apk final

AV Hill

douglas bag

Who was the first Director of the Harvard Fatigue Lab

D.B. Dill

Who won the 1921 Nobel Prize and was the first to Analyze runner physiology

A.V. Hill

John Scott Haldane made an equation based on the fact that this gas is inert

Nitrogen

Bonus: What is the name of the bag to collect expired air

Douglas bag

Are all muscle fibers the same?

They’re recruited according to the size principle:

👉 Type I → Type IIa → Type IIx

Type I (Slow-twitch)

• Slow contraction speed

• High fatigue resistance

• Uses aerobic (oxidative) metabolism

• Best for endurance (running, cycling)

🔹 Type IIa (Fast oxidative-glycolytic)

• Faster contraction

• Moderate fatigue resistance

• Uses both aerobic + anaerobic

• Best for mixed activities (soccer, middle-distance)

fats

•White adipose tissue

–Lipid storage and breakdown (lipolysis)

•Brown adipose tissue

–Transfers energy from food directly into heat.

–Contains many small lipid droplets, mitochondria, and blood vessels.

What are the three energy systems?

ATP-PCr, glycolysis, oxidative

What is the fastest energy system?

ATP-PCr

What is the duration of ATP-PCr system?

0–15 seconds

What fuel does glycolysis use?

Glucose or glycogen

What causes fatigue in glycolysis?

H+ accumulation (acidosis)

What is the most ATP-producing system?

Oxidative system

What fuel is used at low intensity exercise?

Fat

What fuel is used at high intensity exercise?

Carbohydrates

nervous system

• Sympathetic → “fight or flight”
  (↑ HR, ↑ breathing, ↑ blood flow to muscle)

• Parasympathetic → “rest and digest”
  (↓ HR, recovery)

How is the nervous system organized?

CNS (brain and spinal cord) and PNS (sensory and motor nerves)

What is the function of the CNS?

Processes information and controls responses

What is the function of the PNS?

Transmits signals to and from the CNS

What is the difference between afferent and efferent neurons?

Afferent send signals to CNS, efferent send signals from CNS

What is the somatic nervous system?

Controls voluntary skeletal muscle movement

What is the autonomic nervous system?

Controls involuntary functions

What does the sympathetic system do?

Increases heart rate and prepares body for exercise

What does the parasympathetic system do?

Promotes rest and recovery

How are sensory and motor neurons integrated?

Sensory input goes to CNS, which sends motor output to muscles

What is central command?

Brain initiates movement and increases cardiovascular responses before exercise

What do mechanoreceptors detect?

Muscle movement and stretch

What do metaboreceptors detect?

Metabolic byproducts like H+ and CO2

What happens to sympathetic activity during exercise?

It increases

What happens to parasympathetic activity during exercise?

It decreases

The gold standard for measuring energy expenditure directly in normal daily living is direct calorimetry/isotopic measures.

Isotopic measures

Every liter of oxygen consumed burns about one/five calories.

Five calories

An RER of 0.90 burns ~68% of calories from carbohydrate/fat.

Carbohydrate

3.5 mL O2/min/kg (1 MET) represents the typical absolute/relative oxygen uptake at rest.

Relative

A V•O2max value in the 30s is more typical in college-aged females/males.

Females

Fatigue is a ______ drop in performance with rest, whereas muscle damage causes structural impairment that persists despite short-term recovery.

reversible

Glycogen is depleted sequentially during exercise, starting with ______ fibers, followed by Type IIa, and finally Type IIx as intensity increases.

Type I

Glycogen is depleted sequentially during exercise, starting with Type I fibers, followed by ______, and finally Type IIx as intensity increases.

Type IIa

Glycogen is depleted sequentially during exercise, starting with Type I fibers, followed by Type IIa, and finally ______ as intensity increases.

Type IIx

Muscle acidosis from ______ accumulation causes fatigue by inhibiting ATP production.

hydrogen ion (H+)

Muscle acidosis from hydrogen ion (H+) accumulation causes fatigue by inhibiting ______ production.

ATP

Delayed Onset Muscle Soreness (DOMS) is primarily triggered by ______ contractions that physically disrupt the Z-disks within muscle sarcomeres.

eccentric

Delayed Onset Muscle Soreness (DOMS) is primarily triggered by eccentric contractions that physically disrupt the ______ within muscle sarcomeres.

Z-disks

The neuromuscular control theory states that exercise-associated muscle cramps result from ______ via localized muscle fatigue.

motor neuron hyperexcitability

What is the endocrine system?

A system of glands that release hormones into the bloodstream

Where are endocrine glands and what do they produce?

Located throughout the body and produce hormones

How is metabolism controlled during exercise?

