STD 12 - 7. human health and disease — NEET STD 11 Science — Question

Which organ system is lacking in the animals that bear water vascular system?

Failure of insulin production results in

Nissl’s granules are absent in

For the manufacture of gluconic acid and citric acid, which of the following micro-organism is used

The least toxic nitrogen waste of urine is

Each myofibrils of muscles contains

Who first realized the use of yeast in fermentation

Normal activities of the heart are regulated intrinsically, i.e., auto regulated by specialised muscles (nodal tissue), hence the heart is called myogenic. Read following statement and choose correct option for right statements ?
(i) Mass of this tissue is seen in the lower left corner of the right atrium close to the atrio-ventricular septum called the sino-atrial node (SAN).
(ii) A bundle of nodal fibres, atrioventricular bundle (AV bundle) continues from the AVN which passes through the atrio ventricular septum is known as bundle of His.
(iii) Bundle of His immediately divides into a right and left bundle which form Purkinje fibres.
(iv) The nodal musculature has the ability to generate action potentials without any external stimuli, i.e., it is autoexcitable.
(v) The SAN can generate the maximum number of action potentials, i.e., 90-95 min.
(vi) Our heart normally beats 70-75 times in a minute (average 72 beats min).