Survey of Anatomy and Physiology Chap 9 Part One

The Nervous System: The Body's Control Center

9

Part OnePart One

Nervous system is

complex and important to body's control system

Nervous system monitors conditions and takes corrective action when necessary, to keep everything running smoothly

IntroductionIntroduction

Brain and spinal

cord are the central nervous

system (CNS) which controls

the total nervous system

Central Nervous Central Nervous

Everything outside brain

and spinal cord is part of

peripheral nervous

system (PNS)

Peripheral NervousPeripheral Nervous

Figure 9-1Organization of the nervous

system.

Peripheral (PNS) further branched

into somaticsomatic which controls

voluntary (skeletal)

muscles and autonomicautonomic which

control involuntary

muscles

CNS & PNSCNS & PNS

motorSensory-in box

IntroductionIntroduction

Autonomic nervous

system controls smooth muscle

and cardiac muscle, along with

several glands

Autonomic NervousAutonomic Nervous

Autonomic system is

divided into TWO PARTS parasympathetic

system that deals with normal body functioning normal body functioning

and maintenance of homeostasis homeostasis and…

Autonomic Nervous-Autonomic Nervous-Two PartsTwo Parts

Spinal cord is

hollow tube running inside

vertebral column from foramen from foramen

magnum to the magnum to the second lumbar second lumbar (L2) vertebrae

Spinal CordSpinal Cord

Spinal cord is

like a sophisticated

neural neural information information

superhighway

Spinal CordSpinal Cord

31 Pairs of Spinal 31 Pairs of Spinal

NervesNerves

NOTE: There are EIGHT EIGHT cervical spinal

nerves, even though there

are only SEVENSEVEN

vertebrae

Meninges are protective coveringprotective covering of both brain

and spinal cord Meninges help to set up layers that act as

cushioning and shock absorberscushioning and shock absorbers

MeningesMeninges

Three Layers of Three Layers of MeningesMeninges

Protect the CNS from injury

Protect the CNS from injury

There are three distinct layers of meninges:

Outer layer is thick, fibrous tissue called dura dura matermater

Middle layer is wispy, delicate layer resembling spider web called arachnoid materarachnoid mater, acting as shock absorber, and transporting dissolved gases and nutrients as well as chemical messengers and waste products

Third, innermost layer, fused to neural tissue, is pia materpia mater, containing blood vessels that serve brain and spinal cord

Three Layers of Three Layers of MeningesMeninges

Series of spaces associated with meninges

Between dura and vertebral column is space filled with fat and blood vessels called epidural space

Spaces Between Spaces Between MeningesMeninges

The anesthetic agents that are infused

through the small catheter block spinal nerve block spinal nerve roots roots in the epidural space and the sympathetic nerve fibers sympathetic nerve fibers adjacent to them


Used for: pain associated with chest, abdominal, and lower

extremity surgery.

Used for: pain associated with chest, abdominal, and lower

extremity surgery.

Series of spaces associated with meninges

Between dura mater and arachnoid mater is subdural space subdural space filled with tiny bit of fluid


Tiny veins between the surface of the brain and its outer covering (the

dura) stretch and tear, allowing blood to collect

Tiny veins between the surface of the brain and its outer covering (the

dura) stretch and tear, allowing blood to collect

Figure 9-8The meninges of the brain and

spinal cord.

• Dura Mater• Arachnoid mater• Pia Mater

• Dura Mater• Arachnoid mater• Pia Mater

Nerves are part of peripheral peripheral

nervous systemnervous system All nerves consist of bundles

of axon, blood vessels, and axon, blood vessels, and connective connective tissue

Spinal NervesSpinal Nerves

Nerves are connection between CNS and outside world

Nerves are connection between CNS and outside world

Nerves connected

to spinal cord are called spinal nerves, each named for spinal named for spinal cord segmentcord segment to which they are attached


Nerves run run between CNS between CNS and organs or and organs or

tissuestissues, carrying information into and out of CNS


Simplest form of motor output motor output you can make Generally protective, keeping you from harm

