Exam 1 Flashcards
What are the three connective tissue coverings of muscle?
Epimysium (outer), perimysium (around fasciculi), endomysium (around fibers).
Q2: What does the epimysium cover?
A: The entire muscle.
Q3: What does the perimysium surround?
A: Fasciculi (bundles of muscle fibers).
Q4: What does the endomysium cover?
A: Individual muscle fibers.
Q5: How are the connective tissue coverings and tendons related?
A: The coverings are continuous with tendons, transmitting force to bone.
Q6: What is the primary role of tendons?
A: To connect muscle to bone and transmit force.
Q7: What are the two parts of the sarcolemma?
A: Plasmalemma and basement membrane.
Q8: What is the plasmalemma’s function?
A: It conducts action potentials and fuses with tendons.
Q9: Where are satellite cells found, and what is their role?
A: Between the plasmalemma and basement membrane; they help with muscle growth and repair.
Q10: What is sarcoplasm?
A: Gel-like cytoplasm of a muscle fiber.
Q11: What does sarcoplasm contain?
A: Glycogen, myoglobin, and organelles like mitochondria.
Q12: What is the function of T-tubules?
A: Transmit action potentials deep into the muscle fiber.
Q13: How are T-tubules organized?
A: They are interconnected, forming a network within the fiber.
Q14: What is the role of the sarcoplasmic reticulum (SR)?
A: Stores and releases calcium for muscle contraction.
Q15: How does the SR interact with myofibrils?
A: It runs parallel to them, facilitating communication and transport.
Q16: What are myofibrils?
A: Rod-like structures made up of sarcomeres.
Q17: How many myofibrils are in a muscle fiber?
A: Hundreds to thousands.
Q18: What is the functional unit of a myofibril?
A: The sarcomere.
Q19: What gives sarcomeres their striated appearance?
A: The partial overlapping of actin and myosin filaments.
Q20: What happens to sarcomeres during contraction?
A: Actin and myosin filaments slide past each other, increasing overlap.
Q21: What proteins make up thin filaments?
A: Actin, tropomyosin, and troponin.
Q22: What protein primarily makes up thick filaments?
A: Myosin.
Q23: How much muscle cell protein is myosin?
A: Two-thirds.
Q24: What is the role of troponin during contraction?
A: It binds calcium, moving tropomyosin off actin binding sites.
Q25: What triggers excitation–contraction coupling?
A: Excitation of a motor nerve.
Q26: Where does calcium come from during contraction?
A: It is released from the sarcoplasmic reticulum (SR).
Q27: What happens when calcium binds to troponin?
A: Tropomyosin is moved, exposing actin binding sites.
Q28: What is the sliding filament theory?
A: Myosin heads pull actin filaments, shortening sarcomeres.
Q29: What does ATP do during contraction?
A: It allows myosin heads to detach from actin and reset.
Q30: What happens during muscle relaxation?
A: Calcium is pumped back into the SR, and actin-myosin interaction stops.
Q31: Do both contraction and relaxation require energy?
A: Yes, both require ATP.
Q32: What determines fast or slow muscle fiber characteristics?
A: The type of myosin ATPase enzyme.
Q33: Which fibers are fatigue-resistant?
A: Type I (slow-twitch).
Q34: Which fibers produce more force but fatigue quickly?
A: Type II (fast-twitch).
Q35: What are the subtypes of type II fibers?
A: Type IIa, IIx, and IIc.
Q36: Which fiber type has a more developed sarcoplasmic reticulum?
A: Type II fibers.
Q37: How do type I fibers support endurance?
A: Through high aerobic capacity and fatigue resistance.
Q38: Which type of fibers are better for explosive power?
A: Type II fibers.
Q39: How is fiber type determined?
A: By genetics and α-motor neuron innervation.
Q40: Can training change fiber types?
A: Long-term training can cause small shifts in fiber type.
Q41: What does motor unit recruitment affect?
A: The amount of force a muscle produces.
Q42: What is the principle of orderly recruitment?
A: Motor units are recruited in order based on force needs.
