Science Chapter 2 Form 4

7/30/2019 Science Chapter 2 Form 4

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Chapter 2BODY COORDINATION.

2.1 Body Coordination.

the adjustment of our bodys reaction towards any stimulus around us andfrom the inside of our body.

ensures that each part of the body is controlled so that it functions

harmoniously with each other when it receives a stimulus.

there are two types of body coordination :

a) nervous coordinationb) hormonal coordination

Body Coordination.

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Body Coordination

NervousCoordinationcontrolled and

coordinated by thenervous system

HormonalCoordinationcontrolled and

coordinated by theendocrine system

Examplewalking, looking,running, writing,

talking, listening, andreading

Examplebody growth,reproduction,

controlling bloodconcentration, and food

digestion

Importance of body coordination

enables our body organs to function as a unit to detect stimuli and

respond toward them.

controls coordination between stimuli and body responses.

helping us to avoid injuries or dangers.

enables us to adapt to the changes around us.


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2.2 Human Nervous System.

is divided into :

o central nervous system

o peripheral nervous system

the massages carried by the nervous system are electrical signals called

impulses.

chart showing the classification of human nervous system in brief

HumanNervousSystem

CentralNervousSystem

PeripheralNervousSystem

Brain Spinal CordSomaticnervoussystem

Autonomicnervoussystem

CranialNerves

Spinal

Nerves

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Central Nervous System.

the central nervous system is the control centre of the body.

this system consists of :

o brain

o spinal cord

the brain controls all activities of the body like walking and seeing.

the spinal cord controls the reflex actions like pulling the hand away when

the fingers touch a hot object.

the central nervous system receives impulses from the sensory from the

sensory organs or other parts of the body for interpretation.

after an impulses is interpreted, a new impulse is transmitted to the

muscle or gland to respond to the stimuli.

Peripheral Nervous System.

consists of all the nerves which connects the central nervous system to

the receptor and effector located at other parts of the body.

the functions is to transmit impulses from the sensory organs or receptor

through the central nervous system to the muscle for it to respondaccordingly or to the gland to produce the required secretion.

divided into :a) somatic nervous system

controls all the voluntary actions consists of the spinal nerve (from the spinal cord) and the

cranial nerve (from the brain) spinal nerve controls voluntary actions like walking,

scratching, and running.

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cranial nerve controls involuntary actions like talking,smelling, and seeing.

spinal nerve connects the spinal cord with parts of the bodylike the limbs, skin, and abdomen.

cranial nerve connects the brain to sensory organs in the

head and neck like the eyes, nose, ears, tongue, and jaws.b) autonomic nervous system controls involuntary action example ; heartbeat, and contraction of blood vesels. contains nerves which connect the spinal cord to internal

organs and glands like liver, kidneys, heart, and lungs.

Neurone.

is a basic unit of the nervous system. the functions is to carry impulses.

cell body contains nucleus and cytoplasm.

dendron is a cytoplasm projection which spreads out from the cell body.

dendrites is the small branches of dendron.

axon is a long projection from the cell body and surrounded by an

insulating membrane called myelin sheath.

myelin sheath separated by small gaps called nodes of Ranvier.

parts of the neurone and their functions :

Neurone Part FunctionCell body Controls all activities of the neurone.

Dendrite Receive impulses from other neurone andtransmits them to cell body.

Dendron Dendrite that carries impulses towards cell body.

Axon Dendrite that carries impulses out of cell body.

Myelin sheath Insulator on axon that prevents the leakage ofimpulses.

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Increases the speed of impulses transmission.

Types of neurone.

there are three types of neurone :

(a) sensory neurone(b) relay neurone (intermediate neurone)(c) motor neurone

relay nuerone only appears in the central nervous system and connects

the sensory neurone with the motor neurone.

each type of neurone possesses the same basic structure but is different

in terms of its position and function.

the three types of neurone have the following similarities :

o each has a cell body containing nucleus, dendron, dendrite, and

axon,o the main role is to receive and transmit impulses

the end of the neurone is separated by minute space called synapse

which allow impulses to be transmitted in one direction only.

the synapse is found between the axon of a neurone and the dendrite of

the cell body from another neurone.

Characteristics Sensory Neurone Relay Neurone Motor Neurone

Structure

Position of cellbody

In the middle ofneurone

At the center ofneurone

At the end ofneurone

Length ofaxon

Short Changes Long

Movement ofimpulse From the sensoryorgan to the centralnervous system

From the sensoryneurone to themotor neurone inthe central nervoussystem

From the relayneurone going outfrom the centralnervous system tothe effectors

Function Carries impulsesfrom sensory organto central nervous

Transmits impulsesfrom sensoryneurone to motor

Transmits impulsesfrom central nervoussystem to effector

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system neurone

comparison between sensory neuron, relay neurone, and motor neurone.

2.3 Nervous Coordination.

Receptors and effectors.

Receptors is a cell in the sensory organs which detects stimuli resulting

from the changes in the surrounding.

there are five main types of sensory organs :

(a) eyes(b) ears(c) nose(d) tongue(e) skin

Effectors is an organ which responds to the stimuli :

(a) muscles(b) gland

all receptors and effectors are connected to the nervous system by

neurones.

