Week 2- Sensory System Flashcards
These structures receive stimulus
Receptors
These have nerve axons and afferent pathways
Sensory pathways
This part of the nervous system transmit signals
Sensory pathways
This part of the body interprets or integrates sensory inputs
Central Nervous System (CNS)
This part of the nervous system has efferent pathways
Motor System
This part of the nervous system produces a response
Motor System
Two types of receptors
-Nerve cell
-Specialized epithelial cell
Activating receptors is _______ specific.
Stimulus
What happens during activation?
An external stimulus transforms to an electrical signal
Sensory pathways describe the _______ and _____ of the sensory stimulus
-type
-location
Dependent on what type of receptor is activated
Type
Each receptor has a specific _______ on the sensory map in the brain
Location
Collection of cell bodies of the afferent sensory fibers
Dorsal root ganglia (DRG)
The dorsal root ganglion is associated with the ________ of the spinal nerve.
Posterior/dorsal root
What do the dorsal roots contain?
Sensory fibers from the skin, subcutaneous and deep tissues, and viscera
Primary afferent fibers of the dorsal roots are either _____________ or ____________.
-myelinated
-unmyelinated
True or false: Cutaneous, joint, and visceral afferents are unmyelinated
False
The integration of sensory impressions into psychologically meaningful information
Perception
This involves peripheral sensory mechanisms and higher-level
processing
Perception
The location of sensory receptors in the brain
Sensory map
Shows the somatic sensory projections
from the body surface
Sensory homunculus
The ability to use sensory information efficiently
Sensory integration
True or False: Combining several sensory inputs to produce a desired movement
True
What systems are involved in stable standing balance?
Somatosensory (proprioception), vision, vestibular
These structures define the type, location, and intensity of stimulus
Receptors
What do receptors transform an external stimulus into?
Electrical signals
This part of the nervous system transmits an electrical signal to area of brain that corresponds with receptor location
Sensory pathways
Interprets and integrates sensory signals
CNS
Communicates with motor system to produce goal-directed
movement
CNS
Receptors that detect touch, pressure, vibration, proprioception
Mechanoreceptors
Receptors that detect heat and cold
Thermoreceptors
Receptors that detect pain
Nociceptors
Where does proprioceptive sensation come from?
Ligaments, muscles, joints, and tendons
Perception of sensation from inside the body
Interoception
Perception of one’s body in space
Proprioception
This branch of the nervous system transmits information about the senses of touch, pain, temperature,
and body position from sensory receptors to the CNS to regulate behavior
Somatosensory system
What is the first system to function in utero?
Touch
True or False: Proprioceptive receptors (muscle spindles and golgi tendon organs) are well-developed by mid-fetal life
True
When does the fetus respond to touch around the mouth?
7 weeks
When are muscle spindles formed?
12 weeks
When are golgi tendon organs formed?
16 weeks
When does cutaneous sensation spread to the entire body?
17 weeks
True or false: All sensory systems are matured at birth
False
The __________ is completely myelinated at birth
PNS
True or false: Complete structural maturation of sensory pathways occur throughout childhood
True
What happens in the structural maturation of sensory pathways in childhood?
-increased nerve conduction velocity
-redistribution of axon branching
-increased synaptic efficiency
-all the above
all the above
Reflex used by an infant to locate food
Rooting reflex
True or false: Touch is a crucial role in parent-infant attachment, sociability, and cognitive development
True
When does specific touch localization happen?
12-16 months
When do children identify objects by touch?
5 years
When can a baby sense two-point discrimination?
7 years
True or false: Proprioception is not used very early after birth
False
What movements can babies execute regarding proprioception?
-imitation
-reaching
-locomotion
When do muscle spindles mature?
As early as 3 years old
When does proprioceptive acuity for movements improve?
Between 5-12 years
True or false: The sensory system is keenest during late adolescence into early adulthood
True
When does sensory function begin to decline?
Adulthood (specifically middle age)
True or false: Peripheral and central changes always correlate with a decline in function
False
Reaction time peaks in ______, then slows by ____% during middle adulthood
-mid 20s
-20%
What does dry skin and less elasticity lead to?
Compromised precision of cutaneous receptors
How does sensory functioning decline in aging?
-decrease in number of sensory systems
-decrease in functioning of remaining sensory neruons
-structural and physiological changes within the CNS
-all the above
All the above
True or false: Decrease in number of receptors leads to a decline in fine touch, pressure, and vibration sense
True
What does a loss up to 30% of sensory fibers innervating peripheral receptors lead to?
Peripheral neuropathy
True or false: Arthritic changes affect the ability of joint receptors to detect joint motion
True
True or False: There is decreasing feedback that the CNS normally receives during movement when when atrophy is found in muscle spindles, joint receptors, and GTO
True
As redundancy of sensory information decreases because of age-related changes, how do older adults respond to it?
They are forced to compensate more
What are examples of functional consequences in aging?
