Skin is an important and complex organ that performs various functions. It protects the body from external influences (mechanical, chemical, physical). Healthy and intact skin creates a reliable barrier to pathogens. She participates in the processes of respiration, excretion, thermoregulation; its role in metabolism and other vital processes is great.
The outer epidermal layer, or epidermis (I), is isolated in the skin. the skin itself – the dermis (II) and the subcutaneous tissue lying below it – the hypodermis (III).
The epidermis is formed by several dozen layers of epithelial cells lying one above the other. Its thickness is not the same everywhere, the thickest epidermis – up to 1.5 millimeters – has the skin of the soles, palms, and the thinnest – 0.03 millimeters – the skin of the eyelids. Continue reading
All the variety of movements that are constantly performed in the body, provide muscles. Thanks to them, the body is kept in balance and moves in space, respiratory movements of the chest and diaphragm, eye movements, voice formation, swallowing, the most important functions of internal organs, including the work of the heart, are carried out.
Distinguish between smooth and striated muscles.
Smooth muscles (Figure I) form the muscle membrane of the walls of the stomach and intestines. bladder, uterus and other hollow organs, as well as blood and lymph vessels, ducts of glands. They consist of small muscle cells, the length of which, as a rule, does not exceed 100 micrometers. The autonomic nervous system regulates the activity of smooth muscles. They do not obey volitional orders, therefore they cannot be reduced and relaxed arbitrarily. Continue reading
Heartburn (sensation of heat, burning behind the sternum or in the epigastric region) occurs most often as a result of throwing acidic gastric contents into the esophagus, where the reaction of the medium is slightly alkaline.
Heartburn is one of the most common manifestations of diseases of the digestive system: esophagus, stomach, and duodenum. In 60-80% of cases, it accompanies peptic ulcer of the stomach and duodenum, chronic gastritis with increased secretory function.
May be heartburn and a consequence of dysfunction of the lower esophageal sphincter (pulp), located at the junction of the esophagus into the stomach. In such cases, it intensifies when the patient lies in bed or for a long time works in an inclined position, for example, in a garden. Continue reading