First heart sound is produced during closure of
auriculo-ventricular valves
eustachian valve
sinus valve
seminular valves
A.
auriculo-ventricular valves
First heart sound is produced during closure of auriculo- ventricular or AV node. The first sound is lubb. It is low pitched and is of long duration. It is produced by tight closure of bicupsid and tricupsid valve at the start of ventricular contraction.
In motor neuron the impulse following in which direction?
In two direction
In one drection
In all direction
None of the above
Muscular movements of alimentarey canal are known as
peristalsis
diastole
systole
muscles contraction
Fertilization in earthworm is
cross fertilization
combined fertilization
self-fertilization
All of the above
