Exercise & Diving: ECG and Nervous System

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Questions and Answers

During exercise, the decrease in pulse amplitude is primarily attributed to:

Selective vasoconstriction shunting blood towards actively engaged muscle groups. (correct)
A generalized increase in blood flow across all tissues, lowering perceived pressure.
Increased venous return leading to a reduction in cardiac preload and stroke volume.
Vasodilation in non-exercising muscle groups to reduce overall peripheral resistance.

During the diving simulation, the release of norepinephrine, binding to S.A node cells, is the primary driver of the observed decrease in heart rate.

False (B)

Exercise induces an increase in heart rate primarily due to the release of _______________, which subsequently binds to the S.A. node cells of the heart.

norepinephrine

Explain the biophysical mechanism through which baroreceptors mediate the release of acetylcholine during a diving simulation, ultimately affecting heart rate.

Baroreceptors detect high blood pressure, which triggers the release of acetylcholine. Acetylcholine binds to muscarinic receptors on the S.A. node cells (pacemaker cells) in the heart, increasing potassium permeability and hyperpolarizing the cell membrane. This process slows the rate of depolarization, reducing heart rate. Signup and view all the answers

Match the physiological response to the compensatory mechanism during the diving simulation:

Decreased pulse amplitude = Vasoconstriction Decreased heart rate = Acetylcholine release Increased central blood flow = Blood shunting to vital organs Signup and view all the answers

In the context of post-exercise recovery, the restoration of heart rate to normal levels is primarily due to:

The cessation of norepinephrine release, re-establishing baseline sympathetic activity. (C) Signup and view all the answers

Following the diving simulation, the primary mechanism for restoring oxygen balance in peripheral tissues involves an immediate and unrestricted increase in blood supply to these previously deprived areas.

False (B) Signup and view all the answers

During recovery from exercise, the increase in pulse amplitude is attributed to the restoration of blood flow to tissues previously ________________ during exercise.

undersupplied Signup and view all the answers

Explain the physiological feedback loop that governs the adjustment of blood flow to peripheral tissues both during exercise and in the subsequent recovery period.

During exercise, baroreceptors and chemoreceptors detect changes in blood pressure and oxygen levels. This triggers vasoconstriction and shunting of blood to active muscle groups, simultaneously reducing flow to less essential tissues. Post-exercise, as metabolic demands decrease and oxygen levels normalize, vasodilation occurs in previously constricted vessels. The cessation of norepinephrine allows blood flow to redistribute to the tissues that were previously under-supplied, restoring homeostasis. Signup and view all the answers

Match the phase of physiological response with its corresponding cardiovascular effect.

Exercise = Increased heart rate, decreased pulse amplitude Diving Simulation = Decreased heart rate, decreased pulse amplitude Recovery (post-dive) = Restoration of heart rate and pulse amplitude to resting levels Signup and view all the answers

The primary determinant for the increase in tidal volume observed after exercise is:

The need to expel increased carbon dioxide produced during exercise. (C) Signup and view all the answers

An increase in expiratory reserve volume (ERV) contributes to the observed increase in tidal volume following exercise.

False (B) Signup and view all the answers

In the calculation `TLC - VC = estimated _______________ volume`, the formula estimates the air remaining in the lungs after maximal exhalation.

residual Signup and view all the answers

Using a quantitative approach, illustrate how the dynamic changes in tidal, inspiratory reserve, and expiratory reserve volumes collaborate to enhance pulmonary ventilation following a bout of intense exercise.

Increase in tidal volume occurs because as we exercise we create more CO2 that needs to exit the body. This will increase the tidal volume, by tapping into reserves of the IRV and ERV (consequently decreasing both). The magnitude of this enhancement depends on several factors, including exercise intensity, individual fitness level, and pre-existing respiratory conditions. It results in ventilation increasing above normal amount. Signup and view all the answers

Match the lung volume/capacity with its expected change following exercise:

Tidal Volume = Increase Inspiratory Reserve Volume = Decrease Expiratory Reserve Volume = Decrease Vital Capacity = Decrease Signup and view all the answers

In biological terms, why do males generally exhibit larger lung capacities compared to females?

Greater body mass, tissue volume, and oxygen demand associated with larger size. (C) Signup and view all the answers

Predicted vital capacity based on age, height, and sex alone is a completely accurate reflection of measured vital capacity.

False (B) Signup and view all the answers

Increased lung parameters in males are primarily linked to a higher requirement for ___________, due to increased lung size, tissue mass, and cellularity.

oxygen Signup and view all the answers

Assess the limitations of predicting vital capacity using only age, height, and sex, and propose additional physiological parameters that could improve the accuracy of the estimated value.

The prediction of vital capacity based solely on age, height, and sex omits critical factors such as: activity level, smoking history, weight, certain races and other medical conditions. Including additional physiological parameters such as respiratory muscle strength, body composition, and underlying health conditions could significantly refine the estimation. Signup and view all the answers

Match the physiological factor with its related influence on lung capacity:

Body Size = Directly proportional to lung capacity Sex = Males typically have larger lung capacities Age = Can decrease lung capacity due to reduced elasticity Signup and view all the answers

When a worm is placed in a hypertonic solution, the resulting crenation is biophysically driven by:

Osmotic movement of water out of the worm, leading to cellular shrinkage. (D) Signup and view all the answers

If a worm with tissue osmolarity of 300 mOsm is placed in a 20% seawater (approximately 400 mOsm) solution, it will be in a hypotonic environment, causing the worm to gain weight.

