Anatomy and Physiology: Chapter 2 - Cells and Tissues

Key Concepts:

• Organization Levels: Atom → Cells → Tissues → Organs → Systems → Organism

Cells

• Complexity: Cells are complex with components like a control center, internal transportation system, power plants, material factories, and packaging plants.
• Size and Observation: Most cells can only be observed under a microscope:
  • Light Microscope: Uses visible light.
  • Electron Microscope: Provides detailed views of cells.
• Photograph Types:
  • Light Micrograph (LM)
  • Electron Micrograph (EM)

Cell Components

• Gelatinous Substance: Composed of water, proteins, sugars, fats, and minerals.
• Major Parts:
  • Cell Membrane: Thin plasma membrane; regulates substances entering/leaving the cell.
  • Nucleus: Control center; contains nuclear envelope with pores.
  • Chromosomes: Loosely coiled chromatin that condenses during cell division.
  • Gene: Chemical DNA; regulates cell activities.
  • Karyotype: Photograph of chromosomes; used to detect abnormalities.
  • Cytoplasm: Contains cellular components.
  • Mitochondria: Power plants of the cell; play a role in cellular respiration and apoptosis.
  • Endoplasmic Reticulum (ER):
    • Rough ER: Contains ribosomes; involved in protein manufacturing.
    • Smooth ER: Synthesizes steroids, phospholipids, and fatty acids.
  • Golgi Apparatus: Processes and packages proteins; produces lysosomes.
  • Lysosomes: Digestive enzymes; break down foreign matter.
  • Vesicles and Vacuoles: Transport and storage within the cell.
  • Cytoskeleton: Provides structural support and helps with cell movement.

Cell Membrane Function

• Selective Permeability: Allows certain substances to move in/out passively through diffusion, osmosis, and filtration.
• Active Transport: Requires energy (ATP); moves substances against concentration gradients.
  • Examples: Sodium-potassium pumps, phagocytosis, and pinocytosis.

Cell Communication

• Signal Process:
  1. Signal sent (e.g., hormone).
  2. Reception by target cell receptors.
  3. Signal transduction.
  4. Cellular response.

Cell Division

• Mitosis: Process of cell division with stages:
  • Prophase: Chromatin coils into visible chromosomes.
  • Metaphase: Chromosomes align in the center.
  • Anaphase: Chromatids separate.
  • Telophase: Chromosomes uncoil; nuclear membrane re-forms.

Tissues

• Definition: Groups of cells working together.
• Types:
  • Epithelial Tissue: Protection and secretion; forms glands.
  • Connective Tissue: Supports and protects; types include bone, blood, cartilage, etc.
  • Muscle Tissue: Specialized for contraction; types include skeletal, cardiac, and smooth muscle.
  • Nervous Tissue: Transmits information; includes neurons and glial cells.

Membranes

• Types of Membranes:
  • Epithelial Membranes: Cover/line body surfaces.
  • Mucous Membranes: Line cavities opening to the outside.
  • Serous Membranes: Line closed body cavities.
  • Connective Tissue Membranes: Cover bones/cartilage.

Conclusion

• Understanding of cell structure, function, and communication is crucial for further studies in human physiology and understanding diseases.
• The knowledge from the Human Genome Project has been pivotal in advancements in medical technology and treatments.