CH # 9: Nervous System Flashcards by Mary Best

A nerve impulse

A rapid change in membrane potential that involves depolarization and repolarization

Action potential

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2 names 4 the part of a neuron that carries impulses away from cell bodies

This structure is surrounded by many myelinated segments, while the unmyelinated regions between the segments r called the nodes of Ranvier

Axons

Efferent processes

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Paired regions of grey matter scattered through out the white matter of the cerebrum

Functions as a relay station, or areas of synapse, in pathways going 2 and from the cortex.

They decrease muscle tone and inhibit musclar activity and play an important role in maintaining posture and coordinating motor movements

Almost all of a persons dopamine is produced here

Basal ganglia

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The portion of the brain, between the diencephalon and spinal chord, that contains the midbrain, pons and medulla oblongata

Top down: midbrain > pons > medulla oblongata

Controls 3 vital centers of visceral activities:

cardiac center; adjusts heart rate and contraction strength
vasomotor center; regulates blood pressure
respiratory center; regulates rate, rhythm and depth of breathing

Brain stem

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2 names 4 the grove of furrow between the frontal and parietal lobes of the cerebrum

Central sulcus

Fissure of Rolando

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2nd largest part of the human brain, located posterior 2 the pons and medulla oblongata and involved in the coordination of muscular movements

Cerebellum

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A fluid, similar 2 plasm, that fills the subarachnoid space around the brain and spinal cord

Located in the ventricles of the brain

Cerebrospinal fluid

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The largest and uppermost part of the human brain

Concerned w/consciousness, learning, memory, sensations and voluntary movements

Cerebrum

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2 names 4 the branching (treelike) structures of a neuron that receive impulses from other neurons and transmit them 2 the cell body

The number of “branches” varies w/each neuron

Dendrites

Afferent processes

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A crossing over

Usually refers 2 motor fibers that cross over 2 the opposite side in the medulla oblongata

Decussation

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Part of the brain between cerebral hemispheres and the midbrain

Includes the thalamus and hypothalamus

Diencephalon

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White, fatty substances that surrounds many nerve fibers

CNS: produced by oligodendrocytes but NO neurilemma meaning
no regeneration of fibers possible
PNS: produced by Schwann cells 2 form the neurilemma

Myelin

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2 names 4 the layer of cells that surrounds a nerve fiber in the PNS and in some cases produces myelin

Neurilemma

Schwann sheath

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Supporting cells of nervous tissue

Cells in nervous tissue that do not conduct impulses

Neuroglia

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Nerve cell including its processes which includes:
-cell body/soma; nucleus,1 or more nucleolus, cytoplasmic
organelles
-dendrite(s) cytoplasmic extensions/fibers from the cell body
-1 axon; process that projects from the cell body

Conducting cell of nervous tissue that relays impulses

Amitotic: new structures can NOT be made or replaced

Neuron

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A chemical substance that is released from the axon terminals 2 stimulate muscle fiber contraction or an impulse in another neuron

Neurotransmitters

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Short spaces between segments of myelin in a myelinated nerve fiber

Nodes of Ranvier

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Time during which an excitable cell cannot respond 2 a stimulus that is usually adequate 2 initiate an action potential

Refractory peroid

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Process in which a nerve impulse travels along a myelinated nerve fiber by jumping from 1 node of Ranvier 2 the next

Saltatory conduction

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The primary motor area of the brain

Located in the precentral gyrus

Transmits motor impulses 2 the body

Somatomotor cortex

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The primary sensory area of the brain

Located in the postcentral gryus

Receives sensory impulses from the body

Somatosensory cortex

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The region of communication between 2 neurons

Synapse

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2 names 4 a minimum level of stimulation that is required 2 start a nerve impulse or muscle contraction

Threshold stimulus

Liminal stimulus

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Part of the nervous system that includes the brain and the spinal cord in the dorsal cavity, both encased in bone 4 protection:

Brain is in the the cranial vault
Spinal cord is in the vertebral canal of the vertebral column

