Chapter 3 A&P

• Cell theory: Smallest unit capable of all life functions and cells come from pre-existing cells
• Human cells have three basic parts: plasma membrane, cytoplasm, and nucleus
• Interstitial fluid is the fluid between cells and tissues in the body. Cells are submersed in this fluid.
• Blood Plasma is the fluid portion of blood
• Cerebrospinal fluid is the fluid surrounding nervous system organs
• Cellular secretions are secreted by the cell membrane and are not stored in the cell (saliva, mucus)
• Extracellular matrix is a substance that acts as glue to hold cells together
• Tight junctions for a tight seal between 2 or more adjacent cells. They are impermeable junctions and prevent molecules from passing between cells. Found in skin and digestive tissues.
• Desmosomes are junctions between cells that are in areas subject to abrasion. They are anchoring junctions. They bind cells together like molecular velcro and keep sells from tearing apart.
• Cadherins are proteins that create links to attach together in desmosomes
• Gap junctions are specialized junctions that allow the passage of ions and small molecules and they can act as communicating junctions. They are particularly important in heart cells and embryonic cells.
• Plasma membrane is an active barrier separating intracellular fluid from extracellular fluid
• Fluid mosaic model: The model of the cell membrane that describes the structure of the membrane as a series of fluid-filled compartments.
• Glycocalyx are complex sugars on all cell surfaces that aid in recognition, immune response, and communication. They are the "chemical fingerprint".
• Cholesterol is the backbone of the plasma membrane
• Phospholipids form the basic structure of the cell membrane.
• Proteins determine what functions the membrane can perform such as transport, communication, and joining cells to each other or the extracellular matric
• Carbohydrates are found on the outer surface of the membrane and allows recognition and immune response
• Integral proteins are proteins that span the entire plasma membrane
• Peripheral proteins are off to one side of the membrane
• Membrane protein tasks

  Transport

  Receptors for signal transduction

  Enzymatic activity

  Cell-cell recognition

  Anchoring/attachment to extracellular matrix

  Cell-cell joining
• Passive transport is the movement of substances from an area of high concentration to an area of low concentration and requires no energy
• Speed of diffusion is influenced by concentration, molecular size, temperature
• Simple diffusion allows very small molecules to pass through membrane or membrane channels (No energy needed)
• Facilitated diffusion is the movement of molecules (larger or non-lipid soluble or polar) across a membrane with the help of a protein (No energy needed)
• Certain hydrophobic molecules are transported passively down their concentration gradient through facilitated diffusion using carrier mediated facilitated diffusion or channel mediated facilitated diffusion.
• Channel mediated facilitated diffusion creates a pore across the membrane (ions)
• Carrier-mediated facilitated diffusion happens via a protein carrier specific for one chemical and the binding of solute causes transport protein to change shape
• Osmosis is the diffusion of a solvent such as water through a specific channel protein (aquaporin) or through the bilayer
• Osmolarity is the measurement of concentration of solute in a solution
• Isotonic solution has equal concentration of water and solute outside cell
• Hypertonic solution has a higher solute concentration outside of cell causing cell to shrivel
• Hypotonic solution has lower solute concentration outside of cell causing cell to swell/burst
• Active transport requires energy from ATP, moves against concentration gradient, can move molecules into or out of cells
• Antiporters are carrier proteins that can transport 2 substances in opposite directions with ATP
• Symporters are carrier proteins that can transport 2 or more substances in same direction with ATP
• Primary active transport directly invests ATP to transport (Sodium potassium pump) and secondary active transport is a result of primary occurring and is when something else hitches a ride across against its concentration gradient
• Endocytosis transports molecules into the cell by forming vesicles and fusing with the cell membrane
• Phagocytosis is cellular eating of a bulky particle by forming a projecting pseudopod (false foot) around it and enclosing it within a sac called a phagosome.
• Pinocytosis is when the cell gulps a drop of extracellular fluid containing solutes into tiny vesicles (non-specific/no receptors)