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82 Cards in this Set
- Front
- Back
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What ions exerts the greatest influence on the membrane potential?
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K+
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Why does K+ exert a greater influence in the generation of the resting membrane potential than Na+?
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more leak channels for K+ than Na+
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In a cell at 'rest' where the RMP is -70 mV, what are the directions of the electrical gradients for Na+ and K+?
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both are inward
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What are the directions of the electrical gradients for Na+ and K+ at the peak of an action potential
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both are outward
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Why can't you get action potential in a patch of membrane from the soma or dendrites?
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no voltage-gated channels present in this region
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What is it called if the membrane potential in a cell were to change from -62mV to -37mV?
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a depolarization
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How many output neurons characterize the somatic nervous system?
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one
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What do somatic motor neurons innervate?
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skeletal muscle
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What is the name of the near-cell contact between a muscle cell and a neuron?
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neuromuscular junction
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What ratio accurately describes the number of action potentials that must reach the NMJ before the sarcolemma will fire its own ATP?
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1:1
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What muscle type is exclusively-neurogenic and multinucleate?
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skeletal muscle
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Do contractile proteins actually shorten during muscle contraction?
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False
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What shortens in length during a contraction?
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H and I bands
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What is the mechanism responsible for sequestering Ca++ ions within the sarcoplasmic reticulum?
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primary active transport by a carrier protein, a Ca++ metabolic pump, a Ca++ ATPase
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What causes a muscle fiber to relax?
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restoring intracellular Ca++ levels to their normal intracellular concentration, inhibition of an excitatory somatic motor neuron
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The corticospinal tract and the somatic nervous system are one and the same?
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False
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a somatic motor neuron and all the muscle fibers it innervates
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motor unit
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There is a baseline level of muscle contraction even in a relaxed muscle
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True
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What is the result of activating a Golgi tendon organ?
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inhibition of somatic motor neurons that innervate extrafusal fibers
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What chemical bond results from shared electrons between two atoms?
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Covalent bonds
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Hydrogen bonds exist between_______.
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the hydrogen and oxygen atoms of noncovalently-bond water molecules
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What would happen to the pH of a cup of distilled water if you added Hydrogen ions to it?
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the pH would decrease
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What would likely happen to cells within a tissue if the ISF became hypotonic?
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cell volume would increase drastically
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What substance would probably dissolve in an aqueous (water-based) solution?
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polar covalent molecules
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able to reverse the direction of the variable, and maintain it within a viable range
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negative feedback loop
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What is the transport process of 'facilitated diffusion' like the process of 'simple diffusion'?
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both are passive processes
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What is the rate-limiting feature of facilitated diffusion?
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The saturation of the carrier protein substrate receptors
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There are fewer potassium ions in the ISF than there is in the ICF
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Concentration gradients
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What is the primary reason for the -creation- of a negative membrane potential across a cell membrane?
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the unequal distribution of sodium, and potassium, leak channels
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Regulatory protein?
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troponin
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What is the primary reason for the -maintenance- of a negative membrane potential across a cell membrane?
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the action of sodium/potassium metabolic pumps
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pumps more cations out of the cell than it pumps cations into the cell
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sodium/potassium ATPase
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Can action potentials be summed?
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yes
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Can graded potentials be summed?
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no
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What is the mechanism that limits the flow of information to one direction?
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refractory periods
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Can action potentials be changed?
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no
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A neuron depolarized to the threshold membrane potential will release neurotransmitter from its axon terminals?
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True
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A hyperpolarized neuron can release neurotransmitter from its axon terminals?
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False
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IPSPs result from the opening of Na+ ligand-gated channels.
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False
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Neurotransmitters may be either excitatory of inhibitory at the same synapse.
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False
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subdivisions of the autonomic nervous systems?
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enteric nervous system, sypathetic, and parasympathetic
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What has the fastest rate of neurotransmission?
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myelinated axon
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organ-system?
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cardiovascular
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What connective tissues line body cavities, and organs?
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epithelial
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a dynamic equilibrium
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homeostasis
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The matrix component of connective tissue is?
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ISF and the ECF compartments
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What tissues are designed for rapid communication within the body?
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nervous
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Where are voltage-gated channels?
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transmitting ends of neurons
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Extracellular fluid compartments?
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Plasma and ISF
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skeletal?
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voluntary,myogenic, contract, and striated
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cardiac?
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involuntary, cardiac, contract, and striated
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What are Exocrine glands made from?
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epithilial tissue
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atoms?
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electrically neutral
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both + and - charged
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ions
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How do ions move through channel proteins?
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diffusion
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Where are ligand gated channels located on a neuron?
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dendrites and soma
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What is needed for a neuron to reach threshold?
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summation
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What two things are required for AP to occur?
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threshold membrane potential and voltage gated channels
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Mechanism that results in the hyperpolarization of the entire neuron?
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post synaptic inhibition
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What type of graded potential is required to change the Vm from -70 to -80 mv?
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IPSP
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Why are nmj's always excitatory?
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influx of Na+ and depolarization
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What is needed to break a cross-bridge?
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ATP
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A "cross-bridge" forms between what 2 things?
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actin and myosin
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Somatic motor neuron innervated with skeletal muscle
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motor unit
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monitor tension and respond with inhibiting muscle
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GTO
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monitors stretch and respond with contraction?
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muscle spindles
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Contractile proteins?
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myosin and actin
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Regulatory proteins?
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Troponin and Tropomyosin
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Accessory proteins?
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Nebulin and titin
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Na+K+ pump?
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3 Na+ out and 2 K+ in
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runs through both thick and thin filaments, for structural support
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titin
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Just in the actin filaments, for structural support
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nebulin
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Absolute refractory period
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absolutely no more AP's
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Relative refractory period
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relatively generate AP's
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Connective tissues
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bone, brain
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Homeostasis is a fundamental property of?
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cells
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Exchanges of substances are made between?
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fluid compartments
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What happens to a cell in the body if the intersistial fluid around it becomes hypotonic?
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the cells swells
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Distribution of Na+ and K+?
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there is much more Na+ outside than inside the cell, and much more K+ inside than outside the cell
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The distance between membranes at a chemical synapse is measured in?
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millivolts
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What type of monitoring mechanism responds to changes in skeletal muscle length?
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Motor unit
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What shortens during a muscle fiber twitch?
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I band
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