Hormonal dermatosis and baldness in dogs. Endocrine diseases of animals
Veterinary endocrinology, based on clinical and experimental research, is an actively developing science. For last decades Significant success has been achieved in the study of pathologies of the endocrine glands in animals: previously undetected disorders have been described, diagnostic methods and treatment methods have been improved. At the same time, endocrine diseases in productive animals, cats and dogs, are far from a rare phenomenon, which is facilitated by the increasingly complex environmental situation, unbalanced feeding, the use of hormonal drugs, infections, etc.
Organ diseases endocrine system in animals are caused by dysfunction of the hypothalamus and pituitary gland, thyroid and parathyroid glands, adrenal cortex, islets of Langerhans of the pancreas, thymus and gonads. As a rule, endocrine diseases in animals of complex origin are manifested by a variety of clinical signs, including combined lesions of the nervous system, heart, liver, kidneys and other organs and tissues. The determining factor in endocrine diseases in animals is a deficiency or excess of hormone synthesis.
Next, we will look at the most common endocrine pathologies of dogs and cats.
DIABETES MELLITUS
Clinical manifestations of diabetes mellitus in animals are as follows: increased thirst (polydipsia), frequent urination(polyuria), weight loss in the presence of increased appetite (polyphagia). In isolated cases, animals experience decreased activity, weakness of the pelvic limbs, plantigrade gait, refusal to feed, vomiting, lack of bowel movements or diarrhea, dull and poorly maintained coat. In some cases, cataracts develop.
CUSHING'S SYNDROME
Clinical signs of Cushing's syndrome in animals: in 80-90% of cases, increased thirst and urination; a painful state similar to sleep and accompanied by immobility, lack of reactions to external irritations; note sagging of the abdomen (“pot-bellied” appearance); muscle weakness and atrophy; noisy and rapid breathing; up to 70% of cases are symmetrical alopecia and skin atrophy. Testicular atrophy occurs, the sexual cycle in females is absent, obesity develops against the background of increased appetite. Often the presence of long-term non-healing wounds, corneal ulceration, hidden infections urinary tract and the formation of phosphate stones.
ADDISON'S DISEASE
Symptoms of hypoadrenocorticism in animals include: lack of sexual activity, poor appetite, weight loss, dehydration, fatigue and weakness (some individuals are unable to stand). With the acute development of the disease, weakness, vomiting, and diarrhea (often with blood) are observed. When palpating the abdomen, pain is noted. The most characteristic of hypoadrenocorticism is a decrease blood pressure, weakening and slowing of cardiac activity, a drop in muscle tone, a decrease in general excitability, the appearance of collapse and fainting.
HYPERTHYROIDISM is more often diagnosed in cats than in dogs. As a rule, this endocrinopathy occurs in middle-aged and old cats. Most of the sick cats were between 6 and 10 years old; no breed or gender dependency was identified. Dogs have hyperfunction thyroid gland observed at the age of 8-13 years. In most cases, dogs are brought to the veterinarian because of shortness of breath, coughing, difficulty swallowing and the appearance of a mass on the neck.
HYPOTERIOSIS
Clinical manifestations of hypothyroidism in animals: an increase in the size of the thyroid gland - goiter. The development of hypothyroidism in young cats leads to stunted growth and development; they have a disproportionate appearance with a round and short body, a round and thick head, and abnormally short limbs. Such animals often have difficulty defecating.
In dogs with hypothyroidism, lethargy, increased drowsiness, decreased interest and decreased response to external stimuli are noted, a decrease in body temperature and increased thermophilia are recorded. Their appetite is preserved and the individual has a tendency to obesity. In dogs with hypothyroidism, the condition of the skin, subcutaneous layer, and coat worsens. It becomes dull, poorly maintained, symmetrical alopecia appears with hyperpigmentation of the skin on the back of the nose, chest, sides, tail and thighs on the inside. Skin becomes cool and dry. Peeling and blockage of the follicle openings with keratin plugs are often observed, which leads to the appearance of inflammatory processes and acne. When examining your pet’s head, you can see a “sad” face – puffiness (myxedema). Sick animals often have a decreased heart rate.
At the Aibolit veterinary clinic you can conduct a comprehensive examination of a pet with pathology of the adrenal glands, pancreas and thyroid glands, carry out diagnostic studies, conservative and, if necessary, surgical treatment.
04/06/2016, 18:00
Baldness and dermatoses- These are diseases of the skin and hair that not only spoil the appearance, but also greatly complicate the life of the animal. Alopecia (baldness) leads to baldness, and dermatosis irritates the skin. There are many reasons that provoke these diseases, and one of them is an imbalance of sex hormones. Your veterinarian will likely suggest therapy or try to either lower or raise your hormone levels to normal levels. How can we determine that a dog is suffering precisely because of an imbalance of sex hormones?
Symptoms: 
- Soft or dry brittle fur.
- Dandruff.
- Darkening of the skin.
- Acne on the skin.
