HS1-4 Nervous System

Question 1

What are the two distinctive cytoplasmic processes of neurons?

Answer 1

dendrite; axon

Question 2

Define nerve.

Answer 2

collection of nerve axons or fibers bound together with connective tissue

Question 3

Where are nerves generally located?

Answer 3

outside of the CNS

Question 4

Nerves located within the CNS are called

Answer 4

fiber tracts

Question 5

Define plexus.

Answer 5

collection of nerves from multiple sources, serving as an area of redistribution

Question 6

Define ganglion.

Answer 6

collection of nerve cell bodies outside CNS

Question 7

A collection of nerve cell bodies within the CNS is called

Answer 7

a nucleus

Question 8

Define sensory neuron.

Answer 8

a neuron that conducts impulses towards (afferent) the CNS

Question 9

Define motor neuron.

Answer 9

a neuron that conducts impulses away (efferent) from the CNS

Question 10

What is the function of somatic motor neurons?

Answer 10

innervates skeletal muscle

Question 11

Describe the composition of somatic motor neurons.

Answer 11

composed of one neuron whose cell body is within the CNS and whose axon contacts multiple fibers

Question 12

What is the function of visceral (autonomic) motor neurons?

Answer 12

conducts motor impulses to smooth muscle, cardiac muscles, and smooth muscles of glands

Question 13

What is the composition of visceral (autonomic) motor neurons?

Answer 13

composed of two-neuron chain

Question 14

Describe preganglionic/presynaptic neurons.

Answer 14

has its cell body located in CNS

Question 15

The axon of preganglionic/presynaptic neurons synapses with

Answer 15

postganglionic/postsynaptic neurons

Question 16

Where are postganglionic/postsynaptic neurons located?

Answer 16

located in pre/paravertebral ganglia (sympathetic) or in terminal ganglia near target organ (parasympathetic)

Question 17

Which specific axons actually contact the target organs?

Answer 17

postganglionic axons

Question 18

What is the function of the autonomic nervous system?

Answer 18

responsible for regulation and control of visceral functions

Question 19

Is the autonomic nervous system a motor system or sensory system?

Answer 19

a motor system

Question 20

The autonomic nervous system is further divided into what subdivisions?

Answer 20

sympathetic and parasympathetic divisions

Question 21

What are synonyms for the terms “sympathetic” and “parasympathetic?”

Answer 21

sympathetic (thoracolumbar) and parasympathetic (craniosacral)

Question 22

Spinal and cranial nerves belong to which division of the nervous system?

Answer 22

PNS

Question 23

What are the types of motor neurons? (2)

Answer 23

general/somatic motor; visceral motor

Question 24

What is the function of general/somatic motor neurons?

Answer 24

contact or innervate skeletal muscle

Question 25

What is the function of visceral motor neurons?

Answer 25

innervate cardiac and smooth muscle

Question 26

What are the types of sensory neurons? (3)

Answer 26

general sensory; visceral sensory; special sensory

Question 27

What do general sensory neurons innervate? (4)

Answer 27

innervate skin, muscles, joints, connective tissue

Question 28

What is the function of general sensory neurons? (5)

Answer 28

convey sensory modalities of pain, thermal sense, touch, pressure, and kinesthesis to spinal cord and brainstem

Question 29

What is the function of visceral sensory neurons? (2)

Answer 29

sends conscious sensations of pain from viscera and sends unconscious visceral reflex sensations from viscera and blood vessels to spinal cord and brainstem

Question 30

What is the function of special sensory neurons? (5)

Answer 30

responsible for smell, vision, hearing, balance, taste

Question 31

Special sensory neurons are exclusively what type of peripheral nerve?

Answer 31

special sensory neurons are exclusively cranial nerves

Question 32

What is synaptic transmission?

Answer 32

chemical communication between neurons

Question 33

What is sensory transduction?

Answer 33

conversion of mechanical or chemical stimuli to electrical impulses conducted by axon

Question 34

Contrast motor and sensory neurons in terms of the locations of their dendrites and synaptic endings.

Answer 34

sensory neurons: dendrites in periphery, synaptic endings in CNS motor neurons: dendrites in CNS, synaptic endings in periphery

Question 35

What are the common phrases used to refer to the sympathetic and parasympathetic divisions of the autonomic nervous system?

Answer 35

sympathetic: fight and flight parasympathetic: rest and digest

Question 36

Describe how innervation of target organs in the autonomic nervous system is accomplished.

Answer 36

preganglionic/presynaptic neuron extends fiber/axon out of CNS to make contact w/ neurons in ganglion of PNS; then postganglionic/postsynaptic neuron makes contact with smooth muscle of target organs

Question 37

Give an example of an organ that receives dual innervation from the sympathetic and parasympathetic divisions. Why might such a system be useful?

Answer 37

the heart; useful for antagonistic effects and therefore used to balance activity of the two divisions

Question 38

Describe the myelination of ANS neurons.

Answer 38

preganglionic neuron is myelinated, but postganglionic cell in PNS is unmyelinated

Question 39

Contrast the somatic and autonomic nervous systems in terms of inhibition.

