Chapter One — Overview

Question 1

Neuron

Answer 1

nerve cell that is the basic building block of the nervous system, specialized to transmit information throughout the body

Question 2

Neuroglia

Answer 2

non-neuronal cells that maintain homeostasis, form myelin, and provide support and protection for neurons in the brain, and for neurons in other parts of the nervous system such as in the autonomic nervous system.

Question 3

Functions of glial cells

Answer 3

to surround neurons and hold them in place, to supply nutrients and oxygen to neurons, to insulate one neuron from another, and to destroy pathogens and remove dead neurons.

Question 4

Dendrite

Answer 4

the branched projections of a neuron that act to conduct the electrochemical stimulation received from other neural cells to the cell body, or soma, of the neuron from which the dendrites project.

Question 5

Soma

Answer 5

cell body; the bulbous end of a neuron, containing the cell nucleus

Question 6

Axon

Answer 6

long, slender projection of a nerve cell, or neuron, that typically conducts electrical impulses away from the neuron’s cell body

Question 7

Morphological differences between axons and dendrites

Answer 7

dendrites often taper while axons usually maintain a constant radius

Question 8

Functional differences between axons and dendrites.

Answer 8

dendrites usually receive signals while axons usually transmit them

Question 9

Size difference between axon and dendrite

Answer 9

dendrites are restricted to a small region around the cell body while axons can be much longer

Question 10

Synapse

Answer 10

structure that permits a neuron to pass an electrical or chemical signal to another cell

Question 11

Chemical synapse

Answer 11

In a chemical synapse, the presynaptic neuron releases a chemical called a neurotransmitter that binds to receptors located in the postsynaptic cell, usually embedded in the plasma membrane.

Question 12

Electrical synapse

Answer 12

In an electrical synapse, the presynaptic and postsynaptic cell membranes are connected by special channels called gap junctions that are capable of passing electric current, causing voltage changes in the presynaptic cell to induce voltage changes in the postsynaptic cell.

Question 13

Neurotransmitter

Answer 13

Neurotransmitters are endogenous chemicals that transmit signals from a neuron to a target cell across a synapse.

Question 14

3-Step Neurotransmitter Process

Answer 14

Neurotransmitters are packaged into synaptic vesicles clustered beneath the membrane in the axon terminal, on the presynaptic side of a synapse. Following an action potential, they are released into and diffuse across the synaptic cleft, where they bind to specific receptors in the membrane on the postsynaptic side of the synapse.

Question 15

Action potential

Answer 15

action potential is a short-lasting event in which the electrical membrane potential of a cell rapidly rises and falls, following a consistent trajectory

Question 16

stores various neurotransmitters that are released at the synapse.

Answer 16

Synaptic vesicle

Question 17

a temporary depolarization of postsynaptic membrane potential caused by the flow of positively charged ions into the postsynaptic cell as a result of opening of ligand-sensitive channels

Answer 17

excitatory postsynaptic potential

Question 18

excitatory postsynaptic potential

Answer 18

temporary depolarization of postsynaptic membrane potential caused by the flow of positively charged ions into the postsynaptic cell as a result of opening of ligand-sensitive channels

Question 19

All or none principle

Answer 19

The amplitude of an action potential is independent of the amount of current that produced it.

Question 20

Axon hillock

Answer 20

The axon hillock is a specialized part of the cell body (or soma) of a neuron that connects to the axon. As a result, the axon hillock is the last site in the soma where membrane potentials propagated from synaptic inputs are summated before being transmitted to the axon.

Question 21

Interneuron, Local circuit neuron

Answer 21

a neuron that forms a connection between other neurons

Question 22

Function of myelin

Answer 22

The fat helps to insulate the axons from electrically charged atoms and ions. The main purpose of a myelin layer (or sheath) is to increase the speed at which impulses propagate along the myelinated fiber. Myelin helps prevent the electrical current from leaving the axon.

Question 23

Main types of neuroglia (3)

Answer 23

Astrocytes, oligodendrocytes, microglial cells

Question 24

Astrocytes (Shape, Prevalence, Major functions)

Answer 24

characteristic star-shaped glial cells in the brain and spinal cord. They are the most abundant cell of the human brain. They perform many functions, including biochemical support of endothelial cells that form the blood–brain barrier, provision of nutrients to the nervous tissue, maintenance of extracellular ion balance, and a role in the repair and scarring process of the brain and spinal cord following traumatic injuries.

Question 25

Blood-brain barrier

Answer 25

a separation of circulating blood from the brain extracellular fluid (BECF) in the central nervous system (CNS)

Question 26

Oligodendrocytes

Answer 26

Their main functions are to provide support and to insulate the axons (the long projection of nerve cells) in the central nervous system (the brain and spinal cord) of some vertebrates. Oligodendrocytes do this by creating the myelin sheath, which is 80% lipid and 20% protein.

Question 27

Schwann Cells (neurolemmocytes)

Answer 27

Schwann cells or neurolemmocytes are the principal glia of the peripheral nervous system (PNS). They are involved in PNS myelination.

