CELL BIOLOGY

 CELL:

It is defined as structural and functional unit of the living body.

General Characterstics of cell:

Each cell in the body -

1. Needs Nutrition and oxygen 

2. Produces its own energy - required for growth, repair and other activites.

3. Eliminates co2 and other metabolic wastes 

4. Maintains the medium i.e. Environment for its survival.

5. Shows immediate response to the entry of invaders such as bacteria / toxic substances into the body.

6. Reproduces by divison ( no exception such as neuron, which do not reproduce. 

FORMATION:

CELL ---> TISSUE ---> ORGANS ----> SYSTEMS

Tissue:

Def- Group of cells havig smiliar function.

It is classified into main 4 types called as " Primary Tissue"

1. Muscle Tissue - skeletal , smooth and cardiac muscle

2. Nervous Tissue - Neurons and supporting cells 

3. Epithelial Tissue - squammous, columnar and cuboidal epithelial cells

4. Connective Tissue - Connective tissue proper, cartilage, bone and blood.

Organ:

Def - Structure i.e. formed by 2 or more primary types of tissues which execute the function of organ.

Types:

1. Tubular / Hollow organs 

2. Compact / Parenchymal organs

Systems:

Def - Group of organs that work together to carry out specific functions of the body.

Types:

1. Digestive system

2. Excretory system

3. Cardiovascular system

4. Respiratory system

5. Reproductive system

6. Enodcrine system

7. Musculoskeletal system

8. Nervous system