2. It includes Central NervousIt includes Central Nervous
System and the PeripheralSystem and the Peripheral
Nervous System.Nervous System.
It acts as a highway forIt acts as a highway for
information to travel. It controlsinformation to travel. It controls
movement in the body and alsomovement in the body and also
converts information for the brainconverts information for the brain
to read and process.to read and process.
What is the Nervous SystemWhat is the Nervous System
3. Two Anatomical DivisionsTwo Anatomical Divisions
Central nervous system (CNS)Central nervous system (CNS)
BrainBrain
Spinal cordSpinal cord
Peripheral nervous system (PNS)Peripheral nervous system (PNS)
All the neural tissue outside CNSAll the neural tissue outside CNS
AfferentAfferent division (sensory input)division (sensory input)
EfferentEfferent division (motor output)division (motor output)
Somatic nervous systemSomatic nervous system
Autonomic nervous systemAutonomic nervous system
General Organization of the nervous system
5. The Nervous system has three major functions:
Sensory – monitors internal & external
environment through presence of receptors
Integration – interpretation of sensory information
(information processing); complex (higher order)
functions
Motor – response to information processed
through stimulation of effectors
muscle contraction
glandular secretion
6. Functions of the NervousFunctions of the Nervous
SystemSystem
1.1. Control center for all body activitiesControl center for all body activities
2.2. Responds and adapts to changes thatResponds and adapts to changes that
occur both inside and outside the bodyoccur both inside and outside the body
(Ex: pain, temperature, pregnancy)(Ex: pain, temperature, pregnancy)
9. Central Nervous System (CNS)Central Nervous System (CNS)
Contains the nerves ofContains the nerves of
thethe brainbrain andand spinalspinal
cordcord
Function =Function = coordinatingcoordinating
center ofcenter of
incoming/outgoingincoming/outgoing
informationinformation
10. Brain is found in theBrain is found in the skullskull & serves as& serves as overall controloverall control
centercenter for the nervous systemfor the nervous system
Spinal Cord is surrounded bySpinal Cord is surrounded by vertebraevertebrae and extendsand extends
down the back of the neck, thorax and abdomendown the back of the neck, thorax and abdomen
Center ofCenter of many reflex actionsmany reflex actions
Provides a linkProvides a link between sensory and motor nervesbetween sensory and motor nerves
Both are enclosed in 3 protective membranes calledBoth are enclosed in 3 protective membranes called
thethe meningemeninge
Space between meninge containsSpace between meninge contains cerebrospinalcerebrospinal
fluidfluid which protects and cushions the CNSwhich protects and cushions the CNS
13. Central Nervous SystemCentral Nervous System
BrainBrain : a mass of 100: a mass of 100
billion neuronsbillion neurons
located inside thelocated inside the
skullskull
-Learning occurs as-Learning occurs as
more and strongermore and stronger
connections areconnections are
made betweenmade between
neuronsneurons
14. BrainBrain
It is one of the largest organs in the body,It is one of the largest organs in the body,
and coordinates most body activities.and coordinates most body activities.
It is the center for all thought, memory,It is the center for all thought, memory,
judgment, and emotion.judgment, and emotion.
Each part of the brain is responsible forEach part of the brain is responsible for
controlling different body functions, suchcontrolling different body functions, such
as temperature regulation and breathing.as temperature regulation and breathing.
15. Anatomy of the BrainAnatomy of the Brain
CerebrumCerebrum : largest part: largest part
of human brainof human brain
- Responsible for:- Responsible for:
- Thought- Thought
- Language- Language
- Senses- Senses
- Memory- Memory
- Voluntary- Voluntary
movementmovement
16. CerebrumCerebrum
It is the largest section of the brainIt is the largest section of the brain
It is located in the upper portion of the brain andIt is located in the upper portion of the brain and
is the area that processes thoughts, judgment,is the area that processes thoughts, judgment,
memory, problem solving, and language.memory, problem solving, and language.
The outer layer of the cerebrum is the cerebralThe outer layer of the cerebrum is the cerebral
cortex, which is composed of folds of graycortex, which is composed of folds of gray
matter.matter.
The cerebrum is subdivided into the left and rightThe cerebrum is subdivided into the left and right
halves called cerebral hemispheres. Eachhalves called cerebral hemispheres. Each
hemisphere has 4 lobes.hemisphere has 4 lobes.