- Abnormal skin appearance or shape of the nipples, breasts, vulva, foreskin of the penis or clitoris, testicles, ovaries and prostate gland.
- Secondary bacterial infection.
- Inflammation of the outer ear with copious discharge sulfur.
- A lack of estrogen and testosterone can result in urinary incontinence.
Where does hair fall out first?
- The perineum (the area between the vulva/scrotum and the anus).
- Stomach.
- Hips.
- Back of the neck.
Reasons:
As a rule, animals whose hormonal balance is disturbed become ill. Depending on what type of disorder is present in the dog’s body, the specialist selects treatment.
One of the reasons is secondary ovarian dysfunction in bitches due to:
- low level of production of sex hormones in the adrenal gland;
- false pregnancy;
- metabolic disorders;
- hormonal imbalance after spaying in intact bitches;
- baldness of the groin and darkening of the skin in Edel Terriers, Boxers and English Bulldogs.
Dachshunds and boxers are most susceptible to this disease.
Primary ovarian dysfunction (hyperestrogenism in bitches)
This condition may be associated with ovarian cysts (especially in English Bulldogs), ovarian tumors (rare), or overdose of estrogen medications. More often, this dysfunction affects older animals.
Increased estrogen levels in male dogs (hyperestrogenism)
Reasons:
- excess estrogen due to testicular tumor;
- Cryptorchidism is a dysfunction of the testes due to undescended testicles.
Boxers, Shelties, German Shepherds, Weimar Pointers, Cairn Terriers, Pekingese and Collies are predisposed to this disease.
Pseudohermaphroditism (a developmental disorder in which the internal genitalia of one sex are combined with the external genitalia of the other sex) occurs in miniature schnauzers. Dermatosis in males is treated with testosterone. The pathology is associated with a decrease in androgen levels. It may occur against the background of atrophy and tumors of the testes.
Diagnostics
To make a correct diagnosis, your veterinarian will need full story your dog's health, including a history of symptoms, injuries and incidents that preceded the illness. The specialist must carefully examine your pet: conduct an external examination, do tests, including a biochemical profile, full analysis blood, urine test, and electrolyte panels. A skin biopsy may be required to show the presence of sex hormones in the skin.
If necessary, your veterinarian will refer you for x-rays, ultrasound, and even laparoscopy (exploratory surgery where a small camera is inserted into the inside of the abdomen to examine organs). This will help detect ovarian or testicular abnormalities or a tumor.
To check adrenal function, an ACTH test may be required to test for the presence of the hormone adrenocorticotropin, and a test for adrenal dysfunction. Hormonal tests are also needed to check your testosterone levels.
Treatment
If your dog is suffering from hormonal imbalances, spaying or neutering is one of the main treatment options. If your dog is undergoing estrogen therapy and the results are not good for his health, your veterinarian should stop the therapy. Anti-dandruff shampoo and medications for treatment or prevention will also be useful. bacterial infections skin and itching.
Today our guest is Svetlana Vladimirovna Vasilyeva, a specialist in laboratory diagnostics, a teacher at the Department of Biochemistry of the Veterinary Academy. She was one of the first in our city to begin studying veterinary endocrinology and developing diagnostic algorithms, and is the author of 15 scientific works in this area. The topic of our conversation is hormonal disorders in small pets.
Svetlana Vladimirovna, do dogs and cats really have hormonal disorders like people?
Yes, this is not surprising: all mammals have endocrine glands that work on the same principle as in humans and secrete hormones. Found and described in animals large number endocrine diseases.
Why are they talking about this only now? It seems that animals have not suffered from such diseases before.
In fact, these diseases have always existed. However, previously they were practically not registered. There was no knowledge, no experience, and there were significantly fewer animals in the city. Indeed, more recently, veterinarians have realized that it is necessary to learn how to diagnose and treat hormonal diseases. Scientific research in this direction has been conducted abroad for many years.
What endocrine diseases are most common?
I can tell from the data own research that hypothyroidism, Cushing's syndrome, diabetes insipidus, type 1 diabetes mellitus, and polycystic ovary syndrome are most common in dogs. In cats, hormonal disorders are generally less common than in dogs, but non-insulin-dependent diabetes mellitus takes the leading position.
How do they manifest themselves?
The fact is that every disease has a specific symptom complex. Much depends on the duration of the process, on individual characteristics body. But any owner should know the main characteristic signs for which an endocrinological examination is indicated. These include increased thirst and urination, changes in appetite, obesity or weight loss. With many hormonal disorders, areas of alopecia appear, the skin often darkens, and the quality of the coat deteriorates. As a rule, these symptoms develop over a more or less long period of time, and the disease has a chronic course.
Can there be congenital hormonal diseases?
Undoubtedly. In such cases, the growth and development of the animal is usually delayed, and rickets often develops.
How dangerous are these diseases?
They are dangerous because they cause significant disruptions metabolic processes in the body, impair the functioning of organs and systems, especially cardiovascular system. Sometimes the disease develops as a result of a tumor of the endocrine gland.
Are these diseases curable?
