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Neuroanatomy: Glial Cells, Myelin Sheath, and Nervous System Functions, Quizzes of Anesthesiology

Definitions and functions of various terms related to neuroanatomy, including neuroglial cells, myelin sheath, white matter, gray matter, olfactory nerves, autonomic and somatic nervous systems, and reflexes. It also covers the differences between neurons and neuroglia, the structure and function of dendrites and axons, and the roles of acetylcholine and acetylcholinesterase.

What you will learn

  • What are glial cells and what are their functions?
  • What is the difference between white matter and gray matter?
  • What are oligodendrocytes and Schwann cells and what is their role in the CNS?
  • What is the autonomic nervous system and what are its motor and sensory branches?
  • What is the cerebral cortex and what is its structural makeup?
  • What are nodes of Ranvier and what is their role in nerve impulse conduction?

Typology: Quizzes

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Uploaded on 01/18/2015

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TERM 1
Neuroglial cells
DEFINITION 1
Glial cells, sometimes called neuroglia or simply glia, are
non-neuronal cells that maintain homeostasis, form myelin,
and provide support and protection for neurons in the brain
and peripheral nervous system.
TERM 2
Neuron
DEFINITION 2
Cells of the nerves that are structurally composed of a cell
body, dendrites, and an axon. They not only initiate nerve
impulses but they also conduct them
TERM 3
White matter
DEFINITION 3
Myelinated axons in the CNS
TERM 4
Gray matter
DEFINITION 4
The part of the CNS made up of neuron cell bodies
TERM 5
Myelin Sheath
DEFINITION 5
Cell membrane of glial cells (oligodendrocytes, Schwann
cells) wrapped around an axon; increases speed of impulse
conduction along the axon.
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Neuroglial cells

Glial cells, sometimes called neuroglia or simply glia, are

non-neuronal cells that maintain homeostasis, form myelin,

and provide support and protection for neurons in the brain

and peripheral nervous system.

TERM 2

Neuron

DEFINITION 2

Cells of the nerves that are structurally composed of a cell

body, dendrites, and an axon. They not only initiate nerve

impulses but they also conduct them

TERM 3

White matter

DEFINITION 3

Myelinated axons in the CNS

TERM 4

Gray matter

DEFINITION 4

The part of the CNS made up of neuron cell bodies

TERM 5

Myelin Sheath

DEFINITION 5

Cell membrane of glial cells (oligodendrocytes, Schwann

cells) wrapped around an axon; increases speed of impulse

conduction along the axon.

Oligodendrocytes

Glial cells in the brain and spinal cord whose cellular

membrane forms the myelin sheath for axons in the CNS

TERM 7

Schwann Cells

DEFINITION 7

Glial cells associated with the peripheral nerves whose

cellular membrane forms the myelin sheath for axons in the

PNS

TERM 8

Nodes of Ranvier

DEFINITION 8

Unmyelinated areas of the axon between two adjacent

Schwann cells that are involved in rapid conduction of nerve

impulses along the axon

TERM 9

Central Nervous System

DEFINITION 9

The central nervous system is the part of the nervous system

consisting of the brain and spinal cord.

TERM 10

Peripheral Nervous System

DEFINITION 10

Nerves outside of the CNS

Corpus Callosum

White fibers that connect and provide communication

pathways between the two cerebral hemispheres

TERM 17

Gyri

DEFINITION 17

The folds that provide the wrinkled appearance of the surface

of the cerebral hemisphere

TERM 18

Sulci

DEFINITION 18

Groove, especially shallow grooves in the cerebral cortex.

TERM 19

Longitudinal fissure

DEFINITION 19

Prominent groove that divides the cerebrum into right and

left cerbral hemspheres

TERM 20

Cerebral hemispheres

DEFINITION 20

The two halves of the cereburm

Cerebellum

Second largest component of the brain; allows the body to

have coordinated movement, balance, posture, and complex

reflexes.

TERM 22

Diencephalon

DEFINITION 22

Serves as a nervous system passageway between the

primitive brain stem and the cerebrum; three major

structures of the diencephalon include the thalamus, the

hypothalamus, and the pituitary.

TERM 23

Thalamus

DEFINITION 23

Part of the diencephalon that acts as a relay station for

regulating sensory impulses to the cerebrum.

TERM 24

Hypothalamus

DEFINITION 24

A portion of the diencephalon that has extensive links to the

brain and to the pituitary gland. It functions as an important

bridge between the nervous and endocrine systems.

