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ISSA CPT practice questions

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Question 1Anatomy and Physiology

In anatomical position, the palms of the hands face which direction?

  1. Downward toward the floor
  2. Forward (anteriorly) Correct answer.
  3. Backward (posteriorly)
  4. Toward the thighs

Explanation

Anatomical position is the standard reference posture: standing upright, feet forward, arms at the sides, and palms facing anteriorly. All directional terms are based on this position.

Question 2Anatomy and Physiology

Which plane divides the body into left and right portions?

  1. Sagittal plane Correct answer.
  2. Oblique plane
  3. Transverse plane
  4. Frontal plane

Explanation

A sagittal plane runs vertically and separates the body into left and right sections. A midsagittal plane divides the body into equal halves.

Question 3Anatomy and Physiology

What is the shaft of a long bone called?

  1. Diaphysis Correct answer.
  2. Periosteum
  3. Metaphysis
  4. Epiphysis

Explanation

The diaphysis is the long central shaft of a long bone and contains the medullary cavity. The epiphyses are the expanded ends, and the periosteum is the outer connective tissue covering.

Question 4Anatomy and Physiology

Which type of muscle tissue is involuntary and striated?

  1. Cardiac muscle Correct answer.
  2. Smooth muscle
  3. Skeletal muscle
  4. Connective tissue

Explanation

Cardiac muscle is striated like skeletal muscle but contracts involuntarily through its own conduction system. Smooth muscle is involuntary but not striated, and skeletal muscle is voluntary and striated.

Question 5Anatomy and Physiology

Which heart chamber pumps oxygenated blood into the systemic circulation?

  1. Right atrium
  2. Right ventricle
  3. Left atrium
  4. Left ventricle Correct answer.

Explanation

The left ventricle receives oxygenated blood from the left atrium and pumps it into the aorta for systemic circulation. Its thick wall reflects the high pressure it must generate.

Question 6Anatomy and Physiology

Where does gas exchange between the lungs and blood primarily occur?

  1. Pleura
  2. Alveoli Correct answer.
  3. Trachea
  4. Bronchi

Explanation

Alveoli are tiny air sacs surrounded by capillaries where oxygen and carbon dioxide diffuse across a thin membrane. Their large surface area supports efficient exchange.

Question 7Anatomy and Physiology

Which part of a neuron primarily receives incoming signals?

  1. Axon terminal
  2. Dendrites Correct answer.
  3. Axon
  4. Soma

Explanation

Dendrites are branched extensions that receive chemical signals from other neurons and carry them toward the cell body. The axon conducts outgoing impulses away from the soma.

Question 8Anatomy and Physiology

Which function is performed by the skeletal system?

  1. Producing blood cells Correct answer.
  2. Producing insulin
  3. Storing bile
  4. Generating heat by shivering

Explanation

Red bone marrow within certain bones produces blood cells through hematopoiesis. The skeletal system also provides support, protection, mineral storage, and leverage for movement.

Question 9Anatomy and Physiology

During a concentric muscle contraction, what happens at the sarcomere level?

  1. The A band shortens noticeably while the I band stays constant in width.
  2. The H zone widens as thin filaments are pulled away from the M line.
  3. The sarcomere shortens as actin filaments slide toward the center. Correct answer.
  4. The I band lengthens as the sarcomere stretches beyond resting length.

Explanation

In the sliding filament model, myosin heads pull actin filaments toward the sarcomere center, shortening the sarcomere. The A band remains constant because thick filaments do not change length.

Question 10Anatomy and Physiology

Type I muscle fibers are best described as:

  1. Slow to fatigue Correct answer.
  2. Large motor neuron
  3. Rapid to fatigue
  4. High peak force

Explanation

Type I fibers are slow-twitch, oxidative fibers with many mitochondria and a rich blood supply, making them resistant to fatigue. They favor endurance activities rather than maximal force.

