A & P - College Network - Chapter 7 The Nervous System

Front 1

Abducens

Back 1

The cranial nerve that innervates the muscle that abducts the eye.

Front 2

Absolute Refractory Period

Back 2

The period during which the neuron is functionally unable to generate a second spike, occurring early in the period of repolarization and afterhyperpolarization.

Front 3

Acetycholine

Back 3

The chemical transmitter used by preganglionic cells.

Front 4

Action Potentials

Back 4

The electrical signals used for long-distance communication in the nervous system.

Front 5

Activation Gate

Back 5

Senses the transmembrane potential and can be opened by depolarization.

Front 6

Adrenal Medullae

Back 6

Endocrine glands that could be thought of as modified sympathetic ganglia.

Front 7

Adrenaline

Back 7

The main form of catecholamine released by the adult adrenal. Also callled epinephrine.

Front 8

Afferent Axons

Back 8

Carry information towards the CNS.

Front 9

Afterhyperpolarization Phase

Back 9

A period during which the membrane potential is even more inside negative than at rest.

Front 10

Agonists

Back 10

Substances similar enough to be legitimate transmitter to activate the receptor.

Front 11

Alpha-Adernergic Receptors

Back 11

Receptors for norepinephrine and epinephrine.

Front 12

Anterior Commissure

Back 12

Smaller and less important fiber tracts that connect corresponding parts of the right and left halves of the CNS.

Front 13

Anterior Horns

Back 13

Central gray matter is shaped like a capital H and the horns are the arms of the H that project anteriorly.

Front 14

Anterior Spinocerebellar Tracts

Back 14

Located within the spinocerebellar pathway, carrying information from muscle and joint receptors to the cerebellum.

Front 15

Arachnoid Matter

Back 15

One of 3 membranes of connective tissue that surround the whole CNS, located between the dura and pia mater.

Front 16

Arachnoid Villi

Back 16

Fingerlike projections of the arachnoid that act as valves projecting through the dura into dural blood sinuses.

Front 17

Association Areas

Back 17

In the cerebral cortex, responsible for forming a unified picture of the sensory world, associating key elements of it with the resources of past experience, and formulating complex behaviors.

Front 18

Astrocytes

Back 18

A class of glial cell in the CNS that control the composition and volume of the fluid microenvironment that surrounds central neurons.

Front 19

Autonomic Nervous System

Back 19

That part of the peripheral nervous system that supplies motor innervation to the viscera.

Front 20

Axon

Back 20

A single tubular structure on the neuron cell body that conducts action potentials.

Front 21

Axon Hillock

Back 21

A single tubular axon that sprouts from the cell body at a bump. Also called an initial segment.

Front 22

Axon Terminal

Back 22

Structures that allow neurons to communicate with each other and with effectors.

Front 23

Basal Ganglia

Back 23

Now called basal nuclei, these are islands of neuron cell bodies in the cerebral white matter.

Front 24

Beta-Adernergic Receptors

Back 24

Receptors for norepinephrine and epinephrine.

Front 25

Caudate Nucleus

Back 25

Islands of neuronal cell bodies in the cerebral white matter that are involved in the control of movement.

Front 26

Central Canal

Back 26

The central gray matter is shaped like a capital H. The crossbar of the H is the central commissure and contains the hollow central canal.

Front 27

Central Commissure

Back 27

The central gray matter is shaped like a capital H. The crossbar of the H is the central commissure.

Front 28

Cerebellum

Back 28

Coordinates and smooth body movements, particularly rapid ones.

Front 29

Cerebral Aqueduct

Back 29

Connects the 3rd and 4th ventricle, running thru the midbrain, dividing it into a dorsal tectum and paired ventral cerebral pednucles.

Front 30

Cerebral Peduncles

Back 30

Structures found in the fourth ventricle.

Front 31

Cerebrospinal Fluid (CSF)

Back 31

Secreted by the choroid plexus, it circulates throughout the ventricles and the subarachnoidal space, providing cushion that gives some protection to the brain and spinal fluid.

Front 32

Chemical Synapse

Back 32

The most common form of synapse in which the axon terminal releases a specific neurotransmitter chemical that acts on the plasma membrane of the target cell, either to excite or to inhibit electrical activity in the recipient cell.

Front 33

Choroid Plexus

Back 33

A membrane attached to the roofs of the four ventricles that secretes CSF.