Hormones regulate fuel use and energy production

How is fluid balance maintained during exercise?

ADH and aldosterone regulate water and sodium retention

Does exercise affect appetite regulation?

Yes, it decreases appetite short-term

All arteries carry oxygenated blood.

FALSE - pulmonary artery

Desmosomes rapidly conduct action potentials in cardiac muscle.

FALSE - gap junctions

Cardiac myocyte resting membrane potential is -90 mV

TRUE

The sympathetic nervous system provides intrinsic control of heart rate.

FALSE - extrinsic

Atrial fibrillation is the leading cause of sudden cardiac death.

FALSE - ventricular

Mean BP is calculated as 1/3 DBP and 2/3 SBP.

False - Swap DBP and SBP

Blood volume is 5 L at rest and ~25 L during exercise

False - 5 L during exercise, CO (or Q) changes with exercise

Radius is the most important determinant of vascular resistance

True

Intrinsic blood flow regulation has metabolic, endothelial, and myogenic mechanisms for vasodilation

True

Hematocrit is the protein that can carry ~1 billion O₂ molecules per red blood cell

False - Hemoglobin

1.Will a higher maximal heart rate improve performance by increasing cardiac output?

●

2.Describe the three main factors that affect stroke volume during exercise.

●

3.What is the Fick equation and relevance?

●

Describe the physiology of cardiovascular drift

Not necessarily, reduces time for cardiac filling. Athletes if anything have lower maximal HR.

2. Preload, contractility, and afterload

3. V•O2 = HR × SV × (a-v-  )O2 difference

4. Dehydration or heat causes drop in plasma volume, heart rate needs to increase to compensate.

Describe the HR, SV, and Q curves as exercise intensity increases.

Second row: Why is EDV higher when supine?

Third row: What are two examples that would cause other organs to ‘steal’ blood flow from the muscle during exercise?

Back row: What are the key feedforward and feedback reflexes that drive BP during exercise? Also, example BP values during aerobic vs resistance exercise?

1.High blood CO2 causes chemical reactions that increase H+ in the CSF, which stimulates central chemoreceptors

2.Excessive lung stretch causes a reduction in breathing depth

3.Scalenes, Sternocleidomastoid, Pectoral

4.Rightward shift in oxyhemoglobin dissociation curve to unload more O2 to tissues

1.Describe the principles of 1) individuality; 2) specificity, 3) reversibility, 4) progressive overload, and 5) variation.

What are the basic concepts of high altitude and our initial cardiorespiratory responses?

2. How does altitude affect our body and exercise performance?

3. Can you acclimate to altitude or use it as a training advantage?

4. What are the risks of high altitude?

5. How does the body respond to other extreme environments, like deep water diving and microgravity in space?

______ hormones are lipid-soluble and bind to receptors ______ the cell, whereas non-steroid hormones require ______ (like cAMP) because they can’t cross the cell membrane.

Steroid; inside; second messengers

During exercise, the liver maintains blood glucose levels by ______ (breaking down glycogen) and ______ (converting non-carbohydrate substrates into glucose).

glycogenolysis; gluconeogenesis

Even though insulin levels ______ during exercise, muscle glucose uptake remains high because exercise ______ insulin sensitivity.

decrease; increases

To prevent dehydration, ADH ______ water reabsorption in the kidneys, while ______ promotes sodium (Na⁺) retention.

increases; aldosterone

The adrenal medulla releases ______ (epinephrine and norepinephrine) to ______ heart rate, blood pressure and ______ free fatty acids (FFAs) for fuel.

catecholamines; increase; mobilize

In cardiac anatomy, the ______ function as the receiving chambers while the ______ function as the pumping chambers, with the ______ specifically having the thickest walls to push blood through the systemic circuit.

atria; ventricles; left ventricle

The myocardium's ability to contract as a single unit is facilitated by ______, which conduct action potentials between cells, and ______, which physically hold the fibers together during contraction.

gap junctions; desmosomes

During Phase 0 of a cardiac myocyte's action potential, there is a rapid influx of ______, while the "plateau" seen in Phase 2 is created by the movement of ______ into the cell while potassium leaves.

sodium; calcium

While the heart's "pacemaker" or ______ has an intrinsic heart rate of approximately ______ beats per minute, the ______ nervous system provides extrinsic control to adjust this rate during exercise.

