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Questions and Answers
Which of the following is NOT a characteristic of the resting membrane potential?
Which of the following is NOT a characteristic of the resting membrane potential?
Active transport differs from facilitated diffusion in that active transport:
Active transport differs from facilitated diffusion in that active transport:
Which of the following substances is least likely to cross cell membranes by simple passive diffusion?
Which of the following substances is least likely to cross cell membranes by simple passive diffusion?
Which of the following is NOT a characteristic of the action potential in skeletal muscles?
Which of the following is NOT a characteristic of the action potential in skeletal muscles?
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Which of the following is NOT required for contraction of skeletal muscles?
Which of the following is NOT required for contraction of skeletal muscles?
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Which of the following is NOT needed for proper function within a chemical synapse?
Which of the following is NOT needed for proper function within a chemical synapse?
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Smooth muscle differs from skeletal muscle in that:
Smooth muscle differs from skeletal muscle in that:
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In order to initiate skeletal muscle contraction, $Ca^{2+}$ should directly bind to:
In order to initiate skeletal muscle contraction, $Ca^{2+}$ should directly bind to:
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Which of the following is NOT one of the functions of proteins in the cell membrane:
Which of the following is NOT one of the functions of proteins in the cell membrane:
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What is this document's origin?
What is this document's origin?
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What can be logically inferred about the document's reliability, given its origin?
What can be logically inferred about the document's reliability, given its origin?
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Which of the following represents the most suitable application of the document's content?
Which of the following represents the most suitable application of the document's content?
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If the document contains inaccurate information, what is the potential consequence?
If the document contains inaccurate information, what is the potential consequence?
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Which action aligns with responsible engagement with the document's content uploaded by an anonymous student?
Which action aligns with responsible engagement with the document's content uploaded by an anonymous student?
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How does the nature of the content (uploaded by a student) affect its status as a reliable source?
How does the nature of the content (uploaded by a student) affect its status as a reliable source?
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What is the implication of the uploader choosing to remain anonymous?
What is the implication of the uploader choosing to remain anonymous?
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In what way might the document be useful despite its uncertain credibility?
In what way might the document be useful despite its uncertain credibility?
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How should you approach the document's information differently compared to peer-reviewed journal articles?
How should you approach the document's information differently compared to peer-reviewed journal articles?
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If the document contradicts information from a trusted textbook, what action should be taken?
If the document contradicts information from a trusted textbook, what action should be taken?
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Which of the following ions is directly required for the release of neurotransmitters at chemical synapses?
Which of the following ions is directly required for the release of neurotransmitters at chemical synapses?
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What primarily determines the resting membrane potential in cells?
What primarily determines the resting membrane potential in cells?
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During an action potential, what characterises the repolarization phase?
During an action potential, what characterises the repolarization phase?
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What is a crucial characteristic unique to excitable cells?
What is a crucial characteristic unique to excitable cells?
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Which of the following best describes the excitatory postsynaptic potential (EPSP)?
Which of the following best describes the excitatory postsynaptic potential (EPSP)?
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In skeletal muscle contraction, what is the role of ATP?
In skeletal muscle contraction, what is the role of ATP?
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What is the primary mechanism by which the speed of impulse transmission is increased in myelinated nerve fibers?
What is the primary mechanism by which the speed of impulse transmission is increased in myelinated nerve fibers?
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Which of the following characteristics are associated with red muscle fibers?
Which of the following characteristics are associated with red muscle fibers?
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How is the intensity of a stimulus encoded in receptor potentials?
How is the intensity of a stimulus encoded in receptor potentials?
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Which of the following substances can move through the cell membrane via channels?
Which of the following substances can move through the cell membrane via channels?
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Flashcards
Anonymous Submission
Anonymous Submission
A document submitted without revealing the submitter's identity.
Student Contribution
Student Contribution
Content provided by a student for educational sharing.
Document Upload
Document Upload
The process of transferring a file to a digital platform.