17. Anatomy of the BrainAnatomy of the Brain
CerebellumCerebellum : at base: at base
of brainof brain
-Responsible for:-Responsible for:
- Muscle- Muscle
coordinationcoordination
- Balance- Balance
- Posture- Posture
18. The CerebellumThe Cerebellum
Second largest portion of the brainSecond largest portion of the brain
Located beneath the posterior part of theLocated beneath the posterior part of the
cerebrumcerebrum
Aids in coordinating voluntary bodyAids in coordinating voluntary body
movements and maintaining balance andmovements and maintaining balance and
equilibriumequilibrium
Refines the muscular movement that isRefines the muscular movement that is
initiated in the cerebruminitiated in the cerebrum
19. Central Nervous SystemCentral Nervous System
Brain (Cont.)Brain (Cont.)
CerebellumCerebellum
The Cerebellum is behind the brain stem. It is similar toThe Cerebellum is behind the brain stem. It is similar to
the Cerebral Cortex because it is divided intothe Cerebral Cortex because it is divided into
hemisphereshemispheres
The Cerebellum controls movement, balance andThe Cerebellum controls movement, balance and
posture.posture.
20. Anatomy of the BrainAnatomy of the Brain
Brain StemBrain Stem : connects: connects
brain to spinal cordbrain to spinal cord
-Responsible for:-Responsible for:
- Breathing- Breathing
- Swallowing- Swallowing
- Heartbeat- Heartbeat
- Blood pressure- Blood pressure
21. Brain StemBrain Stem
Midbrain—Midbrain—acts as a pathway for impulses toacts as a pathway for impulses to
be conducted between the brain and the spinalbe conducted between the brain and the spinal
cord.cord.
PonsPons means bridge—connects the cerebellummeans bridge—connects the cerebellum
to the rest of the brain.to the rest of the brain.
Medulla oblongata—Medulla oblongata— most inferior positionedmost inferior positioned
portion of the brain; it connects the brain to theportion of the brain; it connects the brain to the
spinal cord.spinal cord.
22. Central Nervous SystemCentral Nervous System
Brain (Cont.)Brain (Cont.)
Brain StemBrain Stem
The brain stem is a name for the area of the brainThe brain stem is a name for the area of the brain
between the thalamus and spinal cord. The brain stembetween the thalamus and spinal cord. The brain stem
includes the medulla, pons and midbrain.includes the medulla, pons and midbrain.
The Brain Stem controls most of the basic functions ofThe Brain Stem controls most of the basic functions of
life like breathing, heart rate and blood pressure.life like breathing, heart rate and blood pressure.
Midbrain
Pons
Medulla
25. Central Nervous SystemCentral Nervous System
Brain (Cont.)Brain (Cont.)
ThalamusThalamus
The Thalamus is divided into two sides.The Thalamus is divided into two sides.
The Hypothalamus is positioned inThe Hypothalamus is positioned in
between the two sides.between the two sides.
The Thalamus receives sensoryThe Thalamus receives sensory
information and movement information.information and movement information.
Thalamus
29. Central Nervous SystemCentral Nervous System
Brain (Cont.)Brain (Cont.)
HypothalamusHypothalamus
The hypothalamus is madeThe hypothalamus is made
of several areas of theof several areas of the
lower brain. It is only thelower brain. It is only the
size of a pea which is aboutsize of a pea which is about
1/300 of the entire brain.1/300 of the entire brain.
Hypothalamus
30. Central Nervous SystemCentral Nervous System
Brain (Cont.)Brain (Cont.)
HypothalamusHypothalamus
The Hypothalamus controls bodyThe Hypothalamus controls body
temperature, emotions, hunger, thirst,temperature, emotions, hunger, thirst,
circadian rhythms. Despite its size,circadian rhythms. Despite its size,
the Hypothalamus controls some verythe Hypothalamus controls some very
important functions. One of the mostimportant functions. One of the most
important is the body temperatureimportant is the body temperature
control. It acts as a thermostat so itcontrol. It acts as a thermostat so it
senses the body changes and will tellsenses the body changes and will tell
different parts of the body to adjust.different parts of the body to adjust. Hypothalamus
32. Central Nervous SystemCentral Nervous System
Spinal CordSpinal Cord : Column of nerves: Column of nerves
from brain to tailbone –from brain to tailbone –
protected by vertebrae ofprotected by vertebrae of
spinespine
- Responsible for:Responsible for:
- Conducting impulses- Conducting impulses
between the brain and thebetween the brain and the
rest of the bodyrest of the body
*Impulses may travel as fast at*Impulses may travel as fast at
268 miles/hr268 miles/hr
33. Central Nervous SystemCentral Nervous System
Spinal CordSpinal Cord
StructureStructure
There are 31 pairs of spinal nervesThere are 31 pairs of spinal nerves
which run through the spinal cord.which run through the spinal cord.
