Homeostasis, Sensation and Perception Flashcards
What refers to the simultaneous arrival at each ear of different portions (phases) of the oscillating sound wave
Phase Differences
Which ear receives less intense stimulation in regard to intensity differences?
Ear opposite the source of the sound
What Functions to maintain balance, position of the head in the upright position, and adjustment of eye movement to compensate for head movements
Vestibular system
Which component of the vestibular system responds to force of gravity and informs the brain about head orientation?
Vestibular Sacs
Which component of the vestibular system responds to angular acceleration, but not steady rotation?
Semicircular Canals
Which component of the vestibular system responds weakly to changes in position or linear acceleration?
Semicircular Canals
What are the Utricle and Saccule located within?
Vestibular Sacs
In the vestibular system, what are circular and each contain a patch of receptive tissue containing receptor hair cells?
Utricle and Saccule
What is the cilia embedded in within the utricle and saccule . What does it do when there is motion?
Embedded in an overlaying gelatinous mass containing crystals of calcium carbonate
They shift in response to motion
What are the 3 major planes the semicircular canals approximate?
Sagittal, transverse and horizontal
What are the receptors for the semicircular canals? Where are they?
Receptors are HAIR CELLS, found in the cupula within the ampulla.
Which part of the vestibular system has canals filled with fluid and receptors pick up on differences in fluid motion?
Semicircular Canals
In the vestibular system, what do bipolar cell bodies give rise to?
Afferent Axons of the vestibular nerve (part of CN 8). in the vestibular ganglion
Where do most of the vestibular nerve axons synapse?
Where do SOME of the vestibular nerve axons travel directly to?
within the Medulla Nuclei
SOME travel to the cerebellum
What is the vestibular pathway from the nuclei?
Nuclei –> cerebellum –> Spinal cord –> medulla –> pons
What projections are responsible for feelings of nausea and vomiting during motion sickness (vestibular)?
Projections to the lower brainstem
What do the connections to the cranial nerve nuclei control (vestibular system)?
Eye muscles to compensate for sudden head movements such as running
What is the reflex called that compensates for sudden head movements such as running?
Vestibulo-Ocular reflex
What provides information about what is happening on the surface of our body and inside it
Somatosensation
What part of somatosensation detects pressure, vibration, heat, cooling, and tissue-damaging events (skin)
Cutaneous
What part of somatosensation detects changes in muscle length and force exerted on muscles (body position)
Kinesthesia
What part of somatosensation detects changes in internal organs, including stretch, temperature, and chemicals
Organic
Merkel disks detect?
Touch
Meissner Corpuscles detect?
Touch
Pacinian Corpuscles detect?
Pressure
Ruffini endings detect?
Pressure
What responds to low frequency vibrations on hairy skin?
Unencapsulated nerve endings and Ruffini endings
What are found in the dermis, are largest sensory end organs (visible to naked eye) and sensitive to high-frequency vibration? (Hairless skin)
Pacinian Corpuscles
What are found in epidermis and sensitive to low frequency vibration (Hairless skin)
Meissners Corpuscles
What are found at base of epidermis and respond to skin indentation (hairless skin)
Merkels Disks
Where does somatosensory information enter the central nervous system?
Through cranial and spinal nerves
What drives spinal reflexes that maintain local aspects of pain control and motor compensation?
Somatosensory information
Where does somatosensory information flow from?
Spinal cord to specialized regions of the Thalamus (VPL) through parallel pathways
What does the DCML tract (Dorsal Column Medial Lemniscal) detect?
Precisely localized information - touch, kinesthesia, proprioception
What does the Spinothalamis (Anterolateral) Tract detect?
Poorly localized information - pain, temperature and visceral sensation
Which somatosensory tract detects Precisely localized information - touch, kinesthesia, proprioception
DCML
Which somatosensory tract detects Poorly localized information - pain, temperature and visceral sensation
Spinothalamic (Anterolateral) Tract
Where do thalamic relay neurons project from?
VPL to primary somatosensory cortex
Where is the integration of information about personal and peripersonal space (touch, position, pressure)?
Parietal Lobe (Anterior Parietal Cortex - APL)
What is the relay point for all sensory pathways (EXCEPT olfaction)?
Thalamus
How is the somatosensory cortex arranged?
in cortical columns
T or F? Within a cortical column, neurons respond to a particular type of stimulus applied to a particular part of the body?
True
What responds to original bending and release, but not to steady pressure (adaptation) (not due to fatigue of receptor)
Pacinian Corpuscle
T or F, Pacinian Corpuscles respond well to moving stimuli?
True, used to analyze shapes and textures (hard, soft, sticky, slippery, rough, etc).
What Stimuli are chemical instead of physical stimuli
Chemosenses
What is Related to eating; this sense allows us to determine the nature of things we put in our mouths
Gustation
What are the five qualities of taste?
Salty, Sweet, Umami, Bitter, Sour
What specific biological need does Umami taste provide?
Amino acids
What specific biological need does sweet provide?
Calories
What specific biological need does salt provide?
Sodium chloride (an essential mineral)
What is taste (flavor) comprised of?
taste, texture, temperature and odor
Taste buds are what kind of organs?
