Body Organization and Homeostasis Flashcards

  • Levels of Structural Organization:

    • Molecules: The basic chemical units that come together to form cells.

    • Cells: The smallest units of life; groups of similar cells create tissues.

    • Tissues: Groups of similar cells working together for a specific purpose. Different tissues form organs.

    • Organs: Structures made of two or more tissue types that perform specific functions.

    • Organ Systems: Groups of organs that work together to perform broad functions within the body.

    • Organism: A fully developed individual organism, representing the highest level of organization.

  • Primary Tissue Types:

    • Epithelial Tissue: Covers surfaces and lines internal cavities; it’s protective and involved in absorption.

    • Connective Tissue: Supports structures, binds other tissues together, and stores energy.

    • Muscular Tissue: Helps in movement by contraction.

    • Nervous Tissue: Transmits signals through electrical impulses, facilitating communication in the body.

  • Characteristics of Epithelial Tissue:

    • Layering:

      • Simple Epithelium: One layer of cells, suitable for quick transport.

      • Stratified Epithelium: Multiple layers for protection.

    • Shapes of Cells:

      • Squamous: Flat and thin cells.

      • Cuboidal: Cube-like cells.

      • Columnar: Taller, column-like cells.

    • Functions:

      • Diffusion: Thin layers like in the lungs for gas exchange.

      • Absorption and Secretion: Seen in the intestines for nutrient absorption.

      • Protection: Multi-layered skin prevents injury.

  • Types of Cell Junctions:

    • Tight Junctions: Seal cells together to stop leakage between them.

    • Gap Junctions: Allow communication by letting small molecules pass between cells.

    • Desmosomes: Anchor cells together to withstand stretching and movement.

  • Connective Tissue Structure:

    • Cells: Spread out in a material called the extracellular matrix.

    • Matrix: The non-living material that provides structure and supports cells.

    • Types of Connective Tissue:

      • Fluid: Blood.

      • Supportive: Bone and cartilage.

      • Fibrous: Tendons and ligaments.

  • Overview of Organ Systems:

    1. Integumentary System: Skin that protects and regulates temperature.

    2. Cardiovascular System: Heart and blood vessels that circulate blood.

    3. Lymphatic System: Lymph nodes that fight infections.

    4. Digestive System: Organs like the stomach and intestines for breaking down food.

    5. Respiratory System: Lungs that allow for gas exchange.

    6. Urinary System: Kidneys that filter wastes from blood.

    7. Skeletal System: Bones and joints that provide structure.

    8. Muscular System: Muscles that permit movement.

    9. Nervous System: Brain and nerves that coordinate actions and responses.

    10. Endocrine System: Glands that secrete hormones regulating body functions.

    11. Reproductive System: Organs involved in producing offspring.

  • Body Cavities:

    • Ventral Cavity: Front side, composed of the thoracic (chest) cavity and abdominal cavity.

    • Dorsal Cavity: Back side, includes cranial (skull) and spinal cavities.

  • Tissues and Membranes:     

    • Cutaneous Membrane: Skin that acts as a barrier.

    • Mucous Membrane: Lines openings to the outside, secreting mucus to protect.

    • Serous Membrane: Covers organs in closed cavities, reducing friction.     

  • Homeostasis:

    • The body’s ability to maintain a stable internal environment despite changes.

    • Feedback Mechanisms: Processes that help return to set points (e.g., blood pressure, body temperature). Negative feedback reduces changes, while positive feedback increases them.

  • Discussion on Feedback Mechanisms:

    • Blood pressure adjustments are a good example of negative feedback. The body works to bring it back to normal regardless of whether it goes up or down, whereas positive feedback amplifies a process until it achieves a specific result, like childbirth.