Thursday, 21 January 2016

Tissues, Organs and Systems

Multicellular organisms are made of lots of different cell types, organised to work together. Cells that carry out the Same Function are organised into Tissues (i.e. epithelial), and Different Tissues are organised into Organs, and organs Work Together as Organ Systems.

Tissues
Tissue - A Group of Cells specialised to Work Together to carry out a Particular Function. A tissue can contain more than one cell type.

Examples:
Tissue Type
Explanation
Squamous Epithelium
Single Layer of Flat Cells lining a surface. It's found in many places, including the Alveoli and the Lungs
Ciliated Epithelium
A layer of cells covered in Cilia. It's found in places where things need to be   i.e. the trachea, to Waft Mucus.
Muscle Tissue
Bundles of Elongated cells (Muscle Fibres). There are 3 different types: Smooth, Cardiac, and Skeletal. They're all Slightly Different in structure.
Cartilage
A type of Connective Tissue found in the joints. It also Shapes and Supports the Nose and Windpipe. It is found where cells (chondroblasts) Secrete a Jelly-like substance containing Protein Fibres which become trapped inside.
Xylem Tissue
Two jobs - Transports Water, and Supports the plant. It contains hollow xylem vessel cells (dead) and parenchyma cells (living)
Phloem Tissue
Transports Sugars around the plant. It's Arranged in Tubes and is made up of Sieve Cells, Companion Cells and Regular Plant Cells.

Organs and Organ Systems
Organ - a Group of Different Tissues that Work Together to perform a Particular Function.

LUNGS - Contain squamous epithelial tissue (alveoli), Ciliated epithelial tissue (bronchi), and elastic connective tissue and vascular tissue (blood vessels).
LEAVES - Contain palisade tissue for photosynthesis, epidermal tissue to prevent water loss from the leaf, and xylem and phloem tissues in the veins. 

Each system has a particular function. The respiratory system is made up of the lungs, trachea, larynx, nose, mouth and diaphragm.
The circulatory system consists of the heart, arteries, veins and capillaries.

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