Question 11Anatomy and Physiology

What does a muscle spindle primarily detect?

  1. Joint angle only
  2. Length and stretch rate Correct answer.
  3. Painful stimuli
  4. Tension only

Explanation

Muscle spindles are stretch receptors embedded in muscle that signal changes in muscle length and the speed of stretch. This information supports the stretch reflex and proprioception.

Question 12Anatomy and Physiology

What is the normal pacemaker of the heart?

  1. AV node
  2. SA node Correct answer.
  3. Bundle of His
  4. Purkinje fibers

Explanation

The sinoatrial node generates the heart's normal rhythm because it has the fastest spontaneous depolarization rate. It sets the pace that the rest of the conduction system follows.

Question 13Anatomy and Physiology

During heavy resistance exercise, what is the typical blood pressure response?

  1. Systolic pressure falls while diastolic pressure rises sharply
  2. Both systolic and diastolic pressure rise Correct answer.
  3. Both pressures fall because peripheral vessels dilate
  4. Blood pressure stays unchanged because cardiac output is stable

Explanation

Resistance exercise increases cardiac output and peripheral resistance, so both systolic and diastolic pressures typically rise. This is why breathing patterns and exercise selection matter for clients with cardiovascular risk.

Question 14Anatomy and Physiology

How is most oxygen transported in the blood?

  1. Bound to hemoglobin Correct answer.
  2. As bicarbonate ions
  3. Bound to albumin
  4. Dissolved in plasma

Explanation

About 98% of oxygen is carried bound to hemoglobin inside red blood cells. Only a small fraction dissolves directly in plasma.

Question 15Anatomy and Physiology

Which enzyme begins starch digestion in the mouth?

  1. Lipase
  2. Trypsin
  3. Amylase Correct answer.
  4. Pepsin

Explanation

Salivary amylase starts breaking starch into smaller carbohydrates as food is chewed. Protein digestion begins mainly in the stomach, and fat digestion relies on lipase.

Question 16Anatomy and Physiology

The elbow joint is classified as which type of synovial joint?

  1. Hinge Correct answer.
  2. Saddle
  3. Pivot
  4. Ball-and-socket

Explanation

The elbow is a hinge joint that primarily allows flexion and extension in one plane. Ball-and-socket joints allow motion in multiple planes, and pivot joints allow rotation.

Question 17Anatomy and Physiology

A crowbar used to pry up a heavy object is an example of which class of lever?

  1. Third class
  2. Fourth class
  3. Second class
  4. First class Correct answer.

Explanation

A first-class lever has the fulcrum between the effort and the load, as with a crowbar. Second-class levers place the load between the fulcrum and effort, and third-class levers place the effort between the fulcrum and load.

Question 18Anatomy and Physiology

Which cells are primarily responsible for building new bone tissue?

  1. Osteocytes
  2. Chondrocytes
  3. Osteoclasts
  4. Osteoblasts Correct answer.

Explanation

Osteoblasts synthesize and deposit new bone matrix, then may become osteocytes once surrounded by matrix. Osteoclasts break down bone, and chondrocytes form cartilage.

Question 19Anatomy and Physiology

Which gland secretes insulin?

  1. Adrenal gland
  2. Pituitary gland
  3. Thyroid gland
  4. Pancreas Correct answer.

Explanation

Insulin is produced by beta cells of the pancreatic islets in the pancreas. It lowers blood glucose by promoting cellular uptake and storage.

Question 20Anatomy and Physiology

Why does rigor mortis occur after death?

  1. Rapid ATP synthesis resumes after death
  2. Lactic acid crystallizes in the sarcomere
  3. Lack of ATP prevents myosin detachment Correct answer.
  4. Excess calcium floods the sarcoplasm

Explanation

Muscle relaxation requires ATP to detach myosin heads from actin and to pump calcium back into the sarcoplasmic reticulum. Without ATP production after death, cross-bridges remain attached and muscles stiffen.

