28 Questions
What is the major biochemical transducer that converts potential 'chemical' energy into mechanical energy in muscles?
Myofibrils
Which type of muscle is composed of multinucleated muscle fiber cells surrounded by sarcolemma?
Skeletal muscle
Where in the sarcomere are only actin filaments present?
I band
Which part of the sarcomere includes overlapping myosin and actin filaments?
I band
What is the central line of the sarcomere where myosin filaments are anchored called?
M line
What is the immediate energy source for muscle contraction and relaxation?
Adenosine triphosphate (ATP)
What happens when Ca++ ions bind to troponin C in the thin filaments?
Tropomyosin simply moves out
What occurs during the hydrolysis of ATP by ATPase activity of myosin?
Sliding of thick filaments on thin filaments
What happens when Ca++ ion is pumped back into the sarcoplasmic reticulum?
Troponin inhibits myosin-actin interaction
What enzyme is responsible for hydrolyzing ATP into ADP + Pi + High amounts of energy in muscles?
ATPase
What is the result of myosin detaching from F-actin in muscles?
Induction of muscle relaxation
What are the three types of proteins that compose thin filaments in muscle?
Actin, Tropomyosin, Troponin
Which protein is present in all muscle types?
Tropomyosin
How many subunits make up the protein Troponin?
3
Which type of myosin has ATPase activity?
Heavy mero-myosin 'HMM'
What is the name of the process when acetylcholine binds to its receptor at the motor end plate?
Excitation contraction coupling
What leads to the release of Ca++ from the sarcoplasmic reticulum during muscle contraction?
Inward spread of depolarization along T-tubules channels
What is the effect of two successive stimuli dependant on?
Interval between the first and second stimulus
In which situation is there no response to the second stimulus?
When the second stimulus occurs in L.P.
What is a physiological contracture also known as?
Cramp
What is Rigor mortis characterized by?
Prolonged and reversible
How do smooth muscle fibers connect with each other?
Via gap junctions as a syncytium
Which type of smooth muscle does not obey all or none law?
Multi unit
Which type of nerves supply both motor and inhibitory functions to smooth muscles?
Parasympathetic nerves
What is a characteristic of smooth muscle in terms of sarcomere and striation?
Lacks sarcomeres and striations
Which structure is not present in smooth muscle compared to skeletal muscle?
T tubules
Which property describes the contraction of smooth muscle as 'myogenic'?
Contraction originates within the muscle itself
In comparison to skeletal muscle, what is a characteristic of the movement of smooth muscle?
Rhythmic contraction
Learn about the different types of muscles - skeletal, cardiac, and smooth muscles, as well as the structure of skeletal muscles including muscle fibers, sarcolemma, and myofibrils. Understand how muscles convert chemical energy into mechanical energy.
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