Chapter 11

Question 1

What are the three fundamental steps completed by everything in the nervous system?

Answer 1

1. A sensory function detects internal and external stimuli. (receptors) PNS
2. An interpretation is made (analysis). CNS PNS
3. A motor response occurs (effectors).

Question 2

What are the functions of the nervous system?

Answer 2

-The nervous system detects environmental changes -responds to such events along with endocrine system -responsible for all our behaviors, memories, and movement *It is able to do this because of the excitable characteristic of nervous tissue -Its ability to generate nerve impulses (action potentials)

Question 3

What are the two parts of your nervous system?

Answer 3

Central Nervous System Peripheral Nervous System

Question 4

What does the CNS (central nervous system) consist of?

Answer 4

brain and spinal cord

Question 5

What does the PNS (peripheral nervous system) consist of?

Answer 5

consists of all nervous tissue outside the CNS -Nerves -Ganglia -sensory receptors

Question 6

what is a synaptic cleft?

Answer 6

gap between the pre and post synaptic cells

Question 7

what are dendrites?

Answer 7

-(little trees) are the receiving end of the neuron -short, highly branched structures that conduct impulses toward the cell body

Question 8

what are the functions of neurons?

Answer 8

-gather information at dendrites -process it in the dendritic tree and cell body -transmit the information down their axon to the axon terminals

Question 9

what are synaptic vesicles?

Answer 9

membrane sacs that store packets of neurotransmitter chemicals

Question 10

many neurons contain ____ or ____ types of neurotransmitters?

Answer 10

two or three

Question 11

each neuron has different effects on the ___________ cell

Answer 11

postsynaptic

Question 12

a neuron usually has one neurotransmitter, but can have more than one? T/F?

Answer 12

true

Question 13

what are the four components of most neurons?

Answer 13

-Dendrites -A cell body -An axon -Axon terminals

Question 14

what are the function of astrocytes?

Answer 14

-provide physical support to neurons -maintain the blood-brain barrier -make scar tissue after CNS injury

Question 15

what is the function of Oligodendrocytes?

Answer 15

produce myelin in CNS

Question 16

what is the function of Microglia?

Answer 16

phagocytosis of debris and pathogens

Question 17

what is the function of Ependymal cells?

Answer 17

form and circulate CSF

Question 18

what are neuroglia?

Answer 18

-(glial cells) play a major role in support and nutrition of neurons -they do not generate or conduct nerve impulses

Question 19

what are glial cells?

Answer 19

-(neuroglia) play a major role in support and nutrition of neurons -they do not generate or conduct nerve impulses

Question 20

do glial cells generate nerve impulses?

Answer 20

no

Question 21

what is a synapse?

Answer 21

site of communication between two neurons or between a neuron and another effector cell

Question 22

what does the axon divide into?

Answer 22

-The axon divides into many fine processes called telodendria. -may be highly branched as they interact with the dendrites of “downstream” neurons -the tips swell into bulb-shaped synaptic/axon terminals.

Question 23

what is telodendria?

Answer 23

-The axon divides into many fine processes called telodendria. -may be highly branched as they interact with the dendrites of “downstream” neurons -the tips swell into bulb-shaped synaptic/axon terminals.

Question 24

what is an axon?

Answer 24

conduct impulses away from the cell body toward another neuron or effector cell

Question 25

what is an axon hillock?

Answer 25

where the axon joins the cell body

Question 26

what is an initial segment?

Answer 26

where an action potential begins; just distal to hillock

Question 27

what is an axoplasm?

Answer 27

cytoplasm of the axon

Question 28

what is an axolemma?

Answer 28

plasma membrane of the axon

Question 29

what are the two types of glial cells in the peripheral nervous system?

Answer 29

satellite, Schwann

Question 30

what do satellite cells do in the PNS?

Answer 30

provide physical, chemical support

Question 31

what do schwann cells do in the PNS?

Answer 31

surround axons; myelin

Question 32

what is myelination?

Answer 32

process of forming a myelin sheath which insulates and increases nerve impulse speed

Question 33

what is responsible for myelination in the PNS?

Answer 33

Schwann cells

Question 34

what is responsible for myelination in the CNS?

Answer 34

oligodendrocyte

Question 35

what are the Nodes of Ranvier?

Answer 35

gaps in the myelin sheath

Question 36

the peripheral nervous sytstem is divided into two systems, what are they?

Answer 36

-somatic nervous system (SNS) -autonomic nervous system (ANS)

Question 37

what does the somatic nervous system (SNS) consist of and do?

Answer 37

-Sensory and motor neurons -Conscious control over motor neurons

Question 38

what does the autonomic nervous system (ANS) consist of and do?

Answer 38

-Sensory and motor neurons -No conscious control

Question 39

There are three types of neurons in the SNS. What are they?

Answer 39

-Somatic sensory (afferent) neurons: convey information from sensory receptors in the head, body wall and limbs towards the CNS -Somatic motor (efferent) neurons: conduct impulses away from the CNS to the skeletal muscles under voluntary control -Interneurons: any neurons that conduct impulses between afferent and efferent neurons within the CNS

Question 40

There are three types of neurons in the ANS. What are they?

