Chapter 9 Flash cards

Question 1

What does the central nervous system consist of?

Answer 1

the brain and spinal cord.

Question 2

what does the peripheral nervous system consist of?

Answer 2

all nervous tissue outside the CNS.

Components include nerve and sensory receptors.

Question 3

what is a nerve?

Answer 3

is a bundle of hundreds to thousands of axon plus associated connective tissue and blood vessels that lies outside the brain and spinal cord.

Question 4

how many pairs of cranial nerves emerge from the brain?

Answer 4

12

Question 5

how many nerves emerge from the spine

Answer 5

31

Question 6

what is a structure of the nervous system that monitors changes in external or internal environment?

Answer 6

a sensory receptor

Question 7

this division of the PNS, AKA the afferent division of the PNS conveys input into the CNS from the body.

Answer 7

the sensory division.

Question 8

The afferent division/sensory division of the PNS provides the CNS with what?

Answer 8

sensory information about the somatic senses and special senses.

Question 9

what is a somatic sense?

Answer 9

tactile, thermal, pain, and proprioceptive sensations.

Question 10

what are the special senses?

Answer 10

smell, taste, vision, hearing, and equilibrium

Question 11

Which division of the PNS conveys output from the CNS to effectors?

Answer 11

motor/efferent division

Question 12

the motor or efferent division is subdivided into what two systems?

Answer 12

somatic nervous system and an autonomic nervous system

Question 13

the somatic nervous system conveys output from the CNS to where?

Answer 13

skeletal muscles only.

Question 14

where does the autonomic nervous system convey output from and to?

Answer 14

CNS to smooth muscle, cardiac muscle, and glands.

Question 15

what are the two branches of the autonomic nervous system (ANS)?

Answer 15

sympathetic ad parasympathetic nervous system

Question 16

what is the third branch of the ANS?

Answer 16

enteric nervous system (ENS) (enteron = intenstines).

an extensive network of 100 million neurons confined to the GI tract.

Question 17

What are the three basic functions of the nervous system?

Answer 17

Sensory function
integrative function
Motor function

Question 18

What are the three parts of a neuron?

Answer 18

cell body
dendrites
axon

Question 19

whats another name for cell body

Answer 19

soma

Question 20

what is a collection of neuron cell bodies outside the CNS called?

Answer 20

ganglion (GANGLION= KNOT)

Question 21

What makes up the cell body?

Answer 21

nucleus, cytoplasm with typical organelles.

Question 22

what is a highly branched structure that carries impulses to the cell body?

Answer 22

dendrites

Question 23

what conducts away from the cell body toward another neuron, muscle or gland?

Answer 23

axon

Question 24

what is the cone shaped elevation where the axon joins the cell body?

Answer 24

axon hillock (hillock = small hill)

Question 25

what is the site called where two neurons or a neuron and an effector cell can communicate?

Answer 25

a synapse

Question 26

what are the tiny sacs that store chemicals called neurotransmitters and are released?

Answer 26

synaptic vesicles

Question 27

this structural classification of neuron usually have several dendrites and one axon. most neurons in the brain and spinal cord are of this type

Answer 27

multipolar neurons

Question 28

this structural classification of neurons have one main dendrite and one axon. they are usually found in the retina of the eye, in the inner ear, and in the olfactory area of the brain.

Answer 28

bipolar neurons

Question 29

this structural classification of neurons have dendrites and one axon that are fused together to form a continuous process that emerges from the cell body?

Answer 29

unipolar neurons

Question 30

the dendrites of most unipolar neurons function as what?

Answer 30

sensory receptors.

Question 31

where are the cell bodies of most unipolar neurons located?

Answer 31

the ganglia of spinal and cranial nerves.

Question 32

what are the three functional classifications of neurons

Answer 32

sensory motor interneurons

Question 33

where is the action potential of sensory neurons conveyed into?

Answer 33

the CNS. Most sensory neurons are unipolar.

Question 34

these mostly multipolar in structure neurons convey action potential AWAY from the CNS to effectors:

Answer 34

Motor neurons

Question 35

Most of these neurons are multipolar in structure, integrate incoming sensory information from sensory neurons and then elicit a motor response.

Answer 35

interneurons

Question 36

What makes up half the volume of the CNS, smaller and more numerous than neurons, and support, nourish, and protect neurons

Answer 36

neuroglia

Question 37

What are the function of neuroglia?

Answer 37

support, nourish, and protect neurons. multiply to fill in the space formerly occupied by neurons.

Question 38

these four neuroglia are found in the CNS

Answer 38

astrocytes, oligodendrocytes, microglial cells, and ependymal cells

Question 39

what two neuroglia are found in the PNS?

