Chapter 2: Structure and Function

Question 1

Neurons

Answer 1

Nerve cells, basic unit of the brain

Question 2

Glial cells

Answer 2

Serve various functions in the nervous system, providing structural support and electrical insulation to neurons and modulating neuronal activity

Question 3

Three main types of glial cells

Answer 3

Astrocytes, microglial cells, and oligodendrocytes

Question 4

Astrocytes

Answer 4

Large glial cells with round or radially symmetrical forms; they surround neurons and are in close contact with the brain’s vasculature

Question 5

Blood-brain barrier (BBB)

Answer 5

Created by astrocytes between the tissues of the central nervous system and the blood

The BBB restricts the diffusion of microscopic objects (such as most bacteria) and large hydrophilic molecules in the blood from entering the neural tissue, but it allows the diffusion of small hydrophobic molecules, such as oxygen, carbon dioxide, and hormones.

Question 6

Myelin is formed by _______ in the central nervous system and _______ in the peripheral.

Answer 6

oligodendrocytes, Schwann cells

Question 7

Microglial cells

Answer 7

phagocytes that devour and remove damaged cells. Unlike many cells in the central nervous system, microglial cells can proliferate even in adults (as do other glial cells)

Question 8

Presynaptic

Answer 8

The neuron’s axon’s output synapses make connections onto other neurons or targets

Question 9

Postsynaptic

Answer 9

Other neurons make a connection at input synapses onto their dendrites or elsewhere on the receiving neuron

Question 10

Neurons communicate with other neurons and cells at specialized structures called _______.

Answer 10

synapses

Question 11

The electrical gradient across a neuron’s membrane results from the _______.

Answer 11

asymmetrical distribution of ions

Question 12

What makes a molecule a neurotransmitter?

Answer 12

It is synthesized by and localized within the presynaptic neuron, and stored in the presynaptic terminal before release.

It is released by the presynaptic neuron when action potentials depolarize the terminal (mediated primarily by Ca2+).

The postsynaptic neuron contains receptors specific for it.

When artificially applied to a postsynaptic cell, it elicits the same response that stimulating the presynaptic neuron would.

Question 13

Tachykinins

Answer 13

(brain-gut peptides, which are peptides secreted by endocrine cells and enteric neurons in the GI tract and also neurons in the central nervous system). This group includes substance P, which affects vasoconstriction and is a spinal neurotransmitter involved in pain.

Question 14

Neurohypophyseal hormones

Answer 14

Oxytocin and vasopressin are in this group. The former is involved in mammary functions and has been tagged the “love hormone” for its role in pair bonding and maternal behaviors; the latter is an antidiuretic hormone.

Question 15

Hypothalamic releasing hormones

Answer 15

This group includes corticotropin-releasing hormone, involved in the stress response; somatostatin, an inhibitor of growth hormone; and gonadotropin-releasing hormone, involved with the development, growth, and functioning of the body’s reproductive processes.

Question 16

Opioid peptides

Answer 16

This group is named for its similarity to opiate drugs, and these peptides bind to opiate receptors. It includes the endorphins and enkephalins.

Question 17

Other neuropeptides

Answer 17

This group includes peptides that do not fit neatly into another category, such as insulins, secretins (e.g., glucagon), and gastrins.

Question 18

Action potential (p. 31)

Answer 18

A rapid depolarization and repolarization of a small region of the membrane on the neuron’s output via its axon caused by the opening and closing of ion channels.

Question 19

Amygdala (p. 50)

Answer 19

Collections of neurons anterior to hippocampus in the medial temporal lobe, involved in emotional processing

Question 20

Association cortex (p. 61)

Answer 20

Part of neocortex that involves signals from different inputs (not jsut sensory or motor)

Question 21

Autonomic nervous system (p. 40)

Answer 21

involved in controlling the involuntary action of smooth muscles, the heart, and various glands

Question 22

Axon (p. 27)

Answer 22

The axon is a single process that extends from the cell body.

This structure represents the output side of the neuron. Electrical signals travel along the length of the axon to its end, the axon terminals, where the neuron transmits the signal to other neurons or other targets.

Question 23

Axon collaterals (p. 27)

Answer 23

Some axons branch to form axon collaterals that can transmit signals to more than one cell.

Question 24

Axon hillock (p. 32)

Answer 24

A part of the cell body of a neuron where the membrane potential’s are summer before being transmitted down the axon.

