BIOS 252 MIDTERM STUDY GUIDE
Chapter 10. Muscular Tissue
Location Appearance Control
Skeletal Skeleton Multi-nucleated Voluntary
Striated
Cardiac Heart One nucleus Involuntary
Striated
Smooth Various One nucleus Involuntary
No striations
Sliding filament theory of muscular contraction:
,During muscular contraction:
- Z discs are pulled toward the M line
- A band stays the same
- H zone decreases
- Zone of overlap increases
- I band (thin) decreases in size
Acetylcholine is the neurotransmitter used for muscular contraction.
Endomysium
wraps around each fiber
Perimysium
holds the fascicle together
Epimysium
outermost layer
The two other things necessary for muscular contraction are calcium ions and ATP
Calcium ions are stored in the sarcoplasmic reticulum
Calcium ions are released from the terminal cisterns
Muscle Metabolism
Three ways that ATP is generated:
Creatine phosphate Molecule reacts with ATP to 15 seconds
form creatine phosphate and
ADP. Fast and first method used
Anaerobic glycolysis Without oxygen, uses glycolysis 2 minutes
to produce 2 ATP. Later
becomes lactic acid.
Aerobic respiration In the presence of oxygen Several minutes - hours
, Twitch Contraction:
Brief contraction of all the muscle fibers in a motor unit in response to a single action potential.
Latent period Gap when the stimulus occurs, and the muscle starts to react. Action potential
is moving over the sarcolemma. Calcium is beginning to get released from
terminal cisterns.
Contraction period Calcium bonds to troponin. Troponin and tropomyosin move out of the way of
the myosin binding site at which point the myosin head attaches to the myosin
biding site forming cross-bridge. Myosin rotates and pulls towards the midline
Relaxation period Calcium is pumped back into the sarcoplasmic reticulum; myosin binding sites
are covered. Myosin detaches from actin and tension decreases.
Refractory period Muscle loses excitability (the ability to respond to stimulus). Skeletal = 5
milliseconds. Cardiac = 300 milliseconds. 1 muscular contraction = 50
milliseconds.
Wave summation occurs when a stimulus arrives at different times. One impulse followed by another
impulse followed by another impulse. This produces larger contractions and stronger
contractions.Adding it together, stimuli coming in + stimuli = summulative effect
Unfused tetanus
Occurs when you have your contraction and the muscle only partially relaxes and then you get another
stimuli that comes in and contracts again, repeatedly. Partially relaxing. There is a little bit of a gap
before the next stimuli, it wavers a little bit. Sustained but wavering. You can see the twitch.
Fused tetanus
Individual twitches are fused together. No wavering. Holding a weight. You cannot see the twitch, it just
blends in with one another.
What are the 4 features of muscle?
Elasticity Ability of a tissue to return to its original size and shape (gumby)
Excitability Able to produce an electric current
Contractibility Ability of a tissue to get shorter
Extensibility Ability of a tissue to get longer without being damaged
Chapter 10. Muscular Tissue
Location Appearance Control
Skeletal Skeleton Multi-nucleated Voluntary
Striated
Cardiac Heart One nucleus Involuntary
Striated
Smooth Various One nucleus Involuntary
No striations
Sliding filament theory of muscular contraction:
,During muscular contraction:
- Z discs are pulled toward the M line
- A band stays the same
- H zone decreases
- Zone of overlap increases
- I band (thin) decreases in size
Acetylcholine is the neurotransmitter used for muscular contraction.
Endomysium
wraps around each fiber
Perimysium
holds the fascicle together
Epimysium
outermost layer
The two other things necessary for muscular contraction are calcium ions and ATP
Calcium ions are stored in the sarcoplasmic reticulum
Calcium ions are released from the terminal cisterns
Muscle Metabolism
Three ways that ATP is generated:
Creatine phosphate Molecule reacts with ATP to 15 seconds
form creatine phosphate and
ADP. Fast and first method used
Anaerobic glycolysis Without oxygen, uses glycolysis 2 minutes
to produce 2 ATP. Later
becomes lactic acid.
Aerobic respiration In the presence of oxygen Several minutes - hours
, Twitch Contraction:
Brief contraction of all the muscle fibers in a motor unit in response to a single action potential.
Latent period Gap when the stimulus occurs, and the muscle starts to react. Action potential
is moving over the sarcolemma. Calcium is beginning to get released from
terminal cisterns.
Contraction period Calcium bonds to troponin. Troponin and tropomyosin move out of the way of
the myosin binding site at which point the myosin head attaches to the myosin
biding site forming cross-bridge. Myosin rotates and pulls towards the midline
Relaxation period Calcium is pumped back into the sarcoplasmic reticulum; myosin binding sites
are covered. Myosin detaches from actin and tension decreases.
Refractory period Muscle loses excitability (the ability to respond to stimulus). Skeletal = 5
milliseconds. Cardiac = 300 milliseconds. 1 muscular contraction = 50
milliseconds.
Wave summation occurs when a stimulus arrives at different times. One impulse followed by another
impulse followed by another impulse. This produces larger contractions and stronger
contractions.Adding it together, stimuli coming in + stimuli = summulative effect
Unfused tetanus
Occurs when you have your contraction and the muscle only partially relaxes and then you get another
stimuli that comes in and contracts again, repeatedly. Partially relaxing. There is a little bit of a gap
before the next stimuli, it wavers a little bit. Sustained but wavering. You can see the twitch.
Fused tetanus
Individual twitches are fused together. No wavering. Holding a weight. You cannot see the twitch, it just
blends in with one another.
What are the 4 features of muscle?
Elasticity Ability of a tissue to return to its original size and shape (gumby)
Excitability Able to produce an electric current
Contractibility Ability of a tissue to get shorter
Extensibility Ability of a tissue to get longer without being damaged
