Year 9 Science Organisation of the Human Body

(a) ORGANISM An individual living creature. Plant or animal. A person is an example of an Organism.

(b) BODY SYSTEMS A group of body organs that work together. This is the Digestive System – it breaks down our food. Body systems: Skin, Skeletal, Muscular, Lymphatic (drains fluids), Urinary, Digestive, Circulatory, Endocrine (hormones), Nervous, Respiratory (breathing), Reproductive

(c) ORGANS Two or more different tissues that work together to perform a common function (job). This is a picture of the stomach, an organ in the Digestive System.

This picture shows the wall of the stomach – with different tissue layers, including muscle. (d) TISSUES Tissues are layers of similar cells that perform special functions – muscle, bone and nerves are types of tissues.

(e) A Cell is the basic structural and CELLSfunctional unit for life. Humans are made up of approx. 60 to 100 trillions of cells. Different types of cells perform different jobs in the body. This is a picture of Muscle Cells from the stomach.

Bone Cells These are some of the different cells in the human body. Red and White Blood Cells Cheek Cells List four different types of cells in your books. Nerve Cell Muscle Cells

(f) PARTS OF CELLS (ORGANELLES) Organelles are special parts of the cell. They perform specific functions. E. g. The nucleus of the cell is like its brain. This is a picture of an Animal Cell with Organelles labelled. Can you find the nucleus?

CELLS ARE SMALL…… 1 cm = 10 mm 1 mm = 1000µm (µm is microns) An average cell is about 1/5 of the size of the smallest dot you can make with your pen. A red blood cell is an average sized cell. It is approx. 8µm (0. 008 mm) in diameter – you need a microscope to see it.

Fertilised Ovum (egg cells) are the largest cell in the body at approx. 120µm (0. 125 mm)– you may be able to just see these without a microscope Sperm cells are the smallest cells in the body – their heads are only 4µm (0. 004 mm) wide, but their tails are about 25 µm long (0. 025 mm).

ANIMAL CELLS White Blood Cells (fight infection)

PLANT CELLS Onion Cells

ANIMAL CELLS

PLANT CELLS

COMPARISON BETWEEN ANIMAL AND PLANT ANIMAL CELLS PLANT CELLS Has a thin cell membrane that allows things like water to get through. Has a thick cell wall that gives the cell (and plant) its shape. Has a flexible shape (usually rounded and fluid). Has a definite shape (usually rectangular or square). Has very small vacuoles to store water for the animal. Has large vacuoles to store water for the plant. Does not contain chlorophyll to produce food. Contain chlorophyll, a green substance, that is used to produce food in a process called photosynthesis. This is why they are called producers.