561. Which of the following statement regarding smooth m contraction is INCORRECT?
A. Tonic contraction is independent of nerve supply
B. Partial contraction is maintained due to sinusoidal fluctuation of membrane potential
C. It has the same electro-mechanical coupling time as myocardial muscle
D. Smooth muscle contraction is dependent on extracellular calcium concentration
E. Stretching of smooth muscle lead to reduction of membrane potential & increased tonic contraction.

562. Motor neuron:
A. All motor neuron are myelinated
B. Cell bodies of motor neuron are located in the anterior hom of spinal cord.
C. Motor endplate is the specialized site for neuromuscular transmission
D. Acetylcholine released at motor endplate is a calcium dependent process
E. All of the above

563. Which of the following statement regarding neuromuscular junction is FALSE?
A. Acetylcholine binding to nicotinic receptor at the neuromuscular junction leads to increased NaIK conductance at the motor endplate.
B. Acetylcholine is released in quantum
C. The amount of acetylcholine released into the neuromuscular junction is enough to produce a full endplate potential every time, allowing a propogated response in the muscle.
D. Action potential produced in the muscle is initiated at the motor endplate.
E. All of the above

564. In the myocardium, cholinergic fibers do not innervate:
A. SA node
B. AVnode
C. Bundle of His
D. Ventricle
E. All of the above

565. Which of the following regarding sensory nerve ending is FALSE?
A. Magnitude of generator potential increases with increasing intensity of stimulus
B. Threshold potential of sensory nerve ending is about -10m V
C. Large generator potential are capable of stimulating AP production in the same sensory nerve repeatedly
D. AP is developed in the sensory organ when threshold potential is reached
E. All of the above

566. Which of the following receptors are rapidly adapting sensory receptors?
A. Touch receptors
B. Pain & temperature receptors
C. Muscle spindles
D. Carotid sinus receptors
E. Lung inflation receptors

567. Which of the following statement regarding somato-sensory system is INCORRECT?
A. Conscious sensation is projected from the cortex to the receptor location no matter where along the sensory pathway is stimulated.
B. Receptive field of a sensory unit is discrete & unique to the sensory unit
C. Increasing strength of a stimulus leads to increasing number of sensory organ activated including those not in direct contact with it.
D. Threshold for stimuli among sensory receptors varies
E. All of the above.

568. Resting membrane potential of the ventricular myocardium is:
A. -55 to-65mV
B. –65 to-75mV
C. -75 to-85mV
D. -85 to-95 mV
E. -95 to-105mV

569. Regarding myocardial contraction:
A. Initial rapid depolarization & overshoot is due to opening of slow sodium channels.
B. T tubules is a storage site for calcium ions
C. Duration of atrial myocardial contraction is longer than that of ventricular muscle
D. Calcium diffuse passively out of the myocardium to terminate the contraction phase
E. During tachycardia, myocardial contraction & relaxation phase are shortened equally.

570. Regarding isovolumic contraction phase:
A. It begins as the mitral valve closes
B. It follows ventricular ejection phase
C. It coincides with the dicrotic notch
D. It coincides with the occurrence of ‘v’ wave of the JVP.
E. It is followed by atrial systole


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