Diseases accompanied by a decrease in hormone secretion respond well to replacement therapy. Syndromes of hyperfunction of the endocrine glands, especially tumors, are more difficult to treat.
What advice do you have for readers who notice these signs in their pets?
Be sure to undergo a comprehensive examination. To make a diagnosis, the doctor needs to examine the animal and analyze all the information about the development of the disease. The most important thing is to carry out laboratory diagnostics, including biochemical and clinical blood tests, as well as determination of the concentration of hormones in the blood. In some cases, urine examination, skin scraping, and ultrasound of the endocrine glands may be required. The examination can be done in the clinical-biochemical laboratory of the Academy of Veterinary Medicine.
The laboratory is located at st. Chernigovskaya house 5 in the building of the surgical building. By calling 388-30-51 you can find out more detailed information.
And the last question: after diagnosis, can patients receive your consultation?
Yes, after an appropriate comprehensive examination, we can give an opinion and prescribe a course of treatment.
Thanks for the interesting and important information.
Metabolic disorders are quite often observed in dogs, the cause of which is diseases of the endocrine glands that produce hormones. Hormones are substances that regulate the functions of internal organs. All hormones are interconnected: if the production of one of the hormones is disrupted, the content of others in the body changes, and this can cause serious changes in the animal’s life. for example, a lack of thyroid hormones causes growth retardation, the skin becomes rough and dry, and higher nervous activity is disrupted.
State hormonal imbalance in animals is quite difficult to diagnose. Not all clinics carry out analysis of hormone levels in the blood. The main symptom of endocrinological diseases is changes in the skin and coat. Such conditions are often diagnosed as “vitaminosis”, although in fact true vitamin deficiency in animals is rare. These diseases are difficult to treat, even if the diagnosis is correct. In some cases, medications are prescribed for life. Treatment of endocrine diseases is complex and complex and should only be carried out by a specialist.
The main changes in the skin and coat of dogs with various hormonal disorders are presented in the table (according to V.N. Mitin, 1990).
| Hormonal disorders | Leather | Wool | Localization | Clinical signs | Laboratory blood test results | ||||||
| Estrogenemia (feminization syndrome) | hyperkeratosis and pigmentation, rash appearance | continuous shedding, brittle, sparse hair, baldness | back (“glasses”), genital area, armpits, groin | weakness, depression, exhaustion, disruption of the sexual cycle (estrus). Bitches often develop uterine diseases, and feminizing syndrome in males. | ESR: normal or ++, leukocyte count: normal or ++, leukogram shift to the left, urea: normal or +, creatinitis and cholesterol: normal or + | ||||||
| Hypo- | soft, | wool | neck, ears | oppression, | eosinophilia, | ||||||
| gonado- | thin, | thin, | groin, tail | sometimes obese | cholesterol: | ||||||
| tropism | pliable- | silk | of course | tion. In bitches - | normal or + | ||||||
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wai later | vista |
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lack of technology |
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dry, she- | depig- |
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check, at Kobe- |
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peeling | menta- |
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leu - atrophy |
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(“breadbread- | tion, |
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testicles |
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ment") | hair loss |
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| Hyper- | thin, | wool | back | temperature | blood sugar: | ||||||
| adreno- | dry, dry | soft, | (sides), bottom | body and skin | normal or +, | ||||||
| corti- | barking, sometimes | rare, | belly, | downgraded | alkaline | ||||||
| cism (Cushing's syndrome) | yes pigs are observed | the hair is not brittle, but “pulling” | tail | increased urination, obesity, | phosphatase +, cholesterol + OR++ | ||||||
| mental | ongoing" |
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swelling of the bottom |
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spots |
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belly |
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| Hypo- | thickened | dry, | back | severe depression | ESR: ++, ho- | ||||||
| thyroidism | nay, husk- | dumped- | nose, neck, | tenie (lethar- | lesterine++ | ||||||
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sewing | shaking, | croup, main | gia), |
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non-elas- | dim, | praise | demotion |
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tic, | rare. | that smell | temperature |
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cold | Bald | chest, bottom | bodies, brady- |
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tion | belly | cardia, on late stage diseases - obesity |
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| Diabetes mellitus | weeping eczema | hair loss | eassian | strong thirst and increased | blood sugar + or ++, sa- | ||||||
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sti on |
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new | yr in urine | |||||||
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place ek- |
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urination- |
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lands |
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tion |
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Diabetes mellitus is chronic disease, which increases the concentration of sugar in the blood. Diabetes mellitus occurs when the pancreas does not secrete enough of the hormone insulin or the body's cells are unable to process insulin. Insulin is necessary for the utilization of glucose by the body's cells and fat metabolism in the liver. In both humans and dogs, this disease occurs in the same way and there are several types of diabetes, which are caused by different reasons. A brief description of diabetes is presented in the table. - In case of insulin-dependent diabetes mellitus, the dog is prescribed insulin for life. Currently, insulin is administered not only in the form of injections, but also in the form of capsules (orally), suppositories (into the rectum), nasal drops, etc. It is also recommended to keep in mind that diabetes mellitus often occurs together with other endocrine diseases and diseases of internal organs of various etiologies (pancreatitis, hepatitis). Diabetes mellitus in dogs is characterized by extreme thirst and increased urination. The dog is depressed, quickly gets tired, severe itching is observed, the dog scratches itself until scratches become infected and multiple purulent dermatitis occurs, which is almost not amenable to drug treatment. Diabetes mellitus is often complicated by other diseases: cataracts, nephritis. The diagnosis is made by blood and urine tests: the sugar content in the blood is very high, and it is present in the urine. Treatment is prescribed depending on the type of diabetes (insulin-dependent, non-insulin-dependent) and the concentration of sugar in the urine. The dog needs a complete diet with a reduced amount of meat. Insulin therapy is continued until the dog stops thirst under the supervision of a veterinarian. Methionine, cocarboxylase, and special antidiabetic drugs are also prescribed. If the dog's general condition is good, with proper treatment and diet, it can live for quite a long time.