Reflex actions.

are

automatic and fast response of the body towards external stimuli withoutthe involvement of thinking of the cerebrum.

takes place in the spinal cord.

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Sensory neurone Relay neurone Motor neurone


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it protects us from dangerous situations or injuries.

the path of a reflex action is called a reflex arc.

flow chart showing reflex action occurring through the final cord

example of the receptor : sensory cells situated in the skin

example of the effector : arm muscles

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Receptor

Spinal Cord

Reflex Action

Receptors / SensoryOrgans

Sensoryneurones Synapses

RelayneuronesSynapses

Motorneurones

Effectors /

Muscles

flow chart showing reflex arc of a reflex action


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2.4 The Role of Proprioceptors in Maintaining Balance and Body

Coordination.

Kinaesthetic Senses.

enable us to be aware of the movement and position of the limbs to

maintain balance.

enable us to detect body movements and allow us to button our shirt even

with our eyes closed.

help in maintaining balance and body coordination.

kinaesthetic sensory receptors are found in :

1. muscles2. joints3. ligaments

4. tendons proprioceptors act as sensory organs because of their sensitivity towards

the tension of muscles.

the tension muscles, joints, ligaments, or tendons, will stimulate the

proprioceptors to trigger an impulse and transmit through the nervesthrough the brain.

after an interpretation, an impulse will be transmitted to parts of the body

to coordinate suitable reaction.

example of activities are :

1. playing the piano

2. tying shoelaces without looking3. combing hair without looking into the mirror

2.5 The Human Brain and Its Complexity.

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Human Brain.

the human brain is the most complex organ. it is protected by a hard bone structure called the cranium.

a big portion of neurones is found in the brain.

the main functions of the brain is

1. receive impulses, then2. interpret it, then3. transmit the impulse to the part of the body concerned to respond.

the human brain is divided into three main parts :

(a) Cerebrum

the largest region of the brain.

its folded surface greatly increases the surface area to place moreneurones.

consists of left hemisphere and right hemisphere.

the left hemisphere receive nerve impulses from the right side ofthe body while the right side of the body receive nerve impulsesfrom the left side of the body.

it is the control centre of voluntary actions.

controls mental activities like thinking, memory, and emotions.

controls senses like sight, hearing, smelling, and touching.

controls muscle movement like walking, writing, and running.

(b) Cerebellum

situated at the lower part of the cerebrum and at the back of themedulla oblongata.

has folded surface.

controls body balance.

coordinates muscle movement.

controls activities like riding a bicycle.

(c) Medulla Oblongata

connects the brain with the spinal cord.

it is the control centre of involuntary actions.

controls involuntary actions like :i. breathingii. blood pressureiii. heartbeativ. food digestionv. peristalsisvi. coughing

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medulla oblongata


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vii. sneezingviii.vomitingix. secretion of salivax. enzyme

Voluntary Actions and Involuntary Actions. voluntary actions actions we are aware of and which are done according

to our intention.

involuntary actions actions which carry on automatically.

Effects of injury to certain region of the brain.

an injury to a certain region of the brain resulting from an accident or

sickness will affect the function of a certain part of the body.

in severe conditions, an injury to a certain region of the brain can cause

death.

1. Injury to region controlling movement

results in certain parts of the body to be paralysis

2. Injury to senses of smell and taste

results in the loss of senses of smell and taste

3. Injury to medulla oblongata

results in fatality

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Part thatresponds

Type ofresponses

Stimuli of actions

Region of thebrain whichcontrols the

actions

Impulsetransmission

Type of nerve

involved

Examples

Skeletal muscleslike bisceps

Actions we areaware

Begin in brain

Cerebrum

Brain through themuscles

Somatic nervous

system

Writing, speaking

Internal organslike the heart

Automatic

No Stimuli

MedullaOblongata

Medulla oblngatato organs

Autonomic

nervous system

Heartbeat

Differences Involuntary actionsVoluntary actions


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4. Injury to sense of hearing region

results in deafness

5. Injury to the sense of sight region

results in blindness

6. Injury to the cerebellum

results in the loss of body balance

2.6 Hormonal Coordination The Body.

Hormone.

are chemical substances secreted by endocrine glands.

are complex protein.

initiate most of the chemical reactions which occur in the body.

produced in a small quantity.

carried by the circulation system to all parts of the body.

Endocrine glands and their functions.

Endocrine system.

consists of endocrine glands (ductless gland) that secrete hormone

directly into the bloodstream.

the human endocrine system consists of :

(a) pituitary gland(b) thyroid gland(c) adrenal gland

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(d) pancreas(e) ovary(f) testis

Endocrinegland

(location)

Function ofhormone

Effect of excessivehormone

Effect ofdeficiency of

hormone

Pituitarygland (at thebase of thebrain)

Controls the activityof other endocrineglands.

Control the growth ofmuscles and bones.

Excessive growth(gigantism).

Stunted growth(dwarfism).

Thyroid(under thelarynx/vocalcord at thegland)

Controls the bodymetabolic rate.

Controls growth andmental developmentof children.