Q43: What is the size principle?
A: Smaller type I units are recruited before larger type II units.
Q44: What is rate coding?
A: The frequency of motor unit stimulation (twitch, summation, tetanus).
Q45: What is optimal muscle fiber length?
A: The length at which maximum force is produced.
Q46: How does contraction speed affect force?
A: Eccentric contractions produce more force than concentric.
Q47: What molecule is required for muscle contraction?
A: ATP.
Q48: How does ATP power myosin movement?
A: It provides energy for the myosin head to tilt and reset.
Q49: What happens when ATP is depleted?
A: Muscle fatigue occurs.
Q50: Does fiber composition determine athletic success?
A: No, but it can indicate suitability for endurance or power sports.
Q51: What type of fiber is predominant in endurance athletes?
A: Type I.
Q52: What type of fiber is predominant in power athletes?
A: Type II.
Q53: What are the three types of muscle contractions?
A: Concentric, static (isometric), eccentric.
Q54: Which contraction type produces the most force?
A: Eccentric.
Q55: What happens during static contractions?
A: Muscle generates force without changing length.
Q56: What is the role of joint moment arm in force production?
A: A longer moment arm can increase torque and force.
Q57: What are motor units composed of?
A: A motor neuron and the muscle fibers it innervates.
Q58: What does summation mean in muscle stimulation?
A: Repeated stimuli produce greater force than a single twitch.
Q59: What is tetanus in muscle contraction?
A: A sustained contraction resulting from high-frequency stimulation.
Q60: How does fatigue resistance differ between fiber types?
A: Type I is highly fatigue-resistant; type II fibers fatigue faster.
Q1: What are the key forms of carbohydrate used as energy substrates?
A: Glucose and glycogen.
Q2: What are the key forms of fat used as energy substrates?
A: Free fatty acids (FFAs) and triglycerides.
Q3: What are the building blocks of protein?
A: Amino acids.
Q4: How many kcal/g does carbohydrate provide?
A: 4 kcal/g.
Q5: How many kcal/g does fat provide?
A: 9 kcal/g.
Q6: How many kcal/g does protein provide?
A: 4 kcal/g.
Q7: Which energy substrate is the preferred fuel source during exercise?
Carbohydrate
Q8: Why is carbohydrate the preferred energy source during exercise?
A: It can be metabolized anaerobically and requires less oxygen for complete oxidation than fat.
Q9: Why are fat stores more energy-rich than carbohydrate stores?
A: Fat provides more energy per gram (9 kcal/g vs. 4 kcal/g).
Q10: What must triglycerides be broken down into before they can be used for energy?
A: Glycerol and free fatty acids.
Q11: What are the two main factors that control the rate of energy production?
A: Substrate availability and enzyme activity.
Q12: What are rate-limiting enzymes?
A: Enzymes that control the speed of energy production pathways.
Q13: How is enzyme activity regulated in energy production pathways?
A: Through negative feedback mechanisms.
Q14: What is the role of negative feedback in bioenergetics?
A: It prevents the overproduction of ATP by slowing enzyme activity when energy needs are met.
Q15: What is the primary source of energy for almost all metabolic processes?
A: ATP (adenosine triphosphate).
Q16: How is energy released from ATP?
A: By breaking the bond between the second and third phosphate groups.
Q17: Is the ATP-PCr system aerobic or anaerobic?
Anaerobic
Q18: What enzyme catalyzes the ATP-PCr system?
A: Creatine kinase.
Q19: What is the primary function of the ATP-PCr system?
A: To provide energy for explosive, short-duration movements.
Q20: How long can the ATP-PCr system sustain energy production?
A: About 10 seconds.
Q21: Is glycolysis aerobic or anaerobic?
A: Anaerobic.
Q22: How many ATP molecules are produced by glycolysis from glucose?
A: 2 ATP molecules.
Q23: How many ATP molecules are produced by glycolysis from glycogen?
A: 3 ATP molecules.
Q24: What is a key byproduct of anaerobic glycolysis?
A: Lactic acid.
Q25: For how long does the glycolytic system provide energy?