Front 34

Closed State

Back 34

A Na+ channel state in which the pore is blocked by an internal activation gate that senses the transmembrane potential and can be opened by depolarization, switching the channel to the open state.

Front 35

Commissures

Back 35

Fiber tracts that connect corresponding parts of the right and left halves of the CNS.

Front 36

Convergent

Back 36

Several pathways, possibly carrying different types of information, may make synapses on the same neurons.

Front 37

Corpus Callosum

Back 37

The major commissure.

Front 38

Cortex

Back 38

The bulk of the gray matter of the brain.

Front 39

Cortical Dominance

Back 39

A critical area located in only one hemisphere.

Front 40

Decremental Threshold

Back 40

Stimulation of the dendrites results in a local depolarization that decreases in intensity as it travels through the dendrites to the cell body.

Front 41

Decussate

Back 41

Both sensory and motor pathways cross from one side of the CNS to the other before they enter or leave the brain.

Front 42

Deep Cerebellar Nuclei

Back 42

Embedded within the cerebellum's core of white matter.

Front 43

Depolarization

Back 43

Any change in the direction of a less-negative potential.

Front 44

Diencephalon

Back 44

A division of the prosencephalon vesicle, containing the thalamus and hypothalamus regions.

Front 45

Direct Corticospinal Pathway

Back 45

The pyramidal tracts that carry axons of neurons in the motor cortex and traverse the cord without synapsing until they reach neurons in the spinal segments.

Front 46

Dorsal Column Pathway

Back 46

A pathway located in the posterior funiculus occupies a wedge-shaped sector of the medial posterior cord and carries information about fine touch and pressure sensations.

Front 47

Dorsal Ramus

Back 47

A spinal nerve branch.

Front 48

Dorsal Root Ganglion

Back 48

Contains the cell bodies of somatic sensory afferents.

Front 49

Dorsal Roots

Back 49

Each spinal segment has a pair that projects from the postereolateral surface of each side.

Front 50

Efferent Axons

Back 50

Carry commands to effectors.

Front 51

Endoneurim

Back 51

Encloses each axon.

Front 52

Ependymal Cells

Back 52

A class of glial cells in the CNS.

Front 53

Epineurium

Back 53

A sheath that encloses the entire peripheral nerve.

Front 54

Epithalamus

Back 54

One of the principal diencephalic structures forming the roof of the third ventricle and containing the pineal gland.

Front 55

Excitatory Postsynaptic Potential (EPSP)

Back 55

Postsynaptic potentials that increase the likelihood that the postsnyaptic cell will initiate an action potential at the axon hillock.

Front 56

Extrapyramidal Tracts

Back 56

Originate in brain stem nuclei that receive input from the basal nuclei and cerebellum, control mainly the muscles of the axial skeleton, and mediate less finely controlled movements of the trunk.

Front 57

Fourth Ventricle

Back 57

The hindbrain, connected to the 3rd ventricle by the cerebral aqueduct.

Front 58

G Protein

Back 58

A membrane protein (short for GTP-binding protein) that consists of three subunits designated alpha, beta and gamma.

Front 59

General Association Area

Back 59

Large parts of the temporal, parietal, and occipital lobes that appear to be critical for integrating multiple modes of sensory information into a comprehensive understanding of the situation.

Front 60

General Somatic Senses

Back 60

A class of somatic sensory system that includes touch, temperature, and pain that project from the body surface, as well as muscle, tendon, and joint receptors that give info about position and movement of the body in space.

Front 61

Glia

Back 61

The supporting cells of the nervous system.

Front 62

Glassopharyngeal

Back 62

A cranial mixed nerve that serves part of the tongue and throat. Carries gustatory afferents from posterior tongue/carotid sinus/carotid body that convey info about blood and blood pressure.

Front 63

Gray Matter

Back 63

The central matter of the spinal cord and much of cortex.

Front 64

Gray Ramus

Back 64

A medial spinal nerve branch that connects the base of each ventral ramus to a corresponding sympathetic chain ganglion, part of sympathetic branch of autonomic motor system.

Front 65

Guanylyl Cyclase

Back 65

Converts guanosine triphosphate (GTP) to cyclic guanosine monophosphate (cGMP).

Front 66

Gyri (Gyrus)

Back 66

Ridges that are created by folding the cortex as is grows.

Front 67

Homunculus

Back 67

A map of the cortex representing the body surface.

Front 68

Hyperpolarization

Back 68

Any change in the direction of an even more inside-negative potential.