Question 21Anatomy and Physiology

At which muscle length does active tension reach its peak?

  1. When the muscle is fully shortened and thin filaments overlap each other
  2. When calcium is absent and tropomyosin blocks binding sites
  3. At optimal sarcomere length, where actin-myosin overlap is maximal Correct answer.
  4. When the muscle is stretched to 150% of resting length with no overlap

Explanation

Active tension is greatest at optimal sarcomere length because myosin heads can bind the maximal number of actin sites. Over-stretching reduces overlap, and over-shortening reduces available binding sites.

Question 22Anatomy and Physiology

In the cross-bridge cycle, what does ATP directly provide during muscle contraction?

  1. Detachment of the myosin head from actin Correct answer.
  2. Propagation of the action potential along the sarcolemma
  3. Release of calcium from the sarcoplasmic reticulum
  4. Fusion of acetylcholine vesicles with the axon terminal

Explanation

ATP binding to the myosin head causes it to detach from actin, allowing the cycle to repeat. ATP is also used by calcium pumps, but detachment is a direct ATP-dependent step.

Question 23Anatomy and Physiology

During exercise, increased CO2 and hydrogen ions in working muscle cause what change in oxygen transport?

  1. A rightward shift that increases oxygen unloading Correct answer.
  2. No shift because hemoglobin remains fully saturated
  3. A leftward shift that raises hemoglobin's affinity for oxygen
  4. A rightward shift that reduces oxygen unloading

Explanation

The Bohr effect describes a rightward shift of the oxyhemoglobin dissociation curve when CO2 and H+ rise. This shift lowers hemoglobin affinity for oxygen, so more oxygen is released to active tissues.

Question 24Anatomy and Physiology

According to the size principle, how are motor units recruited as force demand increases?

  1. Random order regardless of size
  2. Largest motor units first
  3. Smallest motor units first Correct answer.
  4. All motor units at once

Explanation

The size principle states that low-threshold, smaller motor units are recruited first, with larger units added as force demand rises. This orderly recruitment supports smooth increases in force.

Question 25Anatomy and Physiology

A drug inhibits acetylcholinesterase at the neuromuscular junction. What is the expected effect?

  1. No change because receptors are unaffected
  2. Immediate relaxation because ACh is broken down faster
  3. Blocked contraction because receptors desensitize
  4. Prolonged contraction because ACh remains in the cleft Correct answer.

Explanation

Acetylcholinesterase normally breaks down acetylcholine to end the signal. If it is inhibited, acetylcholine stays in the synaptic cleft longer and repeatedly stimulates the muscle fiber, prolonging contraction.

Question 26Exercise Physiology and Energy Systems

The phosphagen (ATP-PC) system is the dominant contributor to ATP resynthesis during which type of effort?

  1. A steady jog lasting 30 minutes
  2. A maximal sprint lasting about 6 seconds Correct answer.
  3. A 5-kilometer race
  4. A 3-minute moderate cycle

Explanation

The phosphagen system uses stored ATP and creatine phosphate to resynthesize ATP extremely quickly but in very small quantities, and intramuscular stores are largely depleted within about 10 seconds of maximal effort. Longer efforts rely progressively more on glycolysis and oxidative phosphorylation.

Question 27Exercise Physiology and Energy Systems

Which neurotransmitter is released at the neuromuscular junction to trigger depolarization of the muscle fiber?

  1. Serotonin
  2. Norepinephrine
  3. Dopamine
  4. Acetylcholine Correct answer.

Explanation

The alpha motor neuron releases acetylcholine into the synaptic cleft, where it binds receptors on the motor end plate and initiates an action potential that spreads along the sarcolemma. Acetylcholinesterase then breaks down the transmitter to end the signal.

Question 28Exercise Physiology and Energy Systems

What is the end product of glycolysis that can either enter the mitochondria or be converted to lactate?

