Neurologic Function

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NEUROLOGIC FUNCTION Anatomic and Physiologic Review



Nervous System

CentralNervous

System (CNS)

Brain

andSpinal

Cord

PeripheralNervous

System (PNS)

Cranial nerves;

Spinal Nerves;and Autonomic

Nervous System

Sensory or

afferent

Motor or

efferent

Somatic motor Autonomic

sympathetic parasympathetic enteric



D I V ISI ONS O F T H E N E R V O U S S YS T E M

CNS- integrates the information that it receives from,

and coordinates the activity of, all parts of the bodies

PNS- connects the CNS to limbs and organs

Sensory or afferent- conducts action potential from

sensory receptors to CNS

y Sensory neurons- transmits action potentials from

periphery to the CNS

Motor or efferent-conducts action potentials from CNSto effector organs

y Motor neurons- transmits action potentials from

CNS towards periphery



D I V ISI ONS O F T H E N E R V O U S S YS T E M

Motor nervous system- transmits action potentials of

CNS to skeletal muscles

Autonomic Nervous System- transmits action

potentials from CNS to cardiac muscle, smooth muscle,

and glands.

Sympathetic- mobilize the body's resources

under stress; fight-or-flight response.

Parasympathetic- responsible for stimulation of

activities that occur when the body is at rest; rest-and-

digest.



CE L LS O F T H E N E R V O US S YST EM

Neurons- basic functionalunit of the brain

Dendrites- branch-typestructures for receivingelectrochemical messages.

Axon- a long projectionthat carries electrical

impulses away from thecell body.

Myelinated sheath-increases speed of

conduction



C E L LS O F T H E N E R V O US S YST EM

Ganglia or nuclei- nerve cell bodies occurring inclusters

Center- a cluster of cell bodies with the same

function

Neuroglial cells- serve to support, protect, and

nourish neurons.



NEUROTR ANSMITTERS

Communicates messages from one neuron to another,or from one neuron to a specific target tissue

Manufactured and stored in synaptic vesicles.

Potentiates , terminates and modulates a specific

action, and it can either excite or inhibit activity of

target cell



CNS: BR A IN

The Brain

y 2% of total body

weight,

approximately1400g for young

adult and 1200 in

elderly person.

y major areas:cerebrum, brain

stem, cerebellum,

and diencephalon.



C N S : B R A I N

CERE

BELLU

My Means little brain

y Cerebellar penduncles- attached to the

brainstem by several large connections.

These connections provides routes of

communication between cerebellum and

other parts of the CNS.



C N S : B R A I N

Diencephalon

y Thalamus

Influences mood and registers an unlocalized,uncomfortable perception of pain.

act as a relay between a variety of subcortical areasand the cerebral cortex

y Epithalamus

Involved in emotional and visceral response to odorsand pineal body.

Pineal body: an endocrine gland that may influence

puberty

y Hypothalamus

Plays an important role in maintaining homeostasis.

Control of body temp, hunger and thirst



C N S : B R A I N

CERE

BRU

My Largest part of the brain

y Longitudinal fissure- divides cerebrum into

right and left hemisphere

y Gyri-numerous folds found on the surface of

hemisphere

y Sulci-intervening grooves



C N S : B R A I N

Frontal lobes- control of voluntary motorfunctions, motivations, aggression, mood, and

olfactory(smell) reception.

Parietal lobes- principle center for the

reception and conscious perception of the

most sensory information, (touch,

temperature, balance and taste)

Central sulcus- separates the frontal and

parietal lobe



C N S : B R A I N

Occipital lobe- functions in the reception andperception of visual input and is not distinctly

separate from the other lobes

Temporal lobe- involved in olfactory and

auditory hearing sensations and plays an

important role in memory.

