Ch 2: Structure and Function of the Nervous System

Question 1

3 main parts of the neuron are

Answer 1

•Dendrites: 
receiving information,
•Soma:
assimilating and analyzing information 
•Axons:
conducting the processed information

Question 2

Glia

Answer 2

provide structural support and insulation for neurons

Question 3

Oligodendrocytes

Answer 3

myelinate axons in the brain and spinal cord.

Question 4

Schwann cells

Answer 4

myelinate axons in the periphery of the body.

Question 5

Electrochemical gradient

Answer 5

gradient of electrochemical potential, usually for an ion that can move across a membrane.

Question 6

The gradient consists of two parts:

Answer 6

1. the chemical gradient, or difference in solute concentration across a membrane
2. the electrical gradient, or difference in charge across a membrane.

Question 7

Ionic concentration gradients (difference in solute concentration across a membrane)

Answer 7

A concentration gradient is the process of particles, called solutes, moving through a solution or gas from an area with a higher number of particles to an area with a lower number of particles. The areas are typically separated by a membrane.

Question 8

Electrical gradients as force

Answer 8

A electrical gradient refers to the electrical potential that acts on an ion to drive the movement of the ion in one or another direction. and the electrical gradient, or difference in charge across a membrane.

Question 9

Ion Channels

Answer 9

A single protein or protein complex that traverses the lipid bilayer of cell membrane and form a channel to facilitate the movement of ions through the membrane according to their electrochemical gradient

Question 10

Ion pumps uses actively transport NA+ ions out of the cell and K+ ions into the cell

Answer 10

Ion pumps work to maintain the concentration gradient. In the case of the sodium-potassium pump, it repeatedly transports 3 sodium ions out of the cell while drawing 2 potassium ions into it.
Concentration gradients move ions to the areas of lowest concentration.
Electrical gradients move ions to areas having the opposite electrical charges.

Question 11

Universal features of Action Potentials

Answer 11

(1) rising phase (depolarization)
(2) overshoot, and
(3) falling phase (repolarization)
action potentials are seen as brief spikes (+40 mV).

Question 12

The rising / initial depolarization phase

Answer 12

Neurons will produce an action potential only if the depolarization exceeds threshold of excitation (about 15 mV from resting potential).
Action potentials result in the positively charged sodium ions flow rapidly into the neuron.
Then the charge inside the neuron reverses polarity to become positive, when action potentials are seen as brief spikes (+40 mV).
After depolarization, voltage-gated sodium channels inactivate.

Question 13

The overshoot phase

Answer 13

The all-or-none law states that a neuron will produce either an action potential of maximal strength or none at all. The determination about whether to send an action potential occurs at the axon hillock.

Question 14

The Falling / later repolarization phase

Answer 14

The falling phase (3) or the later repolarizing, descending phase of the action potential is mediated by an increase in K+ conductance that occurs when the K+ channels open. During that phase of repolarization by the K+ current, the Na+ channels close.

Question 15

The absolute refractory phase

Answer 15

The action potential undershoots the resting membrane potential (i.e. hyperpolarized) at the point where the membrane becomes more negative than the resting membrane potential, when the neuron cannot be stimulated no matter how great a stimulus is applied

Question 16

Neurotransmission

Answer 16

Neurotransmitter release at the synapse, into the synaptic cleft

Question 17

Presynaptic terminal

Answer 17

• Point from which an axon releases chemicals into the synapse, known as an end bulb.
• Neurotransmitters are released by the presynaptic neuron when action potentials depolarize its axon terminal.
• Calcium ions are known to mediate the release of neurotransmitter molecules from the presynaptic neuron, known as exocytosis.

Question 18

Grey matter

Answer 18

neurons arranged in layers forming a sheet of tissue

Question 19

White matter

Answer 19

axons and glial cells forming tracts interconnecting the brain

Question 20

1. Rostral:
2. Caudal:
3. Dorsal:
4. Ventral
5. Medial

Answer 20

1. Front (frontal lobe)
2. Caudal (Occipital Lobe
3. Superior (upper part of the brain)
4. Inferior (lower side of the brain)
5. Middle part of the brain

Question 21

Brainstem

Answer 21

Thalamus 
Pons 
Medulla 
Midbrain
Spinal cord

Question 22

Limbic System

Answer 22

Thalamus 
Hypothalamus 
Frontal Lobe 
Olfactory bulb 
Amygdala 
Hippocampus

Question 23

Basal Ganglia (motor skills: movement)

Answer 23

Striatum 
Pallidum 
Thalamus
Subthalamic Nucleus 
Substantia Nigra

Question 24

Motor Cortex

Answer 24

Primary Motor Cortex

:Initiation of voluntary movement

Question 25

Broca’s Area

Answer 25

Speech production and articulation

Question 26

Somatosensory Cortex

Answer 26

Receives tactile information from the body

Question 27

Visual Cortex (occipital lobe)

Answer 27

Detection of simple visual stimuli

Question 28

Auditory Cortex (Temporal Lobe)

Answer 28

Detection of sound quality (loudness, tone)