ch 7 the nervous system and neuronal excitability

Question 1

nervous system

Answer 1

the nervous tissues of the body

Question 2

central nervous system (CNS)

Answer 2

consists of the brain and spinal cord

Question 3

peripheral nervous system (PNS)

Answer 3

consists of all nervous tissue outside the CNS

Question 4

nerve

Answer 4

a bundle of axons that lies outside the brain and spinal cord

Question 5

cranial nerves

Answer 5

12 pairs of nerves that emerge from the brain

Question 6

spinal nerves

Answer 6

31 pairs of nerves that emerge from the spinal cord

Question 7

sensory receptor

Answer 7

a structure that monitors changes in the external or internal environment

Question 8

afferent division of the PNS conveys

Answer 8

input into the CNS from sensory receptors in the body

Question 9

somatic senses

Answer 9

tactile, thermal, pain, and proprioceptive sensations

Question 10

special senses

Answer 10

smell, taste, vision, hearing, and equilibrium

Question 11

efferent division of the PNS conveys

Answer 11

output from the CNS to effectors

Question 12

effectors

Answer 12

muscles and glands

Question 13

somatic nervous system

Answer 13

conveys output from the CNS to skeletal muscles only
- voluntary

Question 14

autonomic nervous system

Answer 14

conveys output from the CNS to smooth muscle, cardiac muscle, and glands
- involuntary

Question 15

two main branches of the ANS

Answer 15

parasympathetic nervous system - rest and digest
sympathetic nervous system - flight or fight

Question 16

enteric nervous system (ENS)

Answer 16

an extensive network of neurons confined to the wall of the GI tract
- helps regulate the activity of the smooth muscle and glands of the GI tract
- can function independently but also communicates with and is regulated by the other branches of the ANS

Question 17

three basic functions of the nervous system

Answer 17

• sensory
• integrative
• motor

Question 18

sensory function

Answer 18

sensory receptors detect external or internal stimuli
- sensory info is conveyed through cranial and spinal nerves of the PNS into the brain and spinal cord of the CNS

Question 19

integrative function

Answer 19

the CNS processes sensory info by analyzing it and making decisions for appropriate responses (integration)

Question 20

motor function

Answer 20

once sensory info is integrated, the CNS may elicit an appropriate motor response
- motor info is conveyed from the CNS through cranial and spinal nerves of the PNS to effectors (muscles and glands)

Question 21

function of dendrites

Answer 21

main input portions of the neuron

Question 22

function of cell body (soma)

Answer 22

control center of the neuron

Question 23

ganglion

Answer 23

a cluster of neuronal cell bodies in the PNS

Question 24

nucleus

Answer 24

a cluster of neuronal cell bodies in the CNS

Question 25

function of axons

Answer 25

output portion of the neuron by generating action potentials and then propagating them toward another neuron, a muscle fiber, or a gland cell

Question 26

axon holliock

Answer 26

where an axon connects to the cell body, where action potentials arise (aka trigger zone)

Question 27

axon collaterals

Answer 27

side branches of an axon

Question 28

axon terminals

Answer 28

the end of axons and it collaterals

Question 29

synaptic end bulb

Answer 29

the tips of axon terminals swell to become bulb shaped structures that can form synapses with other cells

Question 30

synapse

Answer 30

a site of communication between a neuron and a target cell

Question 31

synaptic vesicles

Answer 31

tiny membrane-enclosed sacs within the synaptic end bulbs that store neurotransmitters

Question 32

axonal transport

Answer 32

a process where materials move between the cell body and axon terminals

Question 33

anterograde transport

Answer 33

moves organelles and synaptic vesicles from the cell body to the axon terminals, involves kinesins

Question 34

retrograde transport

Answer 34

moves membrane vesicles and other cellular materials from the axon terminals to the cell body to be degraded or recycled, involves dyneins

Question 35

substances that are moved by retrograde transport

Answer 35

- trophic chemicals such as nerve growth factor - harmful agents such as tetanus toxin and the viruses that cause rabies, herpes simplex, and polio

Question 36

tract

Answer 36

a bindle of axons in the CNS

Question 37

three functional classes of neurons

Answer 37

- sensory/afferent neurons - motor/efferent neurons - interneurons/association neurons

Question 38

sensory/afferent neurons

Answer 38

convey action potentials into the CNS

Question 39

motor/efferent neurons

Answer 39

convey action potentials away from the CNS to effectors in the periphery

Question 40

interneurons/association neurons

Answer 40

located entirely within the CNS between the sensory and motor neurons; responsible for integration

Question 41

neuroglia function

Answer 41

support neurons by nourishing and protecting neurons and maintaining homeostasis in the interstitial fluid that bathes them

Question 42

four types of neuroglia in the CNS

Answer 42

- astrocytes - oligodendrocytes - microglia - ependymal cell

Question 43

astrocytes

Answer 43

have processes that wrap around the capillaries secrete chemicals that maintain the 'tightness' of tight junctions help maintain appropriate chemical environment for the generation of action potentials

Question 44

oligodendrocytes

Answer 44

responsible for forming and maintaining the myelin sheath around axons of neurons in the CNS

Question 45

microglia

Answer 45

function as phagocytes - remove cellular debris formed during normal development of the nervous system and phagocytize microbes and damaged nervous tissue

Question 46

ependymal cell

Answer 46

line the ventricles of the brain and central canal of the spinal cord produce and assist in the circulation of cerebrospinal fluid

Question 47

schwann cells

Answer 47

form myelin sheath around axons of PNS neurons and also participate in axon regeneration

Question 48

myelin sheath

Answer 48

multilayered covering composed of lipids and proteins

Question 49

white matter

Answer 49

composed primarily of myelinated axons

Question 50

gray matter

Answer 50

contains neuronal cell bodies, dendrites, unmyelinated axons, axon terminals, and neuroglia

Question 51

plasticity

Answer 51

the ability to changes based on experience

Question 52

regeneration

Answer 52

the capability to replicate or repair themselves

Question 53

regeneration tube

Answer 53

formed by schwann cells to aid the repair process, guides and stimulates regrowth of the axon

Question 54

two factors of why there is little or no repair of an axon after injury in the CNS

Answer 54

- inhibitory proteins secreted by neuroglia, particularly oligodendrocytes - absence of growth-stimulating cues that were present during fetal development