6)Human Heart

Read the following statements (i - iv) about human heart : (i) Human heart is myogenic and our body has the ability to alter the heart rate , cardiac output but not stroke volume. (ii) P - wave in ECG marks the atrial systole . (iii) Adrenal medullary hormones acts on SA node and increases heart rate. How many statement is/are correct form the above ?

Which one of the following statements is correct about the human circulatory system? (A) Blood transports only oxygen and not carbon dioxide. (B) Human heart has five chambers. (C) Valves ensure that the blood does not flow backwards. (D) Both oxygen-rich and oxygen-deficient blood gets mixed in the heart.

Consider the following four statement (i) - (iv) and select the correct option. (i) SA node is natural pacemaker of heart (ii) Human heart has inter-auricular foramen (iii) Right atrioventricular valve is a semilunar value (iv) Normal systolic and diastolic pressure of human is 120 and 60 mm Hg respectively.

Which of the following statements (s) regarding the cardiac system is/are correct ? (i) Human heart is an ectodermal derivative (ii) Mitral valve guards the opening between the right atrium and left ventricle (iii) SAN is located on the left upper corner of the right atrium (iv) Stroke volume xx Heart rate = Cardiac output.

Human heart is

Assertion : If all external nerve supplies to a human heart are cut there will be no effect on the heart beat. Reason : Human heart is a myogenic heart.

Human heart has

Human heart is derived from

Human heart has interauricular foramen.

The wall of Human heart is thick due to presence of :-