Major organs and
rib cage as main reference sources. In humans, most critical
organs, with the notable exception of the brain, are housed within the torso. In the upper chest, the
heart and
lungs are protected by the
rib cage, and the
abdomen contains most of the organs responsible for
digestion: the
stomach, which breaks down partially digested food via
gastric acid; the
liver, which respectively produces
bile necessary for digestion; the
large and
small intestines, which extract nutrients from food; the
anus, from which
fecal wastes are egested; the
rectum, which stores
feces; the
gallbladder, which stores and concentrates bile; the
kidneys, which produce
urine, the
ureters, which pass it to the
bladder for storage; and the
urethra, which excretes urine and in a male passes
sperm through the
seminal vesicles. Finally, the
pelvic region houses both the male and female
reproductive organs.
Major muscle groups The torso also harbours many of the main groups of muscles in the
tetrapod body, including the
pectoral,
abdominal,
lateral and
epaxial muscles.
Nerve supply The organs, muscles, and other contents of the torso are supplied by nerves, which mainly originate as
nerve roots from the thoracic and lumbar parts of the
spinal cord. Some organs also receive a nerve supply from the
vagus nerve. The
sensation to the skin is provided by the
lateral and dorsal cutaneous branches. Gray797.png|Distribution of cutaneous nerves. Ventral aspect. Dorsal and lateral cutaneous branches labeled at center right. Gray798.png|Dorsal aspect. Ventral and lateral cutaneous branches labeled at center right. ==See also==