Podcast
Questions and Answers
Fast skeletal muscle fibers are primarily adapted for which type of activity?
Fast skeletal muscle fibers are primarily adapted for which type of activity?
Which of the following is NOT a characteristic of red (slow) muscle fibers?
Which of the following is NOT a characteristic of red (slow) muscle fibers?
Which factor does NOT contribute to muscle fatigue?
Which factor does NOT contribute to muscle fatigue?
What is the primary neurotransmitter released at the motor end plate?
What is the primary neurotransmitter released at the motor end plate?
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During isometric contraction, which of the following is true?
During isometric contraction, which of the following is true?
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Which answer corresponds to question number 10?
Which answer corresponds to question number 10?
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What is the answer for question number 58?
What is the answer for question number 58?
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Identify the answer for question number 19.
Identify the answer for question number 19.
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Which answer is associated with question number 41?
Which answer is associated with question number 41?
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Determine the answer for question number 62.
Determine the answer for question number 62.
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Identify the correct answer for question number 82.
Identify the correct answer for question number 82.
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Which statement about the human cell membrane is accurate?
Which statement about the human cell membrane is accurate?
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What is the main extracellular cation found in the human body?
What is the main extracellular cation found in the human body?
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Which function is NOT attributed to proteins in the cell membrane?
Which function is NOT attributed to proteins in the cell membrane?
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What is the correct concentration of NaCl for isotonic saline?
What is the correct concentration of NaCl for isotonic saline?
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Glucose transport across the cell membrane primarily occurs through which method?
Glucose transport across the cell membrane primarily occurs through which method?
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Which of the following accurately describes the sodium-potassium pump?
Which of the following accurately describes the sodium-potassium pump?
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Which fluid compartment is not directly measurable using substances?
Which fluid compartment is not directly measurable using substances?
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What characterizes voltage-gated channels?
What characterizes voltage-gated channels?
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What is the structural unit of a nerve?
What is the structural unit of a nerve?
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Which cells form the outer layer of a myelinated nerve fiber?
Which cells form the outer layer of a myelinated nerve fiber?
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What causes the resting membrane potential?
What causes the resting membrane potential?
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What causes the absolute refractory period in a nerve fiber?
What causes the absolute refractory period in a nerve fiber?
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Which statement about the Na+-K+ pump is incorrect?
Which statement about the Na+-K+ pump is incorrect?
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Which characteristic does NOT apply to the local response of a nerve fiber?
Which characteristic does NOT apply to the local response of a nerve fiber?
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At what membrane potential is the firing level of a stimulated nerve fiber reached?
At what membrane potential is the firing level of a stimulated nerve fiber reached?
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Which statement correctly describes the relative refractory period?
Which statement correctly describes the relative refractory period?
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What is the characteristic of the myelin sheath of a nerve?
What is the characteristic of the myelin sheath of a nerve?
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What does chronaxie signify in neurophysiology?
What does chronaxie signify in neurophysiology?
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What is true about the strength-duration curve of a nerve?
What is true about the strength-duration curve of a nerve?
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Which of the following is NOT a correct statement regarding the sodium-potassium pump?
Which of the following is NOT a correct statement regarding the sodium-potassium pump?
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What is the result of inhibiting Na+/K+ ATPase in a neuron?
What is the result of inhibiting Na+/K+ ATPase in a neuron?
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The local response in a nerve fiber can be characterized by which of the following?
The local response in a nerve fiber can be characterized by which of the following?
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During the absolute refractory period, which statement is true?
During the absolute refractory period, which statement is true?
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Which statement about nerve resting membrane potential is accurate?
Which statement about nerve resting membrane potential is accurate?
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Which defines the local response of a nerve fiber?
Which defines the local response of a nerve fiber?
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What is a consequence of an increased extracellular sodium concentration?
What is a consequence of an increased extracellular sodium concentration?
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What occurs when there is an increase in body temperature?
What occurs when there is an increase in body temperature?
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Which is a response of the body when exposed to cold?
Which is a response of the body when exposed to cold?
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What happens to blood flow during exercise?
What happens to blood flow during exercise?
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On exposure to a hot humid atmosphere, which change occurs?
