sensory system

Question 1

Receptors

Answer 1

receive stimulus
-defines type, location, and intensity of stimulus

Question 2

Sensory Pathways

Answer 2

• nerve axons and afferent pathways
  -transmit electrical signals to area of brain that corresponds with receptor location

Question 3

CNS

Answer 3

interpret and integrate sensory inputs signals
- communicated with motor system to produce goal directed movement

Question 4

Efferent pathways

Answer 4

produce response

Question 5

What are the two types of receptors

Answer 5

1. nerve cells
2. specialized epithelial cell

Question 6

Activation of receptors

Answer 6

-stimulus-specific
-transform an external stimulus to an electrical signal

Question 7

Sensory pathways

Answer 7

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

Question 8

Dorsal Root Ganglion

Answer 8

-a collection of cell bodies of the afferent sensory fibers

Question 9

What is the dorsal root ganglion associated?

Answer 9

the posterior or dorsal root of the spinal nerve

Question 10

What does the dorsal roots contain?

Answer 10

sensory fibers from the skin, subcutaneous and deep tissues, viscera

Question 11

Are the dorsal roots myelinated?

Answer 11

primary afferent fibers of the dorsal roots are either myelinated or unmyelinated: cutaneous, joint and visceral afferents are composed of myelinated

Question 12

Perception

Answer 12

the integration of sensory impressions into psychologically meaningful info

Question 13

Sensory maps

Answer 13

the location of sensory receptors in the brain
Sensory homunculus: shows the somatic sensory projections from the body surface

Question 14

Sensory homunculus

Answer 14

shows the somatic sensory projections from the body surface

Question 15

Sensory integration

Answer 15

the ability to use sensory info efficientyl
-combining several sensory inputs to produce a desired movement
For example: drawing, writing

Question 16

What systems are involved in stable standing balance?

Answer 16

• somatosensory system (proprioception)
• vision
• vestibular system

Question 17

Somatosensory system receptors

Answer 17

1. mechanoreceptors
2. thermoreceptors
3. nociceptors

Question 18

thermoreceptors

Answer 18

heat cold

Question 18

mechanoreceptors

Answer 18

touch, pressure, vibrator proprioception

Question 19

nociceptors

Answer 19

pain (unmyelinated receptors)

Question 20

somatosensory system

Answer 20

Provides sensory information about the body
- Cutaneous sensation of touch (exteroception)
-Proprioceptive sensation from ligaments, muscles, joints, and
tendons

Question 21

exteroception

Answer 21

Cutaneous sensation of touch

Question 22

interoception

Answer 22

perception of sensation from inside the body

Question 23

Proprioception

Answer 23

perception of one’s body in space

Question 24

Function of somatosensory system

Answer 24

Transmits information about the senses of touch, pain, temperature, and body position from sensory receptors to the CNS to regulate behavior

Question 25

Order of sensory system development in PRENATAL

Answer 25

Touch Vestibular Smell Hearing Vision Taste Proprioception The Very Smelly Hippo Very Taste Purple

Question 26

What is the first system to function in utero?

Answer 26

Touch; allows for communication and attachment

Question 27

When are proprioceptive receptors well developed?

Answer 27

mid fetal life

Question 28

What are proprioceptive receptors?

Answer 28

muscle spindles and golgi tendon organs

Question 29

What occurs at 7 weeks prenatal?

Answer 29

fetus responds to touch around motuh

Question 30

What occurs at 12 weeks prenatal?

Answer 30

muscle spindles formed

Question 31

What occurs at 16 weeks prenatal?

Answer 31

golgi tendon organs formed

Question 32

What occurs at 17 weeks prenatal?

Answer 32

cutaneous sensation spreads to entire body

Question 33

Are all sensory systems ready to function at birth?

Answer 33

yes but not matured -PNS is completely myelinated

Question 34

What complete structural maturation of sensory pathways occur t/o childhood?

Answer 34

 Increased nerve conduction velocity  Redistribution of axon branching  Increased synaptic efficiency

Question 35

Maturation: Infancy and Childhood

Answer 35

- touch used by infant to locate food (rooting reflex) -crucial role in parent infant attachment, sociability, cognitive development -Further structural and functional changes occur as the infant and child interact with the world

Question 36

What occurs at 12-16 months maturation of infancy and childhood?

Answer 36

specific touch localization

Question 37

What occurs at 5 years maturation of infancy and childhood?

Answer 37

identify objects by touch

Question 38

What occurs at 7 years maturation of infancy and childhood?

Answer 38

two point discrimination

Question 39

Maturation childhood and infancy proprioception

Answer 39

 Used very early after birth  Execution of purposeful movements such as imitation, reaching, and locomotion  Ability to achieve and maintain upright postures  Muscle spindles mature as early as 3 years old  Proprioceptive acuity for movements improves between age 5-12  Allows for beginning mastery of skills such as hopping, dancing, and gymnastics  Integration of sensation and movement occurs during childhood and continues to develop through adolescence

Question 40

when does integration of sensation and movement occur?

Answer 40

childhood and continues to develop through adolescence

Question 41

When does proprioceptive acuity for movements improve?

Answer 41

between age 5-12

Question 42

Somatosensory system Maturation: Adolescence

Answer 42

 Tactile and proprioceptive senses are further refined  Maturation and integration of somatosensory system processing guide motor abilities and skill refinement

Question 43

When is sensory system the keenest?

Answer 43

late adolescence into early adulthood

Question 44

What occurs to sensory function in adulthood?

Answer 44

begins to decline -Peripheral and central changes are small and gradual -Do not always correlate with a decline in function

Question 45

When do sensory receptor functions decline?

Answer 45

middle age

Question 46

When does reaction time peak? When does it slow down/ by how much?

Answer 46

mid 20's then slows by 20% during middle adulthood

Question 47

Why does skin become dry and less elastic in adulthood?

Answer 47

compromised precision of cutaneous receptors

Question 48

Gradual decline in sensory functioning in Aging?

Answer 48

-Decrease in the number of sensory neurons - Decline in functioning of remaining sensory neurons -Structural and physiological changes within the CNS

Question 49

impact on tactile system in aging?

Answer 49

Skin receptors decrease in number and undergo structural changes  Decrease in number of receptors → decline in fine touch, pressure, and vibration sense  A loss up to 30% of sensory fibers innervating peripheral receptors leads to peripheral neuropathy

Question 50

What is impact on proprioceptive system in aging?

Answer 50

Atrophy of muscle spindles, joint receptors, and GTO’s – decreasing feedback that CNS normally receives during movement - Arthritic changes affect the ability of joint receptors to detect joint motion

Question 51

 Redundancy of sensory information is decreased by agerelated changes → older adults are forced to compensate more functional consequences?

Answer 51

 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