TEST 2: Peripheral Nervous System

Question 1

___pairs of spinal nerves

Answer 1

31 pairs of spinal nerves

• direct enervation to skeletal muscles
• leave cord at different levels
• for each spinal nerve, sensory neurons enter spinal chord through dorsal root and motor neurons leave spinal cord through the ventral root

Question 2

___pairs of cranial nerves

Answer 2

12 pairs of cranial nerves

Question 3

5 Primary classes of sensory receptors

Answer 3

1. Mechanoreceptors
2. Thermoreceptors
3. Nocioceptors
4. Photoreceptors
5. Chemoreceptors

Question 4

Mechanoreceptors

Answer 4

respond to mechanical forces; pressure, touch, vibration, stretch, etc

Question 5

Thermoreceptors

Answer 5

respond to temperature changes

Question 6

Nocioreceptors

Answer 6

respond to painful stimuli

Question 7

Photoreceptors

Answer 7

respond to electromagnetic radiation (light) to allow vision

Question 8

Chemoreceptors

Answer 8

respond to chemical stimuli: food, orders, changes in blood concentrations of substances

Question 9

Specific Sensory Receptors

Answer 9

• Free Nerve Endings
• Joint Kinesthetic Receptors
• Muscle Spindles
• Golgi Tendon Organs

Question 10

Free Nerve Endings

Answer 10

in skin, detect crude touch, pressure, pain, and heat/cold

Question 11

Joint Kinesthetic Receptors

Answer 11

in joint capsules sensitive to joint angles and rate of change of joint angles

Question 12

Muscle Spindles

Answer 12

• enhance normal muscle contraction. anytime a-motor neurons are activated, y-motor neurons are also activated which stretches the spindle. spindle stretch then enhances a-motor neuron activation enhancing muscle contraction
• sense muscle length and rate of change of muscle length
• -specialized intrafusal muscle fibers (4-20 fibers/spindle)
• —contractile ability only at ends of fibers
• —innervated by gamma motor neurons

Question 13

Golgi Tendon Organs

Answer 13

detect tension applied by a muscle to its tendon, producing info about the strength of muscle contraction

• encapsulated sensory receptors through which a small bundle of tendon fibers pass
• 5-25 fibers/GTO
• proximal to musculotendinous junction
• very sensitive to tension (stretch) on tendon
• when GTOs sense tension on the tendon, sensory nerve endings surround he GTOs send that info to spinal cord. Spinal cord responds by causing inhibition of agonists and stimulation of antagonists
• —GTOs protect tendon from tearing

Question 14

How to decrease GTO sensitivity?

Answer 14

resistance training, contributing to strength agains

Question 15

Ennervation Ratio

Answer 15

of muscle fibers/ motor neuron

Question 16

Two parts of Autonomic Nervous System

Answer 16

Sympathetic Nervous System

Parasympathetic Nervous System

Question 17

Sympathetic Nervous System

Answer 17

prepares body to face crisis

Question 18

Parasympathetic Nervous System

Answer 18

Housekeeping System

Question 19

Integration Center

Answer 19

Where sensory impulse terminates, is interpreted, and linked to motor

Question 20

5 steps of Sensory-Motor Integration

Answer 20

1. Sensory stimulus received by sensory receptors
2. Sensory impulse transmitted along sensory neurons to CNS
3. CNS interprets incoming sensory impulses and determines most appropriate response
4. Signals for the motor response are transmitted from the CNS out along motor neurons
5. Motor impulse is transmitter to a muscle (or other end organ) and a response occurs

Question 21

Reflex

Answer 21

simple pre-programmed response

• do not involved higher brain centers
• rapid means of response to some stimuli