A: 20 seconds to 2 minutes.
Q26: What type of energy production is the oxidative system?
Aerobic
Q27: What process feeds the Krebs cycle during carbohydrate oxidation?
A: Glycolysis.
Q28: What are the end products of the Krebs cycle?
A: ATP, NADH, FADH2, and carbon dioxide.
Q29: What is the role of the electron transport chain (ETC)?
A: To use hydrogen ions from glycolysis and the Krebs cycle to produce ATP.
Q30: How many ATP molecules are produced from the oxidation of one glucose molecule?
A: 32 ATP.
Q31: How many ATP molecules are produced from the oxidation of one glycogen molecule?
A: 33 ATP.
Q32: What is β-oxidation?
A: The process of breaking down fatty acids into acetyl coenzyme-A.
Q33: What happens to fatty acids after β-oxidation?
A: They enter the Krebs cycle and the electron transport chain.
Q34: Why is fat oxidation slower than carbohydrate oxidation?
A: It requires more oxygen.
Q35: How much does protein contribute to energy production during exercise?
A: A small amount.
Q36: What must amino acids be converted into to enter energy production pathways?
A: Glucose or other intermediates.
Q37: Can lactate be used as an energy source?
A: Yes, it can be used by the fiber that produced it or transported to other tissues.
Q38: What is the lactate shuttle?
A: The process of transporting lactate to other cells for energy use.
Q39: What is gluconeogenesis?
A: The process of converting lactate to glucose in the liver.
Q40: Are all energy systems active at the same time?
A: Yes, but one system predominates based on the energy demand.
Q41: Which energy system is predominant during a 100m sprint?
A: The ATP-PCr system.
Q42: Which energy system is predominant during a marathon?
A: The oxidative system.
Q43: What determines the predominance of an energy system?
A: The intensity and duration of the activity.
Q44: What does enzyme activity indicate about muscle metabolism?
A: The bioenergetic capacity of the muscle.
Q45: How does training affect oxidative enzyme activity?
A: Training increases enzyme activity.
Q46: Which fiber type has more aerobic enzyme activity?
A: Type I fibers.
Q47: Which fiber type has more anaerobic enzyme activity?
A: Type II fibers.
Q48: How does endurance training affect fiber oxidative capacity?
A: It increases oxidative capacity in all fiber types.
Q49: What factors determine the oxidative capacity of muscle?
A: Oxygen supply, mitochondria, and aerobic enzymes.
Q50: What limits the maximal rate of oxidative metabolism in muscles?
A: Oxygen delivery by the cardiorespiratory system.
Q51: Why are mitochondria important for oxidative metabolism?
A: They are the site of ATP production during aerobic metabolism.
Q52: What are the three basic energy systems?
A: ATP-PCr, glycolytic, and oxidative.
Q53: Which energy system has the highest energy yield?
A: The oxidative system.
Q54: Why is fat considered an energy-dense substrate?
A: It provides 9 kcal per gram.
Q55: Which energy system is the fastest but least efficient?
A: The ATP-PCr system.
Q56: How long does the oxidative system sustain energy production?
A: Indefinitely, as long as oxygen and fuel are available.
Q57: What is the role of creatine kinase in the ATP-PCr system?
A: It catalyzes the transfer of a phosphate group from PCr to ADP to form ATP.
Q58: What causes fatigue in the glycolytic system?
A: The accumulation of lactic acid.
Q59: How does oxygen debt affect recovery after exercise?
A: Oxygen is required to replenish energy stores and remove byproducts.
Q60: What is the primary purpose of the Krebs cycle?
A: To generate electron carriers (NADH, FADH2) for the electron transport chain.
Q: What are the main parts of a neuron?
A: Cell body, dendrites, axon, synapse, neurotransmitters.
Q: What is the primary function of dendrites?
A: To receive signals from other neurons.
Q: What is the role of the axon in a neuron?
A: To transmit signals away from the cell body.
Q: Define the resting membrane potential.
A: The electrical charge difference across the membrane at rest.
Q: What creates the resting membrane potential?
