Chapter 2: Structure and Function of NS

Question 1

Neurons have three major external features

Answer 1

Axon, soma and dendrites

Question 2

_____ are critical for neuron function.

Answer 2

Characteristics of the cell membrane

Question 3

_____ provide vital support for neurons.

Answer 3

Glial cells

Question 4

_____ is responsible for the cell’s resting potential.

Answer 4

Ion distribution

Question 5

_____ are small, transient changes in membrane potential.

Answer 5

Local potentials

Question 6

Sufficient depolarization at the axon hillock opens _____, producing an _____.

Answer 6

Voltage-gated Na+ channels; action potential

Question 7

Drugs and poisons alter _____.

Answer 7

Axon conduction

Question 8

The nervous system breaks into

Answer 8

PNS and CNS

Question 9

CNS functioning is dependent on _____

Answer 9

Structural features

Question 10

The CNS has six distinct regions reflecting _____

Answer 10

Embryological development

Question 11

The cerebral cortex is divided into _____, each having primary, secondary, and tertiary areas.

Answer 11

Four lobes

Question 12

_____ provide energy for the metabolic work of the cell.

Answer 12

Mitochondria

Question 13

Axon terminals contain _____ that are released into the synapse between cells when the action potential arrives.

Answer 13

Synaptic vesicles filled with neurotransmitter molecules

Question 14

The dendrites of a neuron are covered with minute spines that increase the receiving _____ of the cell. These spines are reduced in SIZE in individuals with intellectual impairment and reduced in NUMBER in those with schizophrenia.

Answer 14

Surface area

Question 15

Thousands of receptors that respond to neuro-transmitters released by other neurons are found on _____.

Answer 15

Dendrites, dendritic spines, and soma of the cell.

Question 16

The _____ is located at the juncture of soma and axon and is responsible for summation (or integration) of the multiple signals required to generate an action potential.

Answer 16

Axon hillock

Question 17

Conduction of the action potential along the axon is enhanced by the insulating property of the _____.

Answer 17

Myelin created by nearby glial cells.

Question 18

The nucleus of the cell is located within the soma, and _____ occurs there.

Answer 18

Protein synthesis

Question 19

Transcription of the genetic code for a specific protein by mRNA occurs within the _____, and translation of the “recipe,” carried by the mRNA, occurs on the _____.

Answer 19

Nucleus - transcription

Ribosomes in cytoplasm - translation

Question 20

_____ increase or decrease the production of particular proteins by activating transcription factors in the nucleus.

Answer 20

Changes in synaptic activity

Question 21

_____ is the study of how environmental demands such as diet, environmental toxins, stress, prenatal nutrition, and many others turn on or turn off the expression of specific genes.

Answer 21

Epigenetics

Question 22

Although epigenetic markers do not modify DNA, they can last a lifetime and may be transmitted to future generations. Two common markers are _____

Answer 22

DNA methylation and chromatin remodeling.

Question 23

Derived from very early-stage embryos

Valuable as research tools and potential treatment for many diseases

Answer 23

Embryonic stem cells

Question 24

Undifferentiated cells
Able to proliferate
Can become many different specific cell types

Answer 24

Stem cells

Question 25

Embryonic stem cells that form the nervous system become two primary cell types:

Answer 25

Neurons and Glial cells

Question 26

Convert physical stimuli into electrical signals.

Answer 26

Sensory neurons

Question 27

Found in brain and spinal cord Form interacting neural circuits Responsible for conscious sensations, recognition, memory, decision-making, cognition

Answer 27

Interneurons

Question 28

Direct bio-behavioral responses appropriate for the situation

Answer 28

Motor neurons

Question 29

Cell body; contains nucleus and other organelles.

Answer 29

Soma

Question 30

Projections from the soma that receive information.

Answer 30

Dendrites

Question 31

Extension that conducts electrical signals from the cell body to the terminal buttons.

Answer 31

Axon

Question 32

Receive information from other cells across the gap between them, the synapse.

Answer 32

Dendrites and soma

Question 33

There are thousands of receptors on the _____.

Answer 33

Dendrites and soma

Question 34

Effect on receiving cell may be _____ or _____.

Answer 34

Excitatory or inhibitory.

Question 35

Can change shape rapidly in response to changes in synaptic transmission.

Answer 35

Dendrites and their spines are constantly modified

Question 36

Mental illness, mental impairment, and drug addiction are associated with _____.

Answer 36

Lessening of dendritic spines

Question 37

“Decision point” for the generation of the action potential

Answer 37

Axon Hillock

Question 38

Located near dendrites or soma of neighboring cells Vesicles located here *Contain neurotransmitter chemicals

Answer 38

Terminal Bouton

Question 39

A fatty insulation created by layers of glial cells. | Found on most neurons

Answer 39

Myelin Sheath

Question 40

Myelinated peripheral nerves that serve muscles, organs, and glands.