Question 28

Microglia

Answer 28

a type of glial cell that are the resident macrophages of the brain and spinal cord, and thus act as the first and main form of active immune defense in the central nervous system (CNS). Microglia are constantly scavenging the CNS for damaged neurons, plaques, and infectious agents.

Question 29

Neural circuit

Answer 29

a functional entity of interconnected neurons that is able to regulate its own activity using a feedback loop (similar to a control loop in cybernetics).

Question 30

Summation

Answer 30

Summation, also known as frequency summation is the method of signal transduction between neurons, which determines whether or not an action potential will be triggered by the summation of postsynaptic potentials.

Question 31

Neuropil

Answer 31

Neuropil, sometimes referred to as "neuropile," is a broad term defined as any area in the nervous system composed of mostly unmyelinated axons, dendrites and glial cell processes that forms a synaptically dense region containing a relatively low number of cell bodies.

Question 32

afferent neurons

Answer 32

carry nerve impulses from receptors or sense organs towards the central nervous system

Question 33

efferent neurons

Answer 33

efferent nerves, otherwise known as motor or effector neurons, carry nerve impulses away from the central nervous system to effectors such as muscles or glands (and also the ciliated cells of the inner ear).

Question 34

Central nervous system

Answer 34

the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals; consists of the brain and the spinal cord. Some classifications also include the retina and the cranial nerves in the CNS.

Question 35

Cranial nerve

Answer 35

Cranial nerves are nerves that emerge directly from the brain, in contrast to spinal nerves, which emerge from segments of the spinal cord. In humans, there are traditionally twelve pairs of cranial nerves.

Question 36

Spinal cord

Answer 36

The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain (the medulla oblongata specifically).

Question 37

Peripheral nervous system

Answer 37

The peripheral nervous system (PNS, or occasionally PeNS) consists of the nerves and ganglia outside of the brain and spinal cord. The main function of the PNS is to connect the central nervous system (CNS) to the limbs and organs

Question 38

Somatic nervous system

Answer 38

The somatic nervous system (SoNS or voluntary nervous system) is the part of the peripheral nervous system associated with the voluntary control of body movements via skeletal muscles. The SoNS consists of efferent nerves responsible for stimulating muscle contraction, including all the non sensory neurons connected with skeletal muscles and skin.

Question 39

Autonomic nervous system

Answer 39

The autonomic nervous system (ANS or visceral nervous system or involuntary nervous system) is the part of the peripheral nervous system that acts as a control system functioning largely below the level of consciousness, and controls visceral functions.

Question 40

Parasympathetic nervous system

Answer 40

Part of autonomic nervous system responsible for stimulation of "rest-and-digest" activities that occur when the body is at rest, including sexual arousal, salivation, lacrimation (tears), urination, digestion, and defecation.

Question 41

Sympathetic nervous system

Answer 41

part of autonomic nervous system; general action is to mobilize the body's nervous system fight-or-flight response. It is, however, constantly active at a basic level to maintain homeostasis.

Question 42

Ganglion

Answer 42

mass of nerve cell bodies

Question 43

Nerve

Answer 43

A nerve, is an enclosed, cable-like bundle of axons (the long, slender projections of neurons) in the peripheral nervous system.

Question 44

Nucleus (neuroanatomy)

Answer 44

a brain structure consisting of a relatively compact cluster of neurons. It is one of the two most common forms of nerve cell organization, the other being layered structures such as the cerebral cortex or cerebellar cortex. In anatomical sections, a nucleus shows up as a region of gray matter, often bordered by white matter.

Question 45

Cortex

Answer 45

a sheet-like array of neurons

Question 46

Tract

Answer 46

A neural pathway, neural tract, or neural face, connects one part of the nervous system with another and usually consists of bundles of elongated, myelin-insulated neurons, known collectively as white matter. Neural pathways serve to connect relatively distant areas of the brain or nervous system, compared to the local communication of grey matter. Compare to nerves in PNS.

Question 47

Commisure

Answer 47

a tract that passes the midline of the brain

Question 48

Gray matter

Answer 48

White matter is one of the two components of the central nervous system and consists mostly of glial cells and myelinated axons (the tracts/commisures) that transmit signals from one region of the cerebrum to another and between the cerebrum and lower brain centers.

Question 49

Grey matter

Answer 49

Grey matter (or gray matter) is a major component of the central nervous system, consisting of neuronal cell bodies, neuropil (dendrites and unmyelinated axons), glial cells (astroglia and oligodendrocytes) and capillaries. Grey matter contains neural cell bodies, in contrast to white matter, which does not and mostly contains myelinated axon tracts.

Question 50

Autonomic ganglion

Answer 50

Autonomic ganglia are clusters of neuronal cell bodies and their dendrites and are essentially a junction between autonomic nerves originating from the central nervous system and autonomic nerves innervating their target organs in the periphery.

Question 51

Enteric nervous system

Answer 51

The enteric nervous system (ENS) is a subdivision of the autonomic nervous system (ANS) that directly controls the gastrointestinal system in vertebrates.