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Physiology Ch. 4
Biology of Cell
| Term | Definition |
|---|---|
| ___ and ___ pass through the plasma membrane freely | O2, CO2 |
| Simple diffusion | High -> low concentration. Small molecules, O2 and CO2. |
| Integral proteins | Membrane proteins embedded in membrane |
| Peripheral proteins | Membrane proteins not embedded |
| Cell surface receptors | Proteins in membrane that bind ligands (chemicals, NT). |
| Identity markers | Proteins in membrane that communicate with other cells where they belong in the body |
| Channels | Specific for one ion type, no ATP required. Can be leak or gated, and is important for muscle and nerve cells. |
| Symporters | Type of secondary transport where a molecule is moved in the same direction as the other |
| Antiporters | Type of secondary transport where a molecule is moved in the opposite direction as the other (Na+/K+) |
| Protein carriers | No ATP required, ligand comes in and protein changes shape to admit it in/out of cell. |
| Protein pumps | Requires ATP, pushes molec. against conc. gradient |
| Passive transport | No ATP required |
| Active transport | ATP required |
| Diffusion rate is affected by: | "Steepness" of conc. gradient and temperature (^T, ^movement) |
| The _____ the molecule, the ____ it is at diffusing. | Bigger, slower |
| Polar molecules _______ diffuse across membrane. | Do not |
| Facilitated diffusion | No ATP needed, high -> low. Can be carrier or channel mediated. Ex: GLUTs - glucose transport protein |
| Leak channels | Type of protein channel that is continuously open |
| Gated channels | Type of protein channel that is usually closed. Can be opened from ligands, voltage changes, or pressure changes based on type of protein |
| Uniporter | Can transport only one type of molecule. |
| _____ ions are inside the cell. | Potassium (K+) |
| _____ ions are outside the cell. | Sodium (Na+) |
| Aquaporins | Type of protein channel that facilitates osmosis |
| 1 osmol = | 1 mol solute particles (osmolarity) |
| Osmotic pressure | Determined by # of molecs in soln regardless of size, mass, or valence |
| Tonicity | Ability of soln to change volume/pressure of a cell by osmosis |
| Blood has a normal tonicity of ___. | 0.9% |
| Isotonic | No net flex movement of H2O |
| Hypotonic | H2O rushes in (Cells can lyse) |
| Hypertonic | H2O rushes out (cell shrinks) |
| Hemolysis | Rupturing of red blood cells |
| Primary active transport | Uses energy directly from ATP |
| Secondary active transport | Use electrochemical gradient across membrane to drive processing. Can be antiporters or symporters |
| Ion pumps | Na+/K+ is most famous. Establish conc gradient of cell. |
| Na+/K+ pump pumps ___ Na+ __ of the cell and ___ K+ ___ the cell. | 3, out, 2, into |
| Vesicular transport | Bulk transport that requires ATP |
| Exocytosis | Type of vesicular transport that allows chemicals to exit the cell. Ex: NTs |
| Endocytosis | Type of vesicular transport that allows chemicals to enter the cell. |
| Phagocytosis | Cellular eating, type of endocytosis. Used pseudopedia (false feet) |
| Resting membrane potential (rmp) | Electrical chemical gradient established by plasma membrane, essential for muscle and nerve function. From unequal distribution of ions and elec. charges |
| Rmp for inside of neuron: | -70 milivolts |
| Cell body (soma) | Plasma membrane enclosing a cytoplasm, containing a nucleus, golgi bodies, mitochondria, chromatophilic substance, and having no centrioles (because no mitosis) |
| Neurons contain many _______ in the cell body because they have a ______ metabolic rate. | Mitochondria, high |
| Dendrites | Branch off the cell body. Receive signals and conduct them to cell body. |
| Neurons have: | A cell body, dendrites, axon, cytoskeleton, synaptic knobs, and axon hillock |
| Axolemma | Plasma membrane of the axon |
| Telodendria | Ends of the axon |
| Synaptic knobs | Tips of telodendria that house synaptic vesicles to send signals along synaptic gap |