Answer 39

in somatic reflex arcs, inhibition is exerted by one neuron after another and never directly on skeletal muscle in autonomic reflex arcs, postsynaptic neurons can directly inhibit target organ

Question 40

Where are the cell bodies of preganglionic neurons in the sympathetic division located?

Answer 40

located in intermediolateral gray matter of spinal cord, from T1 to L2 (think thoracolumbar)

Question 41

Describe the organization of autonomic outflow in the sympathetic/thoracolumbar division. (3)

Answer 41

myelinated axons leave spinal cord via ventral root and white rami communicans to prevertebral ganglia; then postganglionic neuron travels peripherally to target organ; then unmyelinated axon returns to spinal nerves via gray rami communicans

Question 42

What is the neurotransmitter between pre- and post-ganglionic neurons in the sympathetic division of the ANS?

Answer 42

acetylcholine

Question 43

What is the neurotransmitter used by the post-ganglionic neurons in the sympathetic division of the ANS?

Answer 43

norepinephrine (except sweat glands, which receive acetylcholine)

Question 44

Where are the cell bodies of preganglionic neurons in the parasympathetic division located? (2)

Answer 44

in brainstem nuclei; in intermediolateral area of spinal cord, from S2 to S4

Question 45

Describe the organization of autonomic outflow in the parasympathetic/craniosacral division.

Answer 45

myelinated axons make synaptic contact w/ postganglionic neurons in 4 ganglia in head and with neurons in terminal ganglia near target organ

Question 46

What are the 4 ganglia located in the head that are important in parasympathetic autonomic outflow?

Answer 46

ciliary, pterygopalatine, submandibular, otic

Question 47

In general, where are the parasympathetic ganglia located relative to their targets?

Answer 47

parasympathetic ganglia are located close to their target tissue

Question 48

Describe the myelination of postganglionic axons in the parasympathetic division.

Answer 48

unmyelinated (same in sympathetic)

Question 49

What is the neurotransmitter between pre- and post-ganglionic neurons in the parasympathetic division of the ANS?

Answer 49

acetylcholine (like sympathetic division)

Question 50

What is the neurotransmitter used by the post-ganglionic neurons in the parasympathetic division of the ANS?

Answer 50

acetylcholine (same as the pre-ganglionic neurons)

Question 51

In general, where are the sympathetic ganglia located relative to their targets?

Answer 51

not located near target organs, since they are located pre- or para-vertebrally

Question 52

What is the effect of the sympathetic division on salivary glands?

Answer 52

decreases saliva

Question 53

What is the effect of the sympathetic division on lacrimal glands?

Answer 53

inhibits secretion of tears

Question 54

What is the effect of the sympathetic division on gastric/intestinal glands?

Answer 54

inhibits secretion of gastric or digestive juices

Question 55

What is the effect of the sympathetic division on the liver? (2)

Answer 55

promotes glycogenolysis and decreases secretion of bile

Question 56

What is the effect of the sympathetic division on the pancreas?

Answer 56

inhibits secretion of pancreatic enzymes

Question 57

What is the effect of the sympathetic division on the kidney?

Answer 57

constricts vessels, resulting in decreased urine formation

Question 58

What is the effect of the sympathetic division on the urinary bladder?

Answer 58

promotes urine retention

Question 59

Draw a diagram showing the organization of nerves in the CNS and PNS.

Answer 59

Question 60

Draw a diagram showing the divisions of the nervous system.

Answer 60

Question 61

Draw a diagram showing the organization of peripheral nerves.

Answer 61

Question 62

Contrast the presynaptic fiber length in the parasympathetic and sympathetic systems.

Answer 62

parasympathetic - long presynaptic fibers (rest and diget); sympathetic - short presynaptic fibers (fight or flight)

Question 63

Where are the ganglia in the sympathetic nervous system located?

Answer 63

paravertebrally (near spinal cord)

Question 64

What are the common terms used to describe the parasympathetic and sympathetic nervous systems?

Answer 64

parasympathetic = rest and digest sympathetic = fight or flight

Question 65

\*\*Label the following diagram of the spinal cord.

Answer 65

Question 66

What is the difference in myelination between white matter and grey matter?

Answer 66

white matter = myelinated grey matter = unmyelinated

Question 67

Why is the spinal column longer than the spinal cord?

Answer 67

because the spinal column develops faster than the spinal cord

Question 68

Where on the spinal column does the spinal cord end?

Answer 68

L2 @ conus medullaris

Question 69

\*\*Draw a diagram showing how the effects of herniation differ between the cervical and lumbar regions.

Answer 69

Question 70

What is the cauda equina?

Answer 70

the spinal region (inferior to L2) at which the spinal roots continue streaming downwards after the spinal cord ends @ L2 @ conus medullaris

Question 71

What is the common site for lumbar punctures (to extract CSF)?

Answer 71

L3-L5 in the subarachnoid space (it's expanded in the L3-L5 region, where it's called the lumbar cistern)

Question 72

What is safer for the patient in lumbar punctures — puncturing above or below the desired space?

Answer 72

better to puncture below

Question 73

Vertebral arteries in the spinal cord give rise to

Answer 73

anterior/posterior spinal arteries

Question 74

What is the function of segmental medullary arteries?

Answer 74

to reinforce anterior/posterior spinal arteries

Question 75

What is the function of radicular arteries?

Answer 75

to supply spinal roots