  1. Pyruvate Correct answer.
  2. Glucose-6-phosphate
  3. Acetyl-CoA
  4. Glycerol

Explanation

Glycolysis converts one glucose molecule into two three-carbon pyruvate molecules. Pyruvate can be transported into the mitochondria for oxidation or reduced to lactate when glycolytic flux outpaces mitochondrial capacity.

Question 29Exercise Physiology and Energy Systems

Approximately how many ATP molecules are produced from the complete aerobic oxidation of one glucose molecule?

  1. 2
  2. About 30 Correct answer.
  3. 4
  4. 18

Explanation

Complete oxidation of glucose through glycolysis, the Krebs cycle, and the electron transport chain yields roughly 30 to 32 ATP when modern accounting of transport costs is used. The older figure of 36 to 38 overestimates the yield.

Question 30Exercise Physiology and Energy Systems

Where does the Krebs (citric acid) cycle take place?

  1. Outer mitochondrial membrane
  2. Mitochondrial matrix Correct answer.
  3. Sarcoplasmic reticulum
  4. Sarcoplasm

Explanation

The Krebs cycle enzymes reside in the mitochondrial matrix, where acetyl-CoA is oxidized to produce NADH, FADH2, and GTP. The resulting reducing equivalents then feed the electron transport chain on the inner membrane.

Question 31Exercise Physiology and Energy Systems

A respiratory exchange ratio of 0.70 indicates that the predominant fuel being oxidized is:

  1. An even carbohydrate-fat mix
  2. Protein
  3. Carbohydrate
  4. Fat Correct answer.

Explanation

The respiratory exchange ratio is the ratio of carbon dioxide produced to oxygen consumed. A value near 0.70 reflects almost pure fat oxidation, while a value near 1.00 reflects almost pure carbohydrate oxidation.

Question 32Exercise Physiology and Energy Systems

Which statement best defines excess post-exercise oxygen consumption (EPOC)?

  1. The oxygen stored in muscle myoglobin
  2. The drop in blood lactate after exercise ends
  3. Oxygen used to fuel the exercise bout itself
  4. Elevated oxygen consumption above resting levels after exercise ends Correct answer.

Explanation

EPOC is the oxygen taken up above resting baseline after exercise stops. It supports replenishment of phosphocreatine and oxygen stores, lactate clearance, and restoration of body temperature and hormone balance.

Question 33Exercise Physiology and Energy Systems

Which characteristic is typical of Type I (slow-twitch) muscle fibers?

  1. High mitochondrial density Correct answer.
  2. Fast contraction velocity
  3. High glycolytic enzyme activity
  4. Large motor neuron size

Explanation

Type I fibers are densely packed with mitochondria and capillaries and rely primarily on oxidative metabolism, which supports fatigue resistance. They are innervated by smaller motor neurons and contract more slowly than Type II fibers.

Question 34Exercise Physiology and Energy Systems

What is the net ATP yield from anaerobic glycolysis of one glucose molecule to two lactate molecules?

  1. 2 ATP Correct answer.
  2. 6 ATP
  3. 8 ATP
  4. 4 ATP

Explanation

Glycolysis produces four ATP per glucose but consumes two during the priming steps, leaving a net gain of two ATP. Converting pyruvate to lactate regenerates NAD+ so glycolysis can continue without oxygen.

Question 35Exercise Physiology and Energy Systems

The lactate threshold is best described as:

  1. The intensity at which lactate first appears in the blood
  2. The intensity at which blood lactate rises faster than it can be cleared Correct answer.
  3. The intensity at which fat oxidation ceases
  4. The peak blood lactate measured after a maximal test

Explanation

Lactate is always present in blood at low levels, so the threshold marks the point where production outpaces clearance and blood lactate begins to accumulate rapidly. Training shifts this point to a higher percentage of maximal oxygen consumption.

