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Chapter 33-2

Organization of the Nervous

SystemBiology 30 -NWRC

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The CNSand the PNS

The CNS consists

of the brain and

spinal cord. It is

mainlyinterneurons it

coordinates the

bodies activities

The PNS consistsof sensory and

motor neurons

which carry info to

and from the CNS.

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The CNS and the PNS

.

Central Nervous System

PeripheralNervous System

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Left & Right sidesare separate

Corpus Callosum :

major pathway

between

hemispheres

Some functions are

lateralized language on left

math, music on right

Lateralization is

never 100%

Brain has2 Hemispheres

Left

Hemisphere

Corpus CallosumRight

Hemisphere

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The Cerebrum

The Cerebrum: The

cerebrum or cortex is

the largest part of the

human brain,associated with

higher brain function

such as thought and

action. The cerebralcortex is divided into

four sections

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Eachhemisphere is

divided into 4 lobesFrontal

Parietal

Occipital

Temporal

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The Cerebrum

FrontalLobe- associatedwith reasoning, planning,parts of speech,movement, emotions, andproblem solving

Parietal Lobe- associatedwith movement,orientation, recognition,perception of stimuli

Occipital Lobe- associated

with visual processing Temporal Lobe- associated

with perception andrecognition of auditorystimuli, memory, and

speech

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Corpus Callosum

Major ( but not only)

pathway between sides

Connects comparable

structures on each side Permits data received

on one side to be

processed in both

hemispheres

Aids motor coordination

of left and right side

Corpus Callosum

Medial surface of right hemisphere

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The Brain Stem

The brainstem is

located at the

juncture of the

cerebrum andthe spinal

column. It

consists of the

midbrain,medulla

oblongata, and

the pons.

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The Brain Stem- medulla oblongata

Controls

Autonomic

Functions

Relays NerveSignals

Between the

Brain and

Spinal Cord

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The Brain Stem- pons

The pons

functions to relay

signals from

the cortex to

assist in thecontrol of

movement,

breathing and is

also involved withthe control of

sleep and

arousal.

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The Brain Stem- hypothalamus

The

hypothalamus

connects with

many other

regions of thebrain and is

responsible for

controlling

hunger, thirst,emotions, body

temperature

regulation, and

circadian

rhythms.

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Peripheral Nervous System

Skeletal

(Somatic)

Sympathetic Parasympathetic

Autonomic

Peripheral Nervous System

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The Somatic Nervous System

PNS

SomaticAutonomic

The somatic nervous

system controls skeletal

muscle as well as external

sensory organs such as

the skin. This system is

said to be voluntary

because the responses can

be controlled consciously.

Reflex reactions of skeletalmuscle however are an

exception. These are

involuntary reactions to

external stimuli.

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The Autonomic Nervous System

PNS

Somatic Autonomic

The autonomic nervous

system controls

involuntary muscles, such

as smooth and cardiac

muscle. This system is

also called the involuntary

nervous system. The

autonomic nervous system

can further be divided intothe parasympathetic and

sympathetic divisions.

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The Autonomic Nervous System

PNS

Somatic

Autonomic

s

ymp

athe

tic

para

sym

path

etic

The Sympathetic Nervous System

Nerves of the sympathetic

division speed up heart rate,dilate pupils, and relax the

bladder. The sympathetic

system is also involved in the

flight or fight response. This is a

response to potential danger

that results in accelerated heart

rate and an increase in

metabolic rate.

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The Autonomic Nervous System

PNS

Somatic

Autonomic

s

ymp

athe

tic

para

sym

path

etic

The Parasympathetic Nervous System

The parasympathetic

division controls

various functions which

include inhibiting heart

rate, constricting pupils,

and contracting thebladder.

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Assessment Questions

1. The CNS is made up of

the brain and spinal cord.

The brain has 100 billion

neurons the spinal cord

is a column of nervesextending from the brain

to the lower back The

PNS is made of bundles

of neurons that branchout to all parts of the body

to send information to

and from the CNS

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Assessment Questions

2. Both systems are part

of the PNS The somatic

communicates sensory

info to the brain and

instruction from the brainto the skeletal muscles.

The autonomic nervous

system carries the

impulse for the brain tothe internal organs and

glands

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Assessment Questions

3. This would involve the

autonomic nervous

system specifically the

sympathetic system.

The end