All characteristics of the internal structure of any birds, as a rule, are determined by the ability of most representatives of this class to flight, and this function is subordinated to all the external and, of course, the internal structure, which is also directly connected with the way of life and the way of obtaining food.
The structure of all organs and systems of this type of living organisms in some point coincides with the structure of other animals, but also have significant differences that are associated with the need for a long stay in the air.
The structure of the skeleton
The musculoskeletal system of birds coincides with the structure of the skeleton of all animals: the skeleton of birds contain ribs, bones of the shoulder girdle, bones of the lower leg and hips, as well as the pelvis and forearms.
Birds also have their own characteristics of the structure of the skeleton, which are in the presence of unique bones, and they include:
The digestive system of birds consists of several components (like other vertebrates):
The digestive tract, which is a certain system:
The beak of birds is the beginning of the digestive system: it limits the oral cavity and the language available there. Further, food through the throat and esophagus (some graintower species of birds have a special extended part goiter which is designed to accumulate dry food) enters the glandular section of the stomach, where it is fermented, and then enters the muscular department, where, due to the contractions of the muscular walls, it is crushed from the participation of the pebbles contained in the stomach. Further, the food enters the small intestine, where it is processed by the enzymes of the liver and the pancreas, and then the remaining food through the rectum and the cloaca are excreted out.
Digestive glands, with the help of which substances required for the process of digesting food are released.
All features of the building of the digestive (and any other) system of birds: processing of food through goiter, lack of teeth, several parts of the stomach ensure relief body weight, and, therefore, the simplicity of flight.
The respiratory system of birds is extremely peculiar, since, again, it depends on the need to fly: for this, the bird has not only light, but also formed so-called breathing bags, thanks to which oxygen intake is ensured during the flight. For example, a dove for this purpose takes about 400 breaths during the flight, while at rest no more than 30.
Through the internal holes of the beak (choanas) and the oral cavity, air follows through the laryngeal gap (it is limited by cartilage) straight into a very long trachea a kind of sound resonator., which can be significantly longer than the neck. The larynx of birds is not equipped with vocal cords, so the sounds with its help are made by few birds.
The trachea can form a loop on a keel or under the skin, and its lower area forms the lower larynx. It is there that the membranes (certain folds of the mucosa) are located, which are equipped with a special muscles and provide a huge range of sounds that birds can boast. Sound vibrations are provided precisely and are provided by passing the air through this complex system.
If we talk about lungs, then in birds they are not so large and differ in the spongy structure (unlike alveolar in mammals). Special bags are combined with the lungs, which pump the air through the lungs, which makes the socalled fourstroke breathing possible: its essence consists in enriching the blood with oxygen, not only during inspiration, but also during the exhalation.
This system in birds is the most complex, closed, and is formed from several, not combined, circulations of blood circulation.
The blood system of birds consists of two parts:
Two circulation circles are:
Nervous system and sensory organs
Compared to reptiles, the nervous system of birds is more developed, and their vision and hearing are formed best, while the sense of smell is weak. The brain in birds is characterized by increased dimensions and a rather complex structure: a more significant cerebellum, eye hillocks and formed hemispheres of the front brain.
Reproduction organs and egg structure
Birds, like all vertebrates, belong to separate organisms, which are characterized by significant sexual dimorphism: females and males are significantly different in appearance.
Birds differ in the internal type of fertilization, which is carried out in the ovaries of female individuals (only the left ovary is developed in birds, which is a feature of the species); The males have paired seeds for propagation.
The main method of reproduction in birds is to deposit eggs that are formed by passing an increasing egg through the egg, ending in the formation of an egg. It is the egg that provides the germ of the bird with all the necessary substances; However, parents are forced to warm the egg, since the embryo needs heat.
In the egg there is a yolk with an embryo disk (it is formed by an egg), and a protein shell is built around it. The yolk contains everything necessary for the formation of the chick and is in an suspended state thanks to special cords (sparse). And these cords provide the opportunity for the embryo is always on top.
In addition to the yolk, the egg contains a protein consisting of organic substances, the function of which is the protection of the embryo. The protein is in the shell forming an air chamber on the dull end of the egg. And for protection and gas exchange in the egg, the shell serves, and gas exchange takes place precisely due to the porosity of this outer shell.
After the process of fertilization and layering of the egg, the development of the embryo begins in it, which requires elevated temperature (at least 38 degrees). It is for this purpose that birds sit on masonry and hatch the chicks. Typically, one of the parents takes this duty, but sometimes both do this in turn. For different species of birds, the period of development of the chick is very significant: it can be from 11 days to 85.
Not all chicks are immediately viable, and there are several types of development of offspring in birds:
Representatives of any type of birds care very much about their offspring, provide it with nutrition, protect it from predators and engage in training until complete independence.
The behavior of birds is based on complex complexes of congenital (otherwise of unconditional) reflexes, which are hereditarily fixed and associated with the main elements of existence: reproduction, nesting, educating offspring, eating, migration and other moments.
As an unconditional stimulus of such reflexes, certain elements of the surrounding space usually act (place and material during nesting, deterioration of feed resources during migrations, and so on) and other representatives of the species (for example, the open beak of the chick in the nest).
However, the behavior of individual individuals is also enriched due to individual experience, t.e. conditional reflexes. So, imitation of parents or partner provides temporary ties and increases the expediency of behavior if the external situation changes (say, a new type of food, or unknown danger sources appear). And such an individual experience can turn into the experience of the entire population, which significantly increases its survival rate.
Inner structure of birds table
|Bird organs system||Organs||Features of the structure of the bird associated with the ability to fly|
|Muscles||Defeated and compounded muscles are developed, the muscles of the legs are also powerfully developed||The wings are driven in motion, work when walking, during takeoff and landing|
|Nervous system||Brain and spinal cord||the cerebellum is responsible for coordination. Birds are characterized by more complex reflexes and instincts|
|Senses||Welldeveloped hearing and eyes; smell, taste, touch developed weaker||vision and hearing are more significant for flying birds|
|Circulatory system||Fourchamber heart, two circles||Big heart large loads, heaps a large amount of blood. It often beats|
|Respiratory system||Sip, larynx, trachea, bronchi, spongy lungs. There are voice ligaments. Air bags||Double breathing due to air bags (the lungs are constantly saturated with oxygen, both in breath and when exhaling)|
|Digestive system||Mouth, sip, esophagus, goiter, intestines are thick and thin, cloak. to the glands||goiter accumulation of food, short back gut. Fast metabolism|
|Excretory system||Kidneys, ureters, cloaca||No bladder, ureters open to the cloak|
|The reproductive system||Males have testes, seven pipelines. In females ovary, oviduct||In females, the right ovary and oviduct does not develop (to relieve weight)|