Ch.2: Structure and Function of the NS

Question 1

neurons

Answer 1

One of two cell types (along with the glial cell) in the nervous system. Neurons are responsible for processing sensory, motor, cognitive, and affective information.

Question 2

glial cells

Answer 2

One of two cell types (along with the neuron) in the nervous system. Glial cells are more numerous than neurons, by perhaps a factor of 10, and may account for more than half of the brain’s volume. They typically do not conduct signals themselves; but without them, the functionality of neurons would be severely diminished. Tissue made of glial cells is termed glia.

Question 3

astrocytes

Question 4

blood brain barrier (BBB)

Answer 4

A physical barrier formed by the end feet of astrocytes between the blood vessels in the brain and the tissues of the brain. The BBB limits which ma- terials in the blood can gain access to neurons in the nervous system.

Question 5

oligodendrocytes

Question 6

myelin

Answer 6

A fatty substance that surrounds the axons of many neurons and increases the effective membrane resistance, helping to speed the conduction of action potentials.

Question 7

microglial cells

Question 8

cell membrane

Question 9

cell body/soma

Question 10

dendrites

Answer 10

Large treelike processes of neurons that receive inputs from other neurons at locations called synapses.

Question 11

spines

Answer 11

A little knob attached by a small neck to the surface of a dendrite. Synapses are located on spines.

Question 12

axon

Answer 12

The process extending away from a neuron down which action potentials travel. The terminals of axons con- tact other neurons at synapses.

Question 13

synapse

Answer 13

The specialized site on the neural membrane where a neuron comes close to another neuron to transmit information. Synapses include both presynaptic (e.g., synaptic vesicles with neurotransmitter) and postsynaptic (e.g., receptors) specializations in the neurons that are involved in chemical transmission. Electrical synapses involve special structures called gap junctions that make direct cytoplasmic connections between neurons.

Question 14

axon collaterals

Answer 14

Branches off an axon that can transmit signals to more than one cell.

Question 15

presynaptic

Answer 15

Referring to the neuron located before the synapse with respect to information flow.

Question 16

postsynaptic

Answer 16

Referring to the neuron located after the synapse with respect to information flow.

Question 17

resting membrane potential

Answer 17

The difference in voltage
across the neuronal membrane at rest, when the neuron is
not signaling.

Question 18

ion channels

Answer 18

A passageway in the cell membrane, formed by a transmembrane protein that creates a pore, through which ions of a particular size and/or charge are allowed to pass.

Question 19

ion pumps

Answer 19

A protein in the cell membrane of a neuron that is capable of transporting ions against their concentration gradient. The sodium–potassium pump transports sodium ions (Na+) out of the neuron and potassium ions (K+) into
the neuron.

Question 20

permeability

Answer 20

The extent to which ions can cross a neuronal membrane.

Question 21

electrical gradient

Answer 21

A force that develops when a charge
distribution across the neuronal membrane develops such that the charge inside is more positive or negative than the one outside. Electrical gradients result from asymmetrical distributions of ions across the membrane.

Question 22

action potential

Answer 22

The active or regenerative electrical signal that is required for synaptic communication. Action potentials are propagated along the axon and result in the release of neurotransmitters.

Question 23

excitatory postsynaptic potential

Question 24

inhibitory postsynaptic potential

Question 25

electrotonic conduction

Answer 25

Also decremental conduction. Ionic current that flows passively through the cytoplasm and across the membrane of an activated neuron that diminishes with distance from the site of generation.

Question 26

voltage-gated ion channels

Question 27

spike-triggering zone

Answer 27

The location, at the juncture of the soma and the axon of a neuron, where currents from synaptic inputs on the soma and distant dendrites are summed and where voltage-gated Na+ channels are located that can be triggered to generate action potentials that can propagate down the axon.

Question 28

axon hillock

Answer 28

A part of the cell body of a neuron where the membrane potentials are summed before being transmitted down the axon.

Question 29

nodes of Ranvier

Question 30

depolarization

Question 31

equilibrium potential

Question 32

hyperopolarized

Question 33

absolute refractory period

Question 34

relative refractory period

Question 35

saltatory conduction

Question 36

synaptic cleft

Answer 36

The gap between neurons at synapses.

Question 37

vesicles

Answer 37

A small intracellular organelle, located in the presynaptic terminals at synapses, that contains neuro- transmitter.

Question 38

microcircuit

Question 39

neural networks

Question 40

CNS

Question 41

PNS

Question 42

Autonomic NS

Answer 42

The body system that regulates heart rate, breathing, and glandular secretions and may become activated during emotional arousal, initiating a fight-or-flight behavioral response to a stimulus. It has two subdivisions, the sympathetic and parasympathetic branches.

Question 43

meninges

Question 44

nucleus

Question 45

layer

Question 46

gray matter

Question 47

white matter

Question 48

tracts

Question 49

commissures

Question 50

brainstem

Question 51

medulla

Question 52

pons

Question 53

cerebellum

Question 54

midbrain

Question 55

thalamus

Question 56

hypothalamus

Question 57

limbic system

Question 58

basal ganglia

Answer 58

A collection of five subcortical nuclei: the caudate, putamen, globus pallidus, subthalamic nucleus, and substantia nigra. The basal ganglia are involved in motor control and learning. Reciprocal neuronal loops project from cortical areas to the basal ganglia and back to the cortex. Two prominent basal ganglia disorders are Parkinson’s disease and Huntington’s disease.

Question 59

hippocampus

Question 60

amygdala

Question 61

pituitary gland

Question 62

sulci

Question 63

gyri

Question 64

central sulcus

Question 65

frontal

Question 66

parietal

Question 67

occipital

Question 68

temporal

Question 69

sylvina fissure

Answer 69

A large fissure (sulcus) on the lateral surface of the cerebral cortex first described by the anatomist Franciscus Sylvius. The Sylvian fissure separates the frontal cortex from the temporal lobe below.

Question 70

insula

Question 71

cytoarchitectonics

Question 72

neocortex

Question 73

somatotopy

Question 74

association cortex

Question 75

prefrontal cortex

Question 76

synaptogenesis

Answer 76

The formation of synaptic connections between neurons in the developing nervous system.

Question 77

synapse elimination

Answer 77

Also pruning. The elimination of some synaptic contacts between neurons during development, including postnatally.