BI451-Lecture-3-Swimming-I-F23.txt

Swimming – Fins and Muscle BI451 Lectures 3 Sept 2023  Objectives • Anatomy of Locomotion » fin design & function » muscle design & function • Types of Locomotion • Biomechanics of Swimming • Modes of swimming • Swim Performance & Energetics » applications » techniques  REVIEW A Review...

Swimming – Fins and Muscle BI451 Lectures 3 Sept 2023  Objectives • Anatomy of Locomotion » fin design & function » muscle design & function • Types of Locomotion • Biomechanics of Swimming • Modes of swimming • Swim Performance & Energetics » applications » techniques  REVIEW A Review of the Properties of Water 1. Density & Viscosity ● Density is 800 times greater than air » neutral buoyancy » good for generating thrust » high resistance to motion = “Drag” Pressure + Frictional drag forces (more later). ● Viscosity is 50 times greater than air » Drag » Turbulence ● Adaptations » streamlining » high proportion of swimming muscles Virtually Incompressible ● Drag & Turbulence  REVIEW Body Shape • 6 Broad Functional Categories (A,B) Rover Predator (C) Lie in wait predator (D) Surface orientated fish (E) Bottom Rover (F) Bottom Clinger Bottom fish Bottom Hider (E-H) (G) Flatfish (H) Rat tail (I) Deep-bodied fish (J) Eel-like fish  I. External Anatomy Functions of fins? I Anatomical Features 1. Fins Convergent Evolution • caudal fin for propulsion • paired-medial fins to control “pitch”, “roll” & “yaw” Fin Rays for structural support • Ceratotrichia (ct) » sharks » stiff, unbranched » cartilage • Lepidotrichia (l) » bony fish » flexible, segmented, branched Lepidotrichia Ceratotrichia Romer, 1986.  (i) Pectoral Fins • Rover predators, Bottom-Rovers » Ventral-below midline » Stability, steering • Very deep-bodied fishes and fast swimming predator rovers (tuna) » long and pointy • Slower swimming predator rovers » more rounded • Deep-bodied fishes: High on sides » maneuverability, picking-up food • Exaggerated, Large » Flying or Gliding (skates, rays, flying fishes) »Display (lionfish) • Rigid Stabilizers/Diving Planes in sharks Pterois volitans (ii) Pelvic Fins Ancestral Condition • ventral, posterior location » assist steering and breaking • Rover Predators, Bottom-Rovers » sharks, salmonids, sturgeon Adaptations • More anterior, below pectoral fins » maneuverability » Deep-bodied Fishes » Centrachids (blue gill), tilapia • Large, anterior holding structures » bottom clingers (sculpin) • Absent or Reduced in eel-like fishes eel sculpin (iii) Dorsal & Anal Fins • Rover predators, Bottom-Rovers » long » stability, steering • Fast Swimmers (tuna, mackeral) » rearmost fins = finlets » foremost dorsal, pectoral fins fold into slots to reduce drag • Anguilliform swimmers (eel-like fishes) » very long dorsal & anal fins, which may unite with caudal fin Anguilla rostrata Eel Petromyzon marinus (iv) Caudal Fin Aspect Ratio (AR) = h2 • Primarily for Propulsion SA Shape provide info about how fish swims/lifestyle (1) Homocercal • upper & lower lobes of equal size • vertebral column = modified base • most bony fishes • Two Additional Sub-types (i) Lunate » stiff keel-like caudal peduncle » deeply forked (high aspect ratio) e.g. fast swimmers (tuna, marlin) (ii) Isocercal » lack well-defined lobes (e.g. killifish) (iv) Caudal Fin continued (2) Heterocercal • upper lobes longer than lower • vertebral column extends into upper lobe » Stiff in Sharks which generates lift » Flexible in Sturgeon which does not generate lift Diphycercal • dorsal & ventral fins merge to form one long caudal fin » Lungfishes (v) Adipose Fin • fleshy, lacks fin rays. Is not for fat storage. • Vestigial? • important for swimming in post-larval stage? • increases swimming efficiency. Flow sensor, or creates turbulent flow over caudal fin? •“precaudal flow sensor” allowing improved maneuverability in turbulent waters. • Characteristic in salmonidae, smelts, catfishes Fin Spines stickleback Derived in several groups of fishes Frequently in Centre of Body Mass • dorsal, anal &/or pectoral • defense by increasing effective size » larger than mouth of predator. Steve Irwin 1962-2006 • often associated with poison glands » catfishes, stingrays, lionfish Plotosidae catfish Dasyatis americana Vertebral column Cartilage or bone. Incompressible but flexible (bends). Central axis for muscle attachment. One myomere per vertebrae X-ray NS NA HS HA C 2. Muscular System • majority of body mass » 60 % in trout • vertically organized into “W-shaped” myomeres Supermarket version REVIEW SLIDE ATP Production via Oxidative Phosphorylation From Randall et al. 1997.  REVIEW SLIDE Oxidative-Phosphorylation Takes Place Across the Inner Mitochondria Membrane Inner Outer Outer Membrane Intermembrane Matrix space (i) H+-pumping by e– Inner transport chain Membrane Matrix Cristae (ii) H+-gradient established (iii) diffusion of H+ → ATP production via ATP synthase Modified from Hill,Wyse & Anderson (2004) Two Main Types of Muscle Fiber Moyle & Cech 2000 (i) Red Muscle Aerobic Endurance • Slow speed of contraction • Fatigue resistant fibers » numerous mitochondria » high myoglobin content; O2 buffering/storage » slow ATP consumption rate • ATP supplied via oxidative phosphorylation » lipid (+ amino acids) » low glycogen content • Abundant capillary supply; O2 delivery • Small diameter » low strength contraction • Endurance, Sustained Low Speed Swimming (ii) White Muscle Anaerobic burst • ATP produced via Glycolysis » high [glycogen] » aka. Fast Twitch Glycolytic • High contraction velocity • Low capillary supply + low Myoglobin » aka. white fibres • Low mitochondrial supply • THICK fibre - more tension with contraction. 2.7x red muscle » intensive or burst swimming; short term activity. » acceleration » lactate buildup. Oxygen Debt. Recovery needed. Track stars in sprint and distance Life Style Reflects Muscle Fibre Use & Make-Up • Continuously, Highly Active » Red Muscle » Marlin • Intermittent, Sustained High Speed Swimming » Large lateral band of red muscle concentrated in Caudal Peduncle (10-20 %) » Open water predators (striped bass, bluefish) • Intermittent Burst of Activity » mainly white muscle with thin band red muscle » Rover Predators, Lie-in-Wait Predators (dogfish (shark), trout, bass, pike) Used in concert as swimming style changes