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 1. Locomotion

Description

3. Respiration

-Using cytoplasmic projection-extending its pseudopodia, anchoring the tips to the ground and followed by the flow of cytoplasm - Engulfs food by phagocythosis, feeds on microscopic organism -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

2. Feeding

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 efficiently division of labour enables organism to do various tasks and function efficiently and systematically achieve higher growth rate able to adapt and survive in diverse habitat and environment carry out all living process more efficiently

Cells Organisation In Humans

Tissues  four major types: 2. Epithelial tissues 3. Muscle tissues 4. Connective tissues 5. Nerve tissues

1. Types of epithelial tissues in human

Functions of epithelial tissues For protection, secretion and absorption Examples: 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).

2. Muscle tissues  Three types:  smooth muscle – found along the wall of digestive tract, blood vessels, bladder and reproductive tract which responsible for the involuntary actions of the body  skeletal muscle – attached to the bones of the skeleton which responsible for the voluntary movements of the body  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: 5. transmit impulses/signals 6. controls and coordinates all activities of the body

Exercise • Complete the table below about the functions of each tissue. Types of tissues 1. Epithelial tissues 2. Muscle tissues 3. Connective tissues 4. Nerve tissues

Functions

Answers Types of tissues

Functions

1. Epithelial tissues

Protection Secretion Absorption

2. Muscle tissues

Smooth muscles – involuntary actions Skeletal muscles – voluntary actions Cardiac muscle – pump blood to all parts of the body

3. Connective tissues

Bind structures together Provide support and protection

4. Nerve tissues

Transmit signals Controls and coordinate all activities of the body

Organs 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

- Example :Skin

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

 11 major system: 2. Integumentary system 3. Circulatory system 4. Endocrine system 5. Lymphatic system 6. Nervous system 7. Digestive system 8. Muscular system 9. Excretory system 10.Skeletal system 11.Respiratory system 12.Reproductive system •

Body system.doc