Question

Myogenic heart is not present in which of the following?
A. Man
B. Limulus
C. Frog
D. Mussel

Answer 1

Hint: The intrinsic property of the cardiac muscles forms the myogenic heart. The flow of blood in the blood is controlled by the rhythmic contraction and relaxation of the cardiac muscles. The myogenic heart is mainly the characteristic of vertebrates and Mollusca where the continuous rhythmicity of the heart is observed. Each time of heat muscle contraction will lead to blood flow and also the formation of a pulse.

Complete answer:
Homo sapiens (order: Primates) fall under the Infraclass: Eutheria falling under the sub-class: Theria of class: Mammalia. The class Mammalia falls under the sub-phylum: Vertebrata. So the heart of man is myogenic and is four-chambered.

Hence the option A. Man is correct.

Additional Information:
Limulus belongs to the phylum: Arthropoda. Arthropoda contains the neurogenic heart. The order of Limulus is Xiphosura.

Hence the option B . Limulus is incorrect.

Frog or Rana tigrina (order: Anura) falls under the class: Amphibia. Amphibia also falls under the category of sub-phylum: Vertebrata. So the heart of a frog is myogenic and is three-chambered. Hence the option C. Frog is correct.

Like vertebrates, Mollusca also possesses myogenic heat. Mussel comes under the class: Bivalvia under the order: Unionoida of phylum: Mollusca.
Hence the option D. Mussel is correct.

Note:
The neurogenic heart is a characteristic of lower invertebrates including Phylum: Annelida and Insecta. In the case of the neurogenic heart, the heart is under nervous control (ganglia operated). So when a neurogenic heart is removed from the organism, the body stops beating but the myogenic heart beats for some time after the removal from the body.