Front 69

Hyperpolarizing Inhibitory Postsynaptic Potential

Back 69

Postsynnaptic potentials that trend to decrease the likelihood that the postsynaptic cell will initiate an action potential at the axon hillock.

Front 70

Hypoglossal

Back 70

The cranial nerve that innervates the muscles of the tongue.

Front 71

Inactivated State

Back 71

When the inactivation gate remains closed, the channel cannot be reopened by depolarization.

Front 72

Inactivation Gate

Back 72

Once the channel has entered the open state this gate can swing into place and close the channel. While the inactivation gate remains closed, the channel cannot be reopened by depolarization.

Front 73

Inferior Hypogastric Ganglia

Back 73

1 of 4 major unpaired prevertebral ganglia located in the abdomen and pelvis.

Front 74

Inferior Mesenteric Ganglia

Back 74

1 of 4 major unpaired prevertebral ganglia located in the abdomen and pelvis.

Front 75

Initial Segment

Back 75

A singular tubular axon that sprouts from the cell body at a bump. Also called the axon hillock.

Front 76

Interneurons

Back 76

Also called associated neurons, these are most numerous neurons that have their processes entirely within the CNS and are involved in processing information for an appropriate response.

Front 77

Internodes

Back 77

Regular intervals in which myelinated axons are surrounded by a mulitlayered sheath formed by ganglia.

Front 78

Inotropic Receptors

Back 78

One type of neurotransmitter receptor that is also an ion channel. Binding of the transmitter to the ionotropic receptor opens the channel, resulting directly in a permeability change.

Front 79

Lateral Spinothalamic Tracts

Back 79

Contains the spinothalamic pathway.

Front 80

Lateral Ventricles

Back 80

The paired, C-shaped ventricles within the cerebral hemispheres.

Front 81

Longitudinal Fissures

Back 81

Separates the cerebrum into R and L hemispheres.

Front 82

Medulla Oblongta

Back 82

A region of the brain stem.

Front 83

Melatonin

Back 83

A hormone secreted by the pineal gland, contributes to control of the body sleeping-waking cycle.

Front 84

Meninges

Back 84

3 membranes of connective tissue that surround the whole CNS. The outermost membrane is tough dura mater. Just deep to the dura is the arachnoid, and inside that the pia mater.

Front 85

Mesencephalon (midbrain)

Back 85

The midbrain portion of the brain stem.

Front 86

Metabotropic Receptor

Back 86

A receptor that is coupled to intracellular second messengers by way of the G proteins and may be coupled to different second messenger systems in different cell types.

Front 87

Metencephalon

Back 87

The cerebellum and pons portion of brain stem.

Front 88

Microglia

Back 88

The cells of nonspecific immune system rather than true glia cells--they are the form that macrophages take in brain.

Front 89

Midbrain

Back 89

Also known as the mesencephalon, located within the brain stem.

Front 90

Mixed Nerves

Back 90

Nerves that contain both afferent and efferent axons.

Front 91

Monoamine Oxidase

Back 91

An enzyme that packages for reuse or breaks down any given molecule of recovered norepinephrine.

Front 92

Monsynaptic Stretch Reflex

Back 92

The only human reflex that is monosynaptic, in which there are no interneurons in the reflex arc and all integration takes place as synapses of the sensory neurons on the motor neurons. A stretch reflex may be evoked tapping on a muscle or its tendon.

Front 93

Myenlencephalon

Back 93

The medulla oblongta portion of the brain stem.

Front 94

Myelin

Back 94

A fatty substance that insulates axons.

Front 95

Myelin Sheaths

Back 95

Surround the dome axons of some central neurons.

Front 96

Nerve Fibers

Back 96

Long axons found in peripheral nerves that have threadlike appearance.

Front 97

Neural Tube

Back 97

Originates in the early development and is formed from a dorsal infolding of ectoderm, the outermost of the 3 embryonic cell layers.

Front 98

Nodes of Ranvier

Back 98

Sites in myelinated axon in which the sheath is interrupted at regular intervals, leaving the axonal membrane bare.

Front 99

Occipital Lobes

Back 99

The most caudal lobes that are site of primary visual area.

Front 100

Oculomotor

Back 100

The cranial nerve that contains efferents that innervate 4 of the 6 extrinsic eye muscles and parasympathetic fibers that innervate the iris of the eye.

Front 101

Oligodendrocytes

Back 101

A class of glial cell in the CNS that is responsible for laying down myelin sheaths that surround axons of some central neurons.