False (B) Signup and view all the answers

Hypertonic solutions cause cells to ____________, while hypotonic solutions cause cells to swell.

shrink Signup and view all the answers

Describe a detailed mechanism by which changes in osmolarity influence cell volume, including the roles of aquaporins, osmotic pressure gradients, and cellular membrane dynamics.

Aquaporins, membrane-spanning proteins, function as highly selective water channels, facilitating rapid bidirectional water transport across the cell membrane. In hypertonic extracellular environments, a higher solute concentration outside the cell creates an osmotic imbalance. This osmotic pressure gradient drives water movement through aquaporins from the intracellular space (low solute concentration) to the extracellular space (high solute concentration). As water exits the cell, the cell volume decreases—a process referred to as crenation or shrinkage. The cell membrane responds by folding or shrinking to accommodate the reduced cell volume. Conversely, in hypotonic extracellular environments, the higher solute concentration inside the cell draws water inward through aquaporins, leading to cell swelling and potentially lysis if unchecked by regulatory mechanisms. Signup and view all the answers

Match the solution tonicity with the expected cellular response:

Isotonic = No Change in Cell Volume Hypertonic = Cell Shrinkage Hypotonic = Cell Swelling Signup and view all the answers

In an isotonic solution, red blood cells maintain a biconcave shape primarily due to:

Equilibrium in water movement across the cell membrane, preserving cell volume. (B) Signup and view all the answers

In a hypotonic solution, the RBC diameter decreases as water moves out of the cell, causing it to shrink.

False (B) Signup and view all the answers

In a hypertonic solution, water moves _________ of the RBCs causing the cells to shrink.

out Signup and view all the answers

Provide a detailed biophysical explanation of why RBCs swell and can potentially lyse in a hypotonic solution, incorporating principles of osmotic pressure, membrane tensile strength, and regulatory mechanisms.

In a hypotonic environment, the concentration of water outside the cell is greater than that inside the cell. This creates a water potential gradient that favors the movement of water from the extracellular fluid, across the semi-permeable cell membrane, and into the RBC cytoplasm through aquaporins. As water influx exceeds efflux, the intracellular volume gradually increases. Ultimately, the cell expands beyond its inherent tensile strength, leading to membrane rupture and cellular lysis. Signup and view all the answers

Match the solution type with the corresponding change in RBC diameter.

Hypotonic = Increase in RBC diameter Hypertonic = Decrease in RBC diameter. Isotonic = No change to RBC Diameter Signup and view all the answers

An increase in the mass of an animal is directly proportional to an increase in its metabolic rate due to:

The greater quantity of tissue requiring more energy and oxygen for maintenance. (C) Signup and view all the answers

In larger animals, cellular respiration occurs less within the body, leading to lower carbon dioxide production and reduced need for metabolic rate increase.

False (B) Signup and view all the answers

As mass increases, the metabolic rate typically ___________ as well due to the heightened need for energy and oxygen.

increases Signup and view all the answers

Explain the complex relationship between body mass, surface area to volume ratio, and metabolic rate. Include a discussion of how these factors impact heat dissipation across organisms of varying sizes.

An increase in animal size (and thus mass) is associated with a decrease in surface area to volume ratio. Metabolic heat production is related to volume. Since mass increases at a much greater rate than surface area (volume increases with the cube of the radius, while surface area increases by the square of the radius), larger animals produce more heat than they can dissipate through their external surface. As a result of all this, larger animals tend to have lower mass-specific metabolic rates. Signup and view all the answers

Match aspects of body size with the function.

Metabolic Rate = Related proportionally to Mass Surface Area to Volume Ratio = Decreases with size (Less Heat Loss) Tissue Oxygen Demand = Requires increase with mass Signup and view all the answers

Temperature increase is expected to increase metabolic rate until:

Temperature is too low or too high, which cause enzymes to slow down or become denatured, which prevent chemical reactions from happening. (C) Signup and view all the answers

If Q10 is around 2 this means that the metabolic rate has decreased by half.

False (B) Signup and view all the answers

The Q10 calculation gives us a measurement of metabolic rate at high temperature divided by the metabolic rate at a temperature _______ degrees lower.

10 Signup and view all the answers

Discuss the mechanism that links enzymes and temperature.

Mealworms are ectotherms meaning they are dependent on the temp. of the environment around them. Temperature adjustment will affect glycolysis and the TCA cycle. This is because they are dependent and catalyzed by enzymes. Enzymes allow a process to happen more rapidly by lowering the activation energy needed. Enzyme function changes with temperature, therefore changing the rate of a reaction or chemical process. Higher temperatures = faster metabolic rate. Lower temperatures = lower metabolic rate. However too cold or too hot of temps can denature enzymes, prohibiting chemical processes to occur. Signup and view all the answers

Link the metabolic outcome with the temperature change.

Temperature Increases = Metabolic Rate Increased Temperate Decreases = Metabolic Rate Decreased Temperature Too High = Enzymes Denature (Prohibiting Processes) Signup and view all the answers

Flashcards

Exercise effects on heart rate and pulse amplitude

Exercise increases heart rate and decreases pulse amplitude.

Norepinephrine's effect on heart rate

Norepinephrine release increases heart rate by binding to S.A node cells.