Diabetes insipidus syndrome is a decrease in the production of the hormones oxytocin and vasopressin. This causes a disruption in the water-salt balance of the body, the kidneys lose the ability to concentrate urine, and to compensate for the loss of water and salt, the animal drinks a lot. Dogs experience excruciating thirst if there is no water, they can drink their own urine. At the same time, the appetite is reduced, the coat is dull and easily separated. Diabetes insipidus syndrome - hereditary disease Therefore, sick dogs should not be used for purebred breeding. The disease can also develop due to trauma to the skull or inflammatory diseases brain The diagnosis is made based on pronounced clinical symptoms and urine analysis. Prescribe pituitrin or adiurectin. Young animals can recover (sometimes spontaneously); older dogs are prescribed additional therapy.
Cushing's syndrome is associated with increased levels of glucocorticoid hormones. This disease often manifests itself as skin symptoms (hair loss and baldness) that are detected by the pet owner. In some cases, there is increased thirst and appetite, and the abdomen may become enlarged. Diagnosis of osnbvan on clinical examination and special tests. The disease can be caused by internal causes, when excessive release of hormones occurs due to disruption of the adrenal cortex (tumors, kidney inflammation, etc.). Excessive concentrations of hormones in the body can also occur when they are used excessively (for example, prednisolone) in veterinary practice. Cushing's syndrome, caused by the introduction of medicinal drugs into the body, usually goes away after stopping the drugs. Treatment of Cushing's syndrome depends on its cause: discontinuation of hormonal medicines. In case of excessive secretion of hormones, chloditan is prescribed (this medicine suppresses the secretion of hormones).
Vitamin deficiency diseases. According to the latest data from veterinary science, “city” dogs rarely develop vitamin deficiencies and hypovitaminosis in their pure form. Most often, symptoms of metabolic disorders are observed, which are accompanied by vitamin deficiency. Changes in the physiological balance of vitamins are caused by antibiotics and some other drugs. In addition, it is recommended to remember that many vitamins are absorbed only in combination with other substances or vitamins. for example, vitamins A and D are absorbed by the body only in a certain ratio. Clinical signs of vitamin deficiency are very diverse and can be observed not only with vitamin deficiencies, but also with other diseases (for example, anemia is characteristic of vitamin deficiencies B6 and B12, as well as with internal bleeding and iron deficiency). It is quite difficult to distinguish vitamin deficiency from hypervitaminosis on the basis of clinical signs, and an excess of vitamins is just as dangerous to health as a deficiency. Thus, the prescription of vitamin injections both for the prevention and treatment of “vitaminosis” and other diseases is not always justified. If a dog receives ready-made food, it does not require any other vitamin supplements. Otherwise, the introduction of vitamins into the diet is best done under the supervision of a veterinarian.
Thyroid diseases. The thyroid glands secrete hormones (thyroxine and triiodothyronine) that regulate the rate of metabolism in the body. Low levels of the hormone cause the cells and organs of the body to work more slowly. Then, with normal nutrition, the dog becomes lethargic and develops obesity. Hair falls out on the back and sides. Purulent dermatitis is often observed. Hypothyroidism occurs as a result of dysfunction of the thyroid gland, which may be the result of a disease (autoimmune thyroiditis), tumor or congenital disease. This disease not only has skin manifestations, but also affects all body systems. There are primary (congenital) and functional (complications of other diseases, the effect of medications) hypothyroidism. To confirm the diagnosis, a blood test is performed, based on which the required dose of thyroxine is selected. There is also a pathological enlargement of the thyroid gland (goiter), in which the production of thyroxine may not be impaired. This disease occurs in certain geographical areas where there is insufficient iodine in drinking water. A goiter is detected by palpation of the lower part of the neck (swelling and hardening of the gland). The goiter can grow significantly and put pressure on the esophagus and trachea. Young animals are prescribed iodine preparations, and for old animals or if drug treatment is ineffective, surgical removal of the gland is recommended. 0
Endocrine, or endocrine glands, are all glands or groups of cells whose products, hormones or secretions, due to the lack of their own excretory tracts, are secreted into the blood and lymphatic capillaries and distributed throughout the body through the circulatory system. When hormones entering organs located near, and often far from the place of hormone production, come into contact with specific receptors, they have an inhibitory or activating effect, and often with the autonomic nervous system, on organs involved in metabolism and morphological changes. This contributes to the adequate adaptation of organs involved in metabolism to environmental conditions. Unlike hormones, paracrine signaling substances, when diffused into interstitial tissue, influence cells or groups of cells that are located near the site of product production.