Question 25

Basal ganglia (p. 50)

Answer 25

Collection of nuclei bilaterally located beneath the anterior portion of lateral ventricals 5 nuclei: caudate, putamen, globus pallidus, subthalamic nucleus, substantia nigra action selection, action gating, reward-based learning, motor prep, timing, task switching, and more

Question 26

Brainstem (p. 46)

Answer 26

Region of the nervous system that contains groups of motor and sensory nuclei, nuclei of widespread modulatory neurotransmitter systems, and white matter tracts of ascending sensory info and descending motor signals Medulla, pons and cerebellum, and midbrain

Question 27

Central nervous system (CNS) (p. 40)

Answer 27

The brain and spinal cord

Question 28

Central sulcus (p. 54)

Answer 28

Divides frontal and parietal lobes

Question 29

Cerebellum (p. 42)

Answer 29

“Little brain” Coordination and movement

Question 30

Cerebral cortex (p. 42)

Answer 30

Layered sheets of neurons over the forebrain

Question 31

Commissure (p. 42)

Answer 31

White matter tracts that cross from left to right of CNS or vise versa Corpus callosum is the largest

Question 32

Corpus callosum (p. 42)

Answer 32

Fiber system composed of axons that connect the cortex of the two cerebral hemispheres Largest white matter structure

Question 33

Cytoarchitectonics (p. 54)

Answer 33

Brodmann used the micro anatomy of cells and their organization to subdivide the cortex into 52 regions Can seem unsystematic and is not standardized

Question 34

Dendrites (p. 26)

Answer 34

Dendrites are branching extensions of the neuron that receive inputs from other neurons.

Question 35

Depolarization (p. 32)

Answer 35

A change in the membrane potential in which the electrical current inside the cell becomes less negative. 

Question 36

Electrical gradient (p. 30)

Answer 36

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 gradient result from a symmetrical distributions of ions across the membrane. 

Question 37

Electrotonic conduction (p. 31)

Answer 37

The small electrical current produced by the EPSP is passively conducted through the cytoplasm of the dendrite, cell body, and axon. Passive current conduction is called electrotonic conduction or decremental conduction: “decremental” because it diminishes with distance from its origin—the synapse on the dendrites, in this case.

Question 38

Equilibrium potential (p. 32)

Answer 38

The membrane potential at which given an ion has no net flux across the membrane. (Ions in = ions out)

Question 39

Frontal lobe (p. 53)

Answer 39

Contains motor and prefrontal cortex

Question 40

Gray matter (p. 42)

Answer 40

Regions of the nervous system that contain primarily neuronal cell bodies. Includes the cerebral cortex basil ganglia a nuclei of the thalamus

Question 41

Gyrus (p. 52)

Answer 41

Crowns in cortical sheet

Question 42

Hippocampus (p. 50)

Answer 42

Layered structure in medial temporal lobe, receives inputs and sends projections out to subcortical targets Involved in learning, memory (spatial locations and episodic memory)

Question 43

Hyperpolarization (p. 32)

Answer 43

A change in the membrane potential in which the electrical current inside of the cell becomes more negative. With respect to resting potential a hyperpolarized membrane potential is farther from the firing threshold. 

Question 44

Hypothalamus (p. 49)

Answer 44

Link between nervous system and endocrine system Chief site for hormone production and control Floor of 3rd ventricle Maintains homeostasis

Question 45

Insula (p. 54)

Answer 45

Part of cortex hidden in sylvian fissure Also has extensive reciprocal connections with areas associated with emotion, such as the amygdala, medial prefrontal cortex, and anterior cingulate gyrus As well as with frontal parietal and temporal cortical areas involved with attention, memory, and cognition

Question 46

Ion channel (p. 28)

Answer 46

Proteins with a pore through the center, and they allow certain ions to flow down their electrochemical and concentration gradients.

Question 47

Ion pump (p. 28)

Answer 47

Ion pumps use energy to actively transport ions across the membrane against their concentration gradients—that is, from regions of low concentration to regions of higher concentration.

Question 48

Layer (p. 41)

Answer 48

Neurons are organized in layers, such as in the cerebral cortex

Question 49

Limbic system (p. 50)

Answer 49

Border around brainstem Amygdala, orbiofrontal cortex, portions of basal ganglia

Question 50

Medulla (p. 46)

Answer 50

Brainstem’s most caudal portion Houses cell bodies of many of the twelve cranial nerves, provides sensorimotor innervations to face, neck, abdomen, and throat and ♡ Controls necessary functions like breathing, heart rate, and arousal

Question 51

Microcircuit (p. 39)

Answer 51

A small network of localized interconnected neurons that process specific kinds of information. 

Question 52

Midbrain (p. 48)

Answer 52

Visumotor function

Question 53

Myelin (p. 25)

Answer 53

Glial cells also form the fatty substance called myelin in the nervous system.