TERM 25

Pituitary gland

DEFINITION 25

The master endocrine gland. A pea-sized endocrine gland

located at the base of the brain; made up of the anterior

pituitary gland, which produces seven known hormones, and

the posterior pituitary gland which stores and releases two

hormones from the hypothalamus also called the hypophysis.

Dura mater

The outermost layer of the meninges that covers the brain

and spinal cord; it is considered to be the toughest layer.

TERM 32

Pia mater

DEFINITION 32

Pia mater often referred to as simply the pia, is the delicate

innermost layer of the meninges, the membranes

surrounding the brain and spinal cord.

TERM 33

Arachnoid

DEFINITION 33

The arachnoid mater is the delicate web-like layer of the

three meninges between the dura mater and the pia mater,

the protective membranes that cover the brain and spinal

cord.

TERM 34

Cerebrospinal fluid

DEFINITION 34

Fluid that bathes and protects the brain and spinal cord from

the hard inner surface of the skull and spinal vertebrae.

TERM 35

Blood brain barrier

DEFINITION 35

The functional barrier between the capillaries in the brain

and the nervous tissue; anatomically composed of capillary

walls without the openings found in other capillaries and glial

cells.

12 Cranial Nerves

Cranial nerves, are nerves that emerge directly from the brain and

the brainstem, in contrast to spinal nerves (which emerge from

various segments of the spinal cord).Olfactory I Facial VII Optic II

Auditory (vestibulocochlear) VIIIOculomotor III Glossopharyngeal

IXTrochlear IV Vagus XTrigeminal V Spinal Accessory XIAbducens

VI Hypoglossal XII

TERM 37

Ganglion

DEFINITION 37

Cluster of neuron cell bodies outside of the CNS

TERM 38

Somatic reflexes

DEFINITION 38

A reflex resulting in the stimulation or inhibition of skeletal

muscle contraction

TERM 39

Autonomic reflexes

DEFINITION 39

A reflex that results in stimulation or inhibition of smooth or

cardiac muscle or endocrine gland function; mechanisms of

homeostasis are autonomic reflexes.

TERM 40

Stretch reflex

DEFINITION 40

The stretch reflex is a muscle contraction in response to

stretching within the muscle.

Pupillary Light Reflex

The pupillary light reflex is a reflex that controls the diameter

of the pupil, in response to the intensity (luminance) of light

that falls on the retina of the pupil and the eye, thereby

assisting in adaptation to various levels of

lightness/darkness.

TERM 47

Corneal reflex

DEFINITION 47

The corneal reflex, also known as the blink reflex, is an

involuntary blinking of the eyelids elicited by stimulation of

the cornea, or bright light, though could result from any

peripheral stimulus.

TERM 48

How are the functions of neurons and

neuroglia different from each other?

DEFINITION 48

Neurons are the basic functional units of the nervous system. That is,

they are the smallest pieces of the system that show basic nervous

system functions such as responding to stimuli and conducting impulses

from one part of the cell to another. The neuroglia, or glial cells (from the

Greek glia, meaning "glue"), structurally and functionally support and

protect the neurons. They outnumber neurons about 10 to 1, but they

are not directly involved in the transmission of information or impulses

through the nervous system. Rather, they are important parts of the

infrastructure necessary for the neurons to do their jobs.

TERM 49

Name the parts of a typical neuron.

DEFINITION 49

Dendrite, axon, and cell body

TERM 50

How are the dendrites and axons different in

structure and function?

DEFINITION 50

Dendrites receive stimuli, or impulses, from other neurons and conduct this stimulation to the cell body. Dendrites also may be modified into sensory receptors that receive, or sense, stimuli such as heat, cold, touch, pressure, stretch, or other physical changes from inside or outside the body. Dendrites tend to be short, numerous, multibranched projections extending from the cell body. The axon conducts nerve impulses away from the cell body toward another neuron or an effector cell (a cell that does something when stimulated, such as a muscle or gland cell). In contrast to the short, numerous, branched dendrites, the axon is a single structure that can be very long. For example, a single axon in the horse may extend several feet from the spinal cord all the way to the lower leg. Axons are often covered by a fatty substance called myelin.

What is the difference between gray matter

and white matter?

White matter refers to nervous tissue containing many

myelinated axons. Conversely, nervous tissue that is made

up largely of neuron cell bodies, which are not myelinated,

appears darker and is called gray matter.

TERM 52

What is the relationship between the myelin

sheath and the nodes of Ranvier?

DEFINITION 52

Nodes of Ranvier are small gaps in the myelin sheaths. The

nodesof Ranvier and the myelin work together to enhance

the conduction ofstimuli.