These nerves are called “mixed”These nerves are called “mixed”
nerves because each nerve containsnerves because each nerve contains
a sensory and a motor axon.a sensory and a motor axon.
Information entering from the left sideInformation entering from the left side
of the spinal cord will eventually goof the spinal cord will eventually go
over to the right side of the brain andover to the right side of the brain and
vice versa. The side switching canvice versa. The side switching can
happen as soon as entering thehappen as soon as entering the
spinal cord or until it reaches thespinal cord or until it reaches the
brain.brain.
Spinal Cord
Sensory Neuron
Motor Neuron
Receptor
Effector
34. Central Nervous SystemCentral Nervous System
Spinal Cord (Cont.)Spinal Cord (Cont.)
FunctionFunction
The spinal cord is used for two main functions:The spinal cord is used for two main functions:
It acts as a pathway for information to travel fromIt acts as a pathway for information to travel from
receptors (skin, eyes, mouth…) to the brain and from thereceptors (skin, eyes, mouth…) to the brain and from the
brain to effectors (muscle).brain to effectors (muscle).
The spinal cord can also be a minor coordinating centreThe spinal cord can also be a minor coordinating centre
for some simple reflexes like the withdrawal reflex.for some simple reflexes like the withdrawal reflex.
35. Spinal CordSpinal Cord
Protected by cerebrospinal fluid.Protected by cerebrospinal fluid.
Inner core of the spinal cord contains grayInner core of the spinal cord contains gray
matter.matter.
The outer portion of the spinal cord isThe outer portion of the spinal cord is
myelinated white matter.myelinated white matter.
36. Spinal CordSpinal Cord
Runs through the vertebral canalRuns through the vertebral canal
Extends from foramen magnum to 2Extends from foramen magnum to 2ndnd
lumbar vertebralumbar vertebra
RegionsRegions
CervicalCervical
ThoracicThoracic
LumbarLumbar
SacralSacral
CoccygealCoccygeal
Gives rise to 31 pairs of spinal nerves - all are mixed nervesGives rise to 31 pairs of spinal nerves - all are mixed nerves
41. MeningesMeninges
Dura mater:Dura mater: outermostoutermost
layer; continuous withlayer; continuous with
epineurium of the spinalepineurium of the spinal
nervesnerves
Arachnoid mater:Arachnoid mater: thinthin
and wispyand wispy
Pia mater:Pia mater: bound tightlybound tightly
to surfaceto surface
46. Peripheral Nervous SystemPeripheral Nervous System
Includes both the 12 pairs of cranial nerves and the 31Includes both the 12 pairs of cranial nerves and the 31
pairs of spinal nerves.pairs of spinal nerves.
A nerve is a group or bundle of axon fibers locatedA nerve is a group or bundle of axon fibers located
outside the central nervous system that carriesoutside the central nervous system that carries
messages between the CNS and the various parts ofmessages between the CNS and the various parts of
the body.the body.
Whether a nerve is cranial or spinal is determined byWhether a nerve is cranial or spinal is determined by
where the nerve originates.where the nerve originates.
Cranial nerves arise from the brain, mainly at theCranial nerves arise from the brain, mainly at the
medulla oblongata.medulla oblongata.
47. Autonomic Nervous SystemAutonomic Nervous System
Involved with the control of involuntary orInvolved with the control of involuntary or
unconscious bodily functions.unconscious bodily functions.
It is divided into two branches: sympatheticIt is divided into two branches: sympathetic
branchbranch and parasympathetic branch.and parasympathetic branch.
The sympathetic nerves stimulate the body inThe sympathetic nerves stimulate the body in
times of stress and crisis.times of stress and crisis.
The parasympathetic nerves serve as aThe parasympathetic nerves serve as a
counterbalance for the sympathetic nerves.counterbalance for the sympathetic nerves.
48. Somatic NervesSomatic Nerves
Serve the skin and skeletal muscles.Serve the skin and skeletal muscles.
These are also the nerves that carry motorThese are also the nerves that carry motor
commands to skeletal muscles.commands to skeletal muscles.
Large variety of sensory receptors foundLarge variety of sensory receptors found
in the dermis layer of the skin use somaticin the dermis layer of the skin use somatic
nerves to send their information, such asnerves to send their information, such as
touch, temperature, pressure, and pain, totouch, temperature, pressure, and pain, to
the brain.the brain.
49. Peripheral Nervous System (PNS)Peripheral Nervous System (PNS)
All parts of the nervous systemAll parts of the nervous system lying outsidelying outside
the brain and spinal cordthe brain and spinal cord..
