Fundamental Principles of Human Anatomy & Physiology: The Cell

Fundamental Principles of Anatomy & Physiology

Introduction to Cells

Cells are the basic structural and functional units of all living organisms. Understanding their components and functions is essential for the study of human anatomy and physiology.

• Three Main Parts of a Cell:

  • Plasma (Cell) Membrane: Encloses the cell, regulates entry and exit of substances, and facilitates communication.

  • Cytoplasm: The region between the plasma membrane and the nucleus, containing cytosol, organelles, and inclusions.

  • Nucleus: Contains genetic material (DNA) and controls cellular activities.

• Extracellular Fluid (ECF): Fluid outside the cell, including interstitial fluid (between cells in tissues), blood plasma, lymph, and cerebrospinal fluid (CSF).

• Intracellular Fluid (ICF): Fluid within the cell, primarily the cytosol.

• Cytoplasm vs. Cytosol:

  • Cytoplasm: Includes cytosol, organelles, and inclusions.

  • Cytosol: The fluid portion of the cytoplasm, where many metabolic reactions occur.

• Organelle: Specialized structures within the cell that perform distinct functions (e.g., mitochondria, endoplasmic reticulum, Golgi apparatus).

Additional info: The study of cells (cytology) is foundational for understanding tissue, organ, and system-level physiology.