Sensory system Flashcards
Afferent
Away from stimulus to the central nervous system
Efferent
Motor, from central nervous system to muscle
Dorsal root ganglion
Holds the cell bodies of afferent neurons. contains sensory information from skin, subcutaneous, deep tissues, and viscera
Perception
Turning sensory information into meaningful information
Sensory integration
Ability do you sensory information effectively
Contributors to balance
Somatosensory systems, vision, vestibular
Somatosensory system
Provide sensory information about the body and center to the central nervous system
Exteroception
Touch
Interception
The sensation inside
Proprioception
Knowing one’s body in space
Receptors of the somatosensory system
Mechanoreceptors: touch, pressure, vibration, proprioception
Thermoreceptors: heat and cold
Nociceptors: pain
Somatosensory prenatal development order
Touch (seven weeks), vestibular, smell, hearing, vision, taste, proprioception (mid fetal life)
Infancy and childhood somatosensory system
All sensory systems are ready to function, but not mature. Peripheral nervous system is completely myelinated, increased nerve velocity, increased, pruning or axon branching, increased synaptic efficiencies.
Somatosensory, infancy, and childhood: touch
Rooting reflex used to locate food, crucial for attachment and sociability
12 to 16 months somatosensory system
Touch, localization
Five years somatosensory system
Identify objects by touch
Seven years somatosensory system
Two-point discrimination
Infancy and childhood proprioception
Used very early after birth, posture, muscle spindles mature at three years, mastery increases from 5 to 12 years
Somatosensory system, adolescence
Best during this time. To guide motor abilities and increase skills.
Adulthood somatosensory system
Sensory function begins to decline after it peaks mid 20s. Skin becomes dry and less elastic with less receptors.
Aging somatosensory system
Decrease in sensory function, decrease in sensory neurons, decrease in receptors, increased atrophy, and arthritis. Increased compensation.
Visual system
Dominant sensory, modality, and humans, that controls posture, locomotion, balance, hand functions
4 eye-movements
Saccades, slow pursuit (tracking), vestibular ocular reflex, vergence
Saccades
Quick, Simultaneous movements of the eye from side to side
Slow pursuit (tracking)
Slow control movements
Vestibular ocular reflex
Stabilizes images, moves, headed in the opposite direction of eyes
vergence
Movement of eyes in the same or opposite direction. Convergent or divergence
Visual systems prenatal
Vision forms in thalamus inside diencephalon. Eyeballs form at the fourth week, myelination begin to the 13th week, visual cortex forms during the second half of gestation reflexive eye, blinking at six months.
Visual system newborns
Most pathways develop postnatally, vision is 20/800. Black-and-white vision. Prefer human faces.
Visual systems, infancy, and childhood
Postural control developed, increases, visual interest, head control, increases visual fixation .
Visual symptoms two months
See colors, red and yellow. Track, vertically, horizontally, and circular.
Visual systems Three months.
Prefer colors
Visual systems 4 months
Full color vision, binocular vision at 3 to 5 months
Visual systems one year
2020 vision.
Visual systems, adolescence
More sophisticated vision, and hand eye coordination
Visual systems, age 11
Can indicate the size of an object
Visual systems, age 12
Can determine depth perception
Visual systems adulthood
Cataracs occurs and over 30 years old. After 40 decrease in light, dark adaption. Presbyoa after 45. Vision decreases at years, 60 to 80.
Presbyopia
Degeneration of the eye
Visual systems, older adults
Decreasing visual activity. 60% decrease over 65, 28% decrease over 75. Lots of depth perception by 6 to 75%.
Vestibular system
Position of head in space, and sudden changes, helps with eye stabilization
Linear movement vestibular system
Otolith
Rotational accelerations vestibular system
Semi circular
Vestibular system prenatal
Begin to form from ectoderm at four weeks. At 10 weeks, semi circular canals, utricle’s, and Sacules have formed.
Vestibular systems in infancy and childhood
All myelinated at birth to control against gravity, trunk righting, and equilibrium. Vestibular ocular reflex forms at 2 months
Vestibular system adolescence
Full maturity is reached from 10 to 14 years. Contributes to healthy body scheme and gravitational security.
Gravitational security
Ability to have your feet off the ground to be secure in space
Vestibular system is 9 to 12 years old
Static balance
Vestibular systems, 12 years old
Dynamic balance
Vestibular system adulthood
Age related changes begin in 40s, decreasing sensory cells
Vestibular system’s older adults
Increased dizziness and vertigo. 40% loss of hair cells and 36% loss of peripheral fibers. Increased threshold of excitation in the vestibular nuclei.
