AP BIOLOGY

Detailed explanation-1: -Since the heartbeat is initiated by the SA node and the impulse of contraction originates in the heart itself, the human heart is termed myogenic. The hearts of vertebrates and molluscs are also myogenic.

Detailed explanation-2: -Solution : (1) The heart shows autorhythmicity because the impulse for its rhythmic movement develops inside the heart. Such heart is called myogenic. <br> (2) Some of the cardiac muscle fibres become autorhythmic (self-excitable) and start generating impulses during development.

Detailed explanation-3: -Myogenic heart is the one where the impulses for contraction and relaxation of muscles of heart is generated and transmitted by specialised cardiac muscles. Human heart is myogenic.

Detailed explanation-4: -Myogenic contraction refers to a contraction initiated by the myocyte cell itself instead of an outside occurrence or stimulus, such as nerve innervation. For most invertebrates, heart contraction is initiated and regulated predominantly by external nerves; thus insect hearts are neurogenic.

Detailed explanation-5: -The answer is false. The human heart is made up of four compartments. There are two auricles which are also called as atrium. The atrium receives the deoxygenated blood.