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

Respiratory System Nasal Passage Pharynx Trachea Bronchus Larynx Bronchioles 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 Villi Mouth Liver Pharynx Stomach Large Intestine Small Intestine Oesophagus

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

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 Urethra Penis Seminal vesicle Epididymus Testis

Female Reproductive System Sagittal View Anterior View Fallopian tube Ovary Uterus Vagina Uterus Vagina Fallopian tube Urinary bladder

Nervous System Cerebrum Corpus callosum Cerebellum Thalamus Hypothalamus Midbrain Pons Medulla oblongata Spinal cord

Plant Transport System

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