Viscus

In anatomy, a viscus (pronounced /ˈvɪskəs/) is an internal organ used for breathing in Reptiles. It is also present in humans and is an internal organ of the thorax or abdomen. The viscera, when removed from a butchered animal, are known collectively as offal. Internal organs are also known as "innards", or less formally, "guts" (which may also refer to the gastrointestinal tract).

Reptiles do not have a Diaphragm, but instead use their intercostal muscles and their viscera to create negative pressure and draw air in. Reptiles also breath due to a lack of O2, as opposed to an excess of CO2 like in mammals.

The adjective visceral, also splanchnic,^[1] is used for anything pertaining to the internal organs. Historically, viscera of animals were examined by Roman pagan priests like the haruspices or the augurs in order to divine the future by their shape, dimensions or other factors. This practice remains an important ritual in some remote, tribal societies.

Human viscera

Further information: Organs of the human body by region

Abdomen

• peritoneum
• stomach
• duodenum
• intestine
• colon
• liver
• spleen
• pancreas
• kidney
• adrenal gland
• appendix
• gall bladder

Pelvis and perineum

• pelvis
• coccyx
• ovaries
• Fallopian tube
• uterus
• vulva
• clitoris
• perineum
• urinary bladder
• testicles
• rectum

Innervation

Autonomic nervous system, showing splanchnic nerves in middle, and the vagus nerve as "X" in blue. The heart and organs below in list to right are regarded as viscera.

The viscera are mainly innervated parasympathetically by the vagus nerve and sympathetically by the splanchnic nerves. The sensory part of the latter reaches the spinal column at certain spinal segments. Pain in any viscera is perceived as referred pain, more specifically pain from the dermatome corresponding to the spinal segment.^[2]

References

See also

• Anatomical terms of location
• Visceroptosis