Receptive organs
What is on the anterior 2/3 of tongue, contain 4-6 taste buds each
Fungiform Papillae
What kind of taste bud is eight parallel fold along each edge of the back of the tongue,
contain 1300 taste buds within these folds
Foliate Papillae
What is arranged in an inverted V on posterior 1/3 of tongue, contain 250 taste buds
Circumvallate Papillae
What do taste buds consist of (receptor cells)
20-50 receptor cells arranged like an organge
Where is the cilia located on each taste bud? Where do they project to?
At the end of each cell - project through the opening of the taste bud into the saliva
What is the lifespan of the taste bud receptor?
10 days
T or F? Receptor cells do not fire action potentials, but release transmitter in graded fashion onto nerve endings
True
Which nerve carries anterior taste?
Chorda Tympani (CT)
Which nerve carries anterior tactile (oral sensation)?
Trigeminal (V)
Which nerve carries posterior taste and tactile?
Glossopharyngeal (IX)
Oral sensation combines with retronasal olfaction to produce what in the mouth?
Flavor
What is the first relay station in the gustatory pathway?
Nucleus of the solitary tract in the medulla
From the NTS where does the gustatory pathway travel next?
ventral posteromedial thalamus
From the thalamus, where does the gustatory pathway go next?
gustatory cortex in the frontal insular and opercular cortex
taste is ipsilaterally or bilaterally represented?
Ipsilaterally
Where does the Nucleus of the solitary tract also project to, perhaps contributing to rewarding properties of taste?
Amygdala and hypothalaumus
What conveys not only the nature of objects, but evokes memories and emotion as well?
Olfaction
What helps us identify a large array of environmentally important objects: food, kin, prey, etc.?
Olfaction
What is it called when someone lacks the sense of smell?
Anosmic
What is the specialized organ (in some species) for detecting reproductive cues?
Vomeronasal organ
Olfactory receptor cells reside within two patches of mucous membrane called What? located at the top of the nasal cavity
olfactory epithelium
Where is the olfactory epithelium located?
top of the nasal cavity
How much air that enters the nostril reaches the epithelium? What is needed to sweep air upward?
less than 10%
A sniff
Olfactory mucosa contains nerve endings of which cranial nerve?
Mediates what?
V Pain sensation (amonia)
What is the bone at the base of the rostral part of the brain that has olfactory receptor cell bodies that line it?
Cribriform plate
What is the turnover rate of olfactory receptor cells?
about 60 days
What opens the sodium (Na+) channels to depolarize the cell and convey an AP in olfactory receptors?
Odor molecules that dissolve in the mucus and stimulate receptor molecules on the cilia
Where do axons of receptor cells that enter through the skull through perforated cribiform plate terminate?
Olfactory bulb
Axons synapse with dendrites of __________ in the __________; all cells expressing a particular receptor project to the same glomeruli
Mitral cells,
Olfactory glomeruli
Olfactory tract axons project to the?
Primary olfactory cortex
directly on the pyriform cortex
Where does the pyriform cortex project to?
hypothalamus and dorsomedial thalamus
Where do hypothalamus and dorsomedial thalamus project to?
Orbitofrontal cortex
Where is taste and olfaction combined to convey perception of taste?
Orbitofrontal cortex
Olfactory pathway
Primary olfactory cortex –> hypothalamus and dorsomedial thalamus –> orbitofrontal cortex
Gustatory Pathway
Nucleus of solitary tract –> ventral posteromedial thalamus –> gustatory cortex
Orthonasal detects?
Environmental odors
Retronasal detects?
Food-emitted odors
What combines with taste and oral somatosensory cues to produce a unitary sense of flavor?
Retronasal Olfaction (RO)
What is the stimulus for vision?
Light
What is the perception of color determined by? (3 things)
- Hue - wavelength
- Saturation
- Brightness
What is the outermost layer of the eye, opaque, and does not allow light entry
Sclera
What is the the outer transparent layer at the front of the eye that allows light entry
Cornea
What is the the pigmented ring of muscles situated behind the cornea
Iris
What is the opening of the iris that determines amount of light entry
Pupil
What sits right behind iris, made of transparent layers whose shape is controlled by ciliary muscles. Changes in shape allow the eye to focus images of near or distant objects on the retina (accomodation)
Lens
What is the gelatinous substance giving the eye its bulk
Vitreous Humor
What is the the interior lining of the back of the eye (contains the photoreceptors)?
Retina
What is the central region of retina
Fovea
What is the part of the retina where the axons conveying visual information gather and exit the eye through the optic nerve (this is your blindspot; there are no photoreceptors)
Optic Disk
What is Cooperative movements keeping both eyes fixed upon the same target
Vergence
What is abrupt gaze shifts?
Saccadic
What is purposeful track of object?
Pursuit
What are the photoreceptors of the eye?
Rods and Cones
What photoreceptor provides vision of low acuity and are VERY sensitive to light, but not color?
Rods
Approx how many rods and cones are there?
Rods - 120 million
Cones - 6 million
What photoreceptor provides us with most of the information about our environment, is responsible for daytime vision and high acuity, color vision?
