Exam #3 Flashcards

Question

During exercise regarding the regualtion of Q, considering the Fick equation... (a) What are the factors that cause an increase in Q? (a) What are the factors that cause a decrease in Q?

Answer 1

(a) Increase in Q - ↑ HR due to: ↑ sympathetic nervous system - ↑ SV due to: ↑ Frank-starling (↑ stretch of heart)...→ ↑ EDV & ↑ contraction strength (from ↑ of SNS) (b) Decrease in Q - ↓ HR due to: ↑ parasympathetic nervous system - ↓ SV due to: ↑ MAP

Answer 2

(a) 3 Major Factors to Consider: 1. Changes in end-diastolic volume (EDV) ~ 3 sub-factors to consider 2. Aortic Pressure 3. LV Contraction Strength (b) Frank-Starling Effect: ↑ VR → ↑ EDV → ↑ SV - The greater amt. of blood that can be returned to the heart, the greater the amt. of EDV & SV

Answer 3

1. Effects of venoconstriction on EDV 2. Effects of skeletal muscle pump on EDV 3. Effects of respiratory pump on EDV

Answer 4

- Rest → exercise → ↑SNS activity → ↑# of Epi/NoE released → ↓ diameter of veins (venoconstriction) → ↑ pressure of blood within veins.... - ↑ venous pressure drives ↑ blood back to R atrium * All veins are under **lower pressure** compared to arteries *

Answer 5

(a) Muscle contraction → rhythmic compression of veins → ↑ venous return blood → ↑ EDV * Between contractions, blood refills the blood vessels. This process is repeated with each repition (or contraction). (b) 1-way valves prevent blood flow away from heart (bi.) 1-way valves is open the other way, blue in appearance given O2 has been pulled away from the blood (c) Movement post-exercise maximizes skeletal muscle pump activity. - Active recovery or movement continually activatve skeletal muscle pump, allowing for blood to be pumped, clearing metabolic byproducts via lactate shuttle (d) No skeletal muscle pump during isometric contraction (no rthymic compression) vs. concentric/eccentric

Answer 6

(a) Inverse relationship; if volume ↑, then pressure ↓ and vice versa (b) Respiratory pump considers the thoracic cavity (TC) where the heart is nearly located and abdominal cavity (AC) ... - During inspiration, diaprhagm drops down = TC ↑ in vol & ↓ in pressure, whereas the AC ↓ in vol. & ↑ in pressure i. 1-way valves helps by keeping the blood in the abdominal cavity from flowing back down to the legs - During expiration, diaprhagm goes up = TC then ↓ in vol. & ↑ in pressure, where the AC ↑ in vol & ↓ in pressure - In general: creates a pressure gradient so that it moves blood from our lower limbs, into our midsection (abdomen to thoracic), thus active recovery play a role

Answer 7

(a) LV (b) Afterload or MAP (mean-arterial pressure) (c) inversely ; the greater the afterload/resistance to flow, the smaller the SV (d) local vasodilatos (e) ↑ cardiac contractility due to ↑ SNS stimulation (↑Epi/NoE).

Answer 8

1. Consider the effects of hormones during exercise * ↑ release of Epi/NoE → ↑ cardiac contractility by moving more extracellular calcium into cardiac muscle fiber. * ↑ # Ca 2+ → ↑ # x-bridge formation → ↑ # powerstrokes → ↑ # force produced. 2. Also during exercise: ↑ SNS stimulation of cardiac accelerator nerves (nerves that affect HR), which also releases ↑ # of Ca 2+

Answer 9

(a) During initial transition rest → exercise, Central Command signals **CV control center** which sets general CV response. (b) CV activity during exercise also regulated by **afferent feedback aka exercise pressor reflex** ; to CV control center (bi.) Afferent feedback: i. Heart mechanoreceptors detect changes in stretch in cardiac muscle fibers. ii. Muscle chemoreceptors detect changes in muscle metabolites (Potassium, lactate, lactic acid) iii. Muscle mechanoreceptors (GTO, muscle spindle) are sensitive to tension & stretch of movement. iv. Baroreceptors monitor changes in arterial blood pressure

