Muscles Types and Structure

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What is the major biochemical transducer that converts potential 'chemical' energy into mechanical energy in muscles?

Myofibrils (correct)

ATP

Sarcolemma

Z disc

Which type of muscle is composed of multinucleated muscle fiber cells surrounded by sarcolemma?

Skeletal muscle (correct)

Cardiac muscle

Smooth muscle

Striated muscle

Where in the sarcomere are only actin filaments present?

H zone

M line

I band (correct)

Z disc

Which part of the sarcomere includes overlapping myosin and actin filaments?

I band Signup and view all the answers

What is the central line of the sarcomere where myosin filaments are anchored called?

M line Signup and view all the answers

What is the immediate energy source for muscle contraction and relaxation?

Adenosine triphosphate (ATP) Signup and view all the answers

What happens when Ca++ ions bind to troponin C in the thin filaments?

Tropomyosin simply moves out Signup and view all the answers

What occurs during the hydrolysis of ATP by ATPase activity of myosin?

Sliding of thick filaments on thin filaments Signup and view all the answers

What happens when Ca++ ion is pumped back into the sarcoplasmic reticulum?

Troponin inhibits myosin-actin interaction Signup and view all the answers

What enzyme is responsible for hydrolyzing ATP into ADP + Pi + High amounts of energy in muscles?

ATPase Signup and view all the answers

What is the result of myosin detaching from F-actin in muscles?

Induction of muscle relaxation Signup and view all the answers

What are the three types of proteins that compose thin filaments in muscle?

Actin, Tropomyosin, Troponin Signup and view all the answers

Which protein is present in all muscle types?

Tropomyosin Signup and view all the answers

How many subunits make up the protein Troponin?

3 Signup and view all the answers

Which type of myosin has ATPase activity?

Heavy mero-myosin 'HMM' Signup and view all the answers

What is the name of the process when acetylcholine binds to its receptor at the motor end plate?

Excitation contraction coupling Signup and view all the answers

What leads to the release of Ca++ from the sarcoplasmic reticulum during muscle contraction?

Inward spread of depolarization along T-tubules channels Signup and view all the answers

What is the effect of two successive stimuli dependant on?

Interval between the first and second stimulus Signup and view all the answers

In which situation is there no response to the second stimulus?

When the second stimulus occurs in L.P. Signup and view all the answers

What is a physiological contracture also known as?

Cramp Signup and view all the answers

What is Rigor mortis characterized by?

Prolonged and reversible Signup and view all the answers

How do smooth muscle fibers connect with each other?

Via gap junctions as a syncytium Signup and view all the answers

Which type of smooth muscle does not obey all or none law?

Multi unit Signup and view all the answers

Which type of nerves supply both motor and inhibitory functions to smooth muscles?

Parasympathetic nerves Signup and view all the answers

What is a characteristic of smooth muscle in terms of sarcomere and striation?

Lacks sarcomeres and striations Signup and view all the answers

Which structure is not present in smooth muscle compared to skeletal muscle?

T tubules Signup and view all the answers

Which property describes the contraction of smooth muscle as 'myogenic'?

Contraction originates within the muscle itself Signup and view all the answers

In comparison to skeletal muscle, what is a characteristic of the movement of smooth muscle?

Rhythmic contraction Signup and view all the answers