Chapter 2

Question 1

The nervous system consists of 2 kinds of cells:

Answer 1

Neurons & glia

Question 2

Cells which receive info from & transmit info to other cells

Answer 2

Neurons

Question 3

The surface of a cell; a structure that separates the inside of the cell from the outside environment.
AKA plasma membrane

Answer 3

Membrane

Question 4

The structure that contains the chromosomes; DNA center

Answer 4

Nucleus

Question 5

The structure that performs metabolic activities, providing the energy that the cell requires for all other activities.

Answer 5

Mitochondrion

Question 6

Sites at which the cells synthesize new proteins

Answer 6

Ribosomes

Question 7

Some ribosomes float freely w/in the cell, others are attached to the__________ _________, a network of thin tubes that transport newly synthesized proteins to other locations.

Answer 7

Endoplasmic reticulum

Question 8

Receives excitation thru its dendrites & conducts msgs along its axon to a muscle- has its soma in the spinal cord.

Answer 8

Motor Neuron

Question 9

Specialized at one end to be highly sensitive to a particular type of stimulation, such as light, sound, or touch.

Answer 9

Sensory neuron

Question 10

Branching fibers; receives info from other neurons.

Answer 10

Dendrites

Question 11

At which the dendrite receives info from other neurons.

Answer 11

synaptic receptors

Question 12

The short outgrowths that increase the surface area available for synapses

Answer 12

Dendritic spines

Question 13

Contains the nucleus, ribosomes, & mitochondria.

Answer 13

cell body; soma

Question 14

Fatty substance; insulating sheath covering the axon.

Answer 14

myelin sheath

Question 15

Brings info into a structure

Answer 15

afferent axon (starts w/A as in Admit)

Question 16

carries info away from a structure

Answer 16

efferent axon (starts w/E as in Exit)

Question 17

Neuron whose axons & dendrites are all contained w/in one structure

Answer 17

Interneuron OR Intrinsic neuron

Question 18

Other major component of the nervous system; cells that don’t transfer info over long distances, but exchange chemicals w/adjacent neurons; sometimes act oscillate cell activity

Answer 18

Glia

smaller but more numerous than neurons

Question 19

Star-shaped glia that wrap around the presynaptic terminals of functionally related axons; help synchronize activity; allows axons to send info in waves

Answer 19

Astrocytes

Question 20

Removes waste material, like immune system; viruses,fungi, & other microorganisms

Answer 20

Microglia

Question 21

Cells in the brain & spinal cord that build the myelin sheaths (that surrounds/insulates axon)

Answer 21

Oligodendrocytes

Question 22

Guide the migration of neurons & the growth of their axons & dendrites during embryonic development

Answer 22

Radial glia

Question 23

One of the two main founders of neuroscience; discovered the synapse; 1st person to demonstrate that the individual cells comprising the nervous system remained separate; Showed that they didn’t grow into each other like previously believed.

Answer 23

Santiago Ramon y Cajal

Question 24

Conveys msgs to other neurons, organs, or muscles.

Answer 24

Axon

Question 25

Short unmyelinated section of axon between segments of myelin (gaps in myelin)

Answer 25

Nodes of Ranvier

Question 26

point from which axon releases chemicals that cross thru junction between one neuron & the nxt

Answer 26

Presynaptic terminal (end bulb)

Question 27

Cells in the periphery that build the myelin sheaths

Answer 27

Schwann Cells

Question 28

Mechanism that keeps most chemicals out of the vertebrate brain

Answer 28

Blood-Brain Barrier

Question 29

Advantages of blood-brain barrier

Answer 29

keeps out most viruses, bacteria, & harmful chemicals

Question 30

Disadvantages of blood-brain barrier

Answer 30

keeps out most nutrients & medications; why brain cancer is so intense

Question 31

a difference in electrical charge between the inside & outside of a cell

Answer 31

electrical gradient

Question 32

a difference in electrical charge between 2 locations

Answer 32

polarization

Question 33

difference in voltage in resting neuron-is slightly negative due to negatively charged proteins inside the cell

Answer 33

resting potential

Question 34

protein complex that repeatedly transports 3 sodium ions (Na+) out of the cell while drawing in 2 potassium ions

Answer 34

Sodium-potassium pump

Question 35

Lvl beyond which stimulation of a neuron will produce massive depolarization allowing a rapid flow of sodium ions across the membrane

Answer 35

threshold of excitation

Question 36

rapid depolarization & slight reversal of the usual polarization

Answer 36

action potential

Question 37

membrane channels whose permeability depends on the voltage differences across the membrane

Answer 37

voltage-gated channels

Question 38

The amplitude & velocity of an action potential are independent of the intensity of the stimulus that initiated it.

Answer 38

All or none law

Question 39

time during which a cell resists the production of a further action potential

Answer 39

refractory period

Question 40

the membrane cannot produce an action potential regardless of the stimulation

Answer 40

absolute refractory period

Question 41

a stronger than usual stimulation is required to produce an action potential

Answer 41

relative refractory period

Question 42

swelling where the axon exits the soma; In a motor neuron the action potential begins @ here.

Answer 42

axon hillock

Question 43

Transmission of an action potential down the axon; doesn't directly travel down the axon

Answer 43

Propagation of the action potential

Question 44

flow of action potential from one node of Ranvier to another; "jumping"

Answer 44

Salatory conduction

Question 45

those covered w/a myelin sheath

Answer 45

Myelinated axons

Question 46

neurons w/o axons; exchange info. only w/the closest neurons; do NOT follow all-or-none law

Answer 46

Local neurons

Question 47

membrane potentials that vary in magnitude w/o following the all-or-none law; they decay

Answer 47

Graded potentials

Question 48

How are vertebrate neurons nourished?

Answer 48

Glucose; they depend almost entirely on glucose: a sugar that's one of the few things that can pass thru the barrier.

Question 49

Why is there a resting potential?

Answer 49

'ready to fire' | the resting potential remains stable until the neuron is stimulated

Question 50

difference in distrivution of ions across membrane

Answer 50

concentration gradient

Question 51

refers to increasing the polarization or the difference between the electrical charge of 2 places; less likely to fire

Answer 51

hyperpolarization

Question 52

refers to decreasing the polarization towards zero; more likely to fire

Answer 52

depolarization

Question 53

How does membrane get back to original state of polarization?

Answer 53

the neuron is returned to its resting state by the opening of potassium channels

Question 54

a disease in which the myelin sheath is destroyed & associated w/poor muscle coordination & sometimes visual impairments

Answer 54

multiple sclerosis

Question 55

Chemical events behind the action potential make sense if you remember these 3 principles:

Answer 55

1. @ the start, sodium ions are mostly outside the neuron and potassium ions are mostly inside 2. when the membrane is depolarized, sodium and potassium channels in the membrane open. 3. @ the peak of the action potential, the sodium channels close