Chapter 2: Body Coordination

2.1 Body Coordination.•the adjustment of our body’s reaction towards any stimulus around us and from 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 :

– nervous coordination– hormonal coordination

2.2 Human Nervous System.•is divided into :

– central nervous system– peripheral nervous system

•the massages carried by the nervous system are electrical signals called impulses.

Human Nervous System

Central Nervous System

Peripheral Nervous System

Brain Spinal Cord Somatic nervous system

Autonomic nervous system

Cranial Nerves

Spinal Nerves

Central Nervous System.•the central nervous system is the control centre of the body.•this system consists of :

• brain• 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 respond accordingly or to the gland to produce the required secretion.•divided into :

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.• cranial nerve controls involuntary actions like

talking, smelling, and seeing.• spinal nerve connects the spinal cord with parts

of the body like 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.

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

Function

Cell body Controls all activities of the neurone.

Dendrite Receive impulses from other neurone and transmits 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 of impulses.*Increases the speed of impulses transmission.

Characteristics

Sensory Neurone

Relay Neurone

Motor Neurone

Structure

Position of cell body

In the middle of neurone

At the center of neurone

At the end of neurone

Length of axon

Short Changes Long

Movement of impuls

e

From the sensory organ to the central nervous system

From the sensory neurone to the motor neurone in the central nervous system

From the relay neurone going out from the central nervous system to the effectors

Function

Carries impulses from sensory organ to central nervous system

Transmits impulses from sensory neurone to motor neurone

Transmits impulses from central nervous system to effector

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 :

• eyes• ears• nose• tongue• skin

• Effectors is an organ which responds to the stimuli :• muscles• 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 without the involvement of thinking of the cerebrum.•takes place in the spinal cord.•it protects us from dangerous situations or injuries.•the path of a reflex action is called a reflex arc.

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 :–muscles–joints–ligaments–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 nerves through the brain.

• after an interpretation, an impulse will be transmitted to parts of the body to coordinate suitable reaction.

• example of activities are :–playing the piano–tying shoelaces without looking–combing hair without looking into the mirror

2.5 The Human Brain and Its Complexity.

• 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, then•2. interpret it, then•3. 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 more neurones.

• consists of left hemisphere and right hemisphere.

• the left hemisphere receive nerve impulses from the right side of the body while the right side of the body receive nerve impulses from 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 the medulla oblongata.•has folded surface.•controls body balance.•coordinates muscle movement.•controls activities like riding a bicycle.

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 movementresults in certain parts of the body to be paralysis2) Injury to senses of smell and tasteresults in the loss of senses of smell and taste3) Injury to medulla oblongataresults in fatality4) Injury to sense of hearing regionresults in deafness5) Injury to the sense of sight regionresults in blindness6) Injury to the cerebellumresults 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 :

– pituitary gland– thyroid gland– adrenal gland– pancreas– ovary– testis

Endocrine gland

(location)

Function of hormone

Effect of excessive hormone

Effect of deficiency

of hormone

Pituitary gland (at the base of the brain)

Controls the activity of other endocrine glands. Control the growth of muscles and bones. 

Excessive growth (gigantism). 

Stunted growth (dwarfism).

Thyroid (under the larynx/vocal cord at the gland)

Controls the body metabolic rate. Controls growth and mental development of children.

The metabolic rate becomes very high. Emotions becomes unstable, quick-tempered and eyes protrudes from the eye socket.

The metabolic rate becomes very low. Physical growth become stunted. Development of the brain in children is retarded. Causes goitre.

Adrenal (at the top of both kidneys)

Increases heartbeat and respiration. Increases body metabolisms.

The level of glucose and salt in the blood is high. High blood pressure.

Ability to overcome pressure daily lessens. The muscles become weak. 

Pancreas (behind the stomach) 

To control blood sugar level.

Shortage of glucose in the blood.

Diabetes.

Testis (in the male reproductive system)

Controls the sperm production. Controls the male secondary sex characteristics.

Extreme masculine characteristics.

Sperms produced are immature. Development of secondary sex characteristics are stunted. 

Ovary (in the female reproductive system)

Controls the menstrual cycle. Controls the female secondary sex characteristics.

Extreme feminine characteristics.

Infertility. Menstrual cycle interrupted. Miscarriage of a fetus before time. Development of secondary sex characteristics are stunted. 

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 :

– control and coordinate body functions and activities.– respond to a stimulus.– possess target organ

their differences are :

Nervous system

Differences Endocrine System

Consists of nerves

Coordination Consists of ductless

glandsGoes through the nerves electrochemically

Way of impulse

transmission

Goes through

bloodstream in the form of

hormone

Very fast Speed of impulse

transmission

Slow

A short while

Duration of effect

Long

Specific Target areas WideFast and immediate

Response Slow and continuou

sWriting, dancing

Examples of body

coordination

Growth, body

metabolism

The importance of coordination between the nervous system and the endocrine system.Both system coordinate the appropriate body response towards a stimulus. Example : when fear striking during a fire, the adrenal gland secretes hormone that changes glycogen into glucose for the muscles’ usage. The muscle will gain more energy to enable the person to react faster like running 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 :–depressants

• example : morphine, heroin, barbiturate• to relieve tension.• calm a person’s mind.• slow down response to stimulus.

–stimulants• example : amphetamine, nicotine• increase the metabolic rate.• make a person more active.

–opiates• example : morphine, cocaine• relieve the sensation of pain and anxiety

–hallucinogens• 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 :–opium

• source – flower of the poppy plant

– morphine• source – brown substance processed from

opium– heroin

• source – white or brown powder processed from morphine

– 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 :– high blood pressure– heart problems– damage to the liver– weakened of the immune system– higher occurrence rates of cancer– mental problems– infections of contagious diseases– fatality due to overdose of drugs

2.9 Effects of Excessive Consumption of Alcohol on Body Coordination and 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.

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 person’s 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.