TERM 53

What are the anatomic differences between

the CNS and the PNS?

DEFINITION 53

The central nervous system (CNS) is anatomically composed of the

brain and spinal cord, which are found associated within the

central axis of the animals body. Peripheral means to the side or

away from the center; therefore the peripheral nervous system

(PNS) is made up of those components of the nervous system that

extend away from the central axis outward toward the periphery

of the body.

TERM 54

Which are afferent nerves: motor nerves or

sensory nerves? Which are efferent?

DEFINITION 54

Motor nerves are efferent and sensory nerves are afferent.

TERM 55

Identify each of the following as being

controlled by the autonomic or the somatic

nervous system and as being either sensory

or motor:

DEFINITION 55

Conscious movement of the forelimb: somatic, motor Slowing of

the heart rate in response to an increased blood pressure:

autonomic; sensory for sensing the increased blood pressure and

motor for slowing the heart rate Constriction of blood vessels in

the skin in response to cold temperatures: autonomic; sensory for

sensing the cold temperatures and motor for constricting the

vessels Perception of pain from an injection of antibiotics: somatic,

sensory Perception of the amount of acidity present in the

duodenum: autonomic, sensory

What role do the synaptic cleft, presynaptic

neuron, neurotransmitter, and postsynaptic

neuron play in the continuation of a

depolarization wave from one nerve to

another?

The synapse is the junction between two neurons or a neuron and

a target cell. The synapse consists of a physical gap between the

two cells called the synaptic cleft. The neuron bringing the

depolarization wave to the synapse and releasing the chemical to

stimulate the next cell is called the presynaptic neuron. The

chemical released by the presynaptic neuron is called the

neurotransmitter, and the neuron that contains the receptors that

receive the neurotransmitter is the postsynaptic neuron. In this

way, depolarization continues from one cell to the next.

TERM 62

What is the functional relationship between a

neurotransmitter and a receptor? Will any

neurotransmitter stimulate any receptor?

DEFINITION 62

The neurotransmitter molecules released by the synaptic knob

bind with receptors and trigger a change in the postsynaptic cell.

However, the postsynaptic membrane receptors are very specific

about which neurotransmitters they will bind. If the

neurotransmitter and receptorare not matched, they will not bind

to each other, and no change will be triggered in the postsynaptic

cell. Thus synaptic transmission is only effective if receptors to the

neurotransmitter exist on the postsynaptic cell's membrane.

TERM 63

What is the difference between an excitatory

and an inhibitory neurotransmitter?

DEFINITION 63

Excitatory neurotransmitters have an excitatory effect on the postsynapticmembrane when they combine with their specific receptors. Specifically,excitatory neurotransmitters usually cause an influx of sodium so that thepostsynaptic membrane moves toward threshold. If the postsynapticmembrane is stimulated sufficiently by enough excitatory neurotransmitters,then threshold will be attained and depolarization of the postsynapticmembrane will occur.In contrast, inhibitory neurotransmitters tend to hyperpolarize thepostsynaptic membrane, making the inside of the cell more negative instead ofpositive and moving the charge within the postsynaptic cell farther away fromthreshold. When inhibitory neurotransmitters combine with their specificreceptors on the postsynaptic side, they may cause chloride channels orpotassium channels to open up on the postsynaptic membrane. This allowsthe negatively charged chloride ions (Cl-) to enter the postsynaptic cell andpotassium (K) ions to leave the cell, making the inside of the cell morenegatively charged (a change in charge that is opposite from that needed toreach threshold). TERM 64

How is acetylcholine different from

acetylcholinesterase?

DEFINITION 64

Acetylcholine is a neurotransmitter broken down quickly by

an enzyme called acetylcholinesterase found on the

postsynaptic membrane. The broken down components of

acetylcholine are reabsorbed by the synaptic knob,

reassembled into new acetylcholine molecules, and

repackaged into vesicles for release with the next wave of

depolarization.

TERM 65

What are

catecholamines?

DEFINITION 65

Catecholamines are the neurotransmitters norepinephrine,

epinephrine, and dopamine.

What are GABA and glycine?

Gamma-aminobutyric acid (GABA) and glycine are inhibitory

neurotransmitters. GABA is found in the brain, and glycine is

found in the spinal cord.

TERM 67

What part of the brain is responsible for

conscious thought and perception of

sensations?

DEFINITION 67

Cerebrum

TERM 68

What are the correct names for the bumps

and fissures that make the cerebral cortex

appear wrinkled?

