Understanding Cell Biology: Structure, Tissues, and Systems
The Cell: Fundamental Unit of Life
All living organisms are formed by cells, which remain the functional and structural unit of life. Cells are capable of performing three vital functions: relationship, nutrition, and reproduction. Every cell contains three basic structures: the plasma membrane, the nucleus, and the cytoplasm.
Cellular Morphology
- Disc-shaped: Such as red blood cells.
- Binocular: Prism-shaped.
- Spindle: Spindle-shaped.
- Stellate: Star-shaped.
- Irregular: Various distinct shapes.
When many cells unite, they form a tissue, such as skin.
Biological Tissues
- Integumentary: Protective tissue on the outside of the body.
- Mucous: Tissue protecting internal cavities.
- Adipose: Reserve tissue that stores fat.
- Bone: Supporting tissue.
- Glandular: Secretory tissue.
- Connective: Connects tissues and surrounds organs.
- Muscle: Responsible for movement.
- Nervous: Responsible for coordination.
Systems and Apparatus
Systems consist of various organs associated to perform the same function, often with a preponderance of a single tissue type.
Nutrition Function
Through this function, human beings incorporate nutrients needed for growth. It involves:
- Gastrointestinal: Enters and transforms food into nutrients.
- Respiratory: Incorporates oxygen needed by cells.
- Circulatory: Carries oxygen and nutrients to all cells.
- Urinary: Filters blood to remove wastes.
Relationship Function
Living things relate to each other and their environment using the sense organs, nervous system, endocrine system, and the locomotor system.
Reproduction Function
This function is achieved to perpetuate the species through reproductive processes.
Cytoplasm and Organelles
The cytoplasm is the material between the plasma membrane and the nucleus. Major organelles include:
- Mitochondria: Produces energy.
- Chloroplasts: Present only in photosynthetic organisms.
- Ribosomes: Sites where proteins are produced.
- Endoplasmic Reticulum: A set of tanks extending from the nucleus throughout the cytoplasm.
- Golgi Apparatus: Stacked tanks involved in sugar metabolism.
- Vacuoles: Membrane-bound spaces where substances are stored.
- Lysosomes: Small vesicles with a digestive function.
- Centrosome: The center from which cell division begins.