Understanding Human Cell Anatomy and Physiology

Oct 5, 2024

Anatomy and Physiology of the Human Cell

Introduction

  • Anatomy: Study of form and structure of organisms.
  • Physiology: Study of processes in living organisms, how they function.
  • Pathophysiology: Study of how disease affects normal functioning (to be covered separately).

Basic Structures of the Cell

Cell Membrane

  • Semi-permeable structure.
  • Allows nutrients to enter and waste to leave.
  • Keeps harmful substances out.
  • Maintains cell shape and organelles within.

Cytoplasm

  • Semi-fluid substance inside the cell.
  • Site where all chemical reactions occur.

Organelles

  • Structures within the cytoplasm responsible for cell functions.

Organelles and Their Functions

Nucleus

  • Brain of the cell.
  • Controls cell functions and division.

Nucleolus

  • Located within the nucleus.
  • Important in cell reproduction.
  • Manufactures ribosomes (RNA and protein composition).

Ribosomes

  • Move from nucleus to cytoplasm.
  • Sites for protein synthesis.

Chromatin

  • Located in the nucleus.
  • Loose thread-like arrangement of DNA and protein.
  • Forms chromosomes during cell division.
  • 46 chromosomes per human cell.
  • Chromosomes contain genes with specific DNA sequences.

Mitochondria

  • Powerhouse of the cell.
  • Breaks down carbohydrates, fats, proteins to form ATP (adenosine triphosphate).

Golgi Apparatus

  • Stack of membrane layers in cytoplasm.
  • Produces, stores, and packages secretions for cell discharge.

Endoplasmic Reticulum (ER)

  • Transports materials in/out of the nucleus.
  • Aids in synthesis/storage of proteins.
    • Smooth ER: Fat metabolism, cholesterol synthesis, drug detoxification (not in all cells).
    • Rough ER: Regions where ribosomes attach for protein production.

Lysosomes

  • Digest proteins and fats.
  • Break down old cells, bacteria, and foreign materials.
  • Important for the immune system.

Pinocytic Vesicles

  • Pocket-like folds in the cell membrane.
  • Allow proteins and fat molecules to enter.
  • Folds close to form vacuoles (bubbles in cytoplasm).

Summary

  • Cell structure includes: Cell membrane and cytoplasm.
  • Cytoplasm contains organelles responsible for cell functions:
    • Nucleus, nucleolus, ribosomes, chromatin, mitochondria, Golgi apparatus, endoplasmic reticulum, lysosomes, pinocytic vesicles.

Next Steps

  • Ready for the next video on cell reproduction.