Lecture on Amoebas and Human Anatomy

Amoebas

• Single-celled life forms
• Simplistic, perform all functions within one cell
• Not reliant on multiple cells or structures for survival

Human Complexity

• Multicellular organisms with specialized cells
• Cells have unique roles to maintain homeostasis
• Structured in a complex hierarchy contributing to organism's function

Tissues and Organs

Tissues

• Groups of similar cells performing a common function
• Term “tissue” means “woven”
• Four primary tissue types: nervous, muscle, epithelial, connective

Nervous Tissue

• Provides control and communication
• Two cell types:
  • Neurons: Generate and conduct electrochemical nerve impulses
    • Parts of a neuron: cell body (soma), dendrites, axon
  • Glial Cells: Support, insulate, protect neurons
• Makes up the central nervous system (brain, spinal cord) and peripheral nervous system

Muscle Tissue

• Facilitates movement (voluntary and involuntary)
• Three types:
  • Skeletal Muscle: Voluntary, attaches to bones, supports and moves the body
    • Long, cylindrical cells, striated, multinucleate
  • Cardiac Muscle: Involuntary, found only in the heart
    • Striated, usually uninucleate, branched cells linked by intercalated discs
  • Smooth Muscle: Involuntary, lines walls of blood vessels and hollow organs
    • Non-striated, short tapered cells

Epithelial Tissue

• Lines body cavities and organs, provides protection

Connective Tissue

• Provides support within the body

Histology

History of Histology

• Dependent on microscope invention in the 1590s
• Hans and Zacharias Jansen: Early microscopes
• Anton van Leeuwenhoek: High-power microscopes with up to 270x magnification
• Observed microorganisms, bacteria, spermatozoa, and muscle fibers

Development of Stains

• Critical for studying tissues
• Joseph von Gerlach (1850s): Successfully used carmine stain
  • Important for neural tissue and observing brain cells

Practical Application

Identifying Muscle Tissue Samples

• Recognition of tissue types based on traits such as striations, cell shapes, nuclei count
  • Cardiac Muscle: Branching, striated, uninucleate, intercalated discs
  • Smooth Muscle: Uninucleate, non-striated
  • Skeletal Muscle: Long cells, striated, multinucleate

Conclusion

• Understanding tissue types aids in reading, understanding, and interpreting biological structures
• Supports comprehension of the body's structure and functions