The sensory and motor neurons that connect toThe sensory and motor neurons that connect to
the CNSthe CNS
Function =Function = to carry info between organs of the bodyto carry info between organs of the body
and the CNSand the CNS
Humans haveHumans have
12 paris of cranial nerves (sensory/motor/mixed)12 paris of cranial nerves (sensory/motor/mixed)
which control the head, face, neck, shoulderswhich control the head, face, neck, shoulders
ExceptExcept VAGUS nerve – controls internal organsVAGUS nerve – controls internal organs
31 pairs of spinal nerves (mixed) which take31 pairs of spinal nerves (mixed) which take
impulses to and from the spinal cordimpulses to and from the spinal cord
50. PNSPNS
Somatic & Autonomic NervesSomatic & Autonomic Nerves
Somatic nervesSomatic nerves control skeletal muscle, bones,control skeletal muscle, bones,
skin that a person can controlskin that a person can control
Sensory neuronsSensory neurons which relay info aboutwhich relay info about
environment to CNSenvironment to CNS
Motor neuronsMotor neurons which initiate appropriate responsewhich initiate appropriate response
Autonomic nervesAutonomic nerves control the muscles of thecontrol the muscles of the
glands and internal organs which we can’tglands and internal organs which we can’t
controlcontrol
SympatheticSympathetic && parasympatheticparasympathetic componentscomponents
Reflex Arc
51. SympatheticSympathetic component prepares body for stresscomponent prepares body for stress
[neurotransmitter used=[neurotransmitter used=norepinephrine]norepinephrine]
Diverts blood from internal organs toDiverts blood from internal organs to skeletalskeletal
muscles, heart & brainmuscles, heart & brain
ParasympatheticParasympathetic brings things back to normalbrings things back to normal
[neurotransmitter used=[neurotransmitter used=acetylcholineacetylcholine]]
Work in conjunction/opposition to each otherWork in conjunction/opposition to each other
Ex. “on” / “off” switchesEx. “on” / “off” switches
“FLIGHT OR FIGHT RESPONSE”
52.
53.
54. Peripheral Nervous SystemPeripheral Nervous System
Sensory NeuronsSensory Neurons
Sensory Neurons are neurons which onlySensory Neurons are neurons which only
allow information to travel one way. They canallow information to travel one way. They can
transmit information from Receptors (skin,transmit information from Receptors (skin,
eyes, ears) to the brain and to motor neurons.eyes, ears) to the brain and to motor neurons.
55. Peripheral Nervous SystemPeripheral Nervous System
Motor NeuronsMotor Neurons
Motor Neurons are neurons which only allowMotor Neurons are neurons which only allow
information to travel one way. The transmitinformation to travel one way. The transmit
information from the brain and the spinal cordinformation from the brain and the spinal cord
to the Effectors (Muscles and Glands)to the Effectors (Muscles and Glands)
56. Peripheral Nervous SystemPeripheral Nervous System
Example of a Reflex ArcExample of a Reflex Arc
A reflex arc is the pathway that a nerve reflex, such as theA reflex arc is the pathway that a nerve reflex, such as the
knee jerk reflex, follows.knee jerk reflex, follows.
1.1. A tap on the knee stimulates sensory receptors (tendon),A tap on the knee stimulates sensory receptors (tendon),
generating a nerve signal.generating a nerve signal.
2.2. The signal travels along a nerve to the spinal cord.The signal travels along a nerve to the spinal cord.
3.3. In the spinal cord, the signal is transmitted from the sensoryIn the spinal cord, the signal is transmitted from the sensory
nerve to a motor nerve.nerve to a motor nerve.
4.4. The motor nerve sends the signal back to effectors (muscle)The motor nerve sends the signal back to effectors (muscle)
in the thigh.in the thigh.
5.5. The muscle contracts, causing the lower leg to jerk upward.The muscle contracts, causing the lower leg to jerk upward.
The entire reflex occurs without involving the brain.The entire reflex occurs without involving the brain.
57. Peripheral Nervous SystemPeripheral Nervous System
NervesNerves : visible: visible
bundles of axons andbundles of axons and
dendrites that entenddendrites that entend
from the brain andfrom the brain and
spinal cord to all otherspinal cord to all other
parts of the bodyparts of the body
58. -Responsibilities:-Responsibilities:
-- Sensory nervesSensory nerves --
carry messagescarry messages
from body to brainfrom body to brain
(pain, pressure,(pain, pressure,
temperature)temperature)
-- Motor nervesMotor nerves ––
carry messagescarry messages
from brain to body tofrom brain to body to
respondrespond