The metabolic ratebecomes very high.

Emotions becomesunstable, quick-tempered and eyesprotrudes from theeye socket.

The metabolic ratebecomes very low.

Physical growthbecome stunted.

Development ofthe brain inchildren isretarded.

Causes goitre.

Adrenal (atthe top ofboth kidneys)

Increases heartbeatand respiration.

Increases bodymetabolisms.

The level of glucoseand salt in the bloodis high.

High bloodpressure.

Ability toovercomepressure dailylessens.

The musclesbecome weak.

Pancreas(behind thestomach)

To control bloodsugar level. Shortage of glucosein the blood. Diabetes.

Ovary (in thefemalereproductivesystem)

Controls themenstrual cycle.

Controls the female

Extreme femininecharacteristics.

Infertility.

Menstrual cycleinterrupted.

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secondary sexcharacteristics. Miscarriage of a

fetus before time.

Development ofsecondary sexcharacteristics arestunted.

Testis (in themalereproductivesystem)

Controls the spermproduction.

Controls the malesecondary sex

characteristics.

Extreme masculinecharacteristics.

Sperms producedare immature.

Development ofsecondary sex

characteristics arestunted.

types of hormone and their functions

2.7 Coordination Between The Nervous System and The Endocrine System.

Comparison between nervous coordination and hormonal coordination.

both are important in performing body activities.

hormonal control differs from nervous control in some aspects.

their similarities are :

o control and coordinate body functions and activities.o respond to a stimulus.

o possess target organ

their differences are :

Nervous system Differences Endocrine System

Consists of nerves Coordination Consists of ductlessglands

Goes through the nerveselectrochemically

Way of impulse transmission Goes throughbloodstream in the form

of hormone

Very fast Speed of impulse transmission Slow

A short while Duration of effect Long

Specific Target areas Wide

Fast and immediate Response Slow and continuous

Writing, dancing Examples of body coordination Growth, bodymetabolism

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The importance of coordination between the nervous system and theendocrine system.

Both system coordinate the appropriate body response towards a stimulus.

Example : when fear striking during a fire, the adrenal gland secreteshormone that changes glycogen into glucose for the muscles usage.

The muscle will gain more energy to enable the person to react faster likerunning away from fire.

2.8 The Effects of Drug Abuse on Body Coordination and Health.

Drugs.

defined as a chemical substance which can change the function and

physiology of the body.

used to treat patients.

types of drugs and their characteristics :

o depressants

example : morphine, heroin, barbiturate

to relieve tension.

calm a persons mind.

slow down response to stimulus.o stimulants

example : amphetamine, nicotine

increase the metabolic rate.

make a person more active.o opiates

example : morphine, cocaine

relieve the sensation of pain and anxietyo hallucinogens

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Fear

Autonomic Nervous System

Motor Neurone Adrenal gland

Muscles react quickly

relationship between thenervous system and the

endocrine system.

nerve impulsenerve impulse

causes hormones increasemetabolic rate


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example : marijuana, LSD

causes hallucination.

causes madness and death.

drug abuse occurs if it is used not for medical purposes.

drug abuse can lead to addiction and health deteoration.

types of drugs that are commonly taken by drug addict :o opium

source flower of the poppy planto morphine

source brown substance processed from opiumo heroin

source white or brown powder processed from morphineo marijuana

source leaves and dry flowers of the Cannabis Sativa plant

other than affecting body coordination, drug abuse can also harm our health.It can cause the following health problems :

(a) high blood pressure(b) heart problems(c) damage to the liver(d) weakened of the immune system(e) higher occurrence rates of cancer(f) mental problems(g) infections of contagious diseases(h) fatality due to overdose of drugs

2.9 Effects of Excessive Consumption of Alcohol on Body Coordinationand Health.

alcoholic drinks contain ethanol.

ethanol is produced from the fermentation of glucose by yeast.

examples of alcohol : beer, whisky, vodka, rum, and brandy.

Effects of excessive consumption of alcoholic drinks.

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Effects of excessive consumptionof alcoholic drinks

alcohol slows down

the rate of nerveimpulse transmissionand affects thecentral nervoussystem.

alcohol can damageliver cells, reduce theproduction of bile,cause cirrhosis of theliver (scar tissue) andhepatitis.

in severe cases,

continuousconsumption ofalcohol can causedeath.

response of a drinkerin an emergency isslow.

a drinker cannot drive

safely because hissight is blurred, hishearing is poor, andhis reaction becomesslower.

a drinker uses a

longer time to stop

his vehicle.


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2.10 Importance of Sound and Healthy Mind.

Mind

is the ability of the brain to think and judge.

a healthy mind enables a person to make logical judgment before his acts.

a persons mind determines his emotions and behavior.

a person with a healthy mind will show characteristics such as positive

thinking, independent, caring and responsible.

a person with unhealthy mind will not have self esteem, be short-

tempered, feels worry easily and find it difficult to control his emotions.

Factors that affect Mind

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External factors

Social factors

Environment conditions

Mental stress

Internal factors

Brain injury

Diseases

Hormone imbalance

Drug abuse

Excessive consumption of alcohol

Science Chapter 2 Form 4

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