2.1 Body Coordination

• Body coordination is the adjustment of our body’s reaction towards any stimulus around us.

• Coordination ensures that each part of the body is controlled so that it functions harmoniously.

• Two types of body coordination :a) Nervous coordinationb) Hormonal coordination

Body coordination

Nervous coordinationControlled and coordinated by

the nervous system

Hormonal coordinationControlled and coordinated by

the endocrine system

Walking, looking, writing, talking,listening and reading

Body growth, reproduction, controlling blood flow and

food digestion

divided into

coordinating body activities like

coordinating body activities like

Importance of body coordination

• Enables all body organs to function as a unit to detect stimuli and respond towards them

• Controls coordination between stimuli and body responses

• Helping us to avoid injuries or dangers

• Enables us to adapt to the changes around us

Exercise 2.1

1. What is body coordination?

2. Give two examples of activities controlled by

• Nervous coordination

• Hormonal coordination

2.2 Human Nervous SystemHuman nervous

system

Central nervous system

Peripheral nervous system

Brain(Controls most

body’s activities)

Spinal cord(Controls theReflex action)

Somatic nervous System ( control Voluntary actions)

Autonomic nervous system ( control

Involuntary actions)

12 pairs of Cranial nerves(connected from thecranium to the brain)

31 pairs ofSpinal nerves(connected to

spinal cord)

divided into

divided into divided into

consists of

in textbook page 21.

Neurones

Neurones

Structure :Cell bodyDendronsDendrites

AxonMyelin sheath

Definition :The basic functional

unit of the nervous system

Three types :Sensory neuroneRelay neuroneMotor neurone

• Table below list the parts of the neurone and its function.Parts of the

neuroneFunction

Cell body Integrates the nerve impulses and coordinates the metabolic activities

Dendrons Nerve fibres that receive nerve impulses and send it to the cell body

Dendrites Nerve fibres that receive nerve impulses from other neurones or from external environment and send ot to the cell body

Axon Conducts nerve impulses away from the cell body

Myelin sheath Speed up the transmission of the nerve impulses

The differences between neurones

Characteristics Sensory neurone

Relay neurone

Motor neurone

Structure

Characteristics Sensory neurone

Relay neurone

Motor neurone

Position of cell body

In the middle of neurone

Centre of the neurone

End of neurone

Length of axon

Short Changes Long

Function Carries impulses from sensory organ or receptor to CNS

Transmits impulses fron sensory neurone to motor neurone

Transmits impulses from CNS to effector

Exercise 2.21. Complete the table below to show the types of nerves

in peripheral nervous system that control the following actions.

Spinal nerve cranial nerve autonomic nerve

Action Type of nerve

Running

Smelling

Jumping

Moving the tongue

Pulse

Breathing

2.3 Nervous Coordination

Nervous coordination

Receptor Effector

Definition :A cell in the

sensory organ which detects

stimuli

Examples :Eyes, ears, nose,

Tongue, skins

Definition :An organ which responds to the

stimuli.

Examples :Muscle, glands

• The pathway of impulses in the human nervous system.

Reflex action ( tindakan refleks)

Reflex action

•An automatic response towards a stimuli•Controlled by spinal cord not brain

Advantages :•Allows a fast response towards changes

•Protect us from injuries( cedera)

Examples :•Sneezing

•Our eyes blink when an object comes towards the eyes

Reflex arc (Arka refleks)• A reflex arc is the sequence of pathways

taken by impulses in a reflex action.• Example : ( refer figure 2.11 in textbook

page 27)

Explanation :

• The stimulus is a pricked finger• Impulses travel from pain receptor in the skin

along a sensory nerve to the spinal cord.• Then the impulse crosses a synapse to reach

the relay neurone.• It then carries the impulses through the nerve

cord to a synapse with a motor neurone.• The motor neurone carries impulses to

muscles which respond by pulling the finger away.

• The path taken by an impulse in a reflex arc :

Exercise 2.3

1. What are the receptor and effector in the reflex arc when a person’s finger is pricked by a thorn of a durian fruit?

2. What is the body response that protects us from danger or injury?

3. Name two types of neurone involved in a knee-jerking.

2.4 Proprioceptors for maintaining balance and coordination

Proprioceptors / kinaesthethic sense

Definition : Receptors that are sensitive to movement, pressure or stretching

( stretch receptor) in the body

Example : muscle spindle, together with other receptors in tendons, ligaments

and joints.

Activities : walking on ropes, tying shoelacs without looking,

typing without looking at keyboard

Important : the coordination of muscular activity and the maintenance of balance and posture

2.5 The Human Brain

• The brain can be divided into three main parts : cerebrum, cerebellum, medulla oblongata

• Refer figure 2.14 in textbook page 32.

