뒤로Cytology and Cell Membrane Transport - Anatomy & Physiology
04:26
이 집합의 용어 (20)
Cytology is the study of cells.
A cell is the structural and functional unit of life. The organism's function depends on all cells, and cell structure and function are complementary.
1) Plasma membrane (flexible outer boundary), 2) Cytoplasm (fluid with organelles), 3) Nucleus (DNA-containing control center).
Acts as an active barrier separating intracellular fluid from extracellular fluid and controls what enters and leaves the cell.
Consists of a phospholipid bilayer with polar heads facing water and nonpolar tails inside, with floating specialized membrane proteins (fluid mosaic model).
Proteins firmly inserted into the membrane, mostly transmembrane, with hydrophobic and hydrophilic regions, functioning as transport proteins, enzymes, and receptors.
Loosely attached to integral proteins; function as enzymes, motor proteins, cell-to-cell connectors, and identification markers.
Tight junctions (impermeable seals), desmosomes (anchoring junctions reducing tearing), and gap junctions (channels for small molecule and ion passage).
Movement of substances down their concentration gradient without energy, including diffusion and filtration.
Simple diffusion (hydrophobic substances), facilitated diffusion (carrier or channel-mediated for hydrophilic molecules), and osmosis (water movement).
Passive transport of hydrophilic molecules via carriers or channels down their concentration gradient.
Movement of water across a selectively permeable membrane from low solute (high water) to high solute (low water) concentration.
Tonicity is a solution's ability to change cell shape by altering water volume: isotonic (no change), hypertonic (cell shrinks), hypotonic (cell swells).
Movement of solutes against their concentration gradient using ATP energy.
Uses ATP to change protein shape and pump solutes across membrane, e.g., Na+-K+ pump.
Uses ion gradients created by primary active transport to move other molecules, like sugars and amino acids, into the cell.
Transport of large particles or fluids via vesicles, including endocytosis (into cell) and exocytosis (out of cell).
Phagocytosis is 'cell eating' (solids), pinocytosis is 'cell drinking' (liquids), both forms of endocytosis.
Vesicle merges with plasma membrane to release substances like hormones, waste, or mucus outside the cell.
They act as receptors, transporters, enzymes, and identification markers to interact with the environment.