On exposure to a hot humid atmosphere, which change occurs?
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Which statement about body temperature is correct?
Which statement about body temperature is correct?
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Which condition does NOT happen during heat stroke?
Which condition does NOT happen during heat stroke?
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What generally causes obesity?
What generally causes obesity?
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Which statement about obesity is incorrect?
Which statement about obesity is incorrect?
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What effect does leptin have on feeding?
What effect does leptin have on feeding?
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Which factor is least likely to lead to a decrease in food intake?
Which factor is least likely to lead to a decrease in food intake?
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What is the approximate average hydrostatic pressure in systemic capillaries?
What is the approximate average hydrostatic pressure in systemic capillaries?
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Which component is primarily responsible for oncotic pressure?
Which component is primarily responsible for oncotic pressure?
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The capillary membrane is most impermeable to which substance?
The capillary membrane is most impermeable to which substance?
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In which condition does lung compliance generally increase?
In which condition does lung compliance generally increase?
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Which disorder is commonly associated with reduced chest compliance?
Which disorder is commonly associated with reduced chest compliance?
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Study Notes
Physiology MCQs
- Human cell membrane: Is a bilipid layer membrane. It primarily consists of lipid molecules, not carbohydrates. It's impermeable to lipid-soluble molecules and has integral proteins on its surface.
- Main extracellular cation: Sodium.
- Proteins in cell membrane: Act as carriers, channels, and receptors.
- Isotonic saline: Sodium chloride (NaCl) solution with a concentration of 0.9%.
- Glucose transport: Occurs via secondary active co-transport with sodium ions.
- Sodium-potassium pump: An example of primary active transport, not secondary. It pumps 3 sodium ions out of the nerve fiber and 2 potassium ions into it.
- Integral proteins: Act as carriers, receptors, and enzymes.
- Diffusion rate: Is indirectly proportional to the membrane thickness.
- Connexon: An important component of gap junctions.
- Body weight composition: Primarily water, with significant amounts of proteins, fats, and minerals.
- ICF vs. ECF: Intracellular fluid (ICF) contains a higher concentration of potassium (K+) and phosphate ions compared to extracellular fluid (ECF).
- Body fluid compartments: Can be measured directly using substances, except total body water.
- Voltage-gated channels: Open or close in response to changes in membrane potential.
- Diffusion rate factors: Depends on the total cross-sectional area of the membrane, temperature, and concentration gradient.
- Ligand-gated channels: Open or close when a molecule (e.g., hormone or neurotransmitter) binds to them.
- Active transport: Occurs against electrochemical gradients and requires energy.
- Osmosis: Is a passive process that moves water across a semipermeable membrane from an area of low solute concentration to high solute concentration.
- Secondary active transport: Involves the movement of two substances, one molecule moves down its concentration gradient and the other moves against its concentration gradient.
- Diffusion rate factors: The rate of diffusion increases with larger membrane surface area, higher temperature, and greater lipid solubility of the molecule.
- Reflex arc components: Afferent neuron, sensory receptor, effector organ, and sometimes efferent ganglion.
- Nerve structural unit: The neuron.
- Myelinated nerve fiber outer layer: Schwann cells.
- Resting membrane potential cause: Unequal distribution of ions across the cell membrane, particularly sodium (Na+) and potassium (K+).
- Absolute refractory period: A period of time after an action potential where the neuron cannot be stimulated to fire another action potential. It occurs due to inactivation of voltage-gated Na+ channels.
- Sodium-potassium pump activity: Active at rest, essential for maintaining ion gradients, and it couples 3 Na+ ions out of the nerve fiber to 2 K+ ions in.
- Firing level: The membrane potential (-65mV) at which a nerve fiber will fire an action potential.
- Relative refractory period: The period when the neurons membrane is more difficult to depolarize than normal.
- Saltatory conduction: Fast propagation of action potentials along myelinated nerve fibers, "jumping" from node to node.
- Nerve excitability increase: Hypercalcemia and increased potassium permeability can increase nerve excitability.
- Absolute refractory period: Occurs after depolarization; a period where the membrane cannot be stimulated to fire another action potential.