Question 36Exercise Physiology and Energy Systems

According to the Fick equation, oxygen consumption is the product of:

  1. Tidal volume and breathing frequency
  2. Cardiac output and arteriovenous oxygen difference Correct answer.
  3. Stroke volume and blood pressure
  4. Heart rate and stroke volume

Explanation

The Fick equation states that oxygen uptake equals cardiac output multiplied by the difference in oxygen content between arterial and venous blood. This shows that oxygen use depends on both central delivery and peripheral extraction.

Question 37Exercise Physiology and Energy Systems

According to the size principle, motor units are recruited in which order as force demands increase?

  1. Largest and fastest first
  2. Smallest and slowest first Correct answer.
  3. In random order
  4. Highest threshold first

Explanation

The nervous system recruits motor units from smallest to largest, so low-threshold slow units fire first and high-threshold fast units are added as force demand rises. This orderly recruitment conserves metabolic resources at low forces.

Question 38Exercise Physiology and Energy Systems

The stretch-shortening cycle improves force output mainly by:

  1. Storing and reusing elastic energy in tendon and muscle Correct answer.
  2. Raising oxygen delivery to the working muscle
  3. Lowering motor unit firing frequency
  4. Increasing lactate clearance during the movement

Explanation

A rapid eccentric phase stores elastic energy in the tendon and muscle and triggers stretch reflexes, and the subsequent concentric phase can reuse that energy. The effect depends on a short coupling time between the two phases.

Question 39Exercise Physiology and Energy Systems

Why does fat provide more ATP per gram than carbohydrate?

  1. Fat is metabolized without the Krebs cycle
  2. Fat oxidation requires less oxygen per ATP produced
  3. Fatty acids enter glycolysis directly
  4. Fatty acids are more reduced and donate more electrons to the electron transport chain Correct answer.

Explanation

Fatty acid molecules are highly reduced, so beta-oxidation and the Krebs cycle generate large amounts of NADH and FADH2 per gram. Those electrons drive more ATP synthesis, which is why fat is energy dense despite requiring more oxygen per ATP.

Question 40Exercise Physiology and Energy Systems

Which event causes the myosin head to detach from actin during cross-bridge cycling?

  1. Acetylcholine binding to its receptor
  2. Phosphorylation of tropomyosin
  3. Calcium binding to troponin
  4. ATP binding to the myosin head Correct answer.

Explanation

Binding of a new ATP molecule to the myosin head reduces its affinity for actin and allows detachment. Hydrolysis of that ATP then re-cocks the head for the next power stroke.

Question 41Exercise Physiology and Energy Systems

The oxygen deficit at the start of exercise represents:

  1. Oxygen consumed after exercise above resting values
  2. The total oxygen consumed during the workout
  3. The gap between oxygen demand and aerobic ATP supply before steady state Correct answer.
  4. Lactate converted to glucose in the liver

Explanation

At exercise onset, aerobic ATP production lags behind demand, and the shortfall is covered by stored ATP, phosphocreatine, and glycolysis. The oxygen deficit quantifies that early reliance on anaerobic sources before oxygen uptake reaches steady state.

Question 42Exercise Physiology and Energy Systems

Which hormone is most associated with the catabolic response to prolonged high-intensity training stress?

  1. Testosterone
  2. Insulin
  3. Growth hormone
  4. Cortisol Correct answer.

Explanation

Cortisol rises with prolonged stress and mobilizes fuel while promoting protein breakdown and gluconeogenesis. Insulin, by contrast, is an anabolic storage hormone that falls during exercise.

Question 43Exercise Physiology and Energy Systems

During incremental aerobic exercise, which cardiovascular variable typically plateaus first as intensity approaches maximum?

  1. Heart rate
  2. Stroke volume Correct answer.
  3. Cardiac output
  4. Systolic blood pressure

Explanation

Stroke volume rises early in exercise but tends to level off at roughly 40 to 60 percent of maximal oxygen consumption as filling time shortens and cardiac output climbs. Further increases in cardiac output then come mainly from heart rate.