In what follows, only the macroscopically visible hormone-producing glands, paraganglia, and pancreatic islets will be examined in detail. Thus, in the wall of the stomach and intestines there are numerous, separately lying cells, which, despite differences in structure and produced products, are united into the enteroendocrine system. Cells of similar structure are located in the mucous membrane of the bronchi and urethra, as well as in the kidneys (Andrew, 1981; Bohme, 1992; Grube, 1986; Hanyu et al., 1987; Kitamura et al., 1982; Pearse, 1980). The myocardium contains cells that, due to atrial natriuretic peptide (ANP) during sodium production in the kidneys, have an indirect effect on the volume of extracellular fluid (Forssmann, 1987).
How closely the interaction between the endocrine organs and the autonomic nervous system occurs, which can be considered as a functional unity in the regulation of processes occurring in the body, can be understood from the following: 1) in the central nervous system there is an intensive interaction of the nuclei of the diencephalon with the pituitary gland and the pineal gland, 2) both cells of the enteroendocrine system and the autonomic nervous system produce and secrete neuropeptides.
PITUITARY
The pituitary gland, hypophysis, glandula pituitaria, is an unpaired small organ located between the chiasma opticum and the corpus mamillare ventral to the diencephalon. It consists of the neurohypophysis, which forms on the basis of the diencephalon, and the adenohypophysis, which arises from the pituitary recess lining the roof of the oral cavity. The neurohypophysis is divided into the infundibulum, or pituitary stalk, and the lobus nervosus, or posterior lobe (-/2). The adenohypophysis includes the pars tuberalis, or funnel-shaped lobe (-/3), pars distalis, or anterior lobe (-/3"), pars intermedia, or intermediate lobe (-/4). The pituitary gland is integral part hypothalamic-pituitary system. This is expressed in the fact that hormones released into the blood in the neurohypophysis are formed by neurosecretory neurons, the bodies of which are located in the nucleus supraopticus and nucleus paraventricularis of the hypothalamus. And the functioning of the adenohypophysis is controlled by liberins and statins, which are secreted by the neurons of the small cell nuclei of the gray tuberosity, tuber cinereum.
Rice. 1. Schematic illustration pituitary gland along the midline of a dog (A) and a cat (B)
1 recessus infundibuli; 2 infundibulum, 2" lobus nervosus neurohypophysis; 3 pars tuberalis, 3" pars distalis adenohypophysis; 4 pars intermedia adenohypophysis; 5 cavum hypophysis; 6 dura mater
The pituitary gland in dogs is somewhat flattened, oval, in cats it is spherical. Not only does the size of the pituitary gland vary by breed, but even within the same breed there are individual differences (Latimer, 1942, 1965; White/Foust, 1944; Hanstrom, 1966). The size of the pituitary gland of a dog with an average head size is 10 x 7 x 5 mm, of a cat - 5 x 5 x 2 mm. Under the same housing conditions, the pituitary gland in females is slightly larger than in males, and in pregnant animals it is larger and heavier than in non-pregnant animals (Latimer, 1942; White/Foust, 1944). Male pituitary gland weight various breeds with an average body weight of 11 kg is 0.0658 g, in a female with an average body weight of 8.93 kg - 0.067 g (Latimer, 1942).
The neurohypophysis, neurohypophysis, through the stalk or funnel of the pituitary gland, infundibulum, is in direct connection with the tuber cinereum of the hypothalamus. The pituitary stalk is cylindrical, very short and contains a short recess in the form of a depression in the proximal part, and in cats, reaching the lobus nervosus, recessus infundibuli (-/1). Distally, the pituitary stalk is thicker and passes without a clear boundary into the lobus nervosus, or posterior lobe (-/2’).
The adenohypophysis is larger than the neurohypophysis. Its pars tuberalis, the tuberal or funnel-shaped part, covers the pituitary stalk in dogs and cats. In dogs, the anterior and intermediate lobes of the adenohypophysis (-/3", 4) cover the posterior lobe of the neurohypophysis on all sides, while in cats the proximal portion of the caudal surface of the posterior lobe remains uncovered. With the development between the anterior and intermediate lobes of the adenohypophysis in dogs and In cats, there remains a pituitary cavity, cavum hypophysis (-/ 5), which varies significantly in its length and width.
