Question

The heart of which animal is myogenic in nature?
A. Cockroach
B. Leech
C. Elephant
D. All of the above

Answer 1

Hint: Myogenic means taking place or functioning in ordered rhythmic fashion as of the inherent properties of cardiac muscle rather than specific neural stimuli. Myogenic heartbeat is inaugurated by a specialized group of modified heart muscle fibres.

Complete answer:
Let's discuss the option and find the correct answer.
A. Cockroach: Control of the cockroach heart seems to be organized on three levels. The basic rhythm is myogenic. The timing of the contractions is influenced by inputs from the intrinsic cardiac ganglion cells possibly via a response mechanism involving the contractions of the heart muscle. Hence option A is incorrect .
B. Leech : Two tubular hearts propel blood across the closed circulatory system of the medicinal leech. The hearts are myogenic, but are driven by a centrally generated motor pattern which controls heart rate and intersegmental coordination. Hence option B is incorrect
C. Elephant: The heart of an elephant is myogenic as all the vertebrates have myogenic hearts. Myogenic contraction refers to a contraction initiated by the myocyte cell itself rather than an outside occurrence or stimulus, such as nerve innervation.
Hence option C: Elephant is the correct answer.

Note: Myogenic is the term used for muscles or tissues that can contract on their own, without any external electrical stimulus, from the brain or spinal cord . An example of this phenomena is literally present in our kidneys to regulate the flow of blood in vessels. Another example is the human heart.