T7: Run for your life

• What are tendons?

  Non-elastic tissue that connects muscles to bones
• What is the function of ligaments?

  They join bones together and determine the amount of movement possible at a joint
• What are joints?

  The area where two bones are attached for the purpose of allowing movement
• What are skeletal muscles?

  Muscles attached to bones, arranged in antagonistic pairs
• What are antagonistic muscle pairs?

  Pairs of muscles that pull in opposite directions, where one contracts while the other relaxes
• How do extensors and flexors function at a joint?

  Extensors straighten the joint while flexors bend the joint
• How do the triceps and biceps work together in arm movement?

  When the triceps relaxes, the biceps contracts to lift the arm
• What initiates muscle contraction according to the sliding filament theory?

  Calcium ions released from the sarcoplasmic reticulum upon nervous stimulation
• What happens when calcium ions bind to troponin?

  It changes the shape of the troponin molecule, exposing myosin binding sites
• What forms when myosin binding sites are exposed?

  An actomyosin bridge is formed
• What occurs after ADP and Pi are released during muscle contraction?

  The myosin head moves forward, shortening the sarcolemma
• What happens when free ATP binds to the myosin head?

  The myosin head changes shape and moves back to its original position
• What is the role of ATPase in muscle contraction?

  It breaks ATP back into ADP and Pi to restore the original state
• What happens if stimulation of the muscle is stopped?

  ATP is used to actively transport calcium ions back into the sarcoplasmic reticulum
• What is aerobic respiration?

  The splitting of a respiratory substrate reuniting hydrogen with atmospheric oxygen to release energy
• What is the main waste product of aerobic respiration?

  Carbon dioxide
• How many stages are there in aerobic respiration?

  Four stages
• What are the four stages of aerobic respiration?

  1. Glycolysis
  2. Link Reaction
  3. Kreb’s Cycle
  4. Oxidative Phosphorylation
• Where does glycolysis occur?

  In the cytoplasm
• What are the products of glycolysis?

  2 molecules of pyruvate, 2 molecules of ATP, and 2 molecules of NADH
• What happens to pyruvate in anaerobic respiration?

  It is reduced into lactate with the help of NADH
• What is an oxygen debt?

  The need to oxidize lactate back to pyruvate in the liver
• How does lactate affect blood pH?

  Lactate decreases blood pH, which can affect enzyme activity and cause muscle fatigue
• What occurs in the link reaction of aerobic respiration?

  Pyruvate is bound to coenzyme A, producing acetyl coenzyme A and releasing NADH
• What happens in the Krebs cycle?

  Acetyl-CoA donates 2 carbons to oxaloacetate, producing citrate and generating ATP, NAD, and FAD
• Where do the link reaction and Krebs cycle occur?

  In the mitochondrial matrix
• What is oxidative phosphorylation?

  The process in which ATP is synthesized via chemiosmosis in the electron transport chain
• What is the role of reduced coenzymes in oxidative phosphorylation?

  They carry hydrogen ions and electrons to the electron transport chain
• What occurs during redox reactions in the electron transport chain?

  The electron carrier that passes the electron is oxidized, while the one that receives it is reduced
• How are hydrogen ions transported during oxidative phosphorylation?

  They are actively transported across the membrane into the intermembrane space
• What happens when hydrogen ions diffuse back into the mitochondrial matrix?

  They pass through the protein ATP synthase
• What is produced when hydrogen ions and electrons combine with oxygen?

  Water is produced
• What is the cardiac cycle referred to as myogenic?

  Because the heart can initiate its own contraction
• Where does depolarization originate in the heart?

  In the Sinoatrial Node
• What happens during atrial systole?

  Depolarization spreads through the atria
• Why can't depolarization spread directly to the ventricles?

  Due to the region of non-conductive tissue known as the annulus fibrosus
• What is the role of the Atrioventricular Node?

  It stimulates another region of conducting tissue after atrial systole
• What occurs between atrial systole and ventricular systole?

  A slight delay occurs, allowing the ventricles to fill with blood
• What is the Bundle of His also known as?

  Purkyne Fibres
• How can electrical changes in the heart be measured?

  With an electrocardiogram (ECG)