Q & A

What is the order of depolarization and repolarization in the ventricles?

Depolarization travels from apex to base. So first to depolarize is apex, last is base. Repolarization occurs in the reverse. So first is base, last is apex.

Baroreceptors are most sensitive to what - pulse pressure or mean arterial pressure?

With each systole, the vessel wall (of the carotid & aorta) distends. This stretch stimulates the baroreceptors. Thus, they are sensitive to pulse pressure. Mean arterial pressure is more of an abstract pressure. It is the average pressure in circulation.

With quiet respiration 1/7th of alveolar air is exchanged, what about deep inspiration, what should be denominator taken. Is it FRC or TLC.?

 In quiet breathing , 1/7th fraction of the alveolar air gets replaced with each breath.  With forced inspiration, denominator will still be FRC. At the end of quiet expiration, FRC remained in the lung, and then the person took forced inspiration in the next cycle.

Does  glucagon increases insulin secretion?

Insulin suppresses glucagon secretion. Glucagon stimulates insulin secretion.

 What is pharmaco-mechanical coupling and electromechanical coupling ?

There is electromechanical coupling and pharmaco-mechanical coupling. Electro-mechanical coupling means - Electrical impulse (as in skeletal muscle) results in contraction (which is a mechanical event).Pharmaco - mechanical coupling means - a ligand or a chemical can cause muscle contraction. This is seen in smooth muscle. Chemicals can directly act on smooth muscle to cause the contraction.

Rate of peristaltic movements seen in parts of gut?

Basal Electrical Rhythm  and the spikes at the top of the slow waves coordinate the motility ;

The frequency as follows - Stomach - 3-4/min, Duodenum - 12/min, Jejunum - 9/min ,Ileum - 7/min.

What kind of proteins present in transmembrane receptor which span the membrane?

Hydrophobic. For instance, GPCR is a transmembrane receptor. It is hydrophobic.