When moving through blood vessels, an exchange of matter occurs between it and the tissues of the body. The vascular bed is very long and has many branches that interfere with the normal flow of blood. So, to overcome the whole path, it is necessary to set a certain pressure, and it is precisely what the heart creates.
The structure of this organ in fish is simpler than in terrestrial animals. Knowing how many heart chambers there are in fish and other creatures, a comparative analysis can be made. It will allow you to visually see the differences and similarities of their cardiovascular system.
How many heart chambers do fish have?
The heart of fish is lightweight, only 0.1% of their body weight, although there are exceptions to this rule. And many from school times remember how many fish have heart chambers. Only two - the atrium and ventricle. But they have structural differences. According to the general scheme, two types are distinguished that have similarities and differences.
Both options have four cavities:
- venous sinus;
- Atrial valves
- ventricle;
- a certain formation, in its structure resembling an aortic arch.
Lamellar-gill has an arterial cone, and bony has an arterial bulb. The difference between these schemes lies in the morphofunctional features of arterial formations and ventricles. In the first case, fish have fibrous tissue without valves. In fish belonging to the platelet-gill, the arterial cone contains muscle tissue and a valve system.
Knowing all this, everyone will know how many chambers of the heart the fish have, and what their structure is. Of particular interest is the structure of the myocardium, as it is represented by a homogeneous cardiac tissue. It is thinner than other animals.
Heart work
By how many chambers the heart of fish has, one can determine the principle of this organ and its rhythms. Heart rate (HR) is determined by many factors, including water temperature and fish age.
For clarity, it is proposed to consider the heart rate of carp at room temperature.
Mass of fish | Heart rate |
Juvenile 0.02 g | 80 |
Yearlings 25 g | 40 |
Two years 500 g | thirty |
Scientists concluded that water temperature has a strong influence on the frequency of contractions. The colder in the pond, the slower the heart beats. So, at a temperature of 8 ° C, heart rate is about 25 beats per minute, and at 12 ° C - 40 beats.
Circulation
Knowing what kind of heart the fish have and how many chambers in it, one can imagine the number of circles of blood circulation in them. Due to the fact that there are two chambers, the fish have only one circle of blood circulation, although blood circulates through it for a long time. It takes about two minutes to complete a full circle, and a person’s blood passes two circles in 23 seconds.
The movement of blood from the ventricle begins. From there, it enters through the bulb or arterial cone into the abdominal aorta. The blood is divided into two channels, extending to the gill petals. Two arterioles depart from the petal artery, which form the capillary network. It merges into one efferent arteriole, and it passes into the efferent lobe artery. The latter form the right and left efferent gill arteries.
The carotid arteries extend to the head, and the branchial arteries form the dorsal aorta, which runs along the entire vertebra of the fish. After passing through the whole body, the blood returns to the heart along the venous channel to the venous sinus. The structure of the heart of fish allows you to pump only venous blood. Passing through the gill apparatus, venous blood exchanges gases with water.
The vessels of the circulatory system of fish have a valve apparatus. It prevents the return of blood through the channel. The uniformity of its movement is ensured by smooth filling of the heart, without sharp fluctuations that are observed in humans.
Finally
The structure of the heart of fish is simple. It has only two chambers: the atrium and the ventricle. Uniform filling of the organ with blood and strong branching of the vessels lengthen the passage of blood in a circle. Moreover, in cold water it will take more time for the passage of blood in a circle.