Which one of the following is a regulatory protein of the muscle ?
A. Troponin
B. Myosin
C. Actin
D. Protein- C
Muscles and Neuromusclar Junction
Skeletal muscles_____________?
Skeletal muscles_____________?
A. Contracts when calcium is taken up by sarcoplasmic reticulum
B. Contracts when actin and myosin filaments shorten
C. Contraction is initiated by calcium binding to troponin
D. Contraction is initiated by calcium binding to tropomyosin
Cardiac muscle contracts due to______________?
Cardiac muscle contracts due to______________?
A. Extracellular Ca+2
B. Sarcoplasmic ca+2
C. Extracellular Na+
D. Intracellular Na+
Small packets of acetylcholine released randomly from the nerve cell membrane at rest Produces_______________?
Small packets of acetylcholine released randomly from the nerve cell membrane at rest Produces_______________?
A. Inhibitory post synaptic potential
B. Miniature end plate potential
C. Action potential
D. End plate potential
Upstroke of action potential would lead to________________?
Upstroke of action potential would lead to________________?
A. Net current in an outward direction
B. Cell interior becomes more negative
C. Cell interior becomes less negative
D. None of the above
The main types of muscle cells are______________?
The main types of muscle cells are______________?
A. Skeletal and cardiac
B. Smooth and cardiac
C. Smooth and skeletal
D. All of the above
Two major types of muscle fibres are found in humans_____________?
Two major types of muscle fibres are found in humans_____________?
A. white and brown
B. White and yellow
C. White and gray
D. White and red
The absolute refractory period of an action potential is due to _______________?
The absolute refractory period of an action potential is due to _______________?
A. Insufficient neurotransmitter
B. Depletion of intracellular Na+
C. Inactivation of Na+ k+ ATPase
D. Voltage inactivation of the Na+ channel
Increase in threshold level on applying subthreshold, slowly rising stimulus is known as ___________?
Increase in threshold level on applying subthreshold, slowly rising stimulus is known as ___________?
A. Adaptation
B. Accommodation
C. Refractoriness
D. Electrotonus
The number of muscle fibers in a motor unit are least in______________?
The number of muscle fibers in a motor unit are least in______________?
A. Laryngeal muscles
B. Pharyngeal muscles
C. Muscles of middle ear
D. Extraocular muscles