ReflexesReflexes

Involuntary and usually response gets bigger gets bigger

as stimulus gets bigger

ReflexesReflexes

Amazing thing about

reflexes is that they can often occur without brain being without brain being involvedinvolved, involving only spinal cord

ReflexesReflexes

ReflexesReflexes

*See page 221 for details

Brain acts as main processor and director of

nervous system

The Brain and Cranial The Brain and Cranial NervesNerves

These nerves go

to specific body areas, where

they receive info and send it

back to brain (sensory); brain

sends back instructions to move (motor)

12 Cranial Nerves12 Cranial Nerves

Table 9-5 Cranial Nerves and Functions

Oh, Oh, Oh, To Touch And Feel Vintage

Green Velvet, Simply Heaven

12 Cranial Nerves-A 12 Cranial Nerves-A MnemonicMnemonic

OlfactoryOpticOculomotorTrochlearTrigeminalAbducensFacialVestibulocochlearGlossopharyngealVagusSpinal AccessoryHypoglossal

Brain can be

divided into several

anatomical and functional

sections

The BrainThe Brain

Cerebrum is largest

part of brain Divided into right and

left hemispheres by longitudinal fissure longitudinal fissure Surface is not smooth, but broken by ridges ridges (gyri) and grooves (gyri) and grooves (sulci) (sulci) collectively known as convolutions

The BrainThe Brain

Convolutions

serve very important purpose by increasing increasing surface area surface area of brain, so you can pack more brain in smaller space

The BrainThe Brain

Lobes named for named for skull bones skull bones that cover them and occur in pairs, one in each hemisphere

The BrainThe Brain

Lobes of the BrainLobes of the Brain

Much of information

coming into brain is contralateral,contralateral, meaning the right side of body is controlled by left side of cerebral cortex and left side of body is controlled by right side of cerebral cortex

The Brain Info is The Brain Info is ContralateralContralateral

Figure 9-12External brain anatomy and

lobes.

Cerebellum is

posterior to cerebrum Involved in sensory

collection, motor coordination, and balance

CerebellumCerebellum

Brain stem is stalklike structure stalklike structure inferior to, and

partially covered by, cerebrum Divided into three sections

BrainstemBrainstem

Medulla oblongata: continuous with spinal

cord, responsible for impulses that control heartbeat, respirations, and blood vessel diameter

Brainstem-3 SectionsBrainstem-3 Sections

Pons: just superior to medulla oblongata

and the cerebellum with the upper portions of the brain


Midbrain: most superior portion of the

brain stem, controls visual and auditory systems and controls body movement


Brain stem receives sensory information and

contains control systems for vital processes such as blood pressure, heart rate, and breathing


Figure 9-14A. Embolus traveling to the brain and B. cross-section of

brain showing cerebrovascular accident (CVA).

Read pages 226 to 227Extra credit question on

test will cover “Brain Injury”

Read pages 226 to 227Extra credit question on

test will cover “Brain Injury”

Corpus callosum

Connection allows for cross-communication between right and left sides of brain

Many day-to-day activities, like walking or driving, require both sides of body, and therefore both sides of brain, to be well coordinated

Corpus CallosumCorpus Callosum

Take a BreakTake a Break

FIVE MINUTE BREAK

Peripheral Nervous Peripheral Nervous SystemSystem

Peripheral Nervous System divided into TWO systems, SOMATIC which controls voluntary muscles and the AUTONOMIC nervous system which controls involuntary muscles is divided into:

Sympathetic branch which controls the “fight or flight” reaction; to expend energy.

Parasympathetic branch which is responsible for maintenance of everyday activities and brings you back down to normal from a sympathetic response.