| Axon hillock | "Trip zone", beginning of axon connected to soma that senses threshold of signal |
| Action potential | Nerve impulse. When neuron is adequately excited, generates electric impulse that is conducted along axon. |
| Cell membrane potential | Inside membrane is more negative (bc of proteins), outside more + |
| Outside of the cell, there are more ___, ___, and ____. | Na+, Ca2+, Cl- |
| Inside the cell, there are more ____ and _____. | Proteins, K+ |
| Resistance | Opposes changes in current |
| _____ is a good conductor, ______ increase resistance. | Water, lipids |
| Pumps | Na+/K+ and Ca2+ in neurons, require ATP |
| Stages of voltage-gates ion channels: | Resting (closed), activation (opening), inactivation (closing) |
| Receptive segment | Functional segment of neuron including dendrites and cell body w/ chemically gated channels. |
| Initial segment | Functional segment of neuron including the axon hillock and Na+ and K+ voltage gated channels |
| Conductive segment | Functional segment of neuron including the axon and its telodendria |
| Transmissive segment | Functional segment of neuron including the synaptic knobs with its voltage gated Ca2+ channels and Ca2+ pumps |
| Polarization of action potential: | Polarized (-70mV) -> depolarized (after -55mV) -> repolarized (after 30mV) -> hyperpolarized (ending at -90mV) |
| Action potential stages in axon | Rmp=-70mV. After -55mV is reached, sodium voltage gates open and Na+ enters the cell. At 0mV, Na+ close and K+ opens and K+ leaves the cell until around -90mV (because K+ channels take longer to close). Finally, Na+/K+ pump activates to restore rmp. |
| Myelin _____ the axon. | Insulates |
| Graded potentials | Small, short lived changes in rmp. All of these added together can activate the axon hillock. |
| Exitatory postsynaptic potentials (EPSP) | Depolarization caused by Na+ entry (NTs) |
| Inhibitory postsynaptic potentials (IPSP) | Caused by K+ exit or Cl- entry |
| Summation | Occurs at axon hillock, adds EPSP and IPSPs to see if it reaches threshold for action potential (-55mV) |
| Spatial summation | When multiple locations receive NTs simultaneously |
| Temporal summation | A single neuron repeatedly releases NT and produces multiple EPSPs within very short period of time |
| All-or-none law | Must reach threshold for signal to pass. Signal can't be stronger/weaker; it either is or isn't |
| Depolarization | Beginning of a.p., from -55mV to 0mV |
| Repolarization | Return to - potential as K+ exit through channels |
| Hyperpolarized | Because K+ channels are slow to close (-90mV). Where Na+/K+ pumps kick in. |
| Polarized | Rmp |
| _____ are only found in the synaptic knobs of neurons. | Ca2+ |
| ________-gated channels are on the dendrites and soma. | Chemical (ligand) |
| Refractory period | During depolarization, during which nerve can't send another signal. |
| Synapses | Use chemical and electrical stimuli to pass information between neurons. Can be excitatory or inhibitory based on NT/signal. |
| ___/____ synaptic descriptors can only be ascribed to synapses that are directly interacting. | Pre, post |
| Electrical synapse | Gap junction |
| Acetylcholine (ACh) | NT at neuromuscular junction that is always excitatory to muscle |
| Neuron pools | Can be converging or diverging circuits |
| Converging circuit | Type of neuron pool where many neurons signal to one or two neurons, for important signals. |
| Diverging circuit | Type of neuron pool where one neuron goes to many. Ex: Walking, breathing, and chewing gum at same time. |
| _____ cells scoop NTs out of cleft. | Astroglial |
| At the synaptic knob, with the arrival of action potential: | Voltage-gated Ca2+ channels are opened, Ca2+ comes in and binds to certain proteins to allow vesicles of NT to undergo exocytosis to diffuse into synaptic gap. |
| Astrocytes | Star-shaped neuroglial cell that mops up excess Ca2+ and NT |
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