chapter 2 body coordination

BODY COORDINATION

2.1 Understanding Body Coordination

Two types of coordination

Type of coordination

Nervous coordination

Hormonal coordination

System which controls and coordinates

Nervous system Endocrine system

Examples Walking, writing, reading

Body growth, reproduction, food digestion

1. Coordination is the adjustment of our body responses towards any stimuli from within and outside the body.

koordinasi adalah penyelarasan gerak balas badan kita terhadapsebarang rangsangan dari sekeliling dan dari dalam badan.

STIMULI

NERVOUS SYSTEM

ENDOCRINE SYSTEM

TARGET ORGANS

RESPONSES

2. Body coordination is important to us because:

•It enables us to protect our body from harmful stimuli such ashot objects.

•It enables our body to carry out activities to respond to the stimuli.

•It regulates appropriate responses to stimuli.

2.2 Understanding Human Nervous System

1. Human nervous system is made up of:a) Central nervous system (CNS)

- consists of brain and spinal cordb) Peripheral nervous system (PNS)

- consists of spinal nerves and cranial nerves

2. The pathway of body coordination:

Stimuli Receptor Central nervous system

Effector

Response

Human nervous system

Type of neuronea) Sensory neurone : transmits impulses from the

sensory organ/receptor to the central nervous system.

b) Relay neurone: transmits impulses from sensory neurone to motor neurone.

c) Motor neurone: transmits impulses from central nervous system to effector

Analyse Nervous Coordination

Stimuli

Receptors (in

sensory organs)

Sensory neurone

s

Effectors

(muscles or

glands)

Responses

Relay neurones

Function:Receive stimuli and generatesimpulses.

Function:Carry out appropriate responses.

Function:Enables impulses to be transmitted in one direction only.

Synapse

Synapse

Motor neurones

Reflex action1. Reflex action is an automatic reaction which does not involve

the brain and does not require conscious thought.2. The importance of reflex action is to protects us from

dangerous situation or injuries.3. Different stimuli will cause different reflex actions.

For example:-

Stimuli Reflex action

Flash light Pupils get smaller

Insects touches eyelid Eye blinks

Hungry and smell food Saliva in the mouth

Body gets cold Shivering

3. The nerve impulses pathway in a reflex action is called a reflex arc.

4. The diagram below shows the reflex arc which involves the three types of neurones:-

5. In some reflex arcs only two types neurones are involved.for example, the knee-jerk.

Proprioceptors 1. Proprioceptors or stretch receptor are receptors that are

sensitive to movement, pressure or stretching within the body.2. It maintains body balance and controls muscular activities by

kinaesthetic sense.3. It can be found in muscles, joints, ligaments and tendons.

4. Proprioceptors are important because they enable us a. to be conscious of the position and the posture of our body. Menyedari kedudukan badan b. to detect the movements of our body parts without using our eyes. Mengesan pergerakan anggota badan tanpa melihat.

5. For examples,

The human brainFunction:Controls sensory functions, voluntary actions and mental functions.

Function:Control involuntary actions.

Function:Regulates body movements, maintain posture and balance.

Medulla oblongata

The cerebral cortex is

convoluted to increase the surface area.

Voluntary and involuntary action

VOLUNTARY ACTION

DIFFERENCES INVOLUNTARY ACTION

Action that are under the concsious control

Definitions Action that happens without consciousness

Somatic nervous system

Nervous system involved

Autonomic nervous system

CEREBRUM Part of the brain

MEDULLA OBLONGATA

Examples

The effects of injuries to specific parts of the human brain

Hormonal coordination

Hypothalamus

Pituitary

Thyroid

Adrenal

Pancreas

Testis (male)

Ovary (female)

•Consist of endocrine glands ( a gland without duct)

•Secretes hormones (chemical substances secreted from endocrine glands)

Pituitary gland (MASTER GLAND)

• peanut size

• Growth hormone

• the main gland that stimulates other endocrine glands

• control water absorption from the kidneys

Thyroid gland

•Secretes thyroxine

•Control the rate of metabolism

•Stimulate growth

Adrenal gland

•Secretes adrenaline

•Increase the rate of heartbeat, respiration and glucose level

Pancreas gland•Secretes insulin and glukagon

•Control the sugar level in blood

Testis (male) & Ovary (female)

TESTIS•Secretes testosterone

•Control secondary sexual characteristics

•Control sperm production

OVARY•Secretes oestrogen and progesterone

•Control menstrual cycle

•* Control secondary sexual characteristics

Effects of hormonal imbalance

Gigantism•Excessive of growth hormone

Dwarfism* Lack of growth hormone

Hormonal coordinationGland (Hormone)

Function Shortage effects

Excessive effects

Pitutary gland (growth hormone)

•control other endocrine gland

Dwarfism Gigantism

Thyroid gland (thyroxine)

•Control rate of metabolism

Goiter High metabolic rate

Pancreas (insulin and glucagon)

•Control sugar level in blood

Diabetes Hypoglycemia

Adrenal gland (adrenaline)

•Control heartbeat

Weak muscles Increase blood pressure

Testis (testosterone)

•Control sperm production

Secondary sex characteristics are not well developed

Overdeveloped of sex characteristics

Ovary (oestrogen and progesterone)

•Control menstrual cycle

Irregular menstrual cycle

Overdeveloped of sex characteristics

Comparison between nervous system and endocrine system

SCIENCE PROCESS SKILL/ PAGE 15-16

2.9 DISCUSSION ACTIVITY

Effects of drugs

Effects of alcohol