A: Electrolyte distribution across the membrane.
Q: What happens during depolarization?
A: The inside of the neuron becomes more positive.
Q: What happens during hyperpolarization?
A: The inside of the neuron becomes more negative than at rest.
Q: What are graded potentials?
A: Localized changes in membrane potential.
Q: What triggers graded potentials?
A: Changes in the local environment.
Q: What occurs during an action potential?
A: Complete depolarization of the neuron.
Q: How does myelination affect nerve impulse transmission?
A: It speeds up transmission.
Q: How does the diameter of a neuron affect transmission speed?
A: Larger diameter = faster transmission.
Q: What role do neurotransmitters play at a synapse?
A: They propagate the electrical signal chemically.
Q: Describe the neuromuscular junction.
A: A specialized synapse between a motor neuron and a muscle cell.
Q: Name two major neurotransmitters in the nervous system.
A: Acetylcholine and norepinephrine.
Q: What determines whether a postsynaptic signal continues?
A: The summation of impulses.
Q: What are the main regions of the brain?
A: Cerebrum, diencephalon, cerebellum, brain stem.
Q: What is the frontal lobe’s function in the cerebrum?
A: Motor control functions.
Q: What is the role of the primary motor cortex?
A: Conscious control of skeletal muscles.
Q: What function do pyramidal cells serve?
A: They initiate voluntary movement.
Q: What is the role of the basal ganglia?
A: To initiate sustained movements.
Q: Name the two main components of the diencephalon.
A: Thalamus and hypothalamus.
Q: What does the cerebellum control?
A: Rapid and complex muscular activities.
Q: What are the three parts of the brain stem?
A: Midbrain, pons, medulla oblongata.
Q: How is the spinal cord connected to the brain?
A: Via the medulla oblongata.
Q: What types of fibers does the spinal cord carry?
A: Sensory and motor fibers.
Q: What is the spinal cord’s role in nerve conduction?
A: It conducts impulses to and from the brain.
Q: What is the sensory division’s role in the PNS?
A: It transmits afferent nerve impulses.
Q: Name five types of sensory receptors.
A: Mechanoreceptors, nociceptors, photoreceptors, chemoreceptors, thermoreceptors.
Q: Why are sensory receptors important in exercise?
A: They provide feedback for movement and performance.
Q: What is the motor division’s function in the PNS?
A: It transmits efferent impulses to muscles.
Q: What is the autonomic nervous system responsible for?
A: Control of involuntary functions.
Q: How does the sympathetic nervous system affect heart rate?
A: It increases heart rate and contractility.
Q: What effect does the sympathetic nervous system have on blood flow?
A: It redirects blood to muscles.
Q: What is the parasympathetic nervous system’s role?
A: It controls digestion and relaxation responses.
Q: How does the parasympathetic system oppose the sympathetic system?
A: By slowing heart rate and reducing metabolic activity.
Q: What is sensory input?
A: Signals received from sensory receptors.
Q: Where can sensory input terminate in the CNS?
A: At various levels, including the spinal cord or brain.
Q: What is reflex activity?
A: The simplest form of motor control.
Q: What do muscle spindles monitor?
A: Changes in muscle length.
Q: What do Golgi tendon organs monitor?
A: Tension in the muscle–tendon complex.
Q: What triggers a motor response in the nervous system?
A: α-motor neurons.
Q: What is the role of the cerebrum in exercise?
A: It processes commands and feedback for motor actions.
Q: How does the hypothalamus regulate homeostasis?
A: By controlling body temperature, thirst, and hunger.
Q: What is the importance of the thalamus in sensory processing?
A: It acts as a relay center for sensory signals.
Q: How does the cerebellum aid balance and coordination?
A: By fine-tuning motor activities.
Q: Why is the brain stem vital for survival?
A: It regulates heart rate, breathing, and reflexes.
Q: What role does the medulla oblongata play in exercise?
A: It controls respiratory and cardiovascular responses.
Q: How does myelination improve neural efficiency?
A: By increasing the speed of signal transmission.
