In this chapter, you will learn«
that cells of similar structures are organised into tissues that several tissues may make up an organ that organs are organised into systems to explain the significance of division of labour
Unicellular Organisms
Paramecium
Amoeba
Unicellular Organisms
Paramecium
± Microscopic organism ± Found on surface of water (eg: pond, river) ± Has hair surrounding the body for movement ± Has a mouth
Unicellular Organisms
Amoeba
± Often found at bottom of ponds or under rocks ± Does not move fast ± No arms, legs, eyes, mouth ± Eats by surrounding its prey with its body ± Lives only for 2 days ± Reproduce by spliting itself into 2 new amoebas
Multicellular Organisms
Have many different cells Different cells perform different functions Examples
± Plants ± Humans
Cells in a Human
Examples ± Red blood cell (transport
oxygen)
± Nerve cell (have nerve fibres
to transmit signals to and from the central nervous system)
Cells in a Plant
Examples ± Root hair cell ± Leaf guard cell
From cells to tissues
Tissue ± roup of similar cells that are specialised to perform a particular function
Tissues in a Human
Epithelial tissue ± Covering or lining tissue to protect structure beneath it Connective tissue ± Joins, stores or supports all parts of an organism
Tissues in a Human
Muscle tissue ± Cause movement Nerve tissue ± Carry messages from one part of body to another by conducting electrical signals
Tissues in a Plant
Epidermal tissue ± Protects plant against injury and losing too much water Vascular tissue ± Transports materials within a plant
Tissues in a Plant
Photosynthesis tissue ± Carries out photosynthesis in a plant
From Tissues to Organs
Organ ± roup of specialised tissues that are gathered in a certain part of the body to perform a particular function together
Organs in a Human
Examples
± Skin ± Lungs ± Heart
Organs in a Plant
Examples
± Leaves ± Stem ± Roots ± Flowers
From Organs to Systems
System ± Different organs working together to perform a major function in an organism
Main Organ Systems in a Human
Respiratory system Digestive system Blood circulatory system Skeletal system Muscular system
Respiratory System
Nasal Passage Pharynx Larynx Trachea
Bronchioles
Bronchus
Alveoli
Respiratory System
Respiration
± Process in which cells release energy from the food we eat ± Oxygen is required ± Carbon dioxide is removed
Respiratory System
Mechanics of breathing
Exhalation
Inhalation
Digestive System
Mouth Pharynx
Oesophagus Liver Stomach Large Intestine Small Intestine Villi
Digestive System
Digestion ± Process in which large, insoluble food substances are broken down into smaller, soluble food substances for absorption into blood
Blood Circulatory System
Blood Circulatory System
Transports nutrients, gases, water and hormones to different parts of the body Include red blood cells, white blood cells, heart, blood vessels
Red blood cells White blood cells
Skeletal System
Skeletal System
Supports our body Gives us shape Protects our organs Enables movement
Muscular System
Deltoid Pectoralis major Biceps brachi
Gluteus maximus Rectus femoris
Gastrocnemius
Muscular System
Enables movement by contraction and relaxation of muscles 3 muscle types:
± Skeletal muscles ± Smooth muscles ± Cardiac muscles
Other systems in Human
Reproductive System - Produces sex cells (sperm, ovum) - For reproduction Nervous System - Consists of the brain, spinal cord and nerves found throughout our body - Controls and coordinates functions throughout our body - Enables us to respond to changes around us
Male Reproductive System
Urinary bladder Vas deferens Prostate gland
From Systems to Organisms
Organism ± Made up of different systems working effectively in a coordinated manner
The Human Body - An organism CELLS TISSUES ORGANS SYSTEMS ORGANISM
Division of Labour
Each cell in a multicellular organism does not perform all the bodily functions. Each type of cell specialises in performing one particular function. Different functions in a multicellular organism can be performed at the same time by division of labour.
Division of Labour
Division of labour ± Sharing different functions in an organism among its cells, tissues, organs and systems ± Ensures smooth running and effective working of the different parts in an organisms as well as the organism as a whole