The progenitor of domestic pigs is a wild boar belonging to the cloven-hoofed non-ruminant genus. Currently, these farm animals are bred in many countries around the world. But they are most popular in Europe, Russia and the countries of East Asia.
Appearance of the pig
Domestic pigs do not differ too much from their ancestors, wild boars. The only thing is that pigs are usually not covered with such thick hair. The anatomy of a pig and wild boar is almost identical.
Distinctive features of domestic piglets are:
- compact physique;
- legs with hooves;
- represented by bristle hairline.
An elongated muzzle, ending with a heel that serves when searching for food for loosening the soil - this, of course, is also one of the main characteristic features of a pig. In the photo below you can see how convenient it is for piglets to use this organ, even when kept at home. Represents a piglet piglet cartilaginous movable disk.
The shape of the pig’s head can, among other things, determine its appearance. In representatives of meat breeds, it is somewhat elongated. In greasy piglets, this part of the body has a more rounded shape.
Pig Anatomy: Musculoskeletal System
Piglets belong to the class of mammals. The skeleton of these animals is represented by approximately 200 bones. In this case, the following varieties are distinguished:
- long tubular;
- short
- long curved;
- lamellar.
The skeleton of pigs itself consists of several departments:
- skulls;
- neck
- torso and tail;
- limbs.
The muscular system of the pig is represented by smooth muscles and skeletal muscles. The bones in the body of these animals connect the collagen fibers that form the joints. In total, pigs have several unpaired and about 200-250 paired muscles.
Digestive and excretory system
Piglets - animals are almost omnivorous. And the digestive system in pigs is, of course, very well developed. Its main departments are:
- oral cavity;
- pharynx and esophagus;
- single chamber stomach;
- large and small intestines;
- rectum;
- anus.
The liver is responsible for filtering the blood and neutralizing harmful substances in pigs, as in any other mammals. The stomach in these animals is located in the left hypochondrium, and the pancreas in the right.
Genitourinary System
One of the undoubted advantages of pigs as farm animals is their high fecundity. The reproductive system of boars is represented by the following organs:
- scrotum and testis;
- duct and spermatic cord;
- genitourinary canal;
- penis;
- a special skin fold covering the penis - prepuce.
The reproductive system of a female pig is represented by the following organs:
- ovaries;
- fallopian tubes;
- uterus and vagina;
- external organs.
The pig's sexual cycle can last from 18 to 21 days. These animals carry 110-118 days to their young. In one sow, up to 20 cubs can be born. This is even more than that of rabbits famous for their fertility.
The urinary system of the pig is also presented:
- paired kidneys;
- ureters;
- the bladder;
- urethra
In males, the urethra, among other things, also conducts reproductive products. In pigs, it opens on the eve of the vagina.
Nervous system
Pigs are highly developed animals. It is believed that intellectually they are close to dogs. These animals, for example, can be easily trained to carry out various kinds of commands. Like dogs, pigs are able to return from afar to the places where they once lived.
The nervous system of these animals is represented by:
- brain and spinal cord with ganglia;
- nerves.
The brain of these animals has two hemispheres with convolutions and is covered with bark. Its weight in pigs ranges from 95-145 g. The length of the spinal cord in these animals can be equal to 119-139 cm.
The cardiovascular system
Like other mammals, the heart is the central organ of circulation in pigs. It has a conical shape and a longitudinal partition is divided into the right and left half. Beating rhythmically, the heart of a pig drives blood throughout its body. Each half of the animal’s heart, in turn, is divided by transverse valves into the ventricle and atrium.
Pig blood consists of plasma and red blood cells, platelets and white blood cells floating in it. From the heart through the body of animals, it flows through the arteries, and returns to it through the veins. Also, the pig's circulatory system is represented by capillaries, through the walls of which oxygen enters the tissue.
Various kinds of foreign particles and microorganisms are neutralized in the body of these animals in the lymph nodes.
Features of the structure of the skin of pigs
The thickness of the skin of piglets can vary between 1.5-3 mm. In purebred pigs, this indicator may even be equal to only 0.6-1 mm. In this case, the subcutaneous layer in piglets contains a very large amount of fat and can reach a huge thickness.
Mature males have a shield on the sides of the shoulder girdle and chest, consisting of compacted bundles with fat pads. This formation protects wild boars during fights during the sexual hunt.
Hard hairs of bristles on the skin of pigs alternate with soft ones. The thickness of the hairline in piglets of different breeds may be different. In most cases, bare pigs are bred, of course. But there are breeds, representatives of which are covered with thick hair, about the same as wild boars.
Analyzers, organs of hearing and sight
The pig's cardiovascular system is therefore very well developed. The same goes for other organs of piglets. For example, pig smells are simply excellent.
The organ responsible for the perception of odors in these animals is located in the nasal passage and consists of:
- olfactory epithelium;
- receptor cells;
- nerve endings.
Touch in pigs is carried out by receptors of the musculoskeletal system, mucous membranes and skin. The organs of taste in these animals are papillae located in the mucous membrane of the oral cavity. The eyeballs in pigs connect with the optic nerve to the brain.
The ears of these animals consist of the following departments:
- cochlear part;
- pathways;
- brain centers.