SA node; 60; autonomic

An abnormally fast resting heart rate over 100 bpm is known as ______, whereas a rate below 60 bpm is called ______; a more chaotic arrhythmia characterized by rapid, inefficient atrial contractions is known as ______.

tachycardia; bradycardia; atrial fibrillation

In the Wiggers diagram, ______ occurs when all heart valves are ______, causing ventricular pressure to rise sharply without changes in blood volume.

isovolumetric contraction; closed

Known as the primary resistance vessels, the ______ are the vessels responsible for approximately 70–80% of the total ______ across the systemic circulation.

arterioles; pressure drop

Because the venous system is a low-pressure environment, returning blood to the heart (especially from the lower body) requires ______ valves, the ______, and the respiratory pump.

one-way; skeletal muscle pump

Hematocrit refers to the total percentage of blood volume composed of formed elements; if this value increases without a corresponding increase in plasma volume, ______ will rise, potentially hindering ______.

blood viscosity; blood flow

During exercise, the body uses ______ to locally offset ______, ensuring that blood flow is redistributed to active skeletal muscles.

functional sympatholysis; sympathetic vasoconstriction

To calculate ______ (L/min), you must multiply the ______ (L/breath) by the breathing rate (breaths/min).

Minute Ventilation; Tidal Volume

During the ______ process of inspiration, the ______ move the rib cage up and out while the diaphragm flattens, causing lung volume to ______ and intrapulmonary pressure to decrease.

active; external intercostals; increase

In the oxygen cascade, the partial pressure of oxygen (PO2) starts at ______ mmHg in the air, but it drops to approximately ______ mmHg as it leaves the heart and further decreases to ______ mmHg upon its return to the heart from the muscles.

159; 100; 40

Most oxygen in the blood is transported by ______; oxygen within the muscle cells is transported by ______, which maintains a much ______ affinity for O2.

hemoglobin; myoglobin; higher

Clinicians use spirometry to assess and diagnose ______ by calculating the volume of air exhaled in ______ to the total volume exhaled (FEV1/FVC ratio).

airway disorders; 1 second

While peripheral chemoreceptors in the aortic and carotid bodies are sensitive to changes in blood PO2, PCO2, and H+, the ______ chemoreceptors are primarily stimulated by an increase in ______ ions in the cerebrospinal fluid.

central; H+

During intense exercise, a decrease in blood pH causes the oxygen-hemoglobin dissociation curve to shift to the ______, which allows for more oxygen to be unloaded at the exercising muscle; this phenomenon is known as the ______ Effect.

right; Bohr

The majority (60% to 70%) of carbon dioxide is transported from the tissues to the lungs in the form of ______, a process that begins with the formation of carbonic acid catalyzed by the enzyme ______ within red blood cells.

bicarbonate ions; carbonic anhydrase

At rest, oxygen diffusion capacity is limited due to incomplete lung ______, where primarily only the bottom third of the lung receives blood; however, during exercise, ______ opens the top two-thirds, leading to gas exchange over the full lung surface area.

perfusion; increased systemic blood pressure

Although expiration is normally ______ at rest, during exercise it becomes an ______ process, using the ______ to pull the ribs down and the abdominal muscles to force the diaphragm back up.

passive; active; internal intercostals

The ______ is closely associated with the lactate threshold because both reflect the point at which ______ begin to accumulate as workloads increase.

ventilatory threshold; metabolic byproducts

Following aerobic exercise, the period of lower blood pressure is primarily driven by ______, a process mediated by the release of ______.

peripheral vasodilation; histamine

High pressures generated during the Valsalva maneuver can collapse the ______, significantly reducing ______ and, subsequently, decreasing ______.

great veins; venous return; cardiac output

Among the various chemical buffers in the body, ______ is the most significant in the blood, accounting for approximately 64% of the total buffering capacity used to manage ______.

bicarbonate; exercise-induced acidosis

______ is defined as the explosive aspect of strength and is calculated as the product of ______ and ______.

Muscular power; force; velocity

The principle of ______ states that for the body to continue adapting, the training stimulus must be systematically ______ as the body becomes stronger.

Progressive Overload; increased

The principle of ______ dictates that physiological adaptations are highly related to the specific ______, ______, and ______ of the exercise performed.

Specificity; type; volume; intensity

To optimize performance and avoid premature fatigue, resistance training sessions should prioritize ______ and ______ before smaller or single-joint exercises.

large muscle groups; multi-joint exercises

Resistance training programs that emphasize ______ contractions, where the muscle resists force while lengthening, are essential for maximizing ______ and ______.

eccentric; strength; hypertrophy

Initial strength gains during the first 8–10 weeks are primarily driven by ______, while long-term gains beyond 10 weeks result from ______.

neural adaptations; hypertrophy

Resistance training can reduce autogenic ______ by training the ______ to allow for greater force production without premature muscle relaxation.

inhibition; Golgi tendon organs

Chronic heavy resistance training typically causes a shift in fiber type, where fast-twitch ______ fibers transition into the more oxidative ______ fibers.

type IIx; type IIa