Question 44Exercise Physiology and Energy Systems

Most of the strength gain in the first few weeks of a resistance training program is attributed to:

  1. Muscle fiber hyperplasia
  2. Increased capillary density
  3. Increased mitochondrial density
  4. Neural adaptations such as improved motor unit recruitment Correct answer.

Explanation

Early strength improvements occur before measurable muscle growth and are driven largely by improved motor unit recruitment, firing rate, and intermuscular coordination. Hypertrophy contributes more to strength gains after several weeks of training.

Question 45Exercise Physiology and Energy Systems

During exercise in a hot environment, which heat-loss mechanism becomes the dominant route once sweating begins?

  1. Evaporation Correct answer.
  2. Convection
  3. Conduction
  4. Radiation

Explanation

Evaporation of sweat accounts for most heat loss during exercise in the heat, especially as ambient temperature approaches or exceeds skin temperature. High humidity reduces the vapor pressure gradient and blunts this mechanism.

Question 46Exercise Physiology and Energy Systems

An RER of 1.10 measured at maximal intensity most likely reflects:

  1. Steady-state aerobic metabolism
  2. Carbon dioxide production exceeding oxygen consumption from bicarbonate buffering Correct answer.
  3. A calibration error in the metabolic cart
  4. Predominant fat oxidation

Explanation

Values above 1.00 occur when lactate buffering releases extra carbon dioxide that adds to the exhaled pool, so carbon dioxide output transiently exceeds oxygen uptake. This is common near maximal effort and does not by itself indicate a technical fault.

Question 47Exercise Physiology and Energy Systems

Which factor most directly limits aerobic performance during the first days at high altitude?

  1. Elevated respiratory exchange ratio
  2. Increased plasma volume
  3. Reduced muscle glycogen stores
  4. Lower arterial oxygen saturation from reduced partial pressure of oxygen Correct answer.

Explanation

At altitude the partial pressure of oxygen in inspired air falls, which lowers the driving gradient for diffusion into the blood and reduces arterial oxygen saturation. Plasma volume actually decreases initially, and glycogen stores are not the primary acute limitation.

Question 48Exercise Physiology and Energy Systems

The slow component of oxygen uptake kinetics during heavy constant-load exercise is best explained by:

  1. Recruitment of less efficient type II fibers that raise the oxygen cost Correct answer.
  2. A rise in stroke volume
  3. Depletion of phosphocreatine stores
  4. Reduced motor unit recruitment

Explanation

After the primary fast phase, oxygen uptake may continue to rise slowly during heavy exercise as additional higher-threshold type II fibers are recruited and metabolic inefficiency increases. This slow component can eventually drive oxygen uptake toward maximal values.

Question 49Exercise Physiology and Energy Systems

Why does carbohydrate oxidation yield more ATP per liter of oxygen consumed than fat oxidation?

  1. Carbohydrate contains more carbon per molecule
  2. Carbohydrate is more oxidized so needs less O2 per ATP Correct answer.
  3. Fat oxidation occurs without oxygen
  4. Fat requires more ATP to enter the mitochondria

Explanation

Carbohydrate is already partially oxidized, so a given amount of oxygen supports more ATP synthesis than it does during fat oxidation. This is why carbohydrate becomes advantageous when oxygen supply limits performance.

Question 50Exercise Physiology and Energy Systems

Which statement about lactate is most accurate?

  1. Lactate cannot be reconverted into glucose
  2. Lactate is formed from pyruvate and can be used as fuel by other tissues Correct answer.
  3. Lactate is the direct cause of the burning sensation in muscle
  4. Lactate is produced only when oxygen is completely absent

Explanation

Lactate is produced when pyruvate is reduced by lactate dehydrogenase, and it can be shuttled to other muscles, the heart, or the liver for oxidation or gluconeogenesis. Production rises whenever glycolytic flux exceeds mitochondrial clearance, not only when oxygen is entirely absent.