Module 4: Support & Movement Flashcards
(58 cards)
which muscles type is involved in the function of the digestive tract and blood vessels?
smooth muscle
how does cardiac muscle differ from the other types of muscle?
it contains branched cells
true or false?
myofibrils are the alternating light-dark units that produce the banded appearance of muscle fibres.
false - sarcomeres are the alternating light-dark units that produce the banded appearance of myofibrils, which are the strands that make up each muscle fibre.
which type of muscles have one nucleus per muscle cell
cardiac muscle, smooth muscle
what is the intercalated disk, and which muscle has it?
cardiac muscle fibres interconnect at intercalated disk allowing the electrical signal to pass from one muscle cell to another. -> it helps synchronise heart muscle contraction.
why could it be useful for muscle fibres (cells) to have multiple nuclei?
nuclei enable the cell to make proteins, repair, proteins, and grow proteins.
nuclei direct protein synthesis, growth, and repair along the length of the cell.
which molecules form the thick filaments of sarcomeres?
myosin
which of the following interactions is the molecular basis of muscle contraction?
A) troponin and tropomyosin
B) myosin and thin filaments
C) myosin and thick filaments
D) sarcomeres and T tubules
B
Thin filaments (actin) attach at the ____ line and Thick filaments (myosin) anchor at the ____ line in the centre of the sarcomere.
fill the blank.
Z, M
explain the step of the power stroke of muscle contraction.
power stroke- attach and pull producing force
The phosphate ion is released, and the myosin head moves back to its original position.
three types of microstructure of muscle
1) perimysium 2) epimysium 3) endomysium
muscle cells are stimulated by neurotransmitters released from the synaptic terminal of ______
motor neuron axons
which function associated with muscle would be most directly affected by low levels of calcium
1) ATP hydrolysis
2) muscle contraction
3) the initiation of an action potential
4) muscle fatigue
5) the muscle fibre resting membrane potential
muscle contraction
skeletal fibres may be classified as either oxidative or glycolytic.
what muscles would be called glycolytic?
the ones most easily fatigued
myofibrils are composed of
sarcomere
muscle cells are each innervated by ______, direct from the spinal cord.
fill the blank
motor neuron
force is altered depending on
size (number of muscle fibres), contractile properties (speed, fatigability)
which muscle is better at controlling movement over joints that have a large range of motion between long muscles and shorter-wider muscles?
long muscles
which muscle is better at generating larger forces over a smaller range of joint motion?
shorter-wider muscles
why the physiological cross-sectional area (PCSA) of a muscle is considered one of the greatest predictors of force-generating capacity?
The force a muscle can generate is directly related to its PCSA. As the cross-sectional area increases, there is a larger number of muscle fibres available for contraction.
what are the two important factors that contribute to the calculation of a muscle PCSA?
PCSA = muscle volume/fibre length
when passive force is generated and which factors contribute to it?
- passive force is generated when the muscle is stretched.
- Titin and tendon.
The knee joint has a relatively large range of motion. Is it likely that the muscles that produce force in knee motion are long or short?
long.
Because large PCSA produces more force.
muscle fibres, myofibrils, fascicle
list the top concepts first.
muscle fibres > fascicle > myofibrils
> means ‘consist of’
