sensory system

Question 1

What are the two types of receptors?

Answer 1

Nerve Cell
Specialized epithelial cell

Question 2

What are the sensory pathways?

Answer 2

They describe the type and location of the sensory stimulus
Type: dependent on what type of receptor is activated
Location: each receptor has a specific location on the sensory map in the brain

Question 3

What is dorsal root ganglion? What does it contain? What is mylelinated?

Answer 3

A collection of cell bodies of the afferent sensory fibers

The dorsal roots contain sensory fibers from the skin, subcutaneous and deep tissues, and viscera

Cutaneous, joint, and visceral afferents are composed of mylienated

Question 4

Central nervous system perception? Sensory maps? Sensory integration?

Answer 4

Perception- the integration of sensory impressions into psychologically meaningful information

Sensory maps- the location of sensory receptors in the brain

Sensory integration- the ability to use information efficiently

Question 5

What systems are involved in stable standing?

Answer 5

Somatosensory system (proprioception)
Vision
Vestibular system

Question 6

What are the 3 different types of receptors?

Answer 6

1. Mechanoreceptors- touch, pressure, vibratior, proprioception
2. Thermoreceptors- heat and cold
3. Nociceptors (non mylienated)- pain

Question 7

What is the order of sensory system development? What is the first system to function in utero?

Answer 7

Touch - vestibular- smell- hearing- vision- taste- proprioception

Touch is first

Question 8

Maturation of Sensory system during infancy and childhood

Answer 8

All sensory systems are ready to function at birth
Peripheral nerves are completely myelinated

Complete maturation occurs through increased nerve conduction velocity
Redistribution of axon branching
Increased synaptic efficiency

Question 9

Proprioception at infancy and childhood?

Answer 9

Used very early at birth

Acuity for movements improves between age 5-12

Question 10

Maturation of adolescence

Answer 10

Sensory system is keenest during late adolescence into early adulthood

Question 11

Maturation of adulthood

Answer 11

Sensory function begins to decline in adulthood

Reaction time peaks in mid 20 then slows by 20% during middle adulthood

Question 12

A loss up to 30% of sensory fibers innervating peripheral receptors leads to

Answer 12

Peripheral neuropathy

Question 13

Arthritic changes affect ability to?

Answer 13

Of joint receptors to detect joint motion

Question 14

Importance of the visual system?

Answer 14

Dominant sensory modality in humans
Vital to posture, locomotion, balance, and hand function

Question 15

Visual system prenatal?

Answer 15

Derived from the thalamus in diancephalon
Most peripheral structure develops into the eyeball
4th week- eye forms
13th week- myelination begins

Question 16

Visual acuity for newborns and what do they see? Best distance for fixation?

Answer 16

20/800
Initially see black and white
Best distance for fixation is 7-9 inches

Question 17

Maturation for infancy and childhood at 2 months?

Answer 17

2 months: see 2 colors red and yellow and track vertically horizontally and circular path

4 months: binocular vision between 3-5 months, adult like happens at 2 years old

12 months: adult levels of visual acuity achieved 20/20

Question 18

Children between 4-6 years old are highly dependent on visual feedback for

Answer 18

Upright postural control and balance

Question 19

When do cataracts form?

Answer 19

Form in individuals over 30

Question 20

What happens after age 40 in terms of vision?

Answer 20

Decline in ability to quickly adapt from light to dark

Question 21

What happens at age 45 in terms of vision?

Answer 21

Far sightedness develops

Question 22

Visual system in older adults?

Answer 22

More light required to see decreased ability to adapt from dark to light

Intrastate sensitivity decreases between 65-75 percent and

Question 23

Vestibular system prenatal?

Answer 23

Vestibular structures begin as a thickening of the ECTODERM within the ear in the 4th week of gestation

As fetus in utero, vestibular apparatus provides information about that movement.

Question 24

Is vestibular system completely myelinated at birth?

Answer 24

Yes

Question 25

When is the normal vestibular ocular reflex present infancy and childhood?

Answer 25

2 months of age

Question 26

Maturation of vestibular system adolescence? At 9-12 yrs old gain? At 12 yrs old gain?

Answer 26

Full maturity of vestibular system achieved between 10 and 14 yrs of age

9-12 yrs- gain in static balance
12 yrs- gains in dynamic balance

Question 27

Maturation of adulthood vestibular system

Answer 27

Changes begin at 40 years old, decreased number of sensory cells and nerve fibers in the peripheral nervous system
Neural changes possible in vestibular nerve

Question 28

Vestibular system in older adults, common issues at 50? Issues for over 70 yrs old?

Answer 28

Decline in function with aging
At 50: dizziness and vertigo
At 70: 40% reduction in hair cells and 36% reduction in peripheral nerve fibers