- Local response in nerve fiber: Doesn't obey the all-or-none principle, and can be summated.
- Repolarization: Opening of potassium (K+) channels allows potassium to leave the cell and return the membrane to its resting potential.
- Concerning voltage-gated sodium channels: The inactivation gate closes when the membrane reaches the firing level.
- Acetylcholine action at neuromuscular junction: It triggers postsynaptic depolarization after release from the neuromuscular junction. It is broken down by acetylcholinesterase to prevent continual stimulation.
- Muscle stimulation factors: Includes action potential propagation inward along T-tubules, releasing Ca2+, binding to troponin, and causing contraction.
- Muscle relaxation factors: Decreasing Ca2+ concentration, detaching myosin heads from actin, and returning the muscle to a relaxed state.
- Muscle fatigue causes: Include depletion of acetylcholine at the motor end plate, and insufficient ATP/creatine Phosphate/glycogen supplies.
- All-or-none principle: Applies to individual nerve fibers or muscle cells, but not to whole tissues or organs.
- Mechanisms of neuromuscular transmission: Acetylcholine is released, receptor binding occurs, and an action potential is generated in the muscle fiber. Inhibited by Curare.
- Isometric contraction: Maintaining constant muscle length while contracting; tension increases.
- Isotonic contraction: Maintaining constant tension while muscles shorten.
- Myelin sheath function: Acts as an insulator, speeding up the transmission of nerve impulses. It has gaps (nodes of Ranvier), enabling saltatory conduction.
- Chronaxie: Measures a muscle or nerve fibre's excitability; it's the minimum duration of a stimulus needed to stimulate a reaction at twice the rheobase current.
- Strength-duration curve: Illustrates the relationship between the duration of a stimulus and its intensity required to produce a response. Subthreshold stimuli have no effect.
- Resting membrane potential determinants: Selective permeability of the membrane to different ions, and the activity of the sodium-potassium pump.
- Nerve excitability and stimuli: Nerve excitability increases with a more negative membrane potential.
- Na⁺ influx during stimulus: Increases the membrane potential, making the resting membrane potential more positive.
- Action potential propagation: Faster for myelinated than unmyelinated nerve fibers due to saltatory conduction.
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Biophysics
- Hydrostatic pressure in systemic capillaries: Roughly 35mmHg
- Oncotic pressure determinants: Plasma proteins
- Capillary membrane permeability: Freely permeable to ions.
- Lymphatic obstruction effect: Decreases interstitial fluid volume.
- Lung compliance implications: Increase and decrease are associated with various lung conditions.
- Compliance of large arterial blood vessels: The initial linear relationship between volume and pressure is due to stretching of the elastic fibers. Compliance increases with more stretching of the elastic fibers.
- Vein distensibility: Significantly higher than arteries.
- Starling's law and cardiac muscle: The degree of contraction is proportional to the degree of stretching during filling.
- Force-velocity relationship in skeletal muscle: Isotonic and isometric contraction types.
- Laminar blood flow: Characterized by smooth, layered flow of blood through vessels.
- Murmur: Abnormal heart sounds.
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Metabolism
- Basal metabolic rate (BMR): Metabolic rate at rest. It is higher in men, and lower during pregnancy and old age, as a result of decreased metabolism and less activity.
- Energy equivalent of oxygen: For carbs it is 5 Kcal/L, for fats 4.1 Kcal/L, for proteins 4.7 Kcal/L, and in a mixed diet 4.2 Kcal/L
- Physical heat of food measurement: Indirect calorimetry.
- Respiratory quotient (RQ): Ratio of carbon dioxide produced to oxygen consumed during metabolism.
- Decrease in RQ: Results from different metabolic pathways; e.g., shifting from carbohydrate metabolism to fat metabolism during starvation.
- Respiratory quotient (RQ) of 0.7: Suggests a high-fat diet. A low RQ signifies use of fats, a normal one carbohydrates as fuel.
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Test your knowledge on muscle physiology with this engaging quiz! Questions cover fast and slow muscle fibers, muscle fatigue, and neurotransmitters at the motor end plate. Perfect for students looking to enhance their understanding of how muscles function during various activities.