Lateral fissure- separates most of the

temporal lobe from the rest of the cerebrum



C N S : B R A I N

Brainstem- connects spinal cord to the remainder of the

brain.

y Medulla Oblongata-regulation of heart rate and blood

vessel diameter

Pyramids-transmits action potentials from brain to

motor neurons of spinal cord; is involved in

conscious control of skeletal muscle.

y Pons- (bridge)

relays information from between the cerebrum and

cerebellum

functions such as breathing , swallowing and

balance are controlled in the lower pons

Chewing and swallowing



C N S : B R A I N

y Midbrain-Coordination of eye movement, control of pupil

diameter and lens shape.

Colliculi-mounds found on the dorsal part

Two inferior: relay centers for auditory nervepathways in the CNS pathway

Two superior: visual reflexes

Substantia nigra- black nuclear mass involved in

the regulation of general body movements.



C N S : B R A I N

Meninges and CerebrospinalF

luidy Meninges- protects the brain and spinal cord

Dura mater: most thickest and superficial

surrounds the brain and the spinal cord and isresponsible for keeping in the cerebrospinal fluid.

Arachnoid: interposed between the two othermeninges

separated from the pia mater bythe subarachnoid space.

attached to the inside of the dura, surrounds thebrain and spinal cord but does not line the braindown into its sulci



C N S : B R A I N

Pia mater: the delicate innermost layerenvelops the entire surface of the brain

supplies blood to the superficial areas of the

cortex and supports larger blood vessels passing

over the surface of the brain Astrocytes- anchors pia mater to the brain



C N S : B R A I N

y Cerebrospinal Fluid-

a clear bodily fluid that occupies the

subarachnoid space and the ventricular

system around and insidethe brain and spinal cord

acts as a "cushion" or buffer for the cortex,

providing a basic mechanicaland immunological protection to the brain

inside the skull.



CNS: SPINA L CORD

The Spinal Cordy Extends from the

foramen magnum at thebase of the skull to the2nd lumbar vertebra.

y Cauda equina: theinferior end of the spinalcord and the spinalnerves exiting there w/cresembles a horse·s tail.

y functions primarily inthe transmission of neural signals betweenthe brain and the rest of the body.



CNS: SPINA L CORD

y contains neural circuits that can

independently control numerous

reflexes and central pattern generators

y The spinal cord has three major functions:

Serve as a conduit for motor information,

which travels down the spinal cord.

Serve as a conduit for sensory information,

which travels up the spinal cord.

Serve as a center for coordinating certainreflexes



PNS: CR ANI A L NERVES



No Name Gen. Function Specific Function

I Olfactory S Smell

II Optic S Vision

III Occulomotor M,P Eye movement, pupil constriction,

lens accommodation

IV Trochlear M Eye movement

V Trigeminal S,M Sensory to face and teeth ;

mastication

VI Abducent M Eye movement

VII Facial S,M,P Taste; facial expression; and

salivary & tear glands

VIII Vestibulocochlear S Hearing and balance

IX Glossopharyngeal S,M,P Taste and touch(back of tongue);

swallowing; salivary glands

X Vagus S,M,P Pharynx, larynx and viscera

XI Accessory M Two neck and upper back muscle

XII Hypoglossal M Tongue muscles



PNS: SPINA L NERVES



PNS: SPINA L NERVES

Dorsal roots: sensory

y Transmits sensory impulses from specific areas of body

called ´dermatomesµ to the dorsal horn ganglia.

y Somatic: from tendons, joints and body surfaces

y Visceral: from the internal organs

Ventral: motor

y Transmits impulses from the spinal cord to the body

y Somatic and visceral

Visceral: includes autonomic fibers that control cardiac

muscle and glandular secretions



A UTONOMIC NERVOUS S YSTEM

Regulates theactivities of internalorgans

Maintains andrestores the internalhomeostasis

Two main divisions:y Sympathetic

y Parasympathetic(fight-or-flight)



A UTONOMIC NERVOUS S YSTEMStructure/ Activity Parasympathetic

Effects

Sympathetic Effects

Pupil of Eye Constricts Dilate

Heart rate and force Decreases Increases

BP Decreases Increases

Bronchioles ConstrictsD

ilates

RR Decreased Increased

Peristaltic movement Increased Decreased

Neurologic Function

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