Front 102

Open State

Back 102

1 of 3 states a Na++ channel may exist in which the transmembrane potential and can be opened by depolarization.

Front 103

Paravertebral Chain Ganglion

Back 103

Part of the sympathetic pathway to the effectors.

Front 104

Perineurium

Back 104

A wrapping that separates fascicles from one another.

Front 105

Pia Mater

Back 105

The innermost layer of meninges that surround the whole CNS.

Front 106

Pineal Gland

Back 106

The major structure of the epithalamus that is unpaired, knoblike structure that secretes melatonin.

Front 107

Pituitary Gland

Back 107

An extremely important element of the endocrine system, projects inferiorly from the hypothalamus.

Front 108

Plexi (Plexus)

Back 108

Interlacing networks formed by the ventral rami of all spinal nerves, with the exception of T2-T12, by joining one another lateral to the vertebral column.

Front 109

Polarized

Back 109

A resting cell's membrane in which it is charged electrically with a positive and negative pole.

Front 110

Polysynaptic Withdrawal Reflex

Back 110

The reflex arc includes one or more interneurons. The withdrawal reflex is a commonly experienced polysynaptic spinal reflex that results in a generalized flexion of an appendage in response to an averse stimuli.

Front 111

Pons

Back 111

A region in the brain stem.

Front 112

Postcentral Gyrus

Back 112

The primary somatosensory area of the cortex.

Front 113

Posterior Horns (Dorsal Horns)

Back 113

Central gray matter is shaped like a capital H and the horns are the arms of the H that project posteriorly.

Front 114

Posterior Spinocerebellar Tracts

Back 114

Located within the spinocerebellar pathway, carrying information from muscle and joint receptors to the cerebellum.

Front 115

Postganglionic Neuron

Back 115

The 2nd neuron of the autonomic pathways; In peripheral ganglion, the neuron on which the preganglionic cell's axon synapses and then projects to an effector in a visceral organ.

Front 116

Postsynaptic

Back 116

In a synaptic transmission, the recipient cell.

Front 117

Postsynaptic Potential (PSP)

Back 117

Caused by the binding of transmitter to its receptor initiates a permeability change in the postsynaptic cell.

Front 118

Precentral Gyrus

Back 118

The primary motor areas of the cortex.

Front 119

Prefrontal Cortex

Back 119

Lies rostral to the motor areas of the precentral gyrus, and is important for activities that involve reasoning, complex learning abilities, long-term planning, and judgement and is also involved in mood, emotions and social behavior.

Front 120

Preganglionic Neuron

Back 120

The first neuron of the autonomic pathways; its cell body is in the CNS, and its axon projecting to a peripheral autonomic ganglion.

Front 121

Prevertebral Ganglia

Back 121

The point in which a preganglionic axon synapses on a postganglionic neuron that projects to an effector in the abdominal cavity.

Front 122

Primary Auditory Area

Back 122

Located in the temporal lobe.

Front 123

Primary Brain Vesicles

Back 123

The prosencephalon (forebrain), mesencephalon (midbrain) and rhombencephalon (hindbrain).

Front 124

Prosencephalon (Forebrain)

Back 124

1 of 3 primary brain vesicles.

Front 125

Pyramidal Tracts

Back 125

Carry axons of neurons in the motor cortex that traverse the cord without synapsing until they reach neurons in the spinal segments.

Front 126

Rami Communicate

Back 126

The medial gray ramus and the lateral white ramus that connect the base of each ventral ramus to a corresponding sympathetic chain ganglion, part of the sympathetic branch of the autonomic nervous system.

Front 127

Reflex Arc

Back 127

The organization of neurons and effectors, which is the simplest way of organizing the nervous system to achieve an appropriate response.

Front 128

Relative Refractory Period

Back 128

A period after the absolute refractory period during which a second action potential can be initiated, but the stimulus must be more intense.

Front 129

Resting Potential

Back 129

In the resting cell, the plasma membrane is mainly permeable to K+, and the inside-to-outside concentration gradient tends to drive K+ toward the outside of the cell, giving membrane a slight excess positive charge on the outer surface of the membrane and a corresponding slight excess of negative charge on the outside.

Front 130

Resting State

Back 130

A state in which closed channels could be thought of as available to be opened by depolarization.

Front 131

Rhombencephalon (Hindbrain)

Back 131

1 of 3 primary brain vesicles.

