Kin 446 Exam 1

• Connective tissue that connects skeletal muscles to bones: Tendons
• Muscles that decrease joint angles are called flexors, and muscles that increase joint angles are called extensors
• Calcium is stored in the Sarcoplasmic Reticulum within skeletal muscle fibers
• Three major functions performed by skeletal muscles:

  • Force generation for locomotion and breathing
  • Force generation for postural support
  • Heat production during cold stress
• Neurotransmitter that stimulates muscle cells to depolarize: Acetylcholine
• Enzyme that "breaks down" ATP: ATPase
• Muscle cramps are spasmodic, involuntary muscle contractions
• Exercise-associated muscle cramps theories:

  • Dehydration and Electrolyte Imbalance Theory is least supported by research
  • Muscle cramps can occur without changes in blood electrolyte concentrations
  • Static stretching of affected muscle often relieves cramps
• Most reliable relief for exercise-induced muscle cramps: Passive stretch of the muscle
• Exercise-associated muscle cramps originate at the neuromuscular junction (NMJ)
• Muscle fiber type most numerous in leg muscles of long-distance runners: Type I fibers
• Muscle fiber type most prominent in leg muscles of 100-meter sprinters: Type IIx fibers
• Muscle mass begins to decrease around age 25 due to aging (sarcopenia)
• Phases of sarcopenia muscle mass loss:

  • 10% muscle mass lost between ages 25 to 50
  • Additional 40% muscle mass lost between ages 50 to 80
  • By age 80, one-half of total skeletal muscle can be lost
• Resistance exercise is useful to prevent or delay age-related muscle loss
• Chemical reactions that release energy: Exergonic or exothermic reactions
• Chemical reactions that require energy input: Endergonic or endothermic reactions
• Difference between oxidation and reduction reactions: Oxidation is the loss of an electron, and reduction is the gaining of an electron (OIL RIG)
• Role of two subpopulations of mitochondria in skeletal muscle fibers:

  • Subsarcolemmal mitochondria: below the cell membrane, maintain active transport of ions
  • Intermyofibrillar mitochondria: near contractile proteins, provide energy for muscle contraction
• Enzymes that add a phosphate group: Kinases

  • Enzymes that remove a hydrogen atom: Dehydrogenase
  • Enzymes that rearrange atoms within a molecule: Isomerases
  • Enzymes that catalyze REDOX reactions: NADH and FADH
• ATP-producing pathways:

  • ATP-PCR and Adenylate-Kinase reaction occur in the sarcoplasm
  • Glycolysis occurs in the sarcoplasm
• Storage and usable forms of macronutrients:

  • Carbohydrates: Storage as glycogen, usable as glucose
  • Fats: Storage as TG, usable as Free fatty acids + glycerol
  • Protein: Broken down into amino acids
• Free radicals are highly reactive molecules formed in small quantities in the mitochondria
• Molecule that accepts electrons at the end of the electron transport chain (ETC)
• The connective tissue that connects skeletal muscles to bones is tendons
• Muscles that decrease joint angles are called flexors, and muscles that increase joint angles are called extensors
• Calcium is stored in the sarcoplasmic reticulum within skeletal muscle fibers
• The three major functions performed by skeletal muscles are:

  • Force generation for locomotion and breathing
  • Force generation for postural support
  • Heat production during cold stress
• The neurotransmitter that stimulates muscle cells to depolarize is acetylcholine
• The enzyme that "breaks down" ATP is ATPase
• Muscle cramps are spasmodic, involuntary muscle contractions
• Exercise-associated muscle cramps can originate at the neuromuscular junction (NMJ)
• The most reliable relief for most cases of exercise-induced muscle cramps is a passive stretch of the muscle
• Muscle mass begins to decrease due to aging, associated with a loss of muscle mass called sarcopenia, starting around age 25
• In the first "slow" phase of muscle loss, 10% of muscle mass is lost between the ages of 25 to 50 years. After that, there is a more rapid loss of muscle mass where, from the ages of 50 to years, an additional 40% of muscle mass is lost. By the age of 80, one-half of the total skeletal muscle can be lost
• Resistance exercise remains one of the most useful practical means to delay age-related muscle loss
• Chemical reactions that release energy are known as exergonic reactions or exothermic reactions
• Chemical reactions that require the input of energy are known as endergonic reactions or endothermic reactions
• Oxidation is the loss of an electron, and reduction is the gaining of an electron
• Subsarcolemmal mitochondria are directly below the cell membrane and produce the cellular energy needed to maintain active transport of ions. Intermyofibrillar mitochondria are near the myofibrillar proteins and provide the energy needed to sustain muscle contraction