory receptor cells
What are olfactory glands (bowman’s glands):
They produce mucus that is used to dissolve odor molecules so that transduction may occur
How do the nasal mucosa send impulses along branches of olfactory nerves?
- through the cribriform plate
- synapse with the olfactory bulb
- Impulses travel along the olfactory tract
- Interpretation in the primary olfactory area in the cerebral cortex (temporal lobe)
What is olfactory transduction?
The binding of an odorant molecule to an olfactory receptor protein
How does Olfactory transduction work?
- Chemical reactions involving cyclic AMP (cAMP) cause depolarization
- Action potential travels to the primary olfactory area
- Impulse travels to the frontal lobe (orbitofrontal area) for odor identification
Taste is what kind of sense?
Chemical, but is simpler then olfactory
What are the five primary tastes?
- sour
- sweet
- bitter
- salt
- umami (meaty, savory, and usually a combination of the other four senses)
What are taste buds?
Receptors for the sensation of taste
How many taste buds are found on the tongue?
~ 10,000
Taste buds come contain what three kinds of epithelial cells?
- support cells
- gustatory receptor cells
- basal stem cells
Where can taste buds be found?
tongue, soft palate, pharynx, and epiglottis
What are papillae?
Elevations on the tongue where taste buds are located
What are the fourtypes of papillae?
- vallate papillae
- fungiform papillae
- foliate papillae
- Filiform papillae
What are vallate papillae?
About 12 that contain 100-300 taste buds
What are fungiform papillae?
Scattered over the tongue with about 5 taste buds each
What are foliate papillae?
located in the lateral trenches of the tongue
What are filiform papillae?
They cover the entire surface of the tongue, and they
1. Contain tactile receptors but not taste buds
2. increased friction to make it easier for the tongue to move food within the mouth
What are the three cranial nerves that are involved in the sense of taste?
- facial (VII) nerve
- glossopharyngeal (IX) nerve
- Vagus (X) nerve
What is the facial (VII) nerve?
Carries taste information form the anterior 2/3 of the tongue
What does the glossopharyngeal (IX) nerve?
Carries taste information from the posterior 1/3 of the tongue
What is the vagus (X) nerve?
Carries taste information from taste buds on the epiglottis and in the throat
What is vision?
When we use visible light which is part of the electromagnetic spectrum with wavelengths from about 400 to 700 nm
What is a wavelength?
The distance between two consecutive peaks of an electromagnetic wave
What are the accessory structures of the eyes?
- Eyelids
- Eyelashes
- Eyebrows
- Lacrimal apparatus
- extrinsic eye muscles
What are the palpebral muscles?
Control eye movement
What are extrinsic eye muscles responsible for?
Responsible for moving the eyeball itself in all directions
What is the conjunctiva?
Thin, protective mucous membrane that lines the eyelids and covers the sclera
What is the tarsal plate?
A fold of connective tissue that gives form to the eyelids
What structure contains a row of sebaceous glands that keeps the eyelids from sticking to each other?
The tarsal plate
Why can the eye move in almost any direction?
It can due to the six extrinsic eye muscles.
What are the six extrinsic eye muscles?
- superior rectus
- inferior rectus
- lateral rectus
- medial rectus
- superior oblique
- inferior oblique
What are the layers of the eyeball?
Contain three layers
1. fibrous layer
2. vascular layer
3. inner nervous layer
What is the fibrous layer?
Sclera and Cornea
What is the vascular layer?
Choroid, ciliary body, iris
What is the inner nervous layer of the eye?
Retina
What does the iris do?
Colored portion of the eyeball that controls the size of the pupil based on autonomic reflexes
Where does the retina lie in the eyeball?
The posterior 3/4’s of the inner layer
What is the optic disk?
The point at which the optic nerve exists the eye, which is also the blind spot
What is the macula lutea?
The exact center of the retina, in its center is the fovea centralis
What is the fovea centralis?
The area of highest visual acuity
What are the photoreceptors on the retina?
Rods and cones
What do Rods do?
See in dim light
What do Cones do?
Produce color vision
How does information flow for vision?
1.Starting from photoreceptors
2. information flows through the outer synaptic layer
3.To bipolar cells through the inner synaptic layer
4.To ganglion cells
How does the iris divide the eye?
It divides the eye into a anterior and posterior chamber
What is the anterior chamber?
Between the iris and cornea, and is filled with aqueous humor
What is the posterior chamber?
Lies behind the iris and in front of the lens and is also filled with aqueous humor
What lies beyond the posterior chamber of the eye?
The posterior cavity which is filled with transparent, gelatinous substance, the vitreous humor
Images focused on the retina are what?
Inverted and right to left reversed due to refraction; the brain corrects the image
What structures does light flow through?
- cornea
- Anterior chamber
- pupil
- lens
- Posterior chamber
- virtreous humor
- retina
What is binocular vision?
When the anterior location of our eyes lead to visual field overlap
What is emmetropic mean?
When the eye refracts light correctly and focus a clear image on the retina
What is myopia?
Nearsightedness, concave lens to correct
What is Hyperopia?
Farsightedness, convex lens to correct
What is astigmatism?
Condition where either the cornea or the lens (or both) has an irregular curve. This leads to blurred or distorted vision
How much faster is the transduction of sound vibrations by the ear’s sensory receptors into electrical signals then the eyes photoreceptors?
About 1000x faster
Ear is divided into how many parts ?
Three parts
1. External ear
2. Middle ear
3. Internal ear
What does the external ear contain?
auricle (pinna), external auditory canal, and the tympanic membrane
What are the three bones of the ear?
- Malleus
- Incus
- Stapes
What does the auditory tube do?
From the middle ear into the nasopharynx to regular air pressure in the middle air
What does the inner ear contain?
Cochlea
What does the cochlea do?
Translates vibrations into neural impulses that the brain can interpret as sound, and the semicircular canals that work with the cerebellum for balance and equilibrium
Vibrations are transmitted from the stapes through what?
The oval window to the cochlea as fluid pressure waves and are transmitted into the perilymph of the scala vestibuli
