Special Senses Flashcards
List the five special senses and the sensory organs used to sense them
- Olfaction(Smell)
- Gustation(Taste)
- Vision
- Equilibrium (Balance) - inner ear
- Hearing
An area with a great number of fine touch receptors is the upper lip. What can you predict about the ability of the upper lip to distinguish two points?
they have a greater ability
being bombarded with stimuli during most of the day, and filtering it out from conscious thought.
adaptation
always active with a background level of stimulation that changes when the stimulus increases or decreases
tonic receptors
do tonic receptors adapts slowly/adapts quickly
slowly
do phasic receptors adapts slowly/adapts quickly
quickly
Which type of receptor (tonic/phasic) are normally inactive but becomes active with stimulus for a short period of time
phasic
In regards to location, sensory neurons detects a signal within a specific area
receptive field
Receptive field differ amongst neurons. Certain parts of our body such as our fingers have very small receptive field which allows fo
finer two point touch discrimination
while certain parts of our body such as our thighs have very large receptive fields which makes it
less likely for two point discrimination
what is a modality
type of stimulus or sensation produced such as vision, hearing, taste etc.
What type of receptors are sensitive to light
Photoreceptors
What type of receptors are sensitive to touch
Mechanoreceptors
What type of receptors are sensitive to temp.
Thermoreceptors
What type of receptors are sensitive to sound, or vibration
Mechanoreceptors
What type of receptors are sensitive to smell or odor
Chemoreceptors
What type of receptor is responsive to extremely hot sensations
Nociceptors
Tactile corpuscles respond to what type of sensation
Senses light touch and texture
What type of receptor determines the weight of an object when you pick it up as well as the sense of body position and movement?
proprioceptive receptors
what receptor Senses stimuli external to the body
Exteroceptors
what receptor Senses stimuli from the internal organs
Interoceptors
When you drink a burning hot liquid, the “chest pain” felt in the region of the sternum does not really occur there. What is this type of pain called?
referred pain
Senses pain, and temperature
Free Nerve ending
Senses light touch, pressure
Tactile discs
Senses light touch, hair movement
Hair receptors found around hair follicle
Senses deep pressure, stretch, tickle, vibration
Lamellar corpuscles
Senses muscle stretch
Muscle Spindles
Senses tension on tendons(proprioception)
Tendon organs
Unencapsulated nerve endings
Free Nerve endings
Tactile discs
Hair receptors found around hair follicle
Encapsulated nerve endings
Lamellar corpuscles
Muscle Spindles
Tendon organs
What are the primary tastes?
- -Salty
- -Sweet
- -Umami
- -Sour
- -Bitter
Where are the taste buds located?
back of the mouth
What structures are involved in taking the sense of taste from the taste buds to the brain?
A, first order neurons from __________ project to _______
B, Second order neurons from ________ project to ___________
(activate autonomic reflexes such as salivation, gagging and vomiting) and _______ (thalamus which relays signal to the primary gustatory cortex).`
- First order neurons from the Facial nerve (CN VII), -anterior two third, Glossopharyngeal nerve (CN IX) –posterior one third and vagus nerve(CN X) from the palate, pharynx and epiglottis) projects to a the solitary nucleus of the medulla oblongata .
- Second order neurons to the nuclei in hypothalamus and amygdala that activate autonomic reflexes such as salivation, gagging and vomiting as well as to the thalamus which relays signal to the primary gustatory cortex in the insula and roof of lateral sulcus in the cerebrum where we become conscious of taste.
- Processed signals are then relayed to the orbitofrontal cortex where signals are integrated with signals from the nose and eyes to ultimately form an overall impression of flavor and food palatability.
Where is the primary gustatory cortex located?
insula
Where are integrated with signals from the nose and eyes to ultimately form an overall impression of flavor and food palatability.
Orbitofrontal cortex
What is the exact region of the nasal cavity receptive to smell stimuli?
olfactory epithelium
is where the olfactory fibers enter the olfactory bulbs and synapse with the mitral cells and tufted cells.
glomeruli.
Decoding of odors by the brain is possible because
glomerulus
is formed by the axons from tufted and mitral cells carrying output from the glomeruli.
olfactory tracts.
Olfactory tracts fibers end at the in what lobe
temporal lobe
are neurons that carry fibers back to the olfactory bulbs from the olfactory cortex which changes the quality and significance of odors under different conditions.
olfactory nerve
What are the three general areas or regions of the ear?
outer
middle
inner
The ear performs two major sensory functions. What are they?
hearing and equilibrium
What structures are found at the outer ear?
Pinna
Auditory canal
guard cells
What structure separates the outer ear from the middle ear?
tympanic membrane
What tube between the middle ear and the nasopharynx is responsible for the equalization of pressure when you change elevation?
Eustachian tube
What is the name of the space that encloses the ear ossicles?
tympanic cavity
Name the ear ossicles in sequence from the tympanic membrane to the oval window.
malleus
incus
stapes
What are the muscles of the middle ear and their function?
Strapedius
The Tensor Tympani
Name all the major parts of the inner ear.
Oval window
Cochlea
a fluid similar to the CSF is found between the bony and membranous labyrinths.
perilymph
a fluid similar to the intracellular fluid is found within the membranous labyrinth.
endolymph
function of the cochlea
is the organ of hearing.
