EXPH 386 WVU Exam 3
Steps of Myosin Power Stroke - Answer-1. ATP is cleaved onto the myosin head
2. ATP is hydrolyzed by ATPase and turned into ADP + Pi (this causes weak actin myosin bondage)
3. The Pi is released from myosin. Actin & Myosin enter a strong bond
4. The release of the ADP initiates the power stroke. Myosin head swings 60 degrees pulling actin
towards center of sarcomere.
Length Tension Relationship - Answer-isometric tension generated by the muscle at differing sarcomere
lengths
What happens at optimal sarcomere length? - Answer-this is where maximum force can occur. (2.0 -
2.2)
What happens when the sarcomere is longer than normal? - Answer-The interactions between actin
and myosin are less because actin is too far away therefore force output is less
What happens when the sarcomere is shorter than normal? - Answer-force output is lower due to
interference between opposing actin filaments
, 2 types of skeletal muscle fibers - Answer-Type 1 (slow twitch)
Type 2 (fast twitch)
Characteristics of fast twitch - Answer-1. high capability of electronic transmission of action potentials
2. Rapid calcium release and uptake by SR
3. High myosin ATPase activity
4. High rate of cross-bridge turnover
characteristics of slow twitch - Answer-1. Low myosin ATPase activity
2. Slow Calcium handling and shortening velocity
3. Large and numerous mitochondria
4. Less well-developed glycolytic capacity as compared to type 2
3 subtypes of type 2 - Answer-1. Type II X - intermediate fiber (highest in humans)
2. Type II B - have the most anaerobic potential, most rapid shortening velocity. (think cheetahs or
horses)
3. Type II A - represent the fast oxidative glycolytic fiber
T/F Type II shortening velocity is 3 to 5 times faster than Type I - Answer-T
T/F Type II are highly fatigue resistant and good at prolonged activity? - Answer-F
T/F Type IIa fibers are best for all out max on bench press? - Answer-F
T/F Type IIa fibers are more resistant to fatigue than type IIb? - Answer-true
Steps of Myosin Power Stroke - Answer-1. ATP is cleaved onto the myosin head
2. ATP is hydrolyzed by ATPase and turned into ADP + Pi (this causes weak actin myosin bondage)
3. The Pi is released from myosin. Actin & Myosin enter a strong bond
4. The release of the ADP initiates the power stroke. Myosin head swings 60 degrees pulling actin
towards center of sarcomere.
Length Tension Relationship - Answer-isometric tension generated by the muscle at differing sarcomere
lengths
What happens at optimal sarcomere length? - Answer-this is where maximum force can occur. (2.0 -
2.2)
What happens when the sarcomere is longer than normal? - Answer-The interactions between actin
and myosin are less because actin is too far away therefore force output is less
What happens when the sarcomere is shorter than normal? - Answer-force output is lower due to
interference between opposing actin filaments
, 2 types of skeletal muscle fibers - Answer-Type 1 (slow twitch)
Type 2 (fast twitch)
Characteristics of fast twitch - Answer-1. high capability of electronic transmission of action potentials
2. Rapid calcium release and uptake by SR
3. High myosin ATPase activity
4. High rate of cross-bridge turnover
characteristics of slow twitch - Answer-1. Low myosin ATPase activity
2. Slow Calcium handling and shortening velocity
3. Large and numerous mitochondria
4. Less well-developed glycolytic capacity as compared to type 2
3 subtypes of type 2 - Answer-1. Type II X - intermediate fiber (highest in humans)
2. Type II B - have the most anaerobic potential, most rapid shortening velocity. (think cheetahs or
horses)
3. Type II A - represent the fast oxidative glycolytic fiber
T/F Type II shortening velocity is 3 to 5 times faster than Type I - Answer-T
T/F Type II are highly fatigue resistant and good at prolonged activity? - Answer-F
T/F Type IIa fibers are best for all out max on bench press? - Answer-F
T/F Type IIa fibers are more resistant to fatigue than type IIb? - Answer-true