Peer Learning
Peer Learning
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Privacy in Education
Privacy in Education
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Content Sharing
Content Sharing
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Identity Concealment
Identity Concealment
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Student Collaboration
Student Collaboration
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Digital Platforms
Digital Platforms
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Educational Resources
Educational Resources
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Resting Membrane Potential
Resting Membrane Potential
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Action Potential
Action Potential
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Sodium-Potassium Pump
Sodium-Potassium Pump
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Facilitated Diffusion
Facilitated Diffusion
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Chemical Synapse
Chemical Synapse
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Calcium's Role in Muscle Contraction
Calcium's Role in Muscle Contraction
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Excitatory Post-Synaptic Potential (EPSP)
Excitatory Post-Synaptic Potential (EPSP)
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Hypocalcemia Impact
Hypocalcemia Impact
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Myelination
Myelination
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Selective Permeability
Selective Permeability
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ATP
ATP
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Myosin
Myosin
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Ca2+
Ca2+
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Skeletal muscle contraction
Skeletal muscle contraction
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Neurotransmitter release
Neurotransmitter release
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Repolarization
Repolarization
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Synaptic transmission
Synaptic transmission
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Study Notes
Resting Membrane Potential
- Property of all cells
- Primarily depends on ion gradients (not sodium influx)
- Magnitude varies between cell types
- Mostly due to ion permeability differences (not Gibbs-Donnan effect)
- Not immediately zero if the sodium-potassium pump is blocked
Active vs. Facilitated Diffusion
- Active transport requires energy and a carrier protein
- Active transport moves substances against their concentration gradient
- Facilitated diffusion does not require energy
- Facilitated diffusion moves substances down their concentration gradient
Substances Crossing Cell Membranes by Passive Diffusion
- Potassium (K+)
- Sodium (Na+)
- Water (H₂O)
- Chloride (Cl-)
- Cannot be definitively determined if the list of proteins are included, as the question refers to simple passive diffusion and protein structure would preclude this method of transfer.
Action Potential in Skeletal Muscle
- Typically initiated at the neuromuscular junction (end-plate)
- Leads to the release of calcium from the sarcoplasmic reticulum
- Characterized by a refractory period
- Shape differs from cardiac muscle action potential, and is faster
- Not due to auto-rhythmicity
Skeletal Muscle Contraction Requirements
- Requires an action potential
- Requires myosin
- Requires troponin
- Requires actin
- Does not require extracellular Ca2+ influx. This is for smooth muscle and some other tissues.
Chemical Synapses
- Requires a neurotransmitter from the presynaptic neuron
- Requires a receptor in the postsynaptic neuron
- Requires a mechanism to remove the neurotransmitter
- Requires Ca2+ channels in the presynaptic terminal.
- Does not require Ca2+ channels in the postsynaptic neuron.
Smooth Muscle vs. Skeletal Muscle
- Sharing characteristic: both contain myosin
- Difference: Smooth muscle does not have troponin
- Difference: Smooth muscle contraction is sometimes initiated without an action potential.
- Difference: smooth muscle forms latch bridges (a mechanism for sustained contraction)
Axon Diameter and Transmission Speed
- Transmission speed is slower in smaller-diameter axons
- Transmission speed is slower in unmyelinated axons
- Transmission speed is slower in demyelinated axons.
- Type C fibers have slow speed.
Skeletal Muscle Contraction and Ca2+
- Calcium (Ca2+) binds to troponin to initiate contraction.
Resting Membrane Potential Factors
- Selective permeability of the cell membrane to potassium (K+)
- High concentration of sodium (Na+) outside the cell
- Low concentration of calcium (Ca2+) inside the cell
Cell Membrane Protein Functions
- Assists endocytosis
- Acts as receptors for neurotransmitters
- Promotes cell adhesion
- Acts as enzymes
- Can be hormones
Changes in Cell Membrane Potential
- Action potentials occur in excitable tissues (neurons, muscle cells)
- Local potentials are graded and decremental (not all-or-none)
- Depolarization is primarily due to ion flux
- Repolarization occurs more quickly than depolarization.