What area is found between the scala vestibuli and the scala tympani
The cochlear duct
Trace the pathway of sound waves (pressure waves) from the outer ear to the inner ear
cochlea responds to sounds of different amplitude and frequency. How does the cochlea determine sounds of different amplitude and loudness
The spiral configuration of the cochlea allows for differing frequencies to stimulate specific areas along the spiral,
How does the ear detect sounds with different frequency or pitch?
- Signals from distal end-low pitch.
- Signals from proximal end- high pitch.
Summarize the auditory projection pathway
What is the name of the nerve that carries signals from the cochlea and vestibule to the brain?
Vestibulocochlear nerve
perception of the orientation of the head in space
static equilibrium
Perception of motion or acceleration
dynamic equilibrium
Name the components of the vestibular apparatus
-Semicircular ducts
-Saccule
-Utricle
function of Semicircular ducts
detect angular acceleration- change in the rate of rotation.
function of Saccule
is responsible for static equilibrium and linear acceleration- change in velocity at a straight line
function of Utricle
is responsible for static equilibrium and linear acceleration- change in velocity at a straight line
How does the brain detect equilibrium
Your brain uses the messages it receives from your eyes
How does the brain detect rotational type of movement?
The vestibular receptors
Explain the projection pathway
- Sensory fibers of the vestibular nerve synapses with the macula sacculi, macula utriculi, and semicircular ducts.
- Fibers from the vestibular apparatus leads to four vestibular nuclei on each sides of the pons and medulla.
- Nuclei on both right and left sides communicate with each other so each receives input from both right and left ears.
- Information about the body position and movement is relayed to the
1, Cerebellum: integrates this information in control of head and eye movement, muscle tone, and posture. - 2, Nuclei of the oculomotor, trochlear and abducens nerve so that eye movements can compensate for head movements.
- 3, Reticular formation adjusts breathing and blood circulation to postural changes
- 4, Spinal cord- fibers from vestibulospinal tracts synapse on motor neurons that innervate extensor(antigravity) muscles which allows for quick movement to the trunk and limbs so as to maintain balance.
- 5, The thalamus: relays signal to the A, post central gyrus so that we gain conscious awareness of body position and movement. B, transitional zone from primary sensory to motor cortex which is involved in motor control of the head and body.
Bony socket that the eyeball occupies.
orbit
Protects eyes from the sun glare and enhances facial expression.
eye brows
Blocks foreign object from the eye, keeps the eye moistened, and blocks light stimulation.
eyelid
Guard hairs that help to keep the debris from the eye.
eyelashes
is a transparent mucous membrane which covers the inner surface of the eyelid and anterior surface of the eyeball. It secretes thin film that prevents eyeball from drying. It has a lot of blood vessels and nerves.
conjunctiva
The regions of Tunica Fibrosa (Fibrous/Outer Layer)
sclera
cornea
function of Tunica Fibrosa ,
protects the eyeball and maintains its shape
The regions of Tunica Vasculosa (Vascular Layer)
Iris
Ciliary body
Choroid
function of Tunica Vasculosa
shields the tubular interior of each testicle from further layers of tissue around the outer testicle
The regions of Tunica Interna (Inner Layer)
Nerual Part
Pigmented Part
function of Tunica Interna
allow fluid to flow smoothly
How does the vitreous body differ from the aqueous humor in location and viscosity?
vitreous humor is located in the posterior cavity and is much thicker. Aqueous humor is located in the anterior cavity and is more watery.
What layer of the eye converts visible light into nerve impulses?
retina
what are the type of photoreceptors
Rods
Cones
Intrinsically photosensitive retinal ganglion:
function of rods
sensitive to light, allows us to see in dimly lit rooms.
function of cones
enables color vision. Red, blue and green cones. Allows for clearer and sharper image.
function of Intrinsically photosensitive retinal ganglion
pigment is melanopsin and responds to different levels of brightness and influences the circadian rhythm.
What nerve is composed of axons of the ganglion cells and conducts action potentials to the thalamus of the brain
Optic Nerve
What gland produces tears?
Lacrimal gland
Where is vitreous body found?
large posterior cavity
What is the function of the choroid?
Delivers oxygen and nutrients to the retina.
In what area of the eye is the blind spot located? Why is it called the blind spot?
Optic disc bc there are no photoreceptors
Where visual image arrives after it passes through cornea and lens. Cones are concentrated in this area with no rods.
macala
The center of macula, with highest concentration of cones. Site of the sharpest vision.
fovea centralis
Just medial to the fovea, origin of the optic nerve. The central retinal artery and vein emerge from its center. Has no photoreceptors. AKA the blindspot.
optic disc
What are the two steps in which focusing occurs?
-light passes through the cornea
-light passes through the lens.
Explain the process of accommodation for close and distant vision
for close: ciliary muscle is contracted
for far: ciliary muscle is more relaxed
Explain the process of changes that occur in resting phase versus with lightness
In darkness, Chemically gated sodium channel on the plasma membrane of the photoreceptor is open in the presence of cGMP.
Na flows into the cell and keeps the membrane potential at - 40mV instead of -70mV.
At -40mV, the photoreceptors continuously release glutamate across synapse.
The inner segment continuously pumps sodium ions out of the cytoplasm.
Explain the process of bleaching and regeneration of visual pigments
Explain the visual projection pathway
-Some optic nerve fibers from melanopsin containing ganglion cells end in the superior colliculi and pretectal nuclei of the midbrain which controls visual reflex and pretectal nuclei involved in photopupillary reflex and accommodation reflex.
-Primary visual cortex is connected by association tracts to the visual association area.
