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Cells (Division of Labour ). Chapter 24. 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.
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Cells(Division of Labour) Chapter 24
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 • Group 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 • Group 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
Nasal Passage Pharynx Larynx Trachea Bronchus Bronchioles Alveoli Respiratory System
Respiratory System • Respiration • Process in which cells release energy from the food we eat • Oxygen is required • Carbon dioxide is removed
Exhalation Inhalation Respiratory System • Mechanics of breathing
Mouth Pharynx Oesophagus Liver Stomach Large Intestine Small Intestine Villi Digestive System
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 • 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 • Supports our body • Gives us shape • Protects our organs • Enables movement
Deltoid Pectoralis major Biceps brachi Gluteus maximus Rectus femoris Gastrocnemius Muscular System
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
Urinary bladder Vas deferens Prostate gland Seminal vesicle Epididymus Urethra Penis Testis Male Reproductive System
Fallopian tube Uterus Urinary bladder Vagina Anterior View SagittalView Fallopian tube Uterus Ovary Vagina Female Reproductive System
Cerebrum Corpus callosum Thalamus Hypothalamus Midbrain Cerebellum Pons Medulla oblongata Spinal cord Nervous System
From Systems to Organisms • Organism • Made up of different systems working effectively in a coordinated manner
CELLS TISSUES ORGANS SYSTEMS ORGANISM The Human Body - An organism
Division of Labour • Each cell in a multicellular organism does not perform all the bodily functions. • Each type of cell specialisesin 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