Flashcards in Animal physiology 2 Deck (25):
Muscle fibres contain bundles called ______
What are actin filaments?
Twisted chains of monomers (like a string of beads)
What are myosin filaments?
ordered bundles of tadpole-like molecules
each has head and coiled tail
What are sarcomeres?
repeated units along myofibrils
What borders adjacent sarcomeres?
How do you take muscle to bits?
Skinning - cold glycerol or triton X removes cell and other lipid membranes
Conc. salt solution with no Ca++, actin and myosin separate
What are myofibrils?
Formed when actin and myosin overlap
Who has evidence for the sliding filament theory and what is it?
Gordon, Huxley and Julian
Measured force at different sarcomere lengths, stretch to chosen length then activate electrically, measure force then repeat at different lengths
Force in one sarcomere is proportional to
The number of cross bridges
What are some characteristics of fast twitch muscle fibres?
few mitochondria or blood vessels or myoglobin
What are some characteristics of slow twitch muscle fibres?
many mitochondria and myoglobin
Which insects have synchronous flight muscles? (1 spike per twitch)
Which insects have asynchronous flight muscles? (high wingbeat frequency)
What is a motor unit?
Motor neuron plus muscle fibres
How can force be regulated?
Number of motor units that are active
What are tonic fibres?
Muscle in vertebrates that receive multi-terminal innervation from a single motor neuron axon
They are inexciteable
What is vertebrate twitch muscle fibre?
muscle fibre spikes when PSP generated at a synapse
Does insect muscle fibre spike?
What are the 2 components of respiration?
Internal cellular respiration
What are the definitions of:
Why is diffusion insufficient?
Animal phyla have increased in size
Diffusion distances no longer very small
How is diffusion augmented?
What are diffusion enhancements?
Gas can be converted into non-diffusible form
What are the two main types of bulk transport?