Chapter 13 Test Review- The Peripheral Nervous System

Question 1

Organization of the nervous system

Answer 1

Stimulus information from the afferent division in the PNS is input to the CNS (brain and spinal cord) where it is processed

Info is then output to the efferent division of the PNS for actions to be carried out by the somatic and autonomic nervous systems via skeletal and smooth muscles

Question 2

Sensory division of PNS

Answer 2

Sensory neurons carry signals from muscles/bones/joints/skin/special senses to the CNS

Question 3

Motor division of PNS

Answer 3

Carry signals from CNS to skeletal muscles

Question 4

Origin and number of cranial nerves

Answer 4

12 pairs of cranial nerves

Originate from the brain

Innervate the head and neck

Question 5

Origin and number of spinal nerves

Answer 5

31 pairs of spinal nerves

Originate from the spinal cord and innervate structures inferior to the head and neck

Question 6

Difference between sensory, motor and mixed cranial nerves

Answer 6

Sensory nerves carry signals TO the CNS, motor nerves carry signals FROM the CNS and mixed nerves do both

Question 7

How is cranial nerve #10 from the other cranial nerves

Answer 7

Vague nerve

Only cranial nerves that extends beyond the head and neck

Question 8

Why are spinal nerves mixed nerves?

Answer 8

Because they carry motor AND sensory information between the spinal cord and body

Question 9

Structure of a nerve

Answer 9

Fascicles contain bunches of myelinated axons each encased in endoneurium

The perineurium surrounds each fascicle

Each nerve contains many fascicles and several blood vessels and the nerve is surrounded by the epineurium

Question 10

Spinal nerve plexuses

Answer 10

1. Cervical
2. Brachial
3. Lumbar
4. Sacral

Question 11

Role of PNS in sensations

Answer 11

Sensory receptors receive stimuli, an action potential is created and transmitted via first order neurons to the CNS and second order neuron in posterior horns of the spinal cord

Question 12

What are sensory receptors

Answer 12

Free or encapsulated axonal branches of unipolar sensory neurons with receptive endings, an axon and telodendria

Question 13

Classification of sensory receptors and their functions

Answer 13

General: sensitive to temperature, pain, touch, vibration, pressure, prioprioception

Special: eyes/vision, ears/hearing, olfactory epithelium/smell, gustatory epithelium/taste

Question 14

Function of pseudounipolar sensory neurons in general sensory pathways

Answer 14

Ones found in dorsal root ganglia and those found in cranial nerve sensory ganglia carry info about touch, vibration, pain, temp etc

Question 15

What parts of the brain are involved in control of body movements?

Answer 15

Cerebrum, cerebellum

Question 16

What is decussation?

Answer 16

Crossed track of nerve fibers passing between centers on opposite sides of the nervous system

When’s major ascending sensory pathway crosses the midline

Question 17

What is a reflex arc

Answer 17

Chain of events in which a sensory stimulus leads to a predictable motor response

Question 18

3 events in a reflex arc

Answer 18

1. Detection and delivery of stimulus
2. Integration
3. Delivery of motor response