Cones
What photoreceptor is located int he fovea?
Cones
What is is activated by light and hyperpolarizes, reducing inhibitory neurotransmitter release onto bipolar cells, which project to ganglion cells (net result is activation of ganglion cell)
Photoreceptor
___________ do not fire AP, but release glutamate (NT) in graded fashion?
Photoreceptors
How do axons of retinal ganglion cells bring info to the rest of the brain?
By ascending through the optic nerves to the dorsal lateral geniculate nucleus (DLGN) of the thalamus
Where does the dorsal lateral geniculate nucleus project to?
Primary visual cortex (aka striate cortex)
Where do optic nerves cross?
Optic chiasm
The nasal sides of the ganglion cells cross to the __________ DLGN?
contralateral
The axons from the outer halves of the retina project to ___________ DLGN.
Ipsilateral
Each hemisphere receives information from what part of the visual scene?
the contralateral half
Which cells become excited when light falls on the photoreceptors. Specifically, light must fall within the neurons receptive field
Ganglion cells
What are the two types of ganglion cells?
On and Off
Which type of ganglion cell is excited by light falling in the center, inhibited when light falls in surround
“On” ganglion cell
Which type of ganglion cell is inhibited by light falling in the center, but excited when light falls around it?
“Off” ganglion cell
What hues are the three types of receptors in the eye sensitive to, which allows us to detect color?
Blue, green and red
What is it called when someone has red/green color blindness- red and green look yellow, visual acuity is normal (suggesting retina not lacking red or green cones), but rather, red opsin is absent
Protanopia
Path from eye to brain:
Retinal ganglion cells –> lateral geniculate nucleus (LGN) –> Primary visual cortex (striate cortex)
How many layers is the striate cortex?
6
What takes information from striate cortex and combines it
Visual association cortex
What information does the visual association cortex take from the striate cortex and combine (4 things)
- Perception of color
- Analysis and complexity of form
- Perception of movement
- Perception of location
Where do the two streams of analysis for visual association cortex begin? Do they proceed in the same direction?
striate cortex
No, they proceed in different directions
Which visual association stream turns downward, ending in inferior temporal lobe- responsible for recognizing what an object is
Ventral stream
Which visual association stream turns upward ending in posterior parietal lobe- responsible for recognizing where the object is located
Dorsal stream
Maintaining stability (homeostasis) through change
Allostasis
Process of adaptation to acute challenge
Allostasis
The price the body pays for being forced to adapt to adverse or chronic psychosocial or physical stimuli
Allostatic overload
Examples of allostatic overload:
- Extreme change in physical environment
- Chronic exposure to drugs
- Extreme change in psychosocial environment
- Change in physical capacity
_____ is the stimulus-detection process by which our sense organs respond to and translate environmental stimuli into nerve impulses that are sent to the brain.
Sensation
_______ making “sense” of what our senses are telling us – is the active process of organizing this stimulus input and giving it meaning
Perception
defines lowest stimulus quantity that can be perceived from nothing
threshold
Beyond threshold, ______ _______ determines intensity
stimulus magnitude
The lowest intensity at which a stimulus can be detected 50 percent of the time. The lower the absolute threshold the greater the sensitivity.
Absolute threshold
The lowest concentration at which a stimulus can be
identified.
Identification threshold
The smallest difference between two stimuli that people can perceive 50 percent of the time. Sometimes call the “just noticeable difference”
Difference threshold
Conveys information about stimulus intensity and timing – Differs across neurons
Firing rate
Diminishing responsiveness of a sensory receptor to prolonged presentation of a stimulus
Adaptation
Act to modulate relay neurons (turn up or down)
Local circuits
Circumscribed area from which a sensory cell receives information
– Conveys spatial information
receptive fields
Retina
Primary visual cortex
Secondary visual cortex
Cochlear Nuclei
Primary auditory cortex
Vestibular Nuclei
Somatosensory cortex
Spinal cord and brainstem
Somatosensory cortex
Olfactory bulb
Limbic structures, hypothalamus
Medulla
Somatosensory cortex
frequency of vibration, measured in cycles per second (Hertz, Hz)
Pitch
function of intensity or the difference between the apex and nadir of the wave, measured in amplitude ( decibels, dB)
Loudness
quality/complexity of a sound. Determines the nature of the particular sound. Allows us to distinguish an oboe from a flute playing the same note. Most natural stimuli are complex sounds
Timbre
Sound is funneled via the pinna through the external auditory canal to the tympanic membrane (eardrum)
External ear
Hollow region that contains the ossicles (bones) which are
vibrated by the tympanic membrane
Middle ear
Tympanic membrane connects with the malleus and
transmits vibrations via the incus and stapes to the cochlea
Middle ear
Cochlea (land snail) part of inner ear and filled with fluid
Inner ear
the receptive organ within the cochlea
Organ of Corti
Auditory receptive cells
Hair cells
Anchor for hair cells
Basilar membrane
where cilia of hair cells connect here, and is rigid
Tectorial membrane
Moderate to high frequency
detected by
Place coding
Low frequency detected by
Rate coding
