Cow's heart: structure and how it works, possible diseases and their symptoms

During the day, a he althy heart muscle of cattle pumps thousands of tons of blood. This is a hollow, continuously working, cone-shaped organ located between the 3rd and 6th ribs. The he alth of the body depends on the functional state of the heart of a cow, the organ supplies oxygen, nutrients, liquid to the tissues, supports metabolism and the full functioning of internal organs.

How the heart apparatus works

The cow's heart is chambered, the muscle tissues of the chambers contract with a certain rhythm, moving blood flows along an unchanged path: from the venous vessels to the atria, from there to the ventricles, then to the arteries.The continuity of movement and the invariance of the blood path are provided by valves. The work of the body can be divided into three stages:

• compression (systole) - expulsion of the contents of the heart cavity;
• blood promotion;
• relaxation (diastole) - filling the cavity with blood.

In a he althy cow, the listed stages are replaced with a clear frequency. When the ventricles work, pressure rises inside them, the atrioventricular valves close, and the semilunar valves open later. As a result, blood leaves the heart. After the semilunar valves open, the blood flows more calmly, so the myocardium begins to contract more slowly.

The contraction of the ventricles is simultaneous, but the pressure inside them is different. This is due to the fact that the compression of the left ventricle, due to the difference in the thickness of the myocardial wall, is stronger than that of the right one.

How the heart of cattle works

A cow's heart consists of 4 chambers: 2 atria, located in the upper part, and 2 ventricles, occupying the lower part of the organ. The interior is covered with endocardium. The upper and lower chambers are connected by atrioventricular lumens.

Atrials

Atria (atrium) occupy a small part of the upper half of the heart, separated from the ventricles on the outside by the coronal groove. The structure of the chambers is simple, their main element is the comb muscles, which, when contracting, push the blood.

Ventricles (ventriculus) - the main part of the body by volume. The ventricular chambers are not connected, longitudinally demarcated by grooves. The connection between the atria and ventricles is provided by valves.

Valve apparatus

The atrioventricular and semilunar valves function in the cow's heart, opening and closing in accordance with the contractile work of the ventricles and atria. The right atrioventricular valve is tricuspid, the left is bicuspid. The anatomy of the atrioventricular lumen is such that at the stage of functioning of the atria, the valves are pressed by blood to the ventricle.And when the ventricles begin to function, blood pressure raises the valves, causing them to close the gaps. Pocket-shaped semilunar valves close the bases of the arteries.

How intensely the heart contracts depends on:

• weather conditions;
• cow age;
• physical condition of the body.

A newborn calf's blood moves at a frequency of 140 pulsations per minute. In one-year-olds, the indicator drops to 100 pulsations, in adult cows - up to 60.

Fibrous skeleton

Fibrous rings adjoin the aorta and two atrioventricular lumens. Over the years, the cartilage covering these elements of the organ becomes thicker. Inside the rings are the left and right heart bones. In fact, fibrous formations are the skeletal basis of the heart, on which muscle tissues and valves are held.

circulation circles

Like all mammals, cows have two circulations:

1. Big - systemic. Beginning - the aorta emerging from the left ventricle. End - venous vessels entering the right atrium.
2. Small. Beginning - the pulmonary artery, leaving their right ventricle. The end is the pulmonary vein directed to the left atrium.

The structure of the heart and circulatory system ensures that venous (carrying carbon dioxide) and arterial (oxygenated) blood cannot mix.

Vessels and nerves of the heart

Large vessels are connected by anastomoses - the smallest capillaries. Anastomoses are:

• arterial - connecting two arteries;
• venous - two veins;
• arterial-venous - connecting artery and vein.

The functioning of the heart muscle is provided by the autonomic nervous system. Sympathetic nerves approach the heart, stimulating muscle contractions. And the parasympathetic nerves weaken the contractile work of the heart.

Pericardial sac (pericardium)

The heart of a cow is surrounded by a film of connective tissue. Its task is to protect the heart from surrounding tissues, protect it from mechanical stress, and provide conditions for uninterrupted operation.

Layers of the heart wall

The walls of a cow's heart are made up of three types of tissue - endocardium, myocardium, epicardium.

