A Diagrammatic section across the body in the chest region. Labels: x, the dorsal tube, which contains the spinal cord; the black mass surrounding it is a vertebra; a, the gullet (esophagus), a part of the alimentary canal; h, the heart; sy, sympathetic nervous system; ll, lungs; the dotted lines around them are the pleurae; rr, ribs; st, the breastbone.

Section Across the Body in the Chest Region

A Diagrammatic section across the body in the chest region. Labels: x, the dorsal tube, which contains…

Diagrammatic longitudinal section of the trunk and head. Labels: 1,1, the dorsal cavity; a, the spinal portion; b, the cranial enlargement; c, c, the bodies of the vertebrae forming the partition between the dorsal and ventral cavities; 2, 2, the ventral cavity, subdivided into thoracic cavity (d), abdominal cavity (e), and pelvic cavity (f); g, the nasal cavity; h, the mouth, or buccal cavity. The alimentary canal (al) is represented running through the whole length of the ventral cavity.

Trunk and Head of Human Body

Diagrammatic longitudinal section of the trunk and head. Labels: 1,1, the dorsal cavity; a, the spinal…