physiology

which of the following is known as pacemaker of the heart

• Atrioventricular (AV) node
• Purkinje fibers
• Sinoatrial (SA) node
• Bundle of His

botulinum toxin blocks neuromuscular transmission by

• enhancing the activity of muscle fibers directly
• by binding and blocking the acetylcholine receptors

• by inhibiting acetylcholineextrase enzyme

• blocking the release of acetylcholine at the neuromuscular junction

in conducting system of heart maximum velocity of conduction is seen in:

• Atrioventricular node
• Sinoatrial node
• Bundle of His
• Purkinje fibers

at high temperature muscle becomes stiff because of

• rigor mortis

• accumulation of lactic acid

• denaturation of muscle proteins and formation of cross-links
• dehydration of muscle fibers

draw a neat labelled diagram of neuromuscular junction

A 35yr old woman complains of easy fatigability from past 4 months.

Patient complain of shortness of breath on climbing stairs and inability to do work due to fatigue. She also complains of loss of appetite and weight loss.• Her cycles are irregular and complains of heavy loss of blood during each cycle.

she does not smoke or drink.

•Hemoglobin%- 7.1gm/dl

•RBC count- 3million cells /cumm of blood

•PCV – 23%

what is the most probable diagnosis?