Action Potential Characteristics
- An external stimulus is required to initiate the action potential in skeletal muscle (not SA node)
- Depolarization in cardiac muscle is primarily due to Ca2+ influx, not K+ efflux.
- Cardiac muscle action potentials are longer than skeletal muscle action potentials.
- Action potentials are essential for initiating muscle contraction in all muscle cell types
- Repolarization is mainly due to K+ efflux.
Chemical Synapse Features
- Features of a chemical synapse: convergence, divergence, synaptic delay, postsynaptic inhibitory potential
- Non-features of a chemical synapse: transmission in both directions (usually unidirectional).
Cell Membrane Protein Functions (continued)
- Active transport of potassium (K+)
- Facilitated diffusion of proteins (unlikely, most proteins are too large)
- Influx of sodium (Na+) through channels
- Antibodies (not a typical function of cell membrane proteins)
- Neurotransmitters (not cell membrane proteins, but may be stored or released by them).
Reflex Arc Components
- Receptor (senses stimulus)
- Afferent neuron (carries sensory info)
- Efferent neuron (carries motor information)
Resting Membrane Potential Factors (continued)
- Leak channels (passive ion movement)
- Active transport of potassium out of the cell
- Anions within the cell
Action Potential Features (continued)
- Depolarization, repolarization, refractory period
- Threshold stimulus
- Not preceded by hyperpolarization, usually follows depolarization
Myelination and Vitamin B
- Deficiencies in vitamin B can cause abnormal myelination.
Lipid Function in Cell Membrane
- Acts as a barrier to water-soluble substances
- Does not create channels for fatty acids, nor is directly involved in facilitated diffusion, receptor function, or cell adhesion.
Cell Membrane Protein Functions (continued)
- Active transport
- Ion channels
- Water channels
- Enzymes
Resting Membrane Potential Cause
- Primarily due to potassium (K+) efflux, not sodium or calcium influx.
Na+/K+ Pump Function
- Key role in maintaining cell volume
- Primary in maintaining ion gradients (not the only one), not the main generator of RMP.
- Found in all cells, not just nerve and muscle; its role in RMP is critical in excitable cells.
Cell Membrane Receptors
- Chemical messengers can have multiple receptors with diverse effects
- Receptors are proteins located on the cell membrane
- Receptors are required for chemical messengers to function
- Receptors are not always on the cell membrane, and could be intracellular proteins.
Resting Membrane Potential Main Factor
- Main factor for creating RMP: Leak channels, specifically potassium leak channels.
Action Potential Main Factor
- Main factor for generating action potentials: voltage-gated sodium channels
Skeletal Muscle Cell Characteristics
- Resting membrane potential exists
- Requires extracellular calcium for contraction
- Usually under voluntary control
- Requires ATP for both contraction and relaxation
- Contains creatine phosphate
Skeletal Muscle Action Potential Characteristics
- Faster than cardiac muscle action potentials
- Starts at the neuromuscular junction
- Causes calcium release from sarcoplasmic reticulum
Excitatory Postsynaptic Potential (EPSP)
- Opens ion channels to allow certain ions to pass through
- Neurotransmitter opens ion channels, resulting in EPSP
- EPSPs can summate
Conduction Velocity and Fiber Types
- Slowest conduction velocity: C fibers (small diameter, unmyelinated).
Hypocalcemia and Tetany
- Hypocalcemia causes tetany due to the altered function of ion channels opening more easily.
Muscle Twitch Essentials
- ATP, Myosin, Calcium(Ca2+), Troponin.
Chemical Synapse Features (continued)
- Multiple neurotransmitters can be release
- Neurotransmitters that open chloride channels can be inhibitory.