CNS & PNSCNS & PNS

motorsensory

Peripheral NervousPeripheral Nervous

Peripheral Nervous SystemPeripheral Nervous System

Figure 9-21Nervous system flowchart

Somatic nervous

system provides sensory input for the nervous system to feel the world around you and after interpretation by the brain is sent with motor output to the voluntary skeletal muscles

Somatic Nervous Somatic Nervous SystemSystem

Autonomic system

controls involuntary physiological processes of smooth and cardiac muscles such as blood blood pressure, heart ratepressure, heart rate, respiratory rate, digestiondigestion, and sweatingsweating

Autonomic Nervous Autonomic Nervous SystemSystem

PNS: Compare Somatic PNS: Compare Somatic VS. AutonomicVS. Autonomic

Somatic AutonomicConscious or voluntary regulation

Functions without conscious awareness (involuntary)

Fibers do not synapse after they leave the CNS (single neuron from CNS to effector organ) ONE NERVE FIBER

Fibers synapse again at a ganglion after they leave the CNS (TWO NERVE FIBERS).

Innervates skeletal muscle fibers, always excitatory

Innervates smooth muscle, cardiac and glands; either excitatory or inhibitory

Secretes neurotransmitter (acetylcholine) Ach

Secretes Ach (acetylcholine) and (norepinephrine) Ne


Information from external environment

interpreted by brain stimulates

skeletal muscles

Information from external environment

interpreted by brain stimulates

skeletal muscles

Information from internal

environment interpreted by

brain stimulates cardiac or

smooth muscles

Information from internal

environment interpreted by

brain stimulates cardiac or

smooth muscles


Make synapse in ganglion outside CNS called pre-synaptic junction, then second motor neuron, called postganglionic

neuron, connects to smooth muscle or gland


Unlike somatic motor neurons, autonomic neurons do not connect directly to muscles

Autonomic Nervous Autonomic Nervous SystemSystem

Autonomic nervous

system controls smooth muscle

and cardiac muscle, along with

several glands

Autonomic NervousAutonomic Nervous

Autonomic system is

divided into TWO PARTS parasympathetic

system that deals with normal body functioning normal body functioning

and maintenance of homeostasis homeostasis and…


While sympathetic

nervous system controls controls ““fight-or-fight-or-flightflight”” response

system


Actions of Sympathetic Actions of Sympathetic & Parasympathetic& Parasympathetic

Sympathetic Parasympathetic

Increases alertness, heart rate and dilates bronchial tubes to increase air flow to lungs

Constricts bronchial tubes to decrease air flow to lungs; stimulates secretion of salivary mucus

Stimulates sweat glands; causes “fight or flight” responseStimulates adrenal medulla(adrenals are above kidneys) to secrete epinephrineA.K.A “ADRENALIN”

Has a calming effect and causes the “resting and digesting” state; stimulates intestinal motility and secretion to promote digestion; has NO effect on sweat glands;

Inhibits intestinal motility; dilates blood vessels of skeletal muscles to increase blood flow

Stimulates the bladder wall to contract and the internal sphincter to relax to cause urination

Fight or Flight Fight or Flight

The term "fight or flight" describes a mechanism in the body that enables humans and animals to mobilize a lot of energy rapidly in order to cope with threats to survival.

Fight or Flight MovieFight or Flight Movie

http://cmhc.utexas.edu/stressrecess/Level_One/fof.html

Effect of Stress on Effect of Stress on Your BodyYour Body

http://www.youtube.com/watch?v=jVTw4dypBN8

Figure 9-24A comparison of the parasympathetic and

sympathetic nervous systems.

Review Page 242 in your

text

Review Page 242 in your

text

In Class WORKSHEETIn Class WORKSHEET

Worksheet in class includes Comparing Somatic and

Autonomic Nervous System and identifying two divisions of

Autonomic Nervous System, Sympathetic and ParasympatheticText page 240-242 and charts on slide 55 and 63

For Next ClassFor Next Class

• Review Power Point Presentation Part Two• Watch Videos linked from Canvas “How Neurons

Work” and “How Synapses Work” • Read pages 208 to 212• Take notes on these and bring to class• You will have an IN CLASS worksheet to

complete on “Neuron Structure and Function”• You will be able to use ONLY your notes, no

textbook

Health & Medicine

Survey of Anatomy and Physiology Chap 9 Part One