Does a bug have a heart? Features of anatomy: the heart of insects and other internal organs Insects have a heart.
The heart is presented in the form of a long tubular organ, located longitudinally inside and divided into chambers. Along its length it has several “swells” corresponding to the segments; each of them is a separate chamber.
The posterior end of the heart is closed, while the anterior end is open and continues into the aorta. The heart and aorta together form the dorsal vessel, which represents the vascular part of insects. They usually have no other vessels, although, for example, in Mayflies, three small branches extend from the posterior end of the heart, continuing into the caudal filaments.
Usually there is no separate chamber in the first abdominal segment, where the heart “ends,” but there are exceptions. For example, Cockroaches have chambers in all abdominal segments, and even in the posterior segments. Unlike them, Dragonflies have only one chamber in the heart.
Each camera is equipped with a pair (less often - big amount) stomata, or ostia. Through them, blood is sucked into the heart from the body cavity. The edges of the ostia have inversions, the so-called ostial valves.
The origin of the heart is mesodermal; the organ is formed from cardioblast cells.
In the wall of the heart of insects, like in more highly developed animals, there are three layers. The most important thing that ensures the functioning of the organ is the muscle layer. On the outside there is a sheath of connective tissue, and on the inside the organ is lined with intima. Sometimes its lower wall fuses with the fibers of the dorsal (dorsal) muscle diaphragm located below. (photo)
Location of the heart in the body of an insect
Topography of the insect heart
The heart is located close to the dorsal wall of the body ( ). It is fixed near it either directly (as in Aleurodes), or, more often, with the help of short cords.
From below, the heart comes into contact with the muscular dorsal diaphragm, and in some cases, as mentioned above, this diaphragm starts directly from it and goes in both directions, then growing into the exoskeleton.
The dorsal diaphragm delimits a separate “floor” from the internal cavity of the body - top part, which is called the pericardial space and includes the heart and components. This space is not completely isolated, but partially, since the muscle bundles of the dorsal diaphragm (they are called pterygoid muscles) have a triangular shape, and there are spaces between them. (photo)
Work of the heart
Like other living organisms, the muscle cells of the heart of insects have the function of automatism, that is, the ability to contract independently, independent of the “will” of the owner.
The structure of the body of insects can truly be called the jewelery work of nature. Any subspecies of them - even the Colorado potato beetle, which is so unloved by summer residents, prefers the freedom of a potato patch, or the red cockroach, driven by people from everywhere, has a body anatomy that can compete in its functionality with that of a human. And, undoubtedly, the most important motor in insects is also the heart.
We live in a time when other people or technology can do everything for us. For example, even coursework and dissertations can also be done for us, for example on 5orka.ru. But despite all this, we will still tell you about such a simple and at the same time complex mechanism - about the work of the heart of a small bug. Perhaps for a moment you can forget about the time of information technology and remember a piece of nature, even the smallest one.
So, insects have a chambered heart. It is located inside the abdomen of the insect and is a long muscle in the form of a tube. Each abdominal segment is a separate cardiac chamber.
The anterior end of the “tubular” heart is connected to the aorta, and the posterior end is closed from communication with the vessels. It is the aorta and heart that make up the circulatory system of insects - the dorsal vessel. Insects do not have other arteries, although mayfly larvae have tail thread-like vessels extending from the posterior end of the heart. There are other exceptions - for example, the aforementioned cockroaches have multiple heart chambers even in the back of the chest, and the class of Dragonflies have a single heart chamber.
To allow blood to enter the heart, each chamber is equipped with two tiny openings - ostia (or orifices). Through them, blood from the body cavity passes into the heart, and the return flow of blood through the same holes is prevented by the so-called “volvulus” - ostial valves.
The mesodermal tissue of the heart is formed by special cellular formations - cardioblasts, and the heart wall has as many as three layers. The main working tissue, thanks to which the tubular heart contracts in insects, is muscle, external tissue. The inside of the heart is lined with intimal tissue, and the muscle tissue and intima are connected by connective tissue located between these two layers of the heart wall. There are cases when the muscle tissue of the heart fuses with the muscle fibers of the dorsal diaphragm, located just below.
Despite the apparent primitiveness of insects in general, their heart plays the same role as that of the largest mammal - blue whale. The same automaticity of contractions allows the tiny heart to function autonomously, regardless of the behavior of the insect.
These representatives of the Animal Kingdom can be found almost everywhere. Water, soil, other organisms, air... It's about about insects, the structural features of which we will study in our article.
Body parts and integument
Insects are distinguished by an enviable species diversity: approximately 1.5 million. Moreover, this figure is minimal. Despite this, they all have a common structure plan. The body of insects is clearly divided into three sections. These are the head, chest and abdomen. The middle section bears three pairs of limbs and wings.
The internal organs of insects are reliably protected by the cuticle. His outer layer formed by fatty substances that prevent excessive loss of moisture. Odorous or poisonous glands are also located here. The color of the insect depends on the type of pigments found in the middle layer of the cuticle.
Musculature
Insect muscles are unique. They have extreme contraction power. Thanks to this, some insects can lift a load tens of times greater than their own. Another feature is the frequency of contractions. This determines various shapes flight: active, forward, passive, hovering. Contract limbs and move wings skeletal muscles. It is formed by striated fabric. The heart of insects consists of muscle fibers covered with a layer of epithelium.
Nervous system and sensory organs
These representatives of the phylum Arthropods are characterized by complex behavior. There are many examples of insects that are social: bees, bumblebees, termites, ants. They live in whole groups, in which each member has his own “responsibilities”. All this is possible thanks to the development nervous system insects It is represented by the abdominal chain, which distinguishes the brain, segmental and subpharyngeal nodes - ganglia.
The organs of vision are located on the head. These are simple and compound eyes. The latter form mosaic vision. Each small eye perceives only part of the image, but together a real holistic picture is formed.
The head also contains antennae, which are organs of touch. Similar structures are evenly distributed over the entire surface of the body of insects. They are connected to nerve endings called receptors. They perceive Various types irritations: chemical, mechanical, temperature.
Digestion and excretion
The digestive tract of insects is of a through type. A characteristic feature insects is the presence of salivary glands and the absence of a liver. Some representatives have specialized glandular cells that also secrete enzymes.
Among insects, extraintestinal digestion is also found. For example, larvae ladybugs enzymes are injected into the victim's body. This is how their contents are digested.
The larvae of butterflies, beetles, ants, and mosquitoes develop through metamorphosis. Each of us has seen caterpillars. These are butterfly larvae. At a certain stage of development they turn into a pupa. This is the resting stage of development. The pupa turns into an adult, which moves on to an active lifestyle.
So, insects are representatives of the phylum Arthropods, which are characterized by the following characteristics:
- The body consists of three sections: head, trunk and abdomen.
- The integument is represented by the external skeleton - the cuticle.
- The circulatory system is not closed; the heart looks like a tube consisting of several chambers.
- - numerous Malpighian vessels, breathing - tracheids.
