CVA - locomotion/muscles

• Petromyzontidae

  • Lateral undulation
  • myomere and notochord/segmented muscles
• Chondrichthyes

  • axial undulation (w/ tail)
  • tail creates lift
  • buoyancy (cartilaginous skeleton and lipid stored in liver)
• Actinopterygii

  • undulatory action w/ trunk/tail
  • Buoyancy w/ swim bladder
  • myomere/segmented muscle
• Amphibia

  • epaxial/hypaxial muscle groups
  • legs in "primitive" splayed position
  • sinusoidal lateral curve
  • lateral undulation
• Reptilia

  • snakes: rectilinear, sidewinding, serpentine, concertina
  • land to water (alligator, etc.): high walk, undulation
• mammalia

  • bowed spine/cursorial locomotion
  • legs position beneath the body
  • vertebral column doesn't bend laterally
• What are some forces that oppose locomotion?

  Drag in the water, gravity on earth
• Drag - frictional forces that hold back an object as it moves through a medium
• Frictional drag - due to the viscosity of water

  pressure drag - differense in pressure from front to rear during locomotion
• lateral undulation is achieves by muscles attached to the notochord
• lateral undulation applies force to water
• Sharks have an asymmetric tail. The top lobe pushes up while the bottom lobe pushes down, helping to propel the shark up/down
• Rays and skates use their pelvic fins to propel them
• Rays move by oscillating their fins up and down. Large ceratotrichia helps to make up a lot of surface area
• Fish have scale ridges and a mucus later to adapt against drag
• Transitions

  Fin rays transitioned into bones, metacarpals and phalanges

  More structure in the limb

  The tail ceases to be the primary thing to that moves the animal forward, and are replaced by the pectoral girdle transitioning into feet

  The pectoral girdle detaches from the head for more flexibility
• Lizards have microfolds in their feel to increase surface area of the skin. These folds are arranged in such a way like suction cups for better climbing
• crocodiles have a high walk on land, but use tail undulation in the water. Extreme musculature associated with the tail
• turtles have limb driven locomotion
• in mammals, the rod of the leg is longer which increases distance covered during a stride and speed
• Skeletal Muscles - are associated

  with the skeleton (bones and cartilage)
• Cardiac Muscles - form

  musculature of the heart wall
• Smooth muscles - contribute to

  walls of blood vessels and

  visceral organs
• Sliding filament hypothesis - muscle contractions occur by the shortening of a sarcomere through the binding of myosin and actin myofilamnets. 1 ATP per myosin head for each contraction
• The sliding of actin by myosin generates muscle tension
• Tonic muscles

  • activated from multiple end plates of a neuron
  • activates local sarcomeres
  • slow, sustained movements
• Twitch muscle - each fiber has a single motor end plate
• Slow twitch

  • energy from oxidative metabolism, highly vascularized (red muscle)
  • slow, repetitive movements
• Fast twitch

  • energy from glycolysis (anaerobic metabolism)
  • less vascularized
  • rapid movements, quickly fatigue
• How do muscle groups interact to produce motion?

  Through contractile and elastic energy, muscle groups flex and extend with one another to produce motion
• 3 locomotory convergence examples

  • wings on bats and birds
  • snakes and squirrels gliding
  • sleek swimming of dolphins and sharks
• How do muscles and the skeleton interact to produce motion?

  Through contractile and elastic energy, muscle groups flex and extend with one another. Muscles are attached to bone by ligaments, so when a muscle contracts, it extends or flexes that bone