The respiratory system does not work alone in transporting oxygen through the body. The respiratory system works directly with the circulatory system to provide oxygen to the body. Oxygen taken in from the respiratory system moves into blood vessels that then circulate oxygen-rich blood to tissues and cells.

KEY CONCEPT The respiratory and circulatory systems bring oxygen and nutrients to the cells. The respiratory and circulatory systems work together to maintain homeostasis. The respiratory system moves gases into and out of the blood. The lungs contain the bronchi, bronchioles, and alveoli.

Potential animal organ donors Chimpanzees were originally considered the best option since their organs are of similar size, and they have good blood type compatibility with humans, which makes them potential candidates for xenotransfusions.

Pigs have all of the same thoracic and abdominal organs as humans. There are small differences in a few organs. Liver – the human liver has four lobes: right, left, caudate and quadrate. The fetal pig liver has five lobes: right lateral, right central, left central, left lateral, and caudate.

But when it comes to life-or-death organs, like hearts and livers, transplant surgeons still must rely on human parts. One day, the dream goes, genetically modified pigs like this sow will be sliced open, their hearts, kidneys, lungs and livers sped to transplant centers to save desperately sick patients from death.

Appropriate Animals for Use in Xenotransplantation Scientists and the U.S. Public Health Service advise that domesticated animals such as pigs and cows be considered as potential tissue and organ sources before nonhuman primates, such as monkeys, for a number of health, safety and logistical reasons.

Pigs are found and raised all over the world, and provide valuable products to humans, including pork, lard, leather, glue, fertilizer, and a variety of medicines. Most pigs raised in the United States are classified as meat-type pigs, as they produce more lean meat than lard, a fat used in cooking.

And when they’re not either squealing or talking, pigs will eat almost anything – including human bones. In 2012, a farmer in Oregon, America, was eaten by his pigs after having a heart attack and falling into their enclosure. By the time a concerned relative came looking for him, only his dentures were left.

Their mucky appearance gives pigs an undeserved reputation for slovenliness. In fact, pigs are some of the cleanest animals around, refusing to excrete anywhere near their living or eating areas when given a choice. Pigs are smarter than any other domestic animal.

Sow

Breeds guide

• American Landrace.
• American Yorkshire.
• Angeln Saddleback.
• Arapawa Island.

Boar: a male pig used for breeding. Farrow: to give birth to piglets. Gilt: a female pig that has not given birth to piglets. are usually 8-12 piglets.

Farrowing: giving birth to a litter of pigs.