Surrounded by connective tissue membranes called meninges and cerebral spinal fluid

Central Nervous System

CNS

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Connective tissue membranes that surround the CNS Consists of 3 layers: - dura mater; outer layer - arachnoid; middle layer - pia mater; inner layer

Meninges

The outer layer of meninges that surround the brain and spinal cord Tough, white, connective tissue that is just inside the cranial bones and lines the vertebral canal Contains channels called dural sinuses which collect venous blood 2 return 2 the cardiovascular system

Dura Mater

The middle layer of meninges that surround the brain and spinal cord Resembles a cob web in appearance because it has numerous threadlike strands that attach it 2 the inner most layer There is a sub space beneath it that is filled w/CSF and contains blood vessels

Arachnoid

The sub space beneath the middle layer of the meninges that surround the brain that is filled w/CSF and contains blood vessels

Subarachnoid Space

The inner layer of meninges that surround the brain and spinal cord Thin, delicate membrane that is tightly bound 2 the surface of the brain and spinal cord

Pia Mater

1 part of the CNS Divided in2 4 parts: - cerebrum - diencephalon - brain stem - cerebellum

Brain

Afferent neuron Cell body is in the ganglion outside the CNS and extends in2 the CNS Function is 2 transmit nerve impulses from receptor 2 CNS

Sensory neuron

The largest portion of the brain Divided in2 2 cerebral hemispheres by a deep longitudinal fissure but it is connected by an arching band of white fibers called the corpus callosum. The corpus callosum functions as a communication pathway between the hemispheres Each hemisphere is divided in2 5 lobes: - frontal lobe - parietal lobe - occipital lobe - temporal lobe - insula/island of Reil

Cerebrum

Grey matter that forms the outermost part of the cerebrum Consists of neuron cell bodies and UNmyelinated fibers The center 4 sensory and motor functions: - somatosensory cortex - somatomotor cortex

Cerebral cortex

A region of the cerebral cortex located in the post central gyrus of the parietal lobe This area of the brain is the primary sensory area that receives information from various sense organs and receptors throughout the skin and skeletal muscles Right side receives input from the left side of the body and vice versa

Somatosensory Cortex

A region of the cerebral cortex in the precentral gyrus in the frontal lobe Area responsible 4 muscle contraction allowing us 2 have conscious control of our skeletal muscles The right side controls the left side of the body and vice versa Highly organized in a way similar 2 the primary sensory cortex w/neurons in a specific region responsible 4 controlling movement in a specific part of the body

Somatomotor Cortex

The connective tissue membranes that surround the brain and spinal cord r the?

Meninges

The outer layer is the?

Dura mater

The middle layer is called?

Arachnoid

Innermost layer is called the?

Pia mater

The _________ mater adheres 2 brain tissue and the spinal cord

Pia

The largest [part of the brain is the?

Cerebrum

The _____________ _____________divides the cerebrum in2 2 cerebral hemispheres

Longitudinal fissure

The band of white fibers that connects the cerebral hemispheres is the?

Corpus callosum

The convolutions the surface of the cerebrum r called?

Gyri

The grooves that separate gyri r called?

Sulci

The 4 of the lobes and the bones of the skull have the same?

Name

The outermost portion of the cerebrum that consists of grey matter is called?

Cerebral cortex

Motor speech is controlled primarily by ______________ area in the frontal lobe?

Broca's

The understanding of language is primarily located in ________ area of the temporal lobe?

Wernicke's

____________ matter forms communication pathways

White

The thalamus, hypothalamus epithalamus collectively make up the?

Diencephalon

The ____________ is the largest part of the diencephalon?

Thalamus

The ___________ serves as a connection between the CNS and the endocrine system

Hypothalamus

The most superior part of the brain stem is the?

Midbrain

The middle portion of the brain stem is the?

Pons

Pons means?

Bridge

The inferior part of the brain stem is the?

Medulla oblongata

The 2nd largest portion of the brain is the?