-postural instability
-exaggerated body sway
-balance problems
-gait disturbances
-diminished fine motor coordination
-tendency to drop things held in hands
-difficulty recognizing body or limb positions in space
What does vision provide individuals information about?
-the external world
-identification of external objects and determination of their movement
-where the body is in space, the relationship of one’s body parts, and the motion of one’s body
This is the dominant sensory modality in humans
Visual system
Vision is vital in control of _________.
-posture
-locomotion
-balance
-hand function
Structures and receptors in the eyeball
Peripheral anatomy
How many extraocular muscles do we have?
6
This nerve carries nerve impulses in the visual system
Optic nerve
The occipital cortex contains the ___________ cortex
Visual
True or false: Head position and head control are not important elements leading to visual function
False
How many types of eye movements are controlled by the 6 extraocular muscles?
4
Quick, simultaneous movement of both eyes in the same direction
Saccades
Slow smooth eye movements and allows the eyes to closely follow moving object
Slow pursuit or tracking
Reflex eye movement that stabilizes images on the retina
VOR (vestibulo-ocular reflex)
Produces eye movement in opposite direction to head movement
VOR (vestibulo-ocular reflex)
Simultaneous movement of both eyes in opposite directions
Vergence
Eyes rotate towards each other
Convergence
Eyes rotate away from each other
Divergence
Where does the visual system derive from during the prenatal stage?
Thalamus in diencephalon
True or false: Complete maturation of sensory pathways occur after birth
True
What colors do newborns initially see?
Black and white
The best distance for fixation, regarding newborns, is _____ away from eyes
7-9 inches
What preference do newborns have in visual development?
Pattern preference, especially for a human face
At 2 months old, what colors do infants see?
Red and yellow
How old can infants track vertically, horizontally, and in circular paths?
2 months
When do infants prefer a colored object that has a perception of form?
3 months
When to infants have full color vision?
4 months
Binocular vision matures between ____________.
3-5 months
When does adult-like binocular vision occur?
2 years old
When is adult levels of visual acuity achieved?
12 months
What promotes visual interest?
Postural control
Children between 4-6 years old are highly dependent on visual feedback for _____________ and __________.
-upright postural control
-balance
True or false: Visual perception becomes increasingly more accurate during preschool years
True
When does the visual system mature and become more sophisticated?
Adolescence
This visual system coupling is important in adolescence
Eye-hand coordination and perception-action
When do people have perceptual judgments regarding size of objects?
Age 11
When do adolescents have achieved adult levels of depth perception?
Age 12
How does visual acuity change in adulthood?
-increases in 20s/30s
-remains stable during 40s/50s
-most rapid decline occurs between 60s/80s
Cataracts begin to form in individuals _______ (age).
over 30
When does presbyopia develop? (age)
Age 45
When does one begin to have decline in ability to quickly adapt from light to dark environments? (age)
After age 40
Cataract formation is in _____% of adults over _____
-60%
-65
Macular degeneration is in _____% of adults over _____
-28%
-75
What happens as field of vision diminishes?
There is a loss of depth perception
What do slowed peripheral and central processing impair?
-postural control
-balance
-safety
-independence
This provides information regarding the position of the head in space
Vestibular system
True or false: The visual system detects sudden changes in the direction of movement of the head
False
(vestib system)
Vestibular inputs integrate _______ and ______ information to coordinate motor responses
Visual and proprioceptive information
True or false: The vestibular system assists with eye stabilization and static and dynamic postural stability during standing and walking
True
Vestibular structures begin as a thickening of the ______ within the primitive ear in the ____ week of gestation
-ectoderm
-4th week
As a fetus moves in utero, what provides information about that movement?
Vestibular apparatus
True or false: The vestibular system is completely unmyelinated at birth
False
(it is myelinated)
What is movement behavior developed by?
Movement experience and acquiring postural control against gravity
What does movement behavior lead to during the infancy/childhood stage?
Development of trunk righting and equilibrium reactions
True or false: Rocking and spinning contribute to the maturation of the vestibular system
True
When does development of the ability to relate eye movements to head movements occur?
Infancy/childhood
When is normal VOR present?
By 2 months of age
True or false: There is an increase in vestibular sensitivity from birth to a peak between 6-12 months of age that gradually declines from 2.5 yrs to puberty
True
When is full maturity of the vestibular system achieved?
10-14 yrs of age
Vestibular, visual, and somatosensory systems coordinate to control __________.
Balance
How old do you gain static balance?
9-12 yrs
How old do you gain dynamic balance?
12 yrs
True or false: The number of sensory cells and nerve fibers increase in the PNS during adulthood around age 40
False
True or false: Dizziness and vertigo are common issues for people over age 50
True
There are 40% in hair cells and 36% reduction in peripheral nerve fibers in adults ________ (age)
over 70
What does deterioration in central vestibular integrative functions lead to?
Impaired balance
True or false: The vestibular system becomes unreliable when visual and proprioceptive input conflicts
True
What is the order of sensory system development?
Touch
Vestibular
Smell
Hearing
Vision
Taste
Proprioception