Answer 39

schwann and satellite cells

Question 40

what is the many layered covering composed of lipid and protein around an axon?

Answer 40

myelin sheath

Question 41

how are myelin sheaths formed?

Answer 41

schwann cells in the PNS and oligodendrocytes in the CNS produce myelin sheaths by wrapping themselves around and around axons.

Question 42

what is the gap in the myelin along the axon?

Answer 42

Nodes of Ranvier

Question 43

two diseases that destroy myelin sheaths?

Answer 43

multiple sclerosis and tay sachs

Question 44

Cluster of cell bodies in the PNS

Answer 44

ganglion

Question 45

cluster of cell bodies in the CNS

Answer 45

nucleus

Question 46

what is a bundle of axons that is located in the PNS

Answer 46

Nerve

Question 47

a bundle of axons that is located in the CNS

Answer 47

a tract

Question 48

this type of matter is composed primarily of myelinated axons:

Answer 48

white matter

Question 49

this matter of the nervous system contains cell bodies, unmyelinated axons, terminals, and neuroglia.

Answer 49

gray matter

Question 50

how is there regeneration of PNS neurons?

Answer 50

axons and dendrites in the PNS can be repaired if cell body is intact and Schwann cells functional, they can form a regeneration tube as long as scar tissue does not fill the tube,

Question 51

regeneration of CNS neurons

Answer 51

very limited. inhibited by neuroglia and lack of fetal growth stimulator cues.

Question 52

nerve impulses that allow for communication between neurons

Answer 52

action potential

Question 53

what is a membrane potential

Answer 53

the difference in the amount of electrical chage on the inside of the plasma membrane as compared with the outside.

Question 54

What is a cell that has membrane potential said to be be?

Answer 54

polarized.

Question 55

what is the term for the voltage across the plasma membrane?

Answer 55

resting membrane potential

Question 56

what are the channels that allow ions to move by diffusion from high to low concentration

Answer 56

ion channels

Question 57

two types of ion channels

Answer 57

leakage channels- allow ions to leak through | voltage gated channels- open in response to a change in membrane potential (voltage)

Question 58

What is the "threshold" when an action potential arises?

Answer 58

typically, about -55 mV

Question 59

what are the two main phases of an action potential?

Answer 59

depolarizing phase | repolarizing phase

Question 60

What is the phase where voltage gated Na+ channels open ~ as more Na+ enters cell, membrane potential rises and becomes positive? (-70 ~ 0 ~ +30 mv)

Answer 60

depolarizing phase

Question 61

what is the phase where voltage gated K+ channels open, ~ as more K+ leaves cell, membrane potential is returned to the resting valuse. (+30 ~ 0 ~ -70 mv)

Answer 61

repolarizing phase

Question 62

what is the term for when nerve impulses travel from where they arise (axon hillock) along the axon to the axon terminal?

Answer 62

propagation

Question 63

what is the type of potential conduction that occurs in unmyelinated axons (and in muscle fibers) called?

Answer 63

continuous conduction

Question 64

when current flows from one membrane only at the nodes, the impulses appear to leap from node to node. This type of impulse conduction is called what?

Answer 64

saltatory conduction

Question 65

what are the two most important factors that determine the speed of nerve impulse conduction?

Answer 65

the diameter of the axon and and the presence or absence of a myelin sheath.

Question 66

what is the neuron called sending the signal?

Answer 66

presynaptic neuron

Question 67

what is the neuron receiving the message called?

Answer 67

postsynaptic neuron

Question 68

what separates the presynaptic and postsynaptic neurons?

Answer 68

synaptic cleft, a tiny space filled with interstitial fluid.

Question 69

what are the two types of synapses

Answer 69

electrical and chemical

Question 70

what type of synapse do nerve impulses conduct directly between the plasma membrane of adjacent neurons through gap junctions?

Answer 70

electrical synapse

Question 71

this type of synapse, the most common, nerve impulses in a presynaptic cause the release of neurotransmitter molecules into the synaptic cleft.

Answer 71

chemical synapse

Question 72

three types of ways neurotransmitters are removed:

Answer 72

1) some diffuse away from the synaptic cleft 2) destroyed by enzymes 3) reuptaked back into the neuron that released them. some are transported into neighboring neuroglia (uptake)

Question 73

Types of neurotransmitters

Answer 73

acetylcholine (ACh)- common in PNS a) stimulatory on skeletal muscles b) inhibitory (on cardiac muscle) amino acids a) glutamate, aspartate, GABA Modified amino acids a) norepinephrine, dopamine, serotonin Neuropeptides such as endorphins nitric oxide