Answer 10

↑ Cardiac output... - deeper breathing → improved venous return (via skeletal muscle activity) → ↑ SV (also from metabolic vasodilation in muscles) - SNS → ↑ cardiac rate/HR & ↑ SV (also from metabolic vasodilation in muscles) ↑ Blood flow to skeletal muscles... - Skeletal muscle activity → metabolic vasodilation in muscles - Sympathetic vasoconstriction in viscera

Answer 11

(a) Primary purpose: i. Provides means of gas exchange between the atmosphere and body ii. Gas exchange occurs in two locations: - Alveoli and the capilaries that surround them (alveolar gas exchange) - Capillaries surrounding skeletal muscle (systemic gas exchange) (b) Secondary: Plays role in acid-base balance during heavy exercise - Ex: Bicarbonate buffer (H+ + HCO3- → H2CO3 → H2O + CO2)

Answer 12

(a) Ventilation (VE) = tidal volume (VT) x frequency (f) (ai.) VT = # of air inspired per breath ; F = # of breaths per min. (b) Bicarbonate Buffering: H+ + HCO3- ↔ H2CO3 ↔ H2O + CO2 (c) PCO2 in arterial blood (ci.) ↓ (breathed out) (cii.) ↑

Answer 13

1. Atmospheric air containing O2 moving into the lungs 2. O2 moves into the lungs 3. Blood containing O2 gets transported 4. Once blood reaches the systemic cells, the O2 moves into the systemic cells via gas exchange 5. At the systemic cells, as O2 moves in, CO2 then moves into blood 6. Blood containg CO2 gets transported back to the heart and to the lungs 7. Within the lungs, alveolar gas exchange occurs where CO2 moves into the alveoli 8. CO2 is then expired out into atmospheric air

Answer 14

1. Conducting zone - All structures leading to the respiratory zone - Warm, filters, humidifies air - NO gas exchange - Air trapped here known as "dead space ventilation" 2. Respiratory zone (at the alveoli) - Gas exchange (O2 & CO2)

Answer 15

(a) R ventricle (b) L atrium

Answer 16

(a) Vgas = A/T x D x (P1-P2) (b) Variable: - A = Surface area of diffusion - T = Membrane thickness - D = diffusion coeffcient - (P1-P2) = pressure gradient between two areas

Answer 17

(a) Airflow: Air from atmosphere to aveoli, and back (Inspiration/expiration) (b) Airflow = P1-P2/airway resistance (c) Diameter of airways (d) Common examples of respiratory disfunction: 1. Asthma: can be caused by either or both of the following: - Contraction of smooth muscle of air passageways - Collection of mucous w/n air passageways 2. COPD: usually, a combination of two separate lung diseases: - Chronic bronchitis: Over prod. of mucous - Emphysema: decreased elastictiy of airways 3. Exercise induced asthma: tends to occur during or just after exercise. - Contraction of smooth muscle surrounding airways - Symptoms include wheezing &/or labored breathing - 10% of elite endurance athletes affected

Answer 18

(a) Asthma: Temporary & reversible narrowing of airways (b) COPD (Chronic obstructive pulmonary disease): Constant narrowing of airways → ↑ airway resistance → ↓ expiratory airflow → ↑ # work for respiratory muscles → sensation of being short of breath (aka dsypnea). (bi.) Inspiration: Normal (bii.) Expiration: Labored (airways tend to collapse) (c) Risk factors: 1. Tobacco smoking 2. Family history of emphysema