DEFINITION 68

The folds, called gyri (plural of gyrus), are separated by deep

grooves called fissures and more shallow grooves called sulci

(plural of sulcus). The most prominent groove is the

longitudinal fissure, which divides the cerebrum into right

and left cerebral hemispheres.

TERM 69

What part of the brain is critical for

coordination, posture, and fine motor control?

How does this part of the brain accomplish

these responsibilities?

DEFINITION 69

Cerebellum. The cerebellum compares the movement the

body intends to do with the actual position of muscles and

joints to determine if the intentions of the cerebral cortex are

actually being carried out. If the movements are not being

carried out accurately, the cerebellum will stimulate or inhibit

muscles to fine-tune the movements.

TERM 70

What part of the brain serves as a relay

station for impulses going to and from the

cerebrum?

DEFINITION 70

Diencephalon

Which part of the autonomic nervous system

is responsible for "fight or flight" and which is

responsible for "rest and restore?"

The sympathetic nervous system is responsible for the fight

or flight system and the parasympathetic nervous system is

responsible for the rest and restore system.

TERM 77

Compare and contrast the sympathetic and

parasympathetic nervous systems as far as

their preganglionic neurons; their

postganglionic neurons; where the

preganglionic neurons emerge from the CNS;

their neurotransmitters; and their impact on

the heart, GI tract, blood vessels, bronchiole

diameters, and size of the pupil.

DEFINITION 77

The sympathetic nervous system emerges from the thoracolumbar area. The parasympathetic system emerges from the brain and the sacral vertebral regions and therefore is called the cranial-sacral system. Outside the thoracolumbar area of the spinal column are a series of autonomic ganglia (many ganglion) that form a chain called the sympathetic ganglion chain. The sympathetic preganglionic neuron extends out from the spinal cord and either synapses with a neuron within the ganglion chain or passes through the ganglionic chain and synapses with a neuron located beyond the sympathetic chain. Each sympathetic preganglionic neuron usually synapses with many postganglionic neurons in a wide variety of locations in the sympathetic chain or in ganglions outside the sympathetic chain. The sympathetic postganglionic neuron extends the remaining distance to the target organ. The parasympathetic preganglionic neuron travels directly from the CNS to its target organ, where it synapses with a short postganglionic neuron in the target organ. Thus the parasympathetic preganglionic neuron is relatively long compared with the very short postganglionic neuron. The sympathetic nervous system primarily uses norepinephrine as its key neurotransmitter. The neurons associated with the parasympathetic nervous system secrete acetylcholine as their neurotransmitter.Heart rate: increased by sympathetic and decreased by parasympathetic systemForce of heart contraction: increased by sympathetic, no significant effect from the parasympathetic systemDiameter of bronchioles: increased (dilated) by sympathetic and decreased (constricted) by parasympathetic systemDiameter of pupil: increased (dilated) by sympathetic and decreased (constricted) by parasympathetic systemGastrointestinal motility, secretions, and blood flow: decreased by sympathetic and increased by parasympathetic systemDiameter of skin blood vessels: decreased by sympathetic, no significant effect from parasympathetic systemDiameter of muscle blood vessels: Increased by sympathethic, no significant effect from parasympathetic systemDiameter of blood vessels to kidney: Decreased by sympathetic, no significant effect from parasympathetic system

TERM 78

With which branch of the autonomic nervous

system are the alpha1-, beta1-, and beta2-

receptors associated? What happens to the

body when these particular receptors are

stimulated?

DEFINITION 78

Sympathetic nervous system. Alpha1- adrenergic receptors

typically are found on blood vessels and cause the

vasoconstriction of the skin, GI tract, and kidney associated with

sympathetic stimulation. The increase in heart rate and force of

contraction are the result of stimulation of beta1-adrenergic

receptors by catecholamines, and the bronchodilation associated

with sympathetic stimulation results from beta2-adrenergic

receptor stimulation.

TERM 79

With which branch of the autonomic nervous

system are muscarinic and nicotinic receptors

associated?

DEFINITION 79

Nicotinic acetylcholine receptors are found primarily on the

postganglionic neurons of both the sympathetic and

parasympathetic nervous systems. Muscarinic cholinergic

receptors are found on the target organs and tissues

supplied by the postganglionic neuron of the

parasympathetic nervous system.

TERM 80

What are the differences between an

autonomic reflex and a somatic reflex?

DEFINITION 80

Somatic reflexes involve contraction of skeletal muscles.

Autonomic reflexes regulate smooth muscle, cardiac muscle,

and endocrine glands.

What role do the sensory receptor, sensory

neuron, interneuron, and motor neuron play

in the reflex arc?

