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SEKOLAH BERASRAMA PENUH INTEGRASI GOPENG
CHAPTER 3 :COORDINATION
&RESPONSE
Prepared by :-EN. MUHD FAZLI BIN DOLLAH
Biology Teacher
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LEARNING OUTCOMES
To state the role of nervous system,
To draw & label a diagram to show the organisation of the
nervous system,
To name the main parts of the brain & state their functions
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Body activities are controlled & coordinated bythe nervous system & the endocrine system.
Nervous system sending out nerve impulses.
Endocrine system secreting hormones
Nervous system only found in animals.
Hormones can be found in both animals &plants.
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The Role of the Nervous Systema) Important in detecting changes in the
external as well as internal environment.
b) Sends nerve impulses to effectors so as torespond appropriately to the changes.
c) Coordinates various functions & activitieswhich occur inside the body.
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Organisation of the nervous systemmade up of the Central Nervous System (CNS) & the
Peripheral Nervous System (PNS)
NERVOUS
SYSTEM
CENTRAL
NERVOUS
SYSTEM (CNS)
PERIPHERAL
NERVOUS
SYSTEM (PNS)
Brain Spinal Cord Cranial Nerves Spinal Nerves
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CENTRAL NERVOUSSYSTEM
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Human Brain
The expanded anterior end of the spinal cord.Weight = 1.5 kg & controls all parts of the body(directly @ indirectly).
Surrounded by protective membranes called themeninges. Cerebrospinal fluid (CSF) is foundbetween these layer. supply the neurones inthe brain with O2 & nutrients & removes wasteproduct.
Grey matter forms the outer part of the humanbrain, interior of the brain is made up ofwhitematter.
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BRAIN Grey matter contains
the cell bodies ofneurones
White matter containsthe myelinated axons of
the neurones.
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Cerebrum
The biggest part of the brain. Made up of 2 cerebralhemispheres.
The centre for thinking, reasoning, speech & memory.It integrates impulses from various sensory organs &receptors.
Initiates & controls all voluntary actions (walking, writing,singing)
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CEREBELLUM
-Made up of grey matter(outside) & white matter(inside).
-Has 2 hemispheres.
-Coordinates movement &maintains body balance.
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Medulla
Oblongata
Controls & coordinates all involuntary actions.
Digestion, respiration, & heart beat.
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PARTS NOTES
Pituitarygland
At the base of the cerebrum.
Secreting various hormones to control body functions suchas growth, osmoregulation & reproduction
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HYPOTHALAMUS
Above the pituitary
gland.
Contains severalimportant centres thatcontrol bodytemperature,osmoregulation,
sexual function, thirst,hunger, emotionalactivity & sleep
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THALAMUS Made up of 2 masses of
grey matter.
Lies deep in the cerebralhemispheres.
Contain stations forimpulses that enter thebrain
Gives us the awarenessof impulses as sensationssuch as pain, touch &temperature.
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LEARNING OUTCOMES
To draw & label a diagram of a cross section of
the spinal cord,
To state the main functions of the spinal cord,
To label the structure of an efferent neurone,
To identify the type of the neurone fromdiagrams given,
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SPINAL CORD A dorsal cylinder of neurones
extending from the raindownwards to the level of the2nd lumbar vertebra.
Protected & enclosed bymembranes called meninges &by the vertebral column.
To relay messages to & from thebrain & in some instances,processes, that is, integrates,
sensory information directly
reflex action (knee jerkresponse)
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The central area (grey matter)
made up of motor neurone cell
bodies, synapes & unmyelinated interneurones.
Lighter area (white matter) largely composed of myelinated
neurones
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Each side of thespinal cord are 31pairs of projections =roots.
Each pair consists ofa dorsal root & aventral root.
The roots unite toform a spinal nerve.
The dorsal root has aganglion (a cluster ofcell bodies ofneurones)
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Two main functions of spinal cord :
Connects the peripheral nervous systemto the brain. (sensory organ SC brain SC effectors)
Acts as a minor integrating centre inproducing simple reflex responses such asthe withdrawal of the hand from the hotobject.
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NEURONE
A nerve cell
Dendrites & dendrons function inreceiving nerve impulses &transmitting them to the cellbody.
The axon transmits impulsesfrom the cell body to the terminal
dendrites.
The end of each terminal dendriteis a knob known as the synaptic
knob transmitting impulses to
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The myelin sheath is a fatty
material which surrounds the
axon except at the nodes of
Ranvier speeding up the
transmission of impulses.
(impulses hop from one node of
Ranvier to the next).
3 types of neurones sensory
neurone (afferent neurone),
interneurone (relay neurone) &
motor neurone (efferent
neurone).
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TYPES FUNCTION
SENSORY
NEURONE
(AFFERENT
NEURONE)
Receives impulses from the
sensory organs / receptors &
transmits them to the centralnervous system to be
interrupted.