Answer 19

(a) Capillaries leak fluid which collects in alveoli and space between alveolar wall and capillary wall → ↑ membrane thickness (b) Capillaries leak fluid which collects in alveoli and space between alveolar wall and capillary wall → ↑ membrane thickness .... - But also see the formstion of scar tissue within the walls of alveoli (c) **↓↓**Vgas = A/**↑↑**T x D x (P1-P2)

Answer 20

(a) At rest: (i.) Arterial PO2: 100mmHg (ii.) PO2 (Tissue Fluid): 40mmHg (iii.) Gradient: 60mmHg (iv.) PCO2 (Tissue Fluid): 46mmHg (v.) Arterial PCO2: 40mmHg (vi.) Gradient: 6mmHg (b) During exercise: (i.) Arterial PO2: 100mmHg (ii.) PO2 (Tissue Fluid): 20mmHg (or 2-3mmHg if intense) (iii.) Gradient: 80mmHg (or 98mmHg) (iv.) PCO2 (Tissue Fluid): 48mmHg (v.) Arterial PCO2: 40mmHg (vi.) Gradient: 8mmHg (c) CO2 has a different diffusion coefficient (D), which gas exchnage happens faster (easier) (d) O2 consumption within the tissue fluid as its used in Krebs, ETC, & Beta

Answer 21

(a) Hemoglobin (Hb): Protein found in red blood cells (RBCs) aka erythrocytes (ai.) 4 (aii.) 4 (b) Hb + O2 → Oxyhemoglobin ; oxygen bound to "heme" portion of Hb (bi.) 99% (c) Deoxyhemoglobin ; Hb travels to working muscle (where PO2 is low) as it utilizes O2 at ETC (d) # O2 transported in blood depends on [Blood hemoglobin] (e) 150 grams/liter of blood (f) 130 grams/liter of blood (g) Men as they cary more O2, so tend to be better at aerobic sport/activity

Answer 22

(a) Illustrates relationship between PO2 and binding of O2 to Hb in blood (b) "Dissociation” refers the seperation of O2 from hemoglobin (c) Oxyhemoglobin (ci) Deoxyhemoglobin (d) Factors determining direction: 1. The partial pressure of O2 in blood (PO2) a. High PO2 drives rxn to the right (more oxyhemoglobin). b. Low PO2 drives rxn to the left (more O2 dropped off). 2. The affinity or “bond strength” between Hb and O2. Two related, local factors: a. ↓ pH b. ↑ temp.

Answer 23

(a) Standard Atmospheric Conditions: 1. Assume barometric pressure = 760mmHg 2. Dry-air 3. Sea-level 4. 32°F (b) 90-100mmHg (bi) Helpful because: 1. Arterial PO2 ↓ as we age 2. Arterial PO2 ↓ at high altitude (c) 75% ; 1 molecule of O2 dropped off at muscle & 3 molecules of O2 remain bound to Hb.

Answer 24

(a) As pH decreases, Hb's affinity for O2 ↓, which means ↑ # of O2 is dropped off at working muscles (ai) Curve shifts down and to the right (aii.) It increase the affinity (thus making it harder for O2 to be dropped off) (b) Increase in core temp. (via ATP hydrolysis), ↓Hb's affinity for O2, which means ↑ # of O2 is dropped off at working muscles (bi) Curve shifts up and and to the left

Answer 25

(a) Product of red blood cell metabolism (ai.) Can combine with Hb → lowers Hb's affinity for O2, which means ↑ amt. of O2 dropped off at working muscle (b) Production of RBC [2-3 DPG] increases due to: 1. Exposure to high altitude (% of gas is still the same, just further apart = ↓ pressure) 2. Anemia (low [Hb]); allowing for more O2 to be dropped off

Answer 26

(a) Myoglobin: an oxygen-binding protein (ai.) Cardiac and skeletal muscle fibers (b) T (c) Functions: 1. Transports O2 from sarcolemma to mitochondria (for ETC) ~ PO2 at mito is 1mmHg for ETC 2. Stores small amt. of O2 in muscle cells (used during transition from rest to exercise) ~ Restroration of this occurs w/n fast component of EPOC; TR athelts have ↑ [Mb], therefore O2 deficit time is shorter

