2.4 Proprioceptors in Maintaining Balance and Body Coordination

Proprioceptors in Maintaining Balance and Body Coordination
1. The sense which helps us to detect position and movement of the limbs by using proprioceptors is known as the kinaesthetic sense.
2. Proprioceptor is a group of highly sensitive stretch receptors in muscle, tendons and ligaments.
3. Proprioceptors function to maintain body balance, body posture and coordinate the muscular activities.
4. Proprioceptors are important because they are sensitive to being stretched, twisted or compressed. They act as sensory organs.
5. Proprioceptors are able to respond to stimuli and send out nervous impulses along their nerves to the central nervous system.

6. Proprioceptors enable us to know the movement of our limbs without having to watch them.
7. Examples of activities which are helped by kinaesthetic senses are:
(a)  Playing piano
(b)  Cycling
(c)  Rock climbing
(d)  Wearing shirt
(e)  Clapping hands
(f)   Tying shoe laces without looking

2.3 Nervous Coordination

Nervous Coordination
  1. A stimulus is any change which occurs outside or inside the human body that brings about a response.
  2. A receptor is a cell in the sensory organ which detects stimulus and convert the stimulus into electrical impulses.
  3. There are five main types of sensory organs, the eyes, ears, tongue, nose and skin.
  4. The reaction to a stimulus is called response.
  5. A response may be in the form of movement, caused by muscles or in the form of secretions, produced by glands.
  6. Muscles and glands which respond to stimuli are called effectors.
  7. All receptors and effectors are connected to the nervous system by neurones.


Reflex actions
  1. A reflex action is a fast, automatic and involuntary response towards a stimulus. It is carried out without conscious by the brain.
  2. Reflex actions help us to survive and to protect us from dangerous situation. For example, jerking away of hand when in contact with a hot kettle.
  3. Reflex actions take place in the spinal cord.
  4. The path of reflex action is called a reflex arc.
Flow chart showing reflex action occurring through the spinal cord

Example of reflex action when hand is pricked by a sharp nail

2.2.2 Types of Neurone

Types of Neurone
There are three types of neurone:
(a)  Sensory neurone
(b)  Relay neurone (intermediate neurone)
(c) Motor neurone

Sensory neurone
Relay neurone
Motor neurone
Position in the body
Present in all parts of the body
Present in the brain and the spinal cord only
Present in all parts of the body
Position of cell body
In the middle of neurone
At the centre of neurone
At the end of neurone
Length of axon
Very short
Transmits impulses from a receptor to the central nervous system
Transmits impulses from a sensory neurone to a motor neurone
Transmits impulses from the central nervous system to the effector

2.2.1 Neurone


  Structure of a neurone

  1. The basic unit of the nervous system is neurone.
  2. The function of neurone is to carry impulses.
  3. Each part of s neurone plays an important role in the transmission of nervous impulses.

Neurone Part
Cell body
Controls all activities of the neurone
Transmits impulses towards a cell body
Receives impulse from other neurone and transmits them to cell body
Transmits impulses out of cell body
Myelin sheath

Speed up the transmission of impulses.
Insulator that prevents the leakage of impulses.


1.2 Scientific Investigation

Scientific Method

Scientific method is a body of technique of acquiring knowledge about the nature and its phenomena.

Basics Steps of Scientific Investigation

  1. Identifying problem
  2. Making hypothesis
  3. Plannig the investigation
  4. Identifying and Controlling Variable
  5. Conducting the experiment
  6. Collecting and recording data
  7. Analysing and interpreting data
  8. Making conclusion
  9. Preparing the report

The 2 main scientific skills

  1. Science process skill (Mental skill)
  2. Manipulative skill (Hand skill)

The 6 Science Process Skill (OCCMIP)

  1. Observation
  2. Communication
  3. Classification
  4. Measurement
  5. Inference
  6. Prediction

Examples of Manipulative Skill

  1. Handling apparatus and material correctly.
  2. Handling specimen correctly
  3. Clean apparatus correctly
  4. Storing apparatus and reagents correctly


Hypothesis is a suggested explanation for a specific phenomenon.


Inference is the act or process of deriving a conclusion based on what one already knows.


Variable is a quantity whose value may change in an experiment. It is the parameter that may influence the outcome of an experiment or the data been collected in the experiment.

2.2 Human Nervous System

Human Nervous System
1. The human nervous system is divided into
(a) Central nervous system (or CNS) – consists of the brain and spinal cord.
(b) Peripheral nervous system (or PNS) – consists of the spinal nerves and cranial nerves.
Chart showing the classification of human nervous system

Human nervous system

Central Nervous System
  1. The central nervous system is the control centre of the body.
  2. This system consists of the brain and the spinal cord.
  3. The brain controls all voluntary actions of the body like walking and talking.
  4. The spinal cord controls the reflex actions such as sneezing.

Peripheral nervous system
  1. The peripheral nervous system consists of all the nerves which connect the central nervous system to the receptor and effector located at other parts of the body.
  2. The function of the peripheral nervous system is to transmit impulses from the sensory organ through central nervous system to the effector to respond accordingly.

1.1 The Study of Biology

Biology is the study of life or living organisms.
bios - life
logy - (original: logos) which means study.

Importance of Biology

  1. better understanding on the functions of human body.
  2. better understanding on the causes of diseases and its cure.
  3. better understanding on ecology and henceimprove the management of problems related to the environment.
  4. saving animal and plant species which arefacing extinction.

Fields of Biology Research

  1. Anatomy
  2. Physiology
  3. Cell biology
  4. Molecular biology
  5. Genetics
  6. Microbiology
  7. Bacteriology Entomology
  8. Developmetal biology
  9. Ecology
  10. Zoology
  11. Botany
  12. Taxonomy
  13. Histology

Career Related to Biology

Medicine Doctor, nurse, dentist, pharmacist, veterinarian, physiotherapist
Biotechnology Biotechnologist, nutritionist, food technologist
Agriculture Estate manager, botanist, agricultural officer
Industry Research officer, scientist

Characteristic of Living Organism

Metapolism: Obtain energy for life and activities
Respiration: Breakdown food to obtain energy for growth, movement....
Nutrition: -Sources of energy and growth
-Repair dameged tissue
Locomotion: Moving from place to place (only for animal)
Reproduction: Reproduce offspring
Growth: Increasing in size
Excretion: Expelled waste from body