- Ca2+ needed for neurotransmitter release.
- Postsynaptic neuron activity is influenced by multiple presynaptic neurons,
- Not a feature of chemical synapses: neurotransmitters are stimulatory or inhibitory depending on the postsynaptic receptor, not directly stimulatory.
Cell Membrane Diffusion
- Water (H₂O) can diffuse through the lipid bilayer;
- Calcium (Ca²⁺) can also pass
- Proteins and DNA, are large and don't pass through the lipid bilayer..
Cell Membrane Protein Functions (continued)
- Transporters
- Receptors
- Antigens
Resting Membrane Potential Characteristics
- Characteristic of excitable cells
- Not typically +35mV—it's typically negatively charged
- Decreases with hyperkalemia (high potassium)
- Increases with hypokalemia (low potassium)
- Varies between cell types.
Action Potential Characteristics (continued)
- Graded change
- Not a feature of all synapses
- Characterized by a refractory period
- Prominent feature of various excitable cells, not strictly vascular smooth muscle.
Chemical Synapse Transmission Requirements
- Requires Ca²⁺, receptors, and neurotransmitter (not sodium-potassium pump)
Muscle Fiber Contraction Requirements
- Contraction requires calcium, actin, myosin, and ATP
- Doesn't need myoglobin for contraction
Excitable Cells Feature
- Voltage-gated ion channels are the distinguishing feature, not ATPase or Na+ gradient.
Synaptic Transmission Nature
- Synaptic transmission is predominantly chemical (not electrical) and usually unidirectional
Resting Membrane Potential Factors (continued)
- Due to the diffusion potential generated across the membrane, largely by ions entering and exiting the cell.
Transmission in Nerve Fibers
- Slow in type C fibers
- Saltatory in myelinated fibers (not unmyelinated)
- Faster in fibers with larger diameters
Neuromuscular Junction Transmission
- Calcium influx is essential
- Not blocked by beta blockers, nor atropine, nor affected by acetylcholine.
- Blocked by botulinum toxin.
Excitatory Postsynaptic Potential (EPSP) Characteristics
- Due to neurotransmitter release
- May not necessarily lead to an action potential
- Can summate to reach threshold,
Skeletal Muscle Contraction
- Actin binding sites are covered by tropomyosin at rest to prevent binding
- ATPase is located on the myosin head, NOT the actin
- Calcium binds to troponin, not myosin
- Isometric contraction involves no change in muscle fiber length
Repolarization
- Primarily due to potassium (K+) efflux out of the cell
- Not due influx of chloride or calcium
- Much faster than depolarization
- Coincides with relaxation of the muscle twitch in skeletal muscles
Excitatory Postsynaptic Potential (EPSP) Characteristics (continued)
- May be due to Na+ influx or other ion movements potentially leading to summating signals
- Usually graded
- Can summate, possibly leading to an action potential in the postsynaptic neuron dendrites.
Impulse Transmission Speed and Axons
- Faster if the number of sodium channels increases
- Increased diameter, increased density of voltage-gated ion channels lead to faster speed, not decreased diameter.
Red Muscle Fibers
- Suitable for endurance activities, long contractions (not quick movements)
- Don't fatigue easily
- Store oxygen
- Rich in myoglobin
Receptor Potential Characteristics
- Graded potential, dependent on stimulus intensity
- Not all-or-none
- Affected by changes in stimulation intensity; frequency does not reduce it.
Cell Membrane Passage
- Water and some ions—not all—can pass through the cell membrane without intervention;
- Glucose, proteins and DNA don't diffuse through the membrane
Cell Membrane Protein Functions (continued)
- Transporters
- Enzymes
Studocu Note
- Studocu is not an official academic institution.
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Description
Test your knowledge on the principles of resting membrane potential, action potential in skeletal muscles, and the characteristics of muscle contraction. This quiz challenges you to identify key concepts and applications related to muscle physiology and cell membrane functions.