Similarities and differences between pigs and humans
People, as is well known to everyone, belong to the class of primates and descended from a monkey. Outwardly, man, of course, most of all resembles this particular animal. The same applies to the structure of internal organs. However, in terms of physiology and anatomy, a person is quite close to a pig.
For example, like humans, piglets are omnivores. It is believed that they were once tamed precisely because of this. Wild boars eagerly ate the remnants of human food. The only difference between humans and pigs in this regard is that the latter have fewer bitter taste receptors in the oral cavity. The sweet and bitter piglet perceives a little differently than a person.
As you know, the heart of a pig in structure is not much different from the human heart. Doctors even try to use piglets in this regard as donors for both people and monkeys. The heart of piglets weighs 320 g, in humans - 300 g.
Very similar to human and pig skin. These animals, like humans, can even sunbathe. Similar in structure to humans and pigs as well:
The yellow press sometimes even flashes information that sometimes sows in the USA and China are used to carry human embryos.
What do scientists think
People have been raising piglets for a long time. And the anatomy of pigs is, of course, studied just fine. However, a clear answer to the question of why piglets and primates are so similar, unfortunately, does not exist. In this regard, there are only a few unverified hypotheses. For example, some scientists believe that the pig itself was once descended from a primate.
There is even confirmation of this incredible hypothesis. On the island of Madagascar, researchers found the fossil remains of lemurs with a long snout with a patch. Like pigs, these animals once tore the earth with their nose in search of food. Moreover, instead of hoofs, they had a five-fingered, like a human's hand. And the embryos of modern pigs, oddly enough, have a five-fingered arm and muzzle, like a primate.
Ancient legends are also a kind of confirmation that pigs were once primates. For example, in one of the traditions of the inhabitants of the island of Bot it is stated that in ancient times, the hero Kat made people and pigs in one pattern. However, later piglets wanted to have their own differences and began to walk on four legs.
Diseases of humans and pigs
Scientists have noticed that the similarities between humans and pigs are not limited to the anatomical structure of organs. Almost the same in primates and piglets and diseases. For example, in pigs, as in humans, Alzheimer's disease can be diagnosed in old age. Piglets are also very often obese. Parkinson's disease may also be observed in these animals. The pig in the photo below suffers from just such a disease.
Transgenic animals
The heart and other organs of piglets and humans are similar. But still they are not identical. Experiments on transplanting pork organs to people so far end, unfortunately, failures due to tissue rejection. To solve this problem, scientists began to breed special transgenic pigs. In order to obtain such piglets, two human genes are introduced into the embryo and one pig is turned off.
Many scientists believe that experiments on breeding transgenic pigs in the future can actually help solve the problem of tissue rejection during organ transplants. Confirmations of this, by the way, are already available. For example, in 2011, Russian surgeons successfully transplanted a transgenic pig heart valve into a patient.
Genetically similar
The anatomy and physiology of pigs are such that, according to some scientists, they are an accurate biological model of humans. By the structure of DNA, of course, monkeys are closest to humans. For example, the differences in the genes of humans and chimpanzees is only 1-2%.
But pigs in terms of the structure of DNA are quite close to humans. The similarities between human and pig DNA, of course, are not so great. However, scientists have found that in humans and piglets, some types of proteins are very similar in composition. That is why piglets were once actively used to obtain insulin.
Recently, in the scientific world, there has been much controversy on a topic such as the cultivation of human organs inside piglets. Purely theoretically, carrying out such procedures is nothing impossible. Indeed, the genome of humans and pigs is really similar in some ways.
To get organs, human stem cells can simply be placed in the egg of a sow. As a result, a hybrid will develop, from which in the future not a full-fledged organism will grow, but only one organ. It can be, for example, a heart or a spleen.
Of course, the organs grown inside pigs could save the lives of many people. However, many scientists are opposed to this method. Firstly, carrying out such experiments, of course, is inhumane in relation to the pigs themselves. Secondly, it is believed that raising organs in humans for pigs can lead to the emergence of new genetically modified pathogens that can kill millions of people.
Human pig genome
Pig blood is 70% biologically the same as human blood. This made it possible to conduct one very interesting experiment. Scientists took a pregnant sow and injected human white blood containing genetic information into the embryo. Pregnancy in the animal ended in successful birth.
Researchers subsequently discovered cells containing large areas of both human and pork chromosomes in the blood of piglets that were born. This, of course, became a real sensation in the scientific world. Among other things, such cells in the body of piglets were also resistant. That is, they remained for a long time after birth. Simply put, scientists for the first time obtained a stable human pig genome. Of course, there were few such cells in the body of the test piglets and the animals were in no way similar to humans. However, more than a third of human material in the genome itself was contained.
Other research by scientists
Be that as it may, the anatomy of pigs has been well studied, and the idea of using these animals as donors looks quite attractive. Most scientists at the same time believe that there is nothing impossible in this. Researchers have already made quite serious progress in this regard. For example, scientists managed to find out that nerve cells taken from the body of piglets can put paralyzed people on their feet.
Very high quality contact lenses are already made from pork collagen. The cartilage cells of the ears of piglets are used to grow artificial breasts. Scientists have also created a pig that produces omega-3 fatty acids that are beneficial for the human heart.