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Anatomy & Physiology: Transport, Diffusion, and Intercellular Junctions

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Terms in this set (20)

  • What is diffusion in the context of cell transport?

    Diffusion is the passive movement of molecules from an area of higher concentration to an area of lower concentration.

  • What factors affect the rate of diffusion?

    Factors include concentration gradient, temperature, molecule size, and membrane permeability.

  • Define passive transport.

    Passive transport moves substances across membranes without energy input, relying on concentration gradients.

  • What is active transport?

    Active transport requires energy (ATP) to move substances against their concentration gradient.

  • Name the main types of intercellular junctions.

    Tight junctions, desmosomes, and gap junctions.

  • What is the function of tight junctions?

    Tight junctions seal cells together to prevent leakage of molecules between them.

  • Describe desmosomes.

    Desmosomes are anchoring junctions that provide mechanical strength by linking cytoskeletons of adjacent cells.

  • What role do gap junctions play?

    Gap junctions allow direct communication and passage of ions and small molecules between adjacent cells.

  • How does facilitated diffusion differ from simple diffusion?

    Facilitated diffusion uses carrier proteins to move molecules down their concentration gradient, unlike simple diffusion which is direct.

  • What is osmosis?

    Osmosis is the diffusion of water across a selectively permeable membrane from low to high solute concentration.

  • Explain the importance of the concentration gradient in diffusion.

    The concentration gradient drives diffusion; molecules move from high to low concentration to reach equilibrium.

  • What is the difference between intercellular and extracellular transport?

    Intercellular transport occurs between cells, while extracellular transport involves movement outside cells.

  • How do intercellular junctions contribute to tissue integrity?

    They connect cells physically and functionally, maintaining tissue structure and communication.

  • What is the role of carrier proteins in transport?

    Carrier proteins facilitate the movement of specific molecules across membranes, often in facilitated diffusion or active transport.

  • Define endocytosis.

    Endocytosis is the process by which cells engulf substances into vesicles to bring them inside.

  • Define exocytosis.

    Exocytosis is the process of vesicles fusing with the membrane to release contents outside the cell.

  • What is the significance of selective permeability in membranes?

    It allows cells to control the internal environment by regulating substance entry and exit.

  • How does temperature affect diffusion?

    Higher temperatures increase molecular movement, speeding up diffusion.

  • What is the difference between paracellular and transcellular transport?

    Paracellular transport passes substances between cells; transcellular transport passes substances through cells.

  • Why are intercellular junctions important in epithelial tissues?

    They maintain barrier function and regulate passage of substances between body compartments.