CHAPTER 2

BODY COORDINATIONBODY COORDINATION

2.1 BODY COORDINATION

Definition: the adjustment of our body’s reaction towards any stimulus.

Example: reaction to temperature change

IMPORTANCE OF BODY COORDINATION

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

Helping us to avoid injuries or dangers Enables us to adapt to the changes around us

If a certain of your nervous system does not function properly,

then you can be paralysed.

2.2 THE HUMAN NERVOUS SYSTEM

HUMAN NERVOUS SYSTEM

Brain

Spinal cord

Spinal nerve

Cranial nerve

Central nervous system

Peripheral nervous system

A) CENTRAL NERVOUS SYSTEM

It is the control centre of the body.Brain: control all activities of the bodySpinal cord: control the reflex actions

It receives impulses form the acceptor/receptor (sensory organs), interpret it and sends new impulse to the acceptor (muscle and gland).

Impulse: the electrical signals carrying messages

B) PERIPHERAL NERVOUS SYSTEM

Function: to transmit impulses from the sensory organ or receptor through the central nervous system to the muscle or the gland.

The peripheral nervous system is divided into: Somatic nervous system: control all voluntary

actionsSpinal nerve: walking, scratching, writing (limbs,

skin and abdomen)Cranial nerve: talking, smiling, seeing (head

and neck)

Autonomic nervous system: controls involuntary actions (internal organs)

THE NEURONE

A neurone is a basic unit of the nervous system. Function: to carry impulses

Cell body

dendron

dendrite

myelin sheath

Node of ranvierAxon

Nerve ending

Nucleus

cytoplasm

NEURONE PARTS AND FUNCTIONS

Neurone part Function

Cell body Control all activities of the neurone

Dendrite Receives impulses from other neurone and transmit them to cell body

Dendron Dendrite that carries impulses towards the 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 impulse transmission

Nodes of ranvier Small gaps separating myelin sheath

TYPES OF NEURONES

Neurones are divided into three types based on their functions:

COMPARISON OF THREE TYPES OF NEURONE

CHARACTERISTICS

SENSORY RELAY MOTOR

POSITION OF CELL BODY

In the middle of neurone

At the centre of neurone

At the end of neurone

LENGTH OF AXON

Short Changes Long

CHARACTERISTICS SENSORY RELAY MOTOR

MOVEMENT OF IMPULSE

Sensory organ (acceptor) central nervous system

Sensory neurone motor neurone in the central

relay neurone in the central muscle (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 (muscles and glands)

SIMILARITIES OF THE THREE TYPES OF NEURONE

Each has a cell body containing nucleus, dendron, dendrite and axon

The main role is to receive and transmit impulses

REFLEX ACTION (INVOLUNTARY)

Definition: automatic reaction by an external stimulus without the involvement of thinking.

It takes place in the spinal cord.

The path of reflex action is called a reflex arc.

SPINAL CORD

Connect the brain with the rest of body parts.

REFLEX ARC IN THE KNEE-JERK REACTION

FLOW CHART OF A REFLEX ARC

Stimulus

Receptor

Synapses

Motor Neurone

Relay Neurone

Synapses

Effector

Automatic Response

Sensory Neurone

Synapse: a tiny space that allow impulse to travel from one neurone to another in one direction

2.4 THE ROLE OF PROPRIOCEPTORS IN MAINTAINING BALANCE AND COORDINATION

Kinaesthetic sense enable us to be aware of the movement and position of the limbs to maintain balance.

Importance: help in maintaining balance and body coordination.

Examples: Playing pianoButtoning shirt without lookingCombing hair without looking

PROPRIOCEPTORS/STRETCH RECEPTORS

Found in muscle, ligaments, tendons and joints.

Responsible for kinaesthetic senses to maintain the body balance and coordination without looking at.

Detect the movement, change of position, muscle stretching and contraction.

2.5 HUMAN BRAINCEREBRUM

-control voluntary actions: mental activity,senses and

muscle movement-Largest part

CEREBELLUM-coordinate body balance

-coordinate muscle movement

MEDULLA OBLONGATA-connected to spinal cord

-control involuntary actions

Protected by cranium.

Outer layer is grey matter consists of cell bodies.

Is highly folded to increase the surface area.

Divided into right and left cerebral hemisphere which control opposite side of the body movements.

Thinking, memory, learning

Motor centre

(movement)

Touching (sense in skin and muscle)

Smell and taste

Speech

Hearing

Vision

DIFFERENT CONTROLLING PARTS IN THE BRAIN

THE HUMAN BRAIN

Motor centre

-paralysisSmell and taste

-loss in the ability of smell and taste

Hearing region

-deafness

Sight region-blindness

EFFECTS OF INJURY TO A CERTAIN REGION OF THE BRAIN

Cerebellum-lose body

balanceMedula

oblongata-fatal injury:

death

VOLUNTARY AND INVOLUNTARY ACTIONS

DIFFERENCESVOLUNTARY INVOLUNTARY

Controlled by desire or not

Nervous system involved

Part of brain in control

Pathway of impulse

Speed of response

Yes

Somatic nervous system

Cerebrum

Impulse flows through the cerebrum

Can be slow down or fast

No

Autonomic nervous system

Medulla oblongata

Impulse flows through the medula oblongata

Very fast

2.6 HORMONAL COORDINATION

Hormones: chemical substances secreted by endocrine glands directly into the bloodstream.