Front 132

Schwann Cells

Back 132

In the PNS, the glial cells responsible for myelinating CNS neurons.

Front 133

Somatic Region

Back 133

One region of the PNS that consists of skeletal muscles and body surface.

Front 134

Somatotopy

Back 134

The map-like organization of the brain.

Front 135

Spatial Summation

Back 135

Multiple synapses located on the same postsynaptic cell.

Front 136

Spike

Back 136

When an action potential occurs, the membrane potential changes rapidly from its resting inside-negative value to an inside-positive value (peaking typically in the range of +20 to +50mV) and just as quickly returns to the resting value.

Front 137

Spinal Nerve

Back 137

The major nerves of the spine; there are 31 pairs of spinal nerves.

Front 138

Spinal Reflexes

Back 138

The reflex arc does not include brain neurons and is typically limited to one or a few adjacent spinal segements.

Front 139

Spinocerebellar Pathway

Back 139

Carries information from muscle and joint receptors to the cerebellum.

Front 140

Spinothalamic Pathway

Back 140

Located in the anterior and lateral spinothalamic tracts, the pathway carries information about coarse touch, temperature and pain sensations to the primary somatosensory cortex.

Front 141

Splanchnic Nerve

Back 141

A nerve that a preganglionic axon can follow after passing through the chain ganglion without synapsing.

Front 142

Sulci (Sulcus)

Back 142

Shallow grooves created by folding of the cortex as it grows.

Front 143

Sympathetic Chain Ganglia

Back 143

A paired series lying parallel to the spinal column on each side and connected to the ventral rami of T1 - L1 by rami communicantes.

Front 144

Synapses

Back 144

The points of close contact between axon terminals and the target cells.

Front 145

Synaptic Cleft

Back 145

A narrow space that separates the presynaptic cell and the postsynaptic cell.

Front 146

Synaptic Delay

Back 146

Represents the time required for the presynaptic cell to organize transmitter release, for the transmitter to diffuse to receptors, and for the activated receptors to cause a PSP.

Front 147

Synaptic Fatigue

Back 147

Continual use of a particular pathway may result in depletion of the stores of the transmitter, decreasing the efficacy of the synapses.

Front 148

Synaptic Transmission

Back 148

The process of sending information across synapses.

Front 149

Synaptic Vesicles

Back 149

A small, membrane-bound vesicles that stores neurotransmitter chemicals in the axon terminal.

Front 150

Tectum

Back 150

The roof of the cerebral aqueduct that runs through the midbrain.

Front 151

Telencephalon

Back 151

In the forebrain, the cerebral cortex and basal nuclei.

Front 152

Telodendria

Back 152

Branches formed at the end of axons, ending in axon terminals.

Front 153

Temporal Lobe

Back 153

The site of the primary auditory area.

Front 154

Temporal Summation

Back 154

Several action potentials that arrive one after the other at the same synapse.

Front 155

Thalamocortical Fiber Tracts

Back 155

Relay information from the somatosensory, visual, auditory, olfactory, and gustatory sensory systems to the primary processing areas of the cortex.

Front 156

Third Ventricle

Back 156

Located in the center of the diencephalon.

Front 157

Transverse Fissure

Back 157

Separates the cerebral hemispheres from the cerebellum.

Front 158

Trigeminal

Back 158

A cranial nerve that contains afferents from the face adn innervates masticatory (chewing) muscles.

Front 159

Upstroke

Back 159

A rapid rise in the membrane potential.

Front 160

Vagus

Back 160

The only cranial nerve to extend beyond the head/neck; innervates larynx and contains afferents and parasympathetic efferents from/to thoracic and abdominal viscera.

Front 161

Ventral Horns

Back 161

Central gray matter is shaped like a capital H and the horns are the arms of the H that project anteriorly.

Front 162

Ventral Ramus

Back 162

A spinal nerve branch.

Front 163

Ventral Roots

Back 163

Each spinal segment has a pair that project from the anteriolateral surface.

Front 164

Ventricles

Back 164

A system of four interconnected spaces of the brain filled with CSF.

Front 165

Visceral Region

Back 165

One region of the PNS that consists of the soft internal organs of the digestive system, lungs, hearts, and blood vessels, etc.

Front 166

White Matter

Back 166

Forming the outer layer of the spinal cord; also the location of the cerebral basal nuclei.

Front 167

White Ramus

Back 167

The lateral branch of the rami communicante that connects the base of each ventral ramus to a corresponding sympathetic chain ganglion.