Read the following statements about the internal structure of the human heart:
I. Humans have an auto-excitable, chambered, muscular and myogenic heart.
II. The heart is mesodermal in origin and is present symmetrically between two lungs in the thoracic cavity.
III. The opening between the right atrium and left ventricle is guarded by a tricuspid valve.
IV. Only the sino-atrial node of the heart has the ability to generate action potentials without any external stimuli.
How many statement/s is/are incorrect from the above?
Important Questions on Body Fluids and Circulation
Give the location of the following valve within the human heart.
Thebesian valve
Reason (R): In the heart of the human embryo, oxygenated and deoxygenated blood is completely separated.
Give the location of the following valve within the human heart.
Eustachian valve.
Give the location of the following valve within the human heart.
Bicuspid valve
Match the following related to the cardiac cycle.
| Column I | Column II | ||
| Cardiac Cycle | |||
| Atrial Systole | |||
| Ventricular Systole | |||
| Cardiac Diastole | |||
Assertion : Dub' is one of the sounds of the heart caused during a cardiac cycle.
Reason : The sound is due to closure of semilunar valves present at the bases of aortic arches.
Statement (S): The sinoatrial node is called 'Pace-maker'.
Reason (R): The sinoatrial node contains specialised cardiomyocytes and generates action potentials without any external stimuli.
The correct answer is
| Column A | Column B |
| P. Neurogenic heart. | i. Human |
| Q. Bronchial heart. | ii. King crab |
| R. Pulmonary heart. | iii. Shark |
Give the location of the following valve within the human heart.
Tricuspid valve
| Column – I | Column – II | ||
| a. | Tricuspid valve | i. | Between left atrium and left ventricle. |
| b. | Bicuspid valve | ii. | Between the right ventricle and pulmonary artery. |
| c. | Semilunar valve | iii. | Between the right atrium and right ventricle. |