Characteristics:ProteinReleased in small quantitiesSpecific to target organs Slow to respond

Endocrine glands (ductless glands): coordinate body activities in respond to stimuli by secreting hormones.

PITUITARY GLAND

-Located at the base of cerebrum

-Known as master glands, produce more hormones)

-Controls water absorptions from the kidney

-Stimulates growth

THYROID GLAND (Thyroxine, contains Iodine)

-Located in the neck region (in front of trachea)

-Controls the body’s metabolic rate

-To stimulate growth and mental development

PANCREAS

-Located above the kidney

-Controls the glucose concentration

-Insulin (decrease the glucose concentration)

-Glucagon (increase the glucose concentration)

ADRENAL GLAND (adrenaline)

-Located below the stomach

-Prepares the body to meet emergency situations

- To increase heartbeat and respiration

TESTIS (testosterone)

-Protected by scrotum

-Controls development of secondary sexual

characteristics (deepening of the voice, growth of beard)

-Controls sperms production

OVARY (oestrogen, progesterone)

-Located in the abdomen

-Controls development of secondary sexual

characteristics (development of breasts, menstrual cycle)

-Controls eggs/ovum production

THE EFFECTS OF HORMONAL IMBALANCE

HORMONESEFFECT OF

OVER SECRETION UNDER SECRETION

Growth hormone (pituitary)

Gigantism (child)

Acromegaly (adult)

Dwarfism

Thyroxine (thyroid)

Exophthalmic goitre -Stunted physical and mental (children)-Goitre-Lack of energy (adult)Protuding

eyeballs

Goitre (swelling neck)

HORMONESEFFECT OF

OVER SECRETION UNDER SECRETION

Insulin (pancreas) Low blood sugar level (hypoglecemia)- shock and coma

High blood sugar level (hyperglecemia)

High sugar level in urine (diabetes)

Oestrogen (ovary) Early puberty

Extreme feminine characteristics

Late puberty

Progesterone (ovary)

- Miscarriage

Menstrual disorder

Testosterone (testis)

Early puberty

Extreme masculine characteristics

Late puberty

Low sperm count

2.7 COORDINATION BETWEEN THE NERVOUS SYSTEM AND THE ENDOCRINE SYSTEM

SIMILARITIES

NERVOUS COORDINATION

HORMONAL COORDINATION

•Both involve the passing of information and

•To control and coordinate functions and activities of organs in the

body

COMPARISON BETWEEN NERVOUS COORDINATION AND HORMONAL

COORDINATION

DIFFERENCESNERVOUS

COORDINATIONHORMONAL

COORDINATION

Impulses are sent through

Consists of

Speed of impulses

Effect

Target area

Response

Nerve fibres

Neurones(electrical impulse)

Fast

Localised, temporary, reversible

Muscles, glands

Rapid, short-lived

Blood circulatory system

Hormone (chemical substances)

Slow

Widespread, permanent, irreversible

Target organs only

Slow, diffuse, long lasting

CONCLUSION

The Importance Of Nervous System And Hormonal System Coordination:

•To ensure body functions such as physical, chemical and physiological responses occur at their optimum level.

•It ensures that if one system is not able to respond, then the other will compensate.

2.8 EFFECTS OF DRUG ABUSE ON BODY COORDINATION AND HEALTH Drugs are externally administered chemical

substances that affect the chemical reactions within the body.

TYPES OF DRUGS

EFFECTS OF DRUG ABUSE ON BODY COORDINATION

DRUGS

Nervous system

Distortion of perception,

hallucinations, illusions

Energetic, active, erratic, and

violent behaviour

Slow reaction to stimuli, sleepy, poor muscular coordination

Heart beat, breathing rate, blood pressure(eg: stimulants)

Heart beart, breathing rate, blood pressure

(eg: depressants)

stimulatesslows down

causes

affect

2.9 EFFECTS OF EXCESSIVE CONSUMPTION OF ALCOHOL

ALCOHOLIC DRINKS

2.10 THE IMPORTANCE OF A SOUND AND A HEALTHY MIND

Definition of mind

The ability to think and reason.

a) Healthy mind

Example: short-tempered, caring, positive attitude, rational,

b) Unhealthy mind

Example: low self-esteem, hot-tempered

THE MIND

b) Internal factors

Examples:-hormonal imbalance-drug abuse-excessive consumption of alcohol-brain injury

a) External factors

Examples: -mental stress-social factor

Influenced by