Q: What adaptations occur in the nervous system with training?
A: Increased efficiency of motor unit recruitment.
Q: How do sensory receptors adapt to regular exercise?
A: They become more responsive to changes in muscle length and tension.
Q: What changes occur in the autonomic nervous system with endurance training?
A: Improved parasympathetic control, reducing resting heart rate.
Q: What makes acetylcholine excitatory?
A: It stimulates muscle contraction.
Q: How does norepinephrine affect blood vessels?
A: It causes vasoconstriction in non-working tissues.
Q: What does “afferent” refer to in the nervous system?
A: Signals going to the CNS.
Q: What does “efferent” refer to in the nervous system?
A: Signals leaving the CNS to muscles.
Q: What is the function of thermoreceptors?
A: To detect changes in temperature.
Q: What is the main role of mechanoreceptors?
A: To detect mechanical changes like stretch or pressure.
Q: How does the nervous system contribute to motor learning?
A: By adapting neural pathways for more efficient movement.
Q: What is the role of α-motor neurons in muscle movement?
A: They trigger muscle fiber contraction.
What is glycolysis?
The process of breaking a 6-carbon glucose molecule into two 3-carbon pyruvate molecules.
What does “lysis” mean in glycolysis?
Cutting or splitting.
What is glucose?
A 6-carbon molecule derived from food, like doughnuts, during digestion.
What is the end product of anaerobic glycolysis?
Lactate.
What is the rate-limiting enzyme of glycolysis?
Phosphofructokinase (PFK).
What does glycolysis produce in terms of net ATP?
2 net ATP.
Where does glycolysis occur in the cell?
Cytoplasm (cytosol)
What is the role of oxygen in the Krebs cycle?
Oxygen is required for aerobic processes in the mitochondria.
What happens to pyruvate in the Krebs cycle?
It is converted into acetyl-CoA and enters the cycle.
What is acetyl-CoA?
A 2-carbon molecule that combines with oxaloacetate to form citric acid.
What is the main purpose of the Krebs cycle?
To produce NADH, FADH2, and 2 ATP for oxidative phosphorylation.
How is carbon dioxide released during the Krebs cycle?
A carbon from pyruvate bonds with oxygen, forming CO2.
What is oxidative phosphorylation?
The process of oxidizing NADH and FADH2 to produce ATP.
How much ATP does oxidative phosphorylation produce?
34 ATP.
What is the total ATP yield from one glucose molecule?
38 ATP (2 from glycolysis, 2 from Krebs, 34 from oxidative phosphorylation).
What is beta-oxidation?
The breakdown of fats into 2-carbon molecules that enter the Krebs cycle as acetyl-CoA.
What is gluconeogenesis?
The process of creating new glucose from molecules like amino acids, lactate, or pyruvate.
The process of creating new glucose from molecules like amino acids, lactate, or pyruvate.
Amino acids, lactate, pyruvate.
How does NADH contribute to ATP production?
Each NADH generates 3 ATP in oxidative phosphorylation.
How does FADH2 contribute to ATP production?
Each FADH2 generates 2 ATP in oxidative phosphorylation.
Where does the Krebs cycle occur?
In the mitochondria.
What is the role of oxygen in ATP production?
It combines with carbon to form CO2 and drives aerobic processes.
What is citric acid?
A 6-carbon molecule formed by acetyl-CoA and oxaloacetate in the Krebs cycle.
What is the role of oxaloacetate in the Krebs cycle?
Combines with acetyl-CoA to form citric acid.
How does fat enter the energy pathway?
Fatty acids are broken into acetyl-CoA via beta-oxidation and enter the Krebs cycle.
What is the net gain of ATP from glycolysis?
2 ATP (4 made, 2 used).
What are the main products of the Krebs cycle?
NADH, FADH2, 2 ATP, and CO2.
What happens to NAD+ in the Krebs cycle?
It is reduced to NADH.
How is glucose derived from carbohydrates?
Through digestion, breaking carbs into glucose.
What is the primary function of NADH and FADH2?
To carry electrons to the electron transport chain.