Answer 27

(a) Three modes of CO2 transport in Blood: 1. 10% travels in blood, dissolved in plasma 2. 20% bound to “globin” within Hb → carbaminohemoglobin 3. 70% becomes HCO3- → travels in blood plasma - CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3- (b) Not typically

Answer 28

1. There's a pressure gradient bwteen the working tissue and blood as there's ↑ PCO2 in the working tissue/tissue cells and ↓ in PCO2 within (blood) plasma 2. Gas exhange takes place between working muscle cells and the capillaries that surround them i. 10% CO2 dissolved in plasma ii. 20% CO2 combined with Hb to form carbaminohemoglobin iii. 70% CO2 enters RBC to form carbonic acid (+ H2O) → H+ + HCO3- ~ HCO3- leaves the RBC and is replaced with Cl- (Chloride shift) ~ H+ combines with Hb 3. After gas exchange, this blood becomes part of the venous return

Answer 29

1. There's a pressure gradient bewteen the alveoli and blood as there's ↓ PCO2 in the alveoli and ↑ in PCO2 within (blood) plasma 2. Gas exhange takes place between alveoli and the capillaries that surround them i. CO2 dissolved in plasma enters alveoli ii. CO2 bound to carbaminohemoglobin dissociates and enter alveoli iii. Cl- leaves RBC and HCO3- reenters (Reverse Cl- shift), combining with H+ to form H2CO3 → H2O + CO2 ~ CO2 leaves RBC and enters the alveoli 3. After gas exchange, this blood returns to the L side of heart for systemic circulation, CO2 that enters alveoli gets exhaled out

Answer 30

(a) Repsiratory muscles: A type of skeletal msucle (ai.) Type I muscle fibers (b) Chronic endurance training (bi.) ↑ mito. density, ↑ oxidative capacity, ↑ capillary density, ↑[Mb], ↑ buffering capacity (bii.) ↑ exercise intensity → ↑ pulmonary ventilation → ↑ workload on respiratory muscles (c) Respiratory muscles can fatigue during exercise: 1. Prolonged moderate-intensity: 120+ minutes 2. Very heavy exercise (80-100% VO2 max): ~ 10 minutes

Answer 31

(a) Primary drive to increase ventilation during exercise (b) Medulla oblongata (c) Receptors: i. Peripheral chemoreceptors: - Aortic bodies (in aortic arch): detect ↑PCO2, ↓pH - Carotid bodies (in carotid arteries): ↑PCO2, ↑[H+], *↓PCO2 @ high altitude ii. Skeletal muscle - Chemoreceptors: detect ↑[K], ↑[H+] - Mechanoreceptors: Muscle spindle (stretch), GTO (tension) iii. Signals from stretch receptors in lungs, limit depth of inspiration (ci.) Peripheral chemoreceptors & chemoreceptors in skeletal muscle (d) Respiratory muscle work to increase ventilation