Endocardium

Lines the inside of the heart muscle, has an unequal thickness in different parts of the organ. On the left, it is denser, and most thinned in the region of the tendon strings attached to the left atrioventricular valve. Bovine endocardium consists of 4 layers:

• external - endothelium;
• subendothelial, consisting of loose connective tissue;
• muscular-elastic;
• muscular.

Fibrillation of the endocardium of the ventricles is less pronounced than the lining of the atria.

Myocardium

The muscle layer, in the thickness of which there are nerve fibers responsible for the contractile work of the heart.

Epicardium

The outer shell of a cow's heart. Consists of two layers:

• outer - mesothelium;
• internal, consisting of soft connective tissue.

Possible diseases

When the work of the heart muscle is disrupted, the whole body suffers: metabolism worsens, internal organs do not work correctly due to lack of oxygen and nutrients.The he alth and productivity of the cow is significantly reduced, so farmers should be aware of what symptoms signal heart pathologies that require immediate treatment.

Myocardiofibrosis - dystrophy or degeneration of the heart muscle, manifested by impaired blood circulation.

The symptoms of myocardiofibrosis are as follows:

• puffiness;
• rapid breathing;
• poorly audible pulse;
• tachycardia or arrhythmia;
• mute ripple tones while listening.

Myocardiofibrosis in cows develops for a long time, manifests itself after a few months. A sick cow should be in a warm barn, a high-quality and balanced diet is selected for her, fed in small portions several times a day. The veterinarian prescribes medications that improve blood circulation and suppress the development of the disease.

Myocarditis is an inflammatory process in the myocardium, leading to functional disorders of the heart. The inflamed organ is difficult to contract. Most often, the disease occurs in cows that have undergone intoxication or infection.

Symptoms of myocarditis in cattle:

• increased body temperature;
• fast pulse;
• accelerated or extraordinary contractions of the chambers of the heart;
• poor appetite;
• high blood pressure;
• rapid breathing;
• puffiness;
• blue tint of mucous membranes, skin around the nose and mouth.

Myocarditis is a serious disease that leads to disruption of the functional state of many internal organs. A sick cow should be kept warm and dry, fed in small portions, and given water heated to a comfortable temperature.The veterinarian identifies the cause of the pathology, prescribes medications that extinguish the inflammatory process, normalize the tone of the heart muscle.

Myocardosis - myocardial dystrophy. Often develops from untreated myocarditis.

Symptoms of myocardosis:

• cow weakening;
• failure of rhythmic contractions of the heart;
• puffiness;
• reluctance of the cow to eat food;
• dramatic drop in blood pressure;
• decrease in muscle tone;
• bluish tint of the mucous membranes and skin around the mouth and nose;
• decrease in skin tone.

The sick cow is taken to a warm, dry and calm room. They provide quality food in small portions. The veterinarian identifies the cause of the pathology, prescribes medications that help stop dystrophic processes in the myocardium.

Hydropericarditis - accumulation of serous fluid inside the pericardium without inflammation. They provoke dropsy of the pericardium or other heart diseases, or chronic insufficiency of capillary blood circulation. Signs of dropsy of the pericardium in cattle:

• swelling of the soft tissues of the jaws;
• cow weakening;
• fluctuations in blood pressure;
• decrease in milk production.

The veterinarian prescribes drugs for the underlying pathology of the heart that provoked dropsy. To remove the abdominal fluid recommends diaphoretic, diuretic and iodine-containing medicines. A sick cow is well fed, plentifully watered.

Pericarditis - inflammation of the pericardium, associated either with an infectious lesion or injury to the heart bag. Malnourished cows are more likely to develop the disease, as their metabolism is disturbed.

Symptoms of pericarditis:

• cow weakening;
• rising and then falling body temperature;
• poor appetite;
• rapid breathing;
• decrease in productivity;
• severe tachycardia;
• swelling of the chest, neck, belly;
• worry cow;
• the desire to take a pose in which the chest is higher than the pelvis;
• weak ripple, clear listening noises.

With traumatic pericarditis, therapy is useless, the cow is sent for slaughter. With an infectious pathology, the veterinarian prescribes antibiotics, drugs to restore the work of the heart.The cow should be in a quiet place, eat light food, and cold compresses are placed on her chest.

The heart ensures the proper functioning of the entire body of the cow. It is necessary to know the anatomy of the organ and the symptoms of pathologies in order to timely identify changes that are life-threatening to the animal and begin treatment.

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