PNS, Ch 13

Question 1

Originate from spinal cord and innervate structures below the head and neck. Anterior root contains motor neurons from its horn. Posterior root contains sensory neurons that enter its horn. Posterior/dorsal root ganglion fuses with anterior root to create this. 31 pairs.

Answer 1

Spinal nerves

Question 2

Attach to the brain and mainly innervate structure of the head and neck. Some are purely sensory, others are mixed, others are mostly motor. 12 pairs.

Answer 2

Cranial nerves

Question 3

Each axon in a fascicles is surrounded by its own connective sheath called?

Answer 3

Endoneurium

Question 4

Motor and sensory axons making up a nerve are held together by a connective tissue sheath called?

Answer 4

Epineurium

Question 5

What binds fascicles together in a nerve?

Answer 5

Perineurium

Question 6

Fight or flight division of the ANS. Maintains homeostasis when the body is involved in any type of physical work and mediates the body’s visceral responses to emotion.

Answer 6

Sympathetic nervous system

Question 7

The rest and digest system of the ANS. Plays a role in digestion and in maintaining the body’s homeostasis at rest.

Answer 7

Parasympathetic nervous system

Question 8

Oh, Oh, Oh

Answer 8

I Olfactory
II Optic
III Oculomotor

Question 9

They Traveled And Found

Answer 9

IV Trochlear
V Trigeminal
VI Abducens
VII Facial

Question 10

Voldemort Guarding Very Ancient Horcruxes

Answer 10

VIII Vestibulocochlear
IX Glossopharyngeal
X Vagus
XI Accessory
XII Hypoglossal

Question 11

After leaving the vertebral cavity, the spinal nerve splits into two nerves. One travels to the posterior side of the body. The other travels to the anterior and/or the upper and lower limbs. Mixed nerves that carry sensory and somatic motor info.

Answer 11

Posterior ramus

Anterior ramus

Question 12

Small branches from the anterior ramus that contain visceral motor or autonomic neurons of the sympathetic nervous system, and so are not mixed.

Answer 12

Rami communicantes

Question 13

What do the 31 pairs of spinal nerves consist of?

Answer 13

8 cervical 
12 thoracic spinal 
5 lumbar 
5 sacral 
1 coccygeal

Question 14

The anterior rami of the cervical, lumbar, and sacral spinal nerves come together and merge to form networks of nerves called this.

Answer 14

Nerve plexuses

Question 15

What are the four spinal nerve plexuses?

Answer 15

Cervical
Brachial
Lumbar
Sacral

Question 16

Sensory receptors that are typically close to the surface of the body, detecting stimuli originating outside of it.

Answer 16

Exteroceptors

Question 17

Sensory receptors that generally lie within the body’s interior, detecting stimuli originating from inside the body.

Answer 17

Interocepters

Question 18

Encapsulated exteroceptors or interocepters found in the skin, musculoskeletal, and viscera. Specialized mechanically gated ion channels.

Answer 18

Mechanoreceptors

Question 19

Exteroceptors that respond to thermal stimuli. Most are slowly adapting receptors.

Answer 19

Thermoreceptor

Question 20

Exteroceptors or interoceptor that depolarizers in response to certain chemicals. Internals detect hydrogen ion concentration, the level of carbon dioxide, and the level of oxygen in the body’s fluids. Externals are for smell and taste.

Answer 20

Chemoreceptor

Question 21

Sensory exteroceptors found only in the eye that depolarize in response to light.

Answer 21

Photoreceptors

Question 22

Sensory receptors that depolarize in response to nociception and pain. Generally exteroceptors. Slowly adapting.

Answer 22

Nociceptors

Question 23

The detection of noxious stimuli, and the perception and interpretation of these stimuli.

Answer 23

Nociception

Pain

Question 24

Tapered structures that are found embedded among the regular contractile muscle fibers.

Answer 24

Muscle spindles

The fibers are extrafusal muscle fibers

Question 25

Within each muscle spindle are 2-12 of these. They have contractile filaments composed of actin and myosin at their poles, with a central area where contractile filaments are absent.

Answer 25

Intrafusal muscle fibers

Question 26

Two types of structural and functional classes of sensory neurons innervate the intrafusal fibers. Contain mechanically gated ion channels that open when the fibers are stretched. The first responds during initiation, the second responds to the static length and the position of a limb.

Answer 26

Primary afferent | Secondary afferent

Question 27

Mechanoreceptors composed of an encapsulated bundle of collagen fibers attached to muscle ones. Single somatic sensory axon whose endings are wrapped around collagen fibers. Monster tension generated by contraction.

Answer 27

Golgi tendon organs

Question 28

Reflex arc that involves only a single synapse within the spinal cord between the sensory and motor neurons. One that involves multiple synapses.

Answer 28

Monosynaptic arc | Polysynaptic arc

Question 29

The body's reflexive response to shorten a muscle so that it returns to its optimal length via a monosynaptic reflex.

Answer 29

Simple stretch reflex

Question 30

When tension in the muscle and tendon increase dramatically, the Golgi tendon organs signal the spinal cord and cerebellum, causing events that lead to muscle relaxation. Polysynaptic.

Answer 30

Golgi tendon reflex

Question 31

Involves rapidly conducting nociceptive afferents and multiple synapses in the spinal cord, a polysynaptic reflex.

Answer 31

Flexion/withdrawal reflex

Question 32

Occurs simultaneously with the flexion reflex. Helps keep balance and protects when withdrawing from pain stimuli.

Answer 32

Crossed-extension reflex

Question 33

Most peripheral neuropathies. Often result from injury to a spinal or cranial nerve or to these cell bodies in the spinal cord. Prevents alpha-motor neuron from stimulating a skeletal muscle fiber to contract, can't respond to feedback from muscle spindles.

Answer 33

Lower motor neuron disorders Paralysis Paresis Reduction or absence of stretch reflexes and muscle tone

Question 34

Conditions that result from damage or disease anywhere along the pathways from the motor cortices to the spinal cord.

Answer 34

``` Upper motor neuron disorders Spinal shock Spasticity Babinski sign Plantar reflex ```