Answer 32

(a) Chemoreceptors located in medulla oblongata (central chemoreceptor) Stimulus: ↑ PCO2 (leads to ↑[H+] or ↓pH) Response: Central chemoreceptors are sensitive to changes in pH of the cerebrospinal fluid. An increase in arterial PCO2 results in diffusion of CO2 from the blood into the brain; this lowers pH and stimulates the central chemoreceptor to send signals to the respiratory control center to increase breathing. This results in increased alveolar ventilation and the elimination of CO2. (b) Carotid body (peripheral chemoreceptor) Stimulus: ↑PCO2, ↓pH, ↓PO2 (only at altiude) Response: The carotid body is sensitive to changes in arterial PO2, PCO2, and pH. An increase in arterial PCO2 stimulates the carotid bodies to send signals to the respiratory control center to increase breathing. Similarly, a decrease in either arterial pH and PO2 stimulates the carotid bodies to send signals to the respiratory control center to increase ventilation. (c) Aortic body (peripheral chemoreceptor) Stimulus: ↑PCO2, ↓pH Response: The aortic body is sensitive to changes in arterial PCO2, and pH. Increased arterial PCO2 or a decrease in blood pH stimulates the aortic body to send signals to the respiratory control center to increase breathing. (d) Muscle mechanoreceptors Stimulus: ↑ Muscle contractile activity Response: Skeletal muscle contains several mechanoreceptors (e.g., muscle spindle and Golgi tendon organ). Muscle contractile activity stimulates these receptors to send neural signals to the respiratory control center to increase breathing in direct proportion to the exercise intensity. (e) Muscle chemoreceptors (also called muscle metaboreceptors) Stimulus: ↓pH, ↑ Potassium (K) Response: Skeletal muscle contains chemoreceptors that are sensitive to chemical changes inside and around the muscle fibers. Exercise can decrease muscle pH and increase extracellular potassium concentration; this stimulates these chemoreceptors to send neural signals to the respiratory control center to increase breathing.

Answer 33

(a) Dalton's Law: Total pressure of a gas mixture = Sum of pressures of each gas in the mixture (b) Composition of atmospheric air: - Oxygen = 20.93% - Nitrogen = 79.04% - CO2 = 0.03% (c) 760mmHg

Answer 34

(a) MUST KNOW: Composition of atmospheric air: - Oxygen = 20.93% - Nitrogen = 79.04% - CO2 = 0.03% Barometric pressure at sea level: 760mmHg i. Oxygen: .2093 x 760mmHg = 159 mmHg ii. Nitrogen .7904 x 760mmHg = 600.7mmHg iii. CO2: .0003 x 760mmHg = 0.23mmHg (b) Airflow = P1-P2/resistance to airflow* (*diameter of air passageway) (bi) Rate of airflow decreases as P1-P2 decreases (bii) Smaller gradient leads to a slower and less diffusion

Answer 35

(a) Ions: Any atom that has **gained** or **lost** electrons (a small atom that revolves around the outer circle of a nucleus) (ai.) Cations: Lost electrons. Overall, have a + charge (aii.) Anions: Gained electrons. Overall, have a - charge (b) Acids: Molecules that release H+ into solution, which causes the solution to become more acidic - EX: Lactic acid → Lactate + H+ (c) Bases: Molecules that take up or combine with H+, which removes the H+ from solution, which causes the solution to become more basic or alkalytic - EX: HCO3- + H+ → H2CO3 → H2O + CO2

Answer 36

(a) A quantitative measure of acidity or alkalinity (b) 0 to 14 (c) Acidic (ci.) Basic or alkalytic (d) 7.0 ; neutral (e) OH- & H+ (f) 7.4 ; 7.35 to 7.45

Answer 37

(a) > (ai.) Decrease in pH (b) < (bi.) Increase in pH

Answer 38

(a) ↑ concentration of H+ due to: - Accumulation of acids OR - Loses of bases (ai.) pH drops (down the pH scale) (b) ↓ concentration of H+ due to: - Loss of acids OR - Accumulation of bases (bi.) pH rises (up the pH scale)

Answer 39

(a) Primary Sources of H+ in Working Skeletal Muscles: 1. Aerobic metabolism of CHO, FATS, & proteins produces CO2 (via slow glycolysis or Beta-ox → Krebs), which combines with H2O to form H2CO3, which dissociates into H+ & HCO3-. 2. Fast (or anaerobic) glycolysis produces lactic acid, which dissociates into H+ & lactate. 3. As exercise intensity ↑ , do rates of ATP hydrolysis, which releases greater quantities of H+ into the cellular environment. (b) ATP hydrolysis as it produces OH- , providing a balance. (c) pH ↓

Answer 40

(a) High-intensity muscle contractions lasting > 45 seconds (b) Fatigue: 1. ↑ [H+]: inhibits rate-limiting enzymes in aerobic & anaerobic ATP-producing pathways. The result can be fatigue related to slowing speed of contraction 2. H+ competes with Ca2+ for binding sites on troponin → ↓ # of x-bridges formed → ↓ # of powerstrokes → ↓ # of force produced = fatigue.