Question 54

Neocortex (p. 55)

Answer 54

Cortex that contains six cortical layers or that passed through a developmental stage involving six cortical layers

Question 55

Neural network (p. 39)

Answer 55

A complex Netwerk made up of a long distance connections between various brain regions. Neural networks are macrocircuits composed of multiple embedded microcircuit and they support more complex analysis integrating information processes from many microcircuits

Question 56

Neurotransmitter (p. 35)

Answer 56

A chemical substance that transmits the signal between neurons at chemical synapses.

Question 57

Node of Ranvier (p. 32)

Answer 57

Location at which myelin is interrupted between successive patches of axon, and where an action potential can be generated

Question 58

Nucleus (p. 41)

Answer 58

Relatively compact arrangement of nerve cell bodies and their connections

Question 59

Occipital lobe (p. 54)

Answer 59

At back of the brain Visual info processing

Question 60

Parietal lobe (p. 54)

Answer 60

Somatosensory cortex, gustatory cortex, and parietal association cortex Visuomotor orienting, attention, representation of space Above temporal lobe

Question 61

Peripheral nervous system (PNS) (p. 40)

Answer 61

Comprised of sensory and motor nerves and associated nerve cell ganglia, located outside the central nervous system

Question 62

Permeability (p. 29)

Answer 62

Extent to which ions can cross the neuronal membrane

Question 63

Pituitary gland (p. 49)

Answer 63

Endocrine gland that synthesizes and secretes hormones that aid in regulation of multiple processes to maintain homeostasis, controlled by hypothalamus

Question 64

Pons (p. 47)

Answer 64

“Bridge” between brain and cerebellum Responsible for REM

Question 65

Prefrontal cortex (p. 61)

Answer 65

High-level motor control, planning and executing behavior Large in humans

Question 66

Refractory period (p. 32)

Answer 66

The short period of time following an action potential during which the neuron may not be able to generate action potential‘s or may be able to do so only with larger-than-normal depolarizing currents. 

Question 67

Resting membrane potential (p. 28)

Answer 67

The voltage difference across the neuronal membrane in the resting state is typically about –70 millivolts (mV) inside, which is known as the resting potential or resting membrane potential. This electrical-potential difference means that the neuron has at its disposal a kind of battery; and like a battery, the stored energy can be used to do work—signaling work

Question 68

Saltatory conduction (p. 32)

Answer 68

Mode of conduction in myelinated neurons, in which action potentials are generated down the axon only at nodes of Ranvier. Measurement of the propagation of the action potential gives it the appearance of jumping from node to node. 

Question 69

Somatotopy (p. 58)

Answer 69

Point-for-point representation of the body in the nervous system in the somatosensory cortex

Question 70

Spike-triggering zone (p. 32)

Answer 70

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 the voltage gated sodium channels are located that can be triggered to generate action potentials that can propagate down the axon

Question 71

Spine (p. 27)

Answer 71

Most dendrites also have specialized processes called spines, little knobs attached by small necks to the surface of the dendrites, where the dendrites receive inputs from other neurons.

Question 72

Sulcus (p. 52)

Answer 72

Crevices in cortical sheet Allow for more surface area to be packed into brain Neurons are closer because if sulci

Question 73

Sylvian (lateral) fissure (p. 54)

Answer 73

Divides temporal, frontal, and parietal lobes

Question 74

Synapse (p. 27)

Answer 74

Transmission occurs at the synapse, a specialized structure where two neurons come into close contact so that chemical or electrical signals can be passed from one cell to the next.

Question 75

Synapse elimination (p. 67)

Answer 75

Pruning

Question 76

Synaptic cleft (p. 33)

Answer 76

Gap between neurons at synapses

Question 77

Synaptogenesis (p. 67)

Answer 77

Formation of synapses

Question 78

Temporal lobe (p. 54)

Answer 78

Hippocampus, amygdala, high-order vision, representation of conceptual info, linguistics representation, Sylvian fissure, auditory fissure Below parietal lobe

Question 79

Thalamus (p. 48)

Answer 79

Divided between the left and right Bigger than hypothalamus “Gateway to the cortex”

Question 80

Threshold (p. 32)

Answer 80

The potential value to which the membrane must be depolarized for an action potential to be initiated

Question 81

Tract (p. 42)

Answer 81

Bundle of axons in the CNS, formed from the axons in white matter

Question 82

Ventricle (p. 41)

Answer 82

Any of the four large, interconnected cavities of the brain

Question 83

Vesicle (p. 33)

Answer 83

Small, intracellular organelle, located in presynaptic terminals at synapses, contains neurotransmitter

Question 84

Voltage-gated ion channel (p. 31)

Answer 84

A transmembrane ion channel that changes molecular conformation when the membrane potential changes, altering the conductance of the channel for specific ions

Question 85

White matter

Answer 85

Regions of nervous system composed of axons surrounding myelin. Looks white because of myelin

Question 86

Sympathetic v Parasympathetic branches

Answer 86

Work in opposition to one another