Organisation of the human body

Organisation of the human body

Body is made up of approximately 30 to 40 trilion cells 0 of which there are 230 different types

4 structural level: Cells → Tissues → Organs → Systems

Cells

Basic building blocks of all living things, and the human body is made up of triilions of them

All cells share some common features

Provide structure, take in nutrients, convert energy carry out specialised functions, contain hereditary material, able to make copies of themselves

Cells also contain specialised parts called organelles, performs a specific function within the cell

Different type of cells in the human body

Tissues

Consist of large numbers of the same type of cells and are classified according to the size, shape, functions of their cells

• epithelial tissue/ epithelium

• connective tissue

• muscle tissue

• nervous tissue

Epithelial tissue

Covers the body and lines inner, outer body surfaces, hollow organs and tubes

Protects the body and its internal organs, secretes substances such as hormones, absorbs substance such as nutrients

The cell are very closely packed and the extracellular substance, the matrix, is minimal

Connective tissue

The most ubundant tissue in the body

The connective tissue cells are more widely separated from each other than in epithelial tissues, extracellular substance ( matrix )is present in considerably larger amounts

Fibers present in the matrix, form a supporting network for the cells to attach to

Connective tissue function

Binding and structural support

Protection

Transport

Insulation

Types of connective tissue

Muscular tissue

Can contract and relax, providing movement within the body and of the body itself

Cell are elongated

Cells are densly packed and contain minimal extracellular matrix

• Skeletal muscle

• Smooth muscle

• Cardiac muscle

Nervous tissue

Made up of specialised cells called neurons that can carry electrical impulses

Very little extracellular matrix

Specialised junctions calles synapses facilitate rapid impulse transmission

Found in the brain and the spinal cord

Organs

A tructure in the body made up of different types of tissues that work together to perform a specific function

Contains around 78 organs

Systems

Groups of organs that work together to carry out major functions needed to keep the body alive

Each system has a specific role, such as breathing, digestion, transport, movement, all body systems work together to maintain a stable internal environment