Answer 41

(a) Buffering refers to chemical reactions that minimize change in pH. (b) Buffers: Chemical and physiological mechanisms that help maintain pH. (bi.) Buffers remove hydrogen ions when ↑ [H+] (more acidic) (bii.) Buffers release hydrogen ions when ↓ [H+] (more basic) (c) Ability of buffers to resist changes in pH depends upon: - [Buffer]; the greater the concentration, the greater the ability to resist change in pH (better ability to maintain pH) - Type of buffer: Some buffers are better able to maintain pH vs. others. (d) Interval training

Answer 42

(a) Intracellular buffers are the first line of defense when pH decreases, loacted w/n the muscle cell (buffers pH first) (b) Two Categories: 1. Chemical buffers (within sarcoplasm) 2. Hydrogen ion transporters (embedded within the sarcolemma) a. Move hydrogen ions from inside muscle fiber into interstitial space outside of muscle cells

Answer 43

(Chemical) Intracellular buffers work in two ways: 1. Make strong acids less likely to release H+ into sarcoplasm a. Examples: Bicarbonates and phosphates, including bicarbonate. ~ Bicarbonate is primarily produced in: Stomach, prancreas, and kidneys 2. Pick up (remove) H+ from sarcoplasm, making it less acidic. ~ Will transport H+ out of the muscle cell, maintaining pH w/n the muscle cell

Answer 44

(a) Hydrogen ion transporters in sarcolemma (all require energy): 1. Sodium-Hydrogen Exchanger (NHE) a. Moves one Na+ into muscle cell for every H+ moved out of the cell. 2. Monocarboxylate Transporters (MCT) a. Co-transports one H+ and one lactate out of muscle cell. (b) Monocarboxylate Transporters (MCT); As lactate moves out of the muscle cell, the lactate can be shuttled to various parts of the body via lactate shuttle... 1. 70% oxidized by Type I fibers in heart & within the same or nearby skeletal muscles 2. 20% → liver → glucose, via the process known as gluconeogenesis 3. 10 % → liver where it is synthesized into various amino acids (can also produce substrates from the kreb cycle)

Answer 45

(a) Blood (b) 3 principal buffer systems: 1. Blood proteins: Found in small quantities; not very effective during heavy exercise. 2. Hemoglobin (Hb): Found in great quantities. 6 times more effective than other blood proteins, especially in the form of deoxyhemoglobin. ~ Once Hb drops off O2 at the working muscle, deoxyhemoglobin will then pick up CO2 at the working muscle 3. Bicarbonate (HCO3-): The most important extracellular buffer. ~ A tyep of metabolic compensation: various products of metabolism is used to maintain pH w/n a normal range (7.35-7.45)

Answer 46

(a) Respiratory compensation (b) CO2, via the bicarbonate buffering system (HCO3- + H+ → H2CO3 → H2O + CO2) (c) Human respiratory system provides a rapid means of regulating blood pH by controlling # of CO2 in the blood (d) ↑ (one end of the buffer must also be the same for the other end) (e) ↑ (to get rid of it) (f) Ventilatory rate

Answer 47

(a) Kidneys alter the of HCO3- being released into circulating blood, depending on blood pH. (b) Long-term, hours to days (c) NO! Body relies more on respiratory compensation & acid base balance & metabolic compensation

Answer 48

i. pH - Normal range: 7.35-7.45 - Acidic: < 7.35 - Basic: > 7.45 ii. PCO2 (respiratory variable) - Normal range: 45-35 - Acidic: >45 (↑CO2 = ↑[H+]) - Basic: < 35 iii. HCO3- (metabolic variable) - Normal range: 22-26 - Acidic: < 22 - Basic: > 26