A sensory receptor detects a change either in the external environment

or within the body itself. Once stimulated to threshold, the sensory

receptor sends an action potential (nerve impulse) along the sensory

neuron to the gray matter of the spinal cord or brain stem. In the CNS

gray matter, the sensory neuron synapses with other interneurons, which

serve to integrate the incoming sensory impulse with other impulses

from other sensory neurons. Finally, the integrated response of the reflex

is sent out from the spinal cord or brain stem by the motor neuron, which

ends at the target organ (muscle or endocrine gland).

TERM 82

What is the sensory receptor in the stretch

reflex? What results from the stretch reflex

arc stimulation? Is this an ipsilateral or

contralateral reflex?

DEFINITION 82

A specialized structure within the muscle called the muscle

spindle. Muscle contraction results. Ipsilateral.

TERM 83

What happens in a withdrawal reflex? Is this

reflex more or less complex than the stretch

reflex?

DEFINITION 83

A strong stimulus to a receptor causes the sensory somatic neuron

to send impulses to the spinal cord. This reflex involves synapsing

with several interneurons. Some of these interneurons will

synapse with motor neurons that will cause contraction of a

specific set of muscles responsible for pulling the limb away from

the painful stimulus. Other interneurons will inhibit those opposing

muscle groups so that the withdrawal of the limb is rapid and

complete. This reflex is more complex than a stretch reflex.

TERM 84

How is the crossed extensor reflex tied in with

the withdrawal reflex? Is the crossed extensor

reflex an ipsilateral or contralateral reflex?

DEFINITION 84

When the withdrawal reflex arc is stimulated, the afferent somatic

sensory neuron also synapses with another set of interneurons,

causing extensor muscles in the opposite leg to contract and thus

support the weight of your body when the other leg flexes. Thus

the withdrawal and crossed extensor reflexes are related. The

crossed extensor reflex is a contralateral reflex.

TERM 85

What is the role of the upper CNS on the

reflex arc? If the CNS influence is removed or

blocked, do reflexes become hyporeflexive or

hyperreflexive?

DEFINITION 85

The upper CNS normally produces a dampening or inhibitory

effect on the reflex arc. If it is removed, the reflex becomes

hyperreflexive.

Which of the following is an indication for an

abdominal exploratory surgery? a. routine

ovariohysterectomy b. splenic tumor c.

ruptured bladder d. all of the above e. both b

& c

Both b & c

TERM 92

Which of the following retractors is commonly

used in abdominal exploratory surgeries? a.

Gelpi b. Senn c. Weitlaner d. Balfour e. none

of the above

DEFINITION 92

d. Balfour

TERM 93

Which of the following procedures involves

making an incision into the stomach? a.

abdominal exploratory b. gastrotomy c.

enterotomy d. splenectomy e. laparotomy

DEFINITION 93

b. Gastrotomy

TERM 94

Which intestinal surgey involves removing a

piece of the intestine and suturing the ends of

the remaining intestines back together?

DEFINITION 94

Resection and anastomosis

TERM 95

True or False: Sterile saline can be injected

into the surgical site to check for any leakage

after the anastomosis site has been closed.

DEFINITION 95

True

Which procedure involves surgically attaching

the stomach to the body wall?

Gastropexy

TERM 97

True or False: A gastropexy procedure

prevents future bloat occurrences.

DEFINITION 97

False, a gastropexy only prevents the stomach from twisting

on itself, but the stomach can still bloat.

TERM 98

True or False: A patient that needs to have an

abdominal exploratory for internal

hemorrhage resulting after having been hit by

a car (HBC), should have his/her bladder

expressed before being moved into sx.

DEFINITION 98

False

TERM 99

What are the signs and symptoms of

peritonitis?

DEFINITION 99

Abdominal pain, manifesting as a reluctance to move

due to inflammation of the parietal peritoneum.

Depression, anorexia and lethargy and non-specific

signs of infection or systemic disease.

Vomiting and diarrhoea may occur due to alterations in

intestinal motility and functional ileus.

Hypotension and (septic) shock due to effusion of fluid

into the peritoneum and systemic vasodilation.

Hypothermia or hyperthermia.

TERM 100

What are the signs and symptoms of

intestinal ischemia?

DEFINITION 100

Therefore, decreased blood supply to these organs cause

symptoms related to eating or after-meal digestion,

including:

Abdominal pain after meals.

Weight loss.

Fear of eating or change in eating habits due to post-

meal pain.

Nausea and/or vomiting.

Constipation or diarrhea.