Lecture 4 muscle

Question 1

muscles of the trunk and tail

Answer 1

muscles are separated into blocks called myotomes and myomeres which are seperated by connective tissue called myosepta and myocommata

Question 2

myotomes (3)

Answer 2

• in sharks and bony fishes myotoms are w shaped
• 1 or 2 myotomes per vertebral centrum BUT each myotome may span 3 - 12 intervertebral joints
  -myotomes attach to skin (external) and myosepta, vertical septa or horizontal septa (internal)

Question 3

muscle colours (3)

Answer 3

Red: for sustained movement, small with high amounts of lipids, glycogen, mitochondria, blood vessels, and myoglobin. also produces heat

White: for bursts of movement, low amounts of everything in red, with enzymes of anaerobic glycolysis

Pink: Intermediate between the two, a Band around the red muscle

Question 4

Fin muscles (3)

Answer 4

-derived from myotomes, but no obvious association in adults

-each median fin ray has erector & depressor muscles

-soft fins also have inclinators that can bend the ray

Question 5

swimming modes (4)

Answer 5

Anguiliform(eel) = Characterized by more then one wavelength along the body (not just the caudal fin)

subcarangiliform(catfish): More pronounced use of the caudal fin about one wavelength, use of body too

carangiliform(herring): About half a wavelength used for motion, less body more caudal

thunniform (tuna) : Less than half a wavelength, body is kept mostly rigid by the interlocking zygopophyses’ only caudal fin is used for motion

Question 6

types of movement (6)

Answer 6

Undulation: whole body movement
oscillation: fin movement
supra benthic : just above sea floor (rays)
walking or wriggling on land (mudskippers)
jumping (tuna and needlefish)
gliding (flying fish)

Question 7

swimming speed

Answer 7

-Generally, optimal swimming speed is expected to be around 2 - 3 L/s, but may differ among species

-burst swimming is anything above 2-3 L/s

L/s = body lengths per second

Question 8

Burst swimming

Answer 8

-to avoid predator OR capture prey
-cannot be sustained (muscle fatigue)
-observed ranges: 2 L/s up to 21 L/s

Question 9

Hydrodynamics

Answer 9

look at hydrodynamics pic