2.3 CELL ORGANIZATION The human body is organised in the following way: The organisation of cells in this way enable multicellular organisms to carry out various processes of life such as moving, breathing and reproduction.
Jun 20, 2015
2.3 CELL ORGANIZATION
The human body is organised in the following way:
The organisation of cells in this way enable multicellular organisms to carry out various
processes of life such as moving, breathing and reproduction.
CELLS• Cells performing a particular type of
work are similar in many respects.
• Different cells carry out different types of work and are modified accordingly.
• The human body is made up of various cells that carry out specific functions in the body.
Nerve cell: receive and transmit sensations and nerve impulses
Red blood cell: transport oxygen in the body
Epithelial/ skin cells: prevent the loss of water from the body
Reproductive cells: take part in fertilisation process
Skeletal muscle cell: Controls movements of bones and organs of body
Bone cells: support and protect organs
White blood cell: protect the body from being attacked by microorganisms
TISSUE• Tissue is a group of similar cells that
performs the same work.
• Example: muscle tissue is made of muscle cells.
• There are many types of tissues which include covering tissue or protective tissue, supporting tissue, connecting tissue, muscle tissue, nerve tissue, etcetera.
• Our bodies possess four specific types of tissues which include:
1. Epithelial tissue2. Connective tissue
3. Muscle tissue4. Nerve tissue
ORGANS • An organ is a group of different tissues
performing a particular kind of work.
• An organ consists of two or more type of tissues that perform a certain functions.
• Each type of tissue in an organ helps that organ to perform its function.
• Example: each type of tissue in the heart organ helps it to pump blood to all parts of the body.
SYSTEM • A system is a few organs that work
together to perform a certain function in a life process.
• The systems such as the digestive system, the reproductive system, the excretory system and others work together in harmony in an organism.
Muscular system
Function: contracts and relaxes muscles to move the body
Skeletal system
Function: supports and protects the inner organs of the body
Digestive systemFunction: breaks up food into simpler form so that it is easily absorbed by the body
Respiratory systemFunction: absorbs oxygen and get rids of carbon dioxide and vapour from the body
Blood circulatory systemFunction: transports food substances, oxygen, carbon dioxide and excretory products in the body
Function: responds to sensation from the surroundings and sends impulses from one part of the body to another
Excretory system
Function: removes excretory waste such as urea
Reproductive system
Testis
Penis
Male reproductive system
Function: produces young for the next generation
Organs in systemSystem Organs in systemMuscular All types of muscles and tendonsSkeletal Bones, cartilage, joints, ligamentsDigestive Mouth, oesophagus, stomach, pancreas,
intestines, liverRespiratory Nose, trachea, lungs, bronchus, bronchiole,
alveolusBlood circulatory
Heart, veins, arteries
Nervous Brain, spinal cord, nervesExcretory Kidney, skin, liver, urinary bladder, lungsreproductive Testis, ovary