Set F quiz

• Which one of the following substances increases the rate and the force of contraction of the human heart?

  Adrenaline
• Which one of the following is part of the conduction system in the heart?

  Sinoatrial node, atrioventricular node, bundle of his, purkinje fibres
• Which one of the following causes depolarisation of motor end plates in muscle cells?

  Increased permeability of Na ions
• Which one of the following statements about isometric muscle contraction is correct?

  • the muscle generates tension but its length remains constant
• Which one of the following statements about transverse tubules is correct

  • they are connected to the sarcolemma and extracellular fluid
  • At rest they are relatively impermeable to sodium ions
  • they allow action potential to quickly penetrate deep into the muscle tissue
  • they do contain ion channels
  • they are found in skeletal and cardiac muscle
• When comparing smooth muscle with skeletal muscle, which one of the following statements is correct?

  • skeletal muscle cells are larger than smooth muscle cells
  • contractions are slower and last longer in smooth muscle
  • calcium ions are required for contraction to take place in both types of muscle
  • cross bridges are formed in both types of muscle
• Cross-bridges form between which pair of the following proteins in muscle?

  Actin and myosin
• Compare smooth muscle with skeletal muscle:

  • skeletal muscle cells are larger than smooth muscle cells
  • contractions are slower and last longer in smooth muscle
  • calcium ions are required for contraction to take place in both types of muscle
  • smooth muscle contains less sarcomeres than skeletal muscle
  • cross bridges are formed in both types of muscle
• Which one of the following bone cells re-absorbs bone to release calcium when activated by parathyroid hormone?:

  osteoclast
• The area in the centre of the A band that contains only thick filaments is the?

  • H band
• When calcium ion binds to troponin which one of the following occurs?

  • tropomyosin moves out of the groove between the actin molecules
• The bundle of collagen fibres at the end of a skeletal muscle that attaches the muscle to bone is called:

  • tendon
• The cytoplasm of a skeletal muscle fibre is called the?

  • sacroplasm
• The borders of the sarcomere in skeletal muscle is called the?

  Z lines
• The functional unit of a skeletal muscle fibre is the?

  • sarcomere
• The sarcoplasmic reticulum stores which one of the following?

  calcium ions
• Physical evidence that supports the sliding filament theory of muscle contraction includes which one of the following?

  • decreased distance between Z lines during contraction
• Which one of the following hormones inhibits bone reabsorption?

  • Calcitonin
• Where is an osteocyte found in a bone?

  • Canaliculi
• Where are chondrocytes found in growing long bones?

  • Epiphyseal cartilage
• What do large multinucleated osteoclast cell do in bone?:


  • they reabsorb old bone
• Which one of the following cell types is entrapped to form mature bone?

  • Osteoblast
• Which part of a bone is made of cortical bone?

  shaft
• Compare cardiac muscle with skeletal muscle

  • the mechanical events of contraction are similar in both muscle types
  • the action potential lasts longer in cardiac muscle
  • the refractory period extends the relaxation phase in cardiac muscle
  • contraction of skeletal muscle is stimulated by motor neurons
• Which one of the following is the main reason why small animals have a larger resting metabolic rate per kg body mass than larger animals?

  • Larger surface area to body weight ratio
• Approximately how many KJ of energy are release for each litre of oxygen used by the body?

  • 20 KJ / L
• Which one of the following is the correct equation for calculating the RQ (respiratory quotient)?

  • VCO2 divided by VO2
• Why does fat metabolism generate a lower RQ value than glucose metabolism?

  • Fat molecules contain proportionally less oxygen
• Which one of the following is a hormone that regulates basal metabolic rate in humans?

  • Thyroid hormone
• Which one of the following is a typical % OXYGEN content of expired air at rest?

  • 17%;
• By what factor does gentle stepping exercise increase metabolic rate by ?

  • 2 – 4 fold
• Which one of the following factors should be taken into account in order to calculate metabolic rate more accurately than using KJ / hour?

  • Weight
• Why does anaerobic exercise generate an RQ value greater than 1?

  • Because O2 is transferred to blood at a slower rate than CO2 is lost to the environment
• Which one of the following is most likely to cause the RQ value to exceed a value of 1 when attempting to measure metabolic rate with a Douglas bag?

  • Hyperventilation
• Which one of the following is a typical % CARBONDIOXIDE content of expired air at rest?

  • 4%
• Which one of the following is a typical % CARBONDIOXIDE content of atmospheric / inspired air?

  • 0.03%
• Which one of the following is a typical % NITROGEN content of atmospheric / inspired air?

  • 79%;
• Which one of the following is a typical % OXYGEN content of atmospheric / inspired air?

  • 21%