In a fresh organ, the cut surface of the neurohypophysis appears homogeneous and glassy due to the large number of neurites and glial cells; the cut surface of the adenohypophysis, in which epithelial cells and sinusoidal capillaries predominate, has a granular consistency denser than that of the neurohypophysis. Features of the microscopic structure of the pituitary gland, as well as the role various types cells during the production of individual hormones, as well as the effect on other hormone-secreting glands or other organs, are described in textbooks on histology and physiology (eg, Mosimann / Kohler, 1990; Scheunert / Trautmann, 1987).
Only aa go directly to the posterior lobe of the pituitary gland. hypophysiales caudales. They arise in dogs from the caudal communicating branch of a. intercarotica caudaiis, which runs in the hard shell along the body of the basisphenoid. In cats, these vessels come from the rete mirabile epidurale. After passing a. carotis interna through the diaphragm sellae, diaphragma sellae from it, or from the a. cerebri rostralis, separated by aa. hypophysiales rostrales, which go to the pituitary stalk and the posterior lobe of the adenohypophysis. Often small aa. hypophysiales rostrales arise on each side of the caudal communicating artery, a. communicans caudaiis, and run radially, converging on the pituitary stalk. In the dura mater of the brain at the pituitary gland, the pituitary arteries are connected into one thin network, a plexus (Green, 1951), from which the arteries primarily go to the median eminence, eminentia mediana and infundibulum of the neurohypophysis, as well as to the pars tuberalis of the adenohypophysis. From this primary capillary region in the pituitary stalk, numerous veins are formed, which run distally along the ventral surface of the adenohypophysis, and then into the voluminous sinusoids of the anterior and intermediate lobes. This system makes possible influence liberins and statins produced in the tuber cinereum, and then moving along the tractus tuberoinfumdibularis to the pituitary stalk, after their further transport in the blood, to various cells of the anterior lobe. Numerous veins that drain blood from the pituitary gland soon flow into the sinus cavernosus or the caudal sinus intercavemosus.
Sympathetic nerve fibers from the cranial cervical ganglion go to the pituitary gland or in the form of a perivascular plexus with aa. hypophysiales or in the form of branches n. caroticus internus.
On outer surface of the pituitary gland, the dura mater of the brain forms a thin connective tissue capsule, which at the same time represents a strong connection of the pituitary gland with the flat fossa of the pituitary gland, fossa hypophysiales, on the body of the basisphenoid. In the area of the pituitary stalk there is a hard meninges protrudes above the free edge of the sella turcica, sella turcica in the form of diaphragma sellae, covers most of the pituitary gland on the dorsal side and leaves only a small opening for the passage of the pituitary stalk. In this area, in relation to the pituitary gland, the cavum subarachnoidale ends, which is especially extensive on the dorsal side of it in the form of an interpeduncular cistern, cisterna interpeduncularis. Between the two plates of the dura mater on both sides of the pituitary gland there passes the sinus cavernosus, and caudally from it the sinus intercavernosus. In the region of the latter, a. go to the pituitary gland on each side. carotis interna, or, respectively, in cats - rete mirabile epidurale, n. oculomotorius, n. trochlearis and n. ophthalmicus, as well as n. abducens.
Sh PIROID GLAND (EPIPHYSUS)
The pineal gland, glandula pinealis, is not paired organ. Its cross section is circular. The pineal gland lies between the cerebral hemispheres in front of the roof of the midbrain, tectum mesencephali. Its size varies among animals, and in medium-sized dogs the length reaches approximately 3 mm and the diameter reaches 2 mm. In cats, this ratio is 2x1 mm. Being part of the diencephalon, the pineal gland is connected to the caudal portion of its roof through frenulums, habenulae with a short stalk, pedunculus. The fibers of the commissure of the frenulum, comissura habenularum, pass through this junction. In the body, corpus, pineal gland, in addition to nerve fibers, there are pinealocytes, which, depending on the duration and intensity of light, produce the hormone melatonin. In dogs and cats, regardless of age, especially on the ventral surface of the pineal gland, some pinealocytes contain melanin. Functional meaning these pigmented cells have not yet been studied (Calvo et al., 1992). Considering the connection with the diencephalon, as well as the humoral interaction with other glands that secrete hormones, through melatonin, the pineal gland is an important central authority neurovegetative regulation. At night, melatonin production is more active than during the day, and with the participation of feedback through the cranial cervical ganglion of the sympathetic part of the nervous system and with innervation by sympathetic fibers, the pineal gland can have a controlling effect on biological rhythms. The arteries that supply the pia mater near the pineal gland send thin branches to the interior of the organ. In the pineal gland, the branches branch into sinusoids.
