Snake is the common name for a group of carnivorous, legless and cylindrical reptiles, belonging to the suborder Serpentes, distinguishable from legless lizards by features such as: No eyelids and outer ears. Like other scaly reptiles (Squamata), snakes are ectothermic, amniotic, vertebrates with stacked layers of scales that cover their bodies. Many snakes have skulls with more articulation than their lizard ancestors, allowing them to swallow prey much larger than their heads with highly mobile jaws. To accommodate their slim and narrow body, the snake’s paired organs (such as the kidneys) are arranged in such a way that one is in front of the other instead of parallel to the sides, and most snakes Only one lung works. Some species still maintain a pelvic girdle with a pair of vestigial claws on either side of the cloaca.

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The skeletons of most snakes consist of only the skull, hyoid bone, spine, and ribs, although Henophidia snakes still have vestiges of the pelvis and hind limbs. The snake’s skull consists of a solid and perfect skull, and many other bones attached to it only loosely, namely the highly mobile jawbones, which facilitate the capture and swallowing of prey. big.

The spine of a snake consists of about 200 to 400 (or more) vertebrae. The caudal vertebrae are relatively few in number (usually no more than 20% of the total) and have no ribs, while the trunk vertebrae have 2 articulated ribs.

The snake’s heart is enclosed in a sac, called the pericardium, located at the bifurcation of the bronchi. However, the snake’s heart can move around due to the absence of a diaphragm. This adjustment protects the heart from damage when ingested prey is large and slides along the esophagus. The spleen attaches to the gallbladder and pancreas, helping to filter blood. The thymus, located in the fatty tissue above the heart, is responsible for the production of immune cells in the blood. The snake’s cardiovascular system is also unique in that it has a renal portal system, in which blood from the snake’s tail moves through the kidneys before returning to the heart.

The vestigial left lung is usually small or absent, since the snake’s tubular body requires all organs to be long and thin. In most snakes only the right lung is active. This right lung consists of two parts: the anterior part has blood vessels leading to it, and the posterior part has no role in gas exchange. This ‘bag lung’ is used for hydrostatic purposes to modulate buoyancy in some aquatic snakes, and its function in terrestrial snakes is unknown. Many paired organs, such as the kidneys or sex organs, are alternately arranged in the body, with one part (‘left’ or ‘right’) located directly in front of the other ( ‘right’ or ‘left’) of the institution itself. Snakes do not have lymph nodes.