Cerebellum

The fluid-filled cavities in the brain that r interconnected r?

Ventricles

____________________ fluid is produced in the lateral ventricles and circulates through the 3rd and 4th ventricles 2 the cerebral aqueduct and the central canal of the spinal cord and throughout the subarachnoid layer of the meninges

Cerebrospinal

The nervous system helps 2 maintain hemostasis by regulating vital functions and responding 2 internal and?

External stimuli

Information that is gathered from stimuli, converted 2 nerve impulses and transmitted 2 the brain is reffered 2 as?

Sensory input

Nervous system responds 2 sensory input and integration and sends signals 2 effectors, this is referred 2 as?

Motor functions

Motor signal travel ___________ from the brain

Away

The CNS and PNS r the 2 subdivisions of the?

Nervous system

What r the 2 organs of the CNS?

Brain and spinal cord

Which of these organs have more parts? | brain or spinal cord

Brain

Bundles of nerve fibers that extend from the CNS 2 the peripheral organs r called?

Nerves

Collections of nerve cell bodies outside the CNS r called?

Ganglia

The PNS is subdivided in2 ____________ and ___________ divisions

Afferent and Efferent

______________ divisions transmits impulses from periphral organs 2 the CNS?

Sensory or Afferent

______________ divisions transmits impulses from the CNS 2 peripheral organs

Efferent

The prefix ad- means

Toward

The prefix ex- means

Away

The somatic nervous system is under ____________ control?

Voluntary

Somatic literally means

Related 2 body structures

R impulses 2 skeletal muscles afferent impulses or efferent impulses?

Efferent

Autonomic nervous system is under ______________ control

Involuntary

ANS is further subdivided in2 ___________ and __________ divisions

Sympathetic Parasympathetic

The _________________ nervous system supplies motor impulses 2 cardiac muscle, smooth muscle and glandular epithelium

Autonomic

What r the 2 divisions of the efferent division of the PNS?

Somatic and Autonomic

R efferent impulses motor or sensory?

Motor

What r the 2 divisions of the afferent division of the PNS?

Visceral and Somatic

R afferent impulses motor or sensory?

Sensory

A nerve cell is called?

Neuron

The cell that provides a support system 4 neurons is called?

Neuroglia

The suffix -glia means?

Glue

Neurons do not under go mitosis, the term 4 this is?

Amitotic

The main part of the neuron that contains the nucleus is the?

Cell body

The cytoplasmic extensions that r short and branching and transmit impulses 2 the cell body is the?

Dendrites

The cytoplasmic extension that is elongated that carries impulses away from the cell body is called the?

Axon

The enlargement at the distal end of the telodendria that contains vesicles of neurotransmitters is the?

Synaptic knob

White fatty substance that surrounds nerve fibers is called?

Myelin

Short, unmyelinated regions between 2 segments of myelin in myelinated nerve fiber is called?

Nodes of Ranvier

__________ form the connecting link between the afferent and efferent neurons

Interneurons

A series of fluid-filled (cerebrospinal fluid)cavities found w/in the brain

Ventricles

Cranial nerves associated w/the special senses of smell, vision, hearing and equilibrium and have only sensory fibers

Cranial nerves I, II, VIII

Cranial nerves that r primarily motor in function but does have some sensory fibers 4 proprioception

Cranial nerves III, IV, VI, XI, XIII

Cranial nerves consist of significant amounts of both sensory and motor fibers

Cranial nerves V, VII, IX, X

31 pairs of (mixed)nerves emerge laterally from the spinal cord Each is connected 2 the spinal cord by 2 types of roots: - dorsal root; sensory only - ventral root; motor only

Spinal nerves

Spinal nerves C1 - C8

Cervical nerves

Spinal nerves T1 - T12

Thoracic nerves

Spinal nerves L1 - L5

Lumbar nerves

Spinal nerves S1 - S5

Sacral nerves

Spinal nerve Co

Coccygeal nerve

An autonomic involuntary response 2 some change, either inside or outside the body

Reflex