SCH ITIC gland
The thyroid gland, glandula thyreoidea, consists of the left and right lobe lobus sinister
A) et lobus dexter, as well as the isthmus connecting them, isthmus. The shape of each lobe varies considerably in dogs and cats, being oval and slightly flattened at the sides, and in cats, most often thinner than in dogs. The lobes, from dark red-brown to gray-red in color, have a consistency similar to that of the liver. In adult animals, the thyroid gland may be denser, while in cats it may be softer. The incidence of isthmus in cats varies (16-87%). In dogs it depends on body size. Half have an isthmus large dogs, in a third of medium-sized dogs and a quarter of small dogs (Heller, 1932). Both lobes are located in dogs on the dorsolateral surface of the trachea and run parallel to it. In rare cases, the gland may be located slightly cephalad or caudally. At ultrasound examination in dogs, the thyroid gland appears caudal to the larynx as a homogeneous fusiform structure and is clearly demarcated from surrounding structures (Wisner et al., 1991). In cats, both lobes are higher on the dorsal side than in dogs, therefore they can be located between the trachea and esophagus and be covered dorsolaterally by m. longus capitis. In the presence of an isthmus, the caudal poles of both lobes are connected, and the isthmus passes along the ventral surface of the trachea. The epithelial cells of the thyroid follicles produce the hormones thyroxine and triiodothyronine, which play big role in metabolic processes. These epithelial cells are separated from the epithelium of the root of the tongue during development. Then they reach the lateral surfaces of the first tracheal ring through the ductus thyreoglossus. Between these cells there are always so-called C-cells. They produce calcitonin, which, together with parathyroid hormone, is involved in maintaining a constant calcium level.
The relative mass of the thyroid gland in dogs and cats is maximum at the time of birth, and decreases in the first weeks after birth. Regardless of breed, the absolute and relative mass of the thyroid gland varies.
Absolute and relative weight of the thyroid gland in dogs and cats
(Haensly et al., 1964; Heller, 1932; Latimer, 1939; Meissner, 1924; Meyer, 1952; Schneebeli, 1958; Schweinhuber, 1910):
Table 1
Accessory thyroid glands, glandulae thyroideae accessoriae, can form during development from separated parts of the thyroid gland, which is more common in dogs than in cats. They can occur at the base of the tongue, along the neck, in the mediastinum near the heart, or near the aortic arch. Their size varies greatly and they can often only be detected by histological examination. If part of the ductus thyreoglossus remains during development, it may develop into a cyst in the neck area.
The main vessel supplying the thyroid gland is a. thyreoidea cranialis. It arises from a. carotis communis at the level of the annular tracheal membrane (ligament), membrana cricotrachlealis or the first tracheal cartilage. In addition to branches to the pharynx, larynx and adjacent muscles, this artery gives off ramus dorsalis et ramus ventralis along the corresponding parts of each lobe of the thyroid gland to both the thyroid gland and the epithelial bodies. The area where thin a. thyreoidea caudalis (-/1) varies. Most often, it arises from the brachiocephalic trunk, truncus brachiocephalicus or the costocervical trunk, truncus costocervicalis. Less often it is formed from the right subclavian artery, a. subclavia dextra. A. thyreoidea caudalis always accompanies n. laryngeus recurrens (-/5) and connects through anastomoses with the dorsal branch of a. thyreoidea cranialis.
Extraglandular veins are different not only in different animals, but also on different sides of the body of the same animal, and connect with each other. V. thyreoidea cranialis (-/n) and often double v. thyreoidea media (-/t) drains blood into v. jugularis is on its side. Arcus laryngeus caudalis (-/p) represents the connection between the left and right v. thyreoidea cranialis, as well as the cranial part of the unpaired v. thyreoidea caudalis (-/u). The last vessel passes along the midline along the ventral surface of the trachea and flows into either the left or right v. brachiocephalica or v. jugularis externa, or interna of the right side.
Rice. 2. Topography of the thyroid gland and left outer epithelial bodies of the dog (according to Borer, 1990)
A glandula thyreoidea; In glandula parathyreoidea; With trachea; D oesophagus; E m. hyopharyngeus; F m. thyreopharyngeus; G m. cricofaringeus; Hm. thyreohyoideus; Lm. sternothyroideus; To cartilago thyreoidea; Lm. cricothyreoideus; Mm. sternohyoideus
a a. carotis communis; b a. thyreoidea cranialis; c - k branches a. thyreoidea cranialis; with ramus dorsalis; dramus ventralis; e ramus sternoclei domastoideus; f ramus laryngeus caudalis; g ramus pharyngeus; h ramus cricothyreoideus; i ramus muscularis; k ramus laryngeus; I a. thyreoidea caudalis; m v. jugularis interna; n v. thyreoidea cranialis; o - s aste der v. thyreoidea cranialis; t v. thyreoidea media; u v. thyreoidea caudalis; v v. laryngea impar; w arcus hyoideus; x anastomose zwischen arcus hyoideus und v. jugularis interna
1 truncus vagosympathicus; 2 n. laryngeus cranialis; 3 ramus internus n. laryngeus cranialis; 4 ramus externus n. laryngeus; 5 n. laryngeus recurrens; 6, 7 rami musculares from ansa cervicalis; 8th connecting branch to the 1st cervical nerve
In the thyroid gland, lymphatic capillaries form a dense network around individual follicles (Rusznyak et al., 1967), and draining lymphatic vessels go to In. retropharyngeus medialis.