Answer 40

Schwann cells

Question 41

Myelinated nerves in the brain and spinal cord.

Answer 41

Oligodendroglia

Question 42

Breaks in the myelin sheath Sites at which action potentials are regenerated. The myelin sheath increases speed of conduction along the axon

Answer 42

Nodes of Ranvier

Question 43

Which part of the neuron performs most metabolic functions?

Answer 43

Soma

Question 44

Neurons synthesize enzymes specific to synthesizing _____

Answer 44

Neurotransmitters

Question 45

_____ may explain some phenomena, such as: differences in monozygotic and dizygotic twins persistence of the drug-taking behavior the link between early abuse or neglect, and clinical depression.

Answer 45

Epigenetics

Question 46

Sites of action of neurotransmitters, hormones, and drugs.

Answer 46

Receptors

Question 47

Proteins that form a channel and which allow molecules to selectively and passively move across the membrane.

Answer 47

Ion Channels

Question 48

Opens when a ligand (NT) binds to a receptor.

Answer 48

Ligand-gated channel (Ionotropic Receptor)

Question 49

Opens when the electrical potential across the membrane is altered.

Answer 49

Voltage-gated channel

Question 50

Glial cells: _____ Form myelin sheaths in peripheral nervous system (PNS) _____ form myelin sheaths in central nervous system (CNS

Answer 50

Schwann cells; Oligodendrocytes/oligodendroglia

Question 51

Provide structural support for neurons | take up excess neurotransmitters.

Answer 51

Astrocytes

Question 52

Remove dying cells responsible for immune response.

Answer 52

Microglia

Question 53

Difference in electrical charge between inside and outside of cell.

Answer 53

Resting membrane potential

Question 54

Inside of cell is more negative than the outside | It is _____.

Answer 54

–70 millivolts (mV) | Polarized

Question 55

Moves 3 Na+ to the outside for every 2 K+ moved to the inside Ions are pumped against their concentration gradients Requires energy

Answer 55

Na+ - K+ Pump

Question 56

Helping to keep the inside of the cell negative.

Answer 56

Na+ - K+ Pump

Question 57

``` Rapid depolarization (movement toward zero) Is propagated down the length of the axon ```

Answer 57

The Action Potential

Question 58

Threshold membrane potential for the generation of an AP is _____.

Answer 58

–50 mV

Question 59

Voltage-gated Na+ channels open at the _____, generating the rapid change down the axon.

Answer 59

Axon hillock

Question 60

If Na+ channels open, Na+ enters cell and causes _____.

Answer 60

Local depolarization

Question 61

The following are examples of _____. Cl– channels are stimulated to open, Cl– enters cell and inside of cell becomes more negative If gated K+ channels open, K+ leaves the cell, the cell becomes more negative.

Answer 61

Local Hyperpolarization

Question 62

Because neurotransmitters act on the postsynaptic membrane, the effects are called:

Answer 62

Excitatory postsynaptic potentials (EPSPs) | Inhibitory postsynaptic potentials (IPSPs)

Question 63

Local potentials are _____. | The larger the stimulus, the greater the magnitude of _____.

Answer 63

Graded; hyperpolarization or depolarization

Question 64

The Na+ channels close and cannot be opened for a fixed period

Answer 64

Absolute refractory period

Question 65

Action potential lasts only _____.

Answer 65

1 millisecond

Question 66

When Na+ channels _____, K+ channels _____, | K+ moves out of the cell and the membrane ...

Answer 66

close; open | Returns to resting potential

Question 67

The membrane overshoots resting potential and is hyperpolarized until excess K+ diffuses away.

Answer 67

Relative Refractory Period

Question 68

Action potentials are _____ Intensity/strength _____ _____ is unrelated to amount of stimulation.

Answer 68

“All or none” Doesn’t ∆ Size

Question 69

Describes the propagation of the AP in a myelinated neuron Conduction “jumps” from one node of Ranvier to the next. Less energy is needed because Na+–K+ pumps are only at the nodes.

Answer 69

Saltatory conduction

Question 70

``` Local anesthesia Blocks _____ (ex: Novocaine) ```

Answer 70

Voltage-gated Na+ channels

Question 71

Two parts that make up the forebrain

Answer 71

Telencephalon and Diencephalon

Question 72

Diencephalon breaks down into

Answer 72

Hypothalamus and thalamus

Question 73

Telencephalon breaks down into

Answer 73

Basal ganglia, limbic system, neocortex

Question 74

The mesencephalon is also known as the

Answer 74

Midbrain

Question 75

The hindbrain is made up of...

Answer 75

Metencephalon | Myelencephalon

Question 76

Myelencephalon is also called the

Answer 76

medulla

Question 77

Metencephalon is made up of

Answer 77

Cerebellum and pons