INTERNEUR
ONE(RELAY
NEURONE)
Transmits impulses from the
central nervous system to the
effector organs to elicit
responses.
MOTORNEURONE
(EFFERENT
NEURONE)
Join the sensory organs with the
motor neurones.
Th d f t i i f
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The mode of transmission ofinformation along the neurone
Information is transmitted along aneurone (electric charges)
A neurone is at rest pump out Na+,pump in K+ by active transport (sodium-potassium pump)
When the neurone is stimulated thesodium-potassium pump breaks down &the ions move in the opposite direction.
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The pathway of transmission ofinformation from receptor to effectors
Stimuli are received byreceptorssend out
information in the form of
nerve impulses
Transmitted along the sensoryneurone to the CNS
integrates & interprets the
information send out
impulses to the effectors viamotor neuroneeffector
response is elicited.
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Transmission of informationacross a synapse
Synapse = a location where a neurone transfersits impulse to another neurone.
2 neighbouring neurones are not directly
connected together but are separated by a verynarrow gap = synaptic cleft
Each terminal dendrite of a pre-synaptic neurone
ends in a synaptic knob.
The synaptic knob is separated from a dendriteof the post-synaptic knob by a synapse @synaptic cleft.
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Transmission of information/nerve impulse along aneurone occurs in the form ofelectric signals, thetransmission of information/ nerve impulse across
a synapse occurs by chemical means.
Within each synaptic knob can be found numeroussynaptic vesicles contain chemicals known asneurotransmitter (acetylcholine & noradrenaline).
When an impulse arrives at the terminal dendrite,synaptic vesicles in the synaptic knobs will releaseneurotransmitter into the synaptic cleft.
The neurotransmitter diffuses across the synapticcleft & finally arrives at the dendrite of the post-synaptic neurone & excites it to produce an
impulse.
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Th l f th
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The role of the synapse
Enable a neurone to have connection with
many othe neurones makes us moresensitive to stimuli, enable to producemultiple responses.
Ensure that impulses flow in one directiononly, from a terminal dendrite of one
neurone to the dendrite of the next neuronebecause neurotransmitters are only producedby terminal dendrites.
VOLUNTARY ACTION & INVOLUNTARY ACTION
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VOLUNTARY ACTION & INVOLUNTARY ACTION
Voluntary action= an action which under onesconscious control. (writing, walking, eating,
raising)
Initiated by the cerebrum. Cerebrum Impulseseffector organ (hand) response
Involuntary action = an action which cannot becontrolled by our conscious mind. Not involvethe cerebrum but rather the medulla oblongata
or the spinal cord.
May involve skeletal muscles or smooth muscle.(knee-jerkresponse)
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Examples of involuntary action : theregulation of blood pressure, the beating of
heart, secretion of a gland (sweating duringhot)
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Reflex Action & Reflex Arc Reflex action = rapid response which is obtained
automatically without conscious thought.
Examples : Rapid & automatic withdrawal of hand when it
accidentally touches a hot object Automatic closing of the eyes when an insect flys towards
the eyes
The knee-jerk reflex
Reflex arc = the pathway of a transmission of nerveimpulse which produces a reflex action
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A reflex action which involves the brain =cranial reflex
A reflex action which involves the spinalcord = spinal reflex
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DISEASES RELATED TO THE NERVOUS SYSTEMPARKINSONS DISEASE (PARKINSONISM) Caused by progressive
degeneration of the basalganglia of the brain.
The brain releases less of a
neurotransmitter calleddopamine. Leads to tremors ofthe hands & legs & rigidity ofparts of the body.
Appears wide-eyed withuncontrolled drooling.
Vision, hearing & intelligence
are not affected.
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EPILEPSY The most common disorders of the brain.
Short, recurrent attacks (epilepticseizures) initiated by the discharge ofelectricity from millions of nuerones in the
brain sensory organs & effector organsmay be stimulated.
The person may see, hear or smellsomething which is actually non-existent.
Skeletal muscle may contract involuntary,lose urinary & bowel control.
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MULTIPLES SCLEROSIS
Caused by progressive destruction & scarring ofthe myelin sheath of neurones in the centralnervous system.
Affects young & middle-aged adults.
Unsteady gait, shaky limbs, rapid involuntarymovements of eyes & speech difficulties.
Suspected to be due to an abnormal response toa viral infection.
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poliomyelitis Caused by an infection of nerves by thepoliovirus paralysis.
Usually occurs during childhood.
The GM of the SC is destroyed.
Infection of the brain may cause death.
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Alzheimers disease A disorder of elderly folks.
Caused by degeneration of neurones inthe brain
Intellectual impairment, memory loss,confusion, irritability & loss of orientationin time & space.
No treatment.
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