2.2 Cell Organisation

2.2 CELL ORGANISATION

What is cell organisation?

Cell organisation – cell that was organise to give orderly structure

Unicellular and multicellular organism

Unicellular organism – made up of one cell

Multicellular organism – made up of many cells, larger in size and more complex

Living processes in Amoeba sp. Living Process Description

1. Locomotion -Using cytoplasmic projection-extending its pseudopodia, anchoring the tips to the ground and followed by the flow of cytoplasm

2. Feeding - Engulfs food by phagocythosis, feeds on microscopic organism

3. Respiration -Exchange of gases through plasma membrane

4. Excretion -By diffusion through plasma membrane

5. Respond to stimuli

-Retreating from adverse stimuli and moves towards favorable stimuli

6. Reproduction -By binary fission (favorable environment) and by spores ( not conductive environment)

7. Growth - By synthesising its cytoplasm

Living process in unicellular organism

Carry out vital functions and perform living process within a cell

Example: Amoeba sp.

Cell specialisation in multicellular organism

Multicellular organism begins life as a single cell

Cell divide repeatedly to form embryo and grow, change shape and adapt to carry out specific functions

To perform specific task, cells differentiate and specialised

Cell specialisation – a process of change and adaptation that a cell undergoes to give it special structures and specific function

Cell organisation in multicellular organism

The same type of cells which carried out a common function are organised into tissues

Different type of tissues group together to form an organ

Several organs group together to form a system

All systems work together to make up an organism

Cell organisation can be summerised as follows

Cell Tissues Organ System Organism

The importance of cell organisation:

a group of cells work efficientlydivision of labour enables organism to do

various tasks and function efficiently and systematically

achieve higher growth rateable to adapt and survive in diverse habitat

and environmentcarry out all living process more efficiently

Cells Organisation In Humans

Tissues

four major types:

1. Epithelial tissues

2. Muscle tissues

3. Connective tissues

4. Nerve tissues

1.Types of epithelial tissues in human

For protection, secretion and absorptionExamples: form the surface of the skin

act as a protective barrier, line the alveoli of the lungs the walls of blood capillaries are thin to allows the exchange of gases to take place efficiently (absorption) and form glands in the skin to secrete sweat glands and oil-secreting glands (sebaceous glands).

Functions of epithelial tissues

2. Muscle tissues Three types:a) smooth muscle – found along the wall of

digestive tract, blood vessels, bladder and reproductive tract which responsible for the involuntary actions of the body

b) skeletal muscle – attached to the bones of the skeleton which responsible for the voluntary movements of the body

c) Cardiac muscles – form the contractile wall of the heart which contract to pump blood to all parts of the body

3. Connective tissues

Loose connective tissues – widespread in the body, binds epithelia to underlying tissues and holds organs in place (E.g. adipose tissue

Dense fibrous connective tissues – a large number of collagenous fibres which are packed closely together (E.g. tendons and ligaments

Functions:• binds structures together, provide support

and protection to other tissues• Examples: tendons - connect muscles to

bones, ligaments - join bones together at joints, cartilage provide support to the nose, ears, cover ends of bones at joints and disc between the vertebrae act as cushion to absorb pressure, bones - provides protection to organs and support the body, blood cells - regulating, transporting and protective functions, adipose tissues acts as energy reserve and provides insulation and protection

4. Nerve tissues

Composed of neurone/nerve cells Consist of a cell body and nerves fibres

(dendrone, dendrites and axon) Three types: afferent, efferent and

interneurones Functions:

1. transmit impulses/signals

2. controls and coordinates all activities of the body

Exercise• Complete the table below about the functions of each tissue.

Types of tissues

Functions

1. Epithelial tissues

2. Muscle tissues

3. Connective tissues

4. Nerve tissues

AnswersTypes of tissues Functions

1. Epithelial tissues

ProtectionSecretionAbsorption

2. Muscle tissues Smooth muscles – involuntary actionsSkeletal muscles – voluntary actionsCardiac muscle – pump blood to all parts of the

body

3. Connective tissues

Bind structures togetherProvide support and protection

4. Nerve tissues Transmit signals Controls and coordinate all activities of the body

formed by two or more types of tissues working together to perform particular functions

individual tissues can’t carried out specific function of an organ

examples of organs – skin, heart, lungs, kidneys, eyes and ears

Organs

- Example :Skin

consist of several organs that work together to perform a common function

System

11 major system:1. Integumentary system2. Circulatory system3. Endocrine system4. Lymphatic system5. Nervous system6. Digestive system7. Muscular system8. Excretory system9. Skeletal system10.Respiratory system11.Reproductive system• Body system.doc