Part of the brain

Specific features Functions

Cerebrum •The largest region•Has folded surface to place more neurones

•Controls voluntary actions•Controls motion and behaviour

Cerebellum •Situated at the lower part of the cerebrum and at the back of the medulla oblongata

•Controls body balance and posture•Coordinates muscle movements

Medulla oblongata

•Connects the brain with the spinal cord

•Controls involuntary actions

Voluntary and involuntary actionsVoluntary actions Difference Involuntary

actionsActions we are aware of Definition Automatic action

Controlled by the cerebrum

Control of action Controlled by medulla oblongata

Under conscious control Action Not under conscious control

Impulses moves from cerebrum to muscles through the spinal cord

Pathway of impulse

Impulses moves from medulla oblongata to organs through the spinal cord

Slow Speed of response

Fast

Walking, thinking, reading, eating

Example Sneezing, breathing, heartbeat,coughing

Effects of injury to a certain region of the brain

Exercise 2.5

1. Classify the actions or activities given under the respective parts of the brain responsible for them.

Dancing cycling holding sneezing swallowing

Tasting toddling looking coughing walking

Listening knee-jerking pulsebeating smelling breathing

Parts of the brain

Cerebrum Cerebellum Medulla oblongata

2. Classify the following activities into voluntary actions and involuntary actions.

Thinking heartbeat remembering walking kicking

Peristalsis looking secreting saliva digestion

dilation of the pupils

Types of action

Voluntary actions Involuntary actions

2.6 Hormonal Coordination

• Refer note “ hormonal coordination” in MS Word.

Exercise 2.6Write out the types of endocrine gland which carry out

the functions as stated.Function Type of endocrine gland

Controls metabolic rate

Controls reabsorption of water in the kidneys

Controls level of sodium ions in the bloodstream

Controls sugar level in the bloodstream

Controls secondary male sexual characteristics

Controls secondary female sexual characteristics

2.7 Coordination Between The Nervous System and The Endocrine System

Similarities

Nervous system

Similarities Endocrine system

Control and coordinate body functionsRespond to a stimulusPosses target organ

Differences

Neurone network, the brain and the spinal cord

Component Endocrine glands

(ductless glands)

Electrochemical impulse

Agent involved Chemical substance

( hormones)

Nerve fibres Transport Bloodstream

Instant; fast; within milliseconds

Speed of reaction Slower; within minutes, hours or even longer

Short-term Effective period Long-term

Specific organs Target areas Wide areas; may be throughout the whole body

Exercise 2.7Fill in the blank with suitable words.1. Impulses transmitted in the endocrine system

are in the form of a chemical substance called _________ .

2. ________ coordination is much faster than _________ coordination.

3. Both the endocrine system and the nervous system function to _________ and _________ body activities.

4. __________ coordination usually occurs continously for a long duration.

2.8 The Effects Of Drug Abuse On Body Coordination And Health

Types of drug

Examples Effects

Stimulants Caffeine, cocaine, nicotine, amphetamine

Increase the metabolis rate,

Make a person more active,

Reduce sleeping and fatique

Depressants Morphine, heroin, barbiturate, tranquilizers

Relieve tension, Calm a person’s mind, Slow down response to stimulus

Anti-depressant

Opium, morphine Relieve pain and ease mental stress, induce sleep

Hallucinogens Marijuana, LSD Cause hallucination, cause madness and death

Inhalants Petroleum, chlorofoam, glue

Causes hallucination, blackouts and increases heartbeat.

Exercise 2.8

1. What is a drug?2. Tick (/) the true statements and cross out (x)

the false statements.a) Morphine is extracted from opium. ( )b) Morphine can be used to relieve pain. ( )c) LSD causes the user to be sleepy and to

vomit. ( )d) Heroin is obtained directly from poppy flower.

( )e) Nicotine can be found in cigarettes. ( )

2.9 The Effects Of Excessive Consumption Of Alcohol On Body Coordination And Health

• Slows down the rate of nerve impulse transmission and affects the central nervous system.

• Damage liver cells, reduce the production of bile, cause cirrhosis of the liver and hepatitis.

• Can cause death.• Response of a drinker in an emergency is

slow, his sight is blurred, his hearing is poor, his reaction become slower.

Exercise 2.9

1. Give three examples of alcoholic drink.

2. Explain why driving under the influence of alcohol ( drunk driving) can cause road accidents.

2.10 Importance Of Sound And Healthy Mind

• The mind is the ability of the brain to think and judge.

Factors that affect the mind

External factors Internal factors

•Social factors•Environment conditions

•Mental stress

•Brain injury•Disease

•Hormonal imbalance•Drug abuse

•Excessive consumption of alcohol

Exercise 2.10

1. State three internal factors that affect the mind.

2. State three external factors that affect the mind.