Answer 40

-Sensory neurons: convey information from sensory receptors located in visceral organs like the stomach or lungs to the CNS (afferent) -Motor neurons: under involuntary control (efferent) conduct nerve impulses from the CNS to smooth muscle, cardiac muscle, glands, adipose -Interneurons/association neurons are mainly located within the CNS between sensory and motor neurons.

Question 41

Motor neurons in the Autonomic Nervous System are divided into two portions. What are they?

Answer 41

-the sympathetic division -the parasympathetic division

Question 42

Name these four areas of a neuron:

Answer 42

Question 43

where is the axon terminal located?

Answer 43

Question 44

where are the dendritic spines located?

Answer 44

Question 45

where is the axoplasm located?

Answer 45

Question 46

where is the initial segment located?

Answer 46

Question 47

what do neurons connect with?

Answer 47

- other neurons - skeletal muscle fibers - gland cells

Question 48

what is a graded potential?

Answer 48

- short term changes that happen in specific spots - temporary, localized change in membrane potential

Question 49

what is an action potential?

Answer 49

electrical event that travels over long distances within the body

Question 50

where is the synaptic activity located?

Answer 50

Question 51

where is the graded potential located?

Answer 51

Question 52

where is the resting potential located?

Answer 52

Question 53

how many types of active gated channels are there?

Answer 53

3

Question 54

where is the information processing located?

Answer 54

Question 55

when ion channels open they allow specific ions to move across the plasma memnrane, down their \_\_\_\_\_\_\_.

Answer 55

electrochemical gradient

Question 56

what is a chemically gated (ligand) channel?

Answer 56

- respond to a neurotransmitter - mainly at the dendrites

Question 57

what is a voltage gated channel?

Answer 57

- respond to changes in the membrane potential - mainly located along the axon

Question 58

what is a mechanically gated channel?

Answer 58

- respond to mechanical deformation | (applying pressure to a receptor)

Question 59

do leakage channels close?

Answer 59

no

Question 60

what is integration?

Answer 60

the process of combining all excitatory and inhibitory inputs and responding accordingly.

Question 61

what is located at part 1 of this picture?

Answer 61

chemically gated ion channels

Question 62

what is located at part 2 of this picture?

Answer 62

voltage gated Na+ channels voltage gated K+ channels

Question 63

what is located at part 3 of this picture?

Answer 63

voltage gated Ca2+ channels

Question 64

when we talk about the resting membrane potential being negative, we are talking about the negatives located where?

Answer 64

on the inside \*The negative sign indicates that the inside of the cell is negative relative to the outside of the cell

Question 65

A cell that exhibits a membrane potential is said to be \_\_\_\_\_\_\_.

Answer 65

polarizing

Question 66

In neurons, a typical value for the RMP is\_\_\_\_\_\_\_

Answer 66

–70 mV

Question 67

From the RMP, graded potentials must first be produced in order to \_\_\_\_\_\_\_\_\_\_\_.

Answer 67

depolarize the cell to threshold

Question 68

what is the depolarizing graded potential?

Answer 68

causes cell to be more positively charged

Question 69

what is a hyperpolarizing graded potential?

Answer 69

causes cell to be more negatively charged

Question 70

graded potentials occur mainly in the dendrites and the cell body of a neuron. do they travel down the axon?

Answer 70

no

Question 71

what are three specific factors that cause RMP?

Answer 71

- leakage channels - negatively charged proteins in the cytosol - sodium-potassium

Question 72

If left unchecked, inward leakage of Na+ would eventually do what to the resting membrane potential?

Answer 72

inward leakage of Na+ would eventually _destroy_ the RMP

Question 73

what are some of the important mechanics of a graded potential?

Answer 73

* Chemically gated channels * Responding to a neurotransmitter * Result in a change in membrane potential * Can be depolarizing or hyperpolarizing

Question 74

what is an action potential?

Answer 74

- a signal which travels the length of the neuron. - the membrane potential reverses and then eventually is restored to its resting state

Question 75

what is a threshold?

Answer 75

- the voltage at which an action potential will be generated - If the sum of the graded potentials reaches threshold, an AP will be produced.

Question 76

what is shown in this image?

Answer 76

graded potential arrives → threshold reached

Question 77

what is shown in this picture?

Answer 77

Voltage-gated sodium channels open → depolarization

Question 78

what is shown in this image?

Answer 78

Depolarization complete → sodium channels inactivated → potassium channels open → repolarization starts

Question 79

what is shown in this image?

Answer 79

Potassium channels close Slight hyperpolarization → return to resting potential

Question 80

Why are neurons that are lost to injury or disease seldom replaced?

Answer 80

They lack centrioles

Question 81

Which glial cells are found only in the PNS?

Answer 81

Schwann cells

Question 82

Which nervous system component controls skeletal muscle contractions?

Answer 82

somatic nervous system