Answer 49

Metabolic acidosis occurs due to a gain in the amount of acid in the body. Indeed, even relatively small changes in arterial pH can have a significant negative effect on organ function. A number of conditions and disease states can promote metabolic acidosis: 1. For example, long-term starvation (i.e., several days without food) can result in metabolic acidosis due to the production of ketoacids in the body as a by-product of high levels of fat metabolism. In extreme circumstances, the type of metabolic acidosis can result in death. 2. Diabetes is a common metabolic disease that promotes metabolic acidosis. Uncontrolled diabetes can result in a form of metabolic acidosis called diabetic ketoacidosis. Similar to starvation-induced acidosis, this form of acidosis is also due to the overproduction of ketoacids due to high levels of fat metabolism. Worldwide, numerous deaths occur each year from this form of acidosis.

Answer 50

Metabolic alkalosis results from a loss of acids from the body: 1. Conditions leading to metabolic alkalosis include severe **vomiting** and **diseases such as kidney disorders** that result in a loss of acids. In both of these circumstances, the loss of acids results in an overabundance of bases in the body, leading to metabolic alkalosis

Answer 51

1. The exercise intensity 2. The amount of muscle mass involved 3. The duration of the exercise

Answer 52

1. The first line of defense against exercise-induced acidosis resides in the muscle fiber (i.e., bicarbonate, phosphate, and protein buffers). However, because the muscle fiber’s buffering capacity is limited, additional buffer systems are required to protect the body against exercise-induced acidosis. 2. In this regard, the second line of defense against pH shifts during exercise is the blood buffer systems (i.e., bicarbonate, phosphate, and protein buffers including hemoglobin). Importantly, an increase in pulmonary ventilation during intense exercise assists in eliminating carbonic acid by “blowing off carbon dioxide.” This respiratory compensation to exercise-induced acidosis plays an important role against pH change during intense exercise. Together, these first and second lines of defense protect the body against exercise-induced acidosis.

Answer 53

Movement of air from the environment to the lungs is called pulmonary ventilation and occurs via a process known as bulk flow. **Bulk flow refers to the movement of molecules along a passageway due to a pressure difference between the two ends of the passageway**. Thus, inspiration occurs due to the pressure in the lungs (intrapulmonary) being reduced below atmospheric pressure. Conversely, expiration occurs when the pressure within the lungs exceeds atmospheric pressure.

Answer 54

Inspiration is active during rest and exercise as muscles have to contract to draw air in. At rest, expiration is passive. However, during exercise, expiration becomes active, using muscles located in the abdominal wall (e.g., rectus abdominus and external oblique).

Answer 55

Note that not all of the air that passes the lips reaches the alveolar gas compartment where gas exchange occurs. Part of each breath remains in conducting airways (trachea, bronchi, etc.) and thus does not participate in gas exchange. This “unused” ventilation is called dead space ventilation (VD), and the space it occupies is known as anatomical dead space.

Answer 56

Women have smaller airways compared to men... 1. This is important because a smaller airway results in a greater resistance to airflow, which could **limit the maximal ventilatory capacity during high intensity exercise**. 2. Because women have smaller airways, the energy requirement for breathing during exercise is higher in women compared to men. This is significant because an **increased work of breathing can accelerate the respiratory muscle fatigue** that occurs during prolonged or high-intensity exercise. 3. A growing number of studies suggest that **elite female endurance athletes are more likely to experience exercise-induced hypoxemia** than their male counterparts. It is unclear if the increased incidence of exercise-induced hypoxemia in elite female endurance athletes is due to differences in airway diameter between the sexes.

Answer 57

Tidal volume

Answer 58

Carbonic anhydrase

Exam #3 Flashcards

(83 cards)