Sympathetic nerves to the thyroid gland are formed from the cranial cervical ganglion, and parasympathetic nerves from n. laryngeus cranialis. Individual fibers may emerge from the n end. laryngeus recurrens.
E PITELIAL BODIES (PARATYROID GLANDS)
After developing from the epithelium of the third and fourth gill pouch, the outer epithelial body, glandula parathyreoidea externa, also called glandula parathyreoidea IV, and the inner, glandula parathyreoidea interna, also called glandula parathyreoidea III. The parathyroid hormone they produce, together with calcitonin secreted by the C-cells of the thyroid gland, regulates calcium metabolism.
In dogs, the outer epithelial body has a lenticular or rice grain shape with a smooth surface and is located at the cranial pole or cranial half of the thyroid lobe, less often - near the dorsal edge. In cats, the outer epithelial body is usually located laterally in the caudal half of the thyroid lobe. The size and weight of epithelial bodies in dogs under one year of age depend little on age. The size of the outer epithelial body in large dogs is 3-7 x 2-5.5 x 1.5-2.5 mm, the inner epithelial body is slightly smaller. The color varies from golden yellow to reddish brown and often stands out well against the background of the thyroid gland.
In dogs and cats, the internal epithelial body lies in the middle part of the thyroid lobes in the parenchyma of the thyroid gland, somewhat distant from the medial or dorsal surface and not always noticeable from the outside. In some cases it may be absent (Pinto and Silva, 1947).
The outer epithelial body receives 1-2 rami glandulares from a. thyreoidea cranialis, and venous outflow is carried out through rami glandulares, which flow into v. thyreoidea cranialis or arcus laryngeus caudalis. The internal epithelial body does not have its own arterial or venous branches, but is adjacent to the vessels of the thyroid gland (Orsi et al., 1975).
Sympathetic fibers from the cranial cervical ganglion reach the epithelial bodies, accompanying the arteries; parasympathetic fibers originate from n. laryngeus recurrens.
ADRENAL GLANDS
The adrenal gland, glandula suprarenalis or adrenalis, is a paired organ that consists of the cortex, cortex and medulla, medulla (-/C, 2). On the outside, this organ has a thin connective tissue capsule and is surrounded by connective tissue with fat cells, located on the medial side of the cranial pole of the kidney, retroperitoneally. The adrenal cortex develops from the mesoderm and is influenced mainly by ACTH of the adenohypophysis. The adrenal medulla produces epinephrine and norepinephrine and is primarily regulated by the sympathetic nervous system. On the cut surface of a fresh adrenal gland, the border between the light cortex and the dark medulla is clearly visible macroscopically. In dogs, each adrenal gland (-/A) is elongated, dorsoventrally flattened and has a light gray to white color. In cats, the yellowish-white adrenal glands (-/B) are shorter than in dogs, oval and disc-shaped. The common trunk of the caudal phrenic vein, v., runs along the ventral surface. phrenica caudaiis, and cranial abdominal vein, v. abdominalis cranialis, leaving a superficial groove in cats and a deep groove in dogs. Due to the presence of this deep groove in dogs, two elongated lobes, not completely separated from each other, and two rounded lobes on the right adrenal gland can be distinguished on the right adrenal gland. Common trunk a. phrenica caudaiis and a. abdominalis cranialis passes the adrenal glands from the dorsal side and does not leave a groove.
Rice. 3. Adrenal glands of a dog (A) and a cat (B), view from the ventral side; C - cross section of 1 cortex; 2 medulla. Life size
In adult females, as well as pregnant and lactating ones, the size and weight are larger than in males, as well as in young animals.
In dogs and cats, the adrenal glands are located retroperitoneal and medial to the cranial half of the kidneys, or medial to their cranial pole. The left adrenal gland is connected to the left wall of the aorta caudaiis, the right adrenal gland is connected to the right wall v. cava caudaiis.
The blood supply to the adrenal glands is carried out by numerous aa. suprarenales or directly from the aorta abdominalis, or from a. phrenica caudaiis, a. abdominalis cranialis or a. renalis. After passing through the connective tissue capsule, these branches branch and give off radially voluminous capillaries throughout the entire circumference to the medulla. From the capillary network of the medulla, blood collects in a large central vein and then flows through several vv. suprarenales in v. cava caudalis, v. phrenica caudalis, v. abdominalis cranialis or v. renalis. There are significant individual differences in the number and length of blood vessels. In dogs and cats the smallest vessels are combined in the connective tissue between the kidneys and adrenal glands, which probably explains why at least a small part of the catecholamines produced in the adrenal medulla can reach the kidneys by the shortest route (Christe, 1980; Dempster, 1978; Earle/Gilmore, 1982 ). Lymphatic capillaries are numerous in all parts of the adrenal glands and are located in the form of a network. Through several lymphatic vessels, lymph is collected in the Inn. lumbale aortic.
Rice. 4. Location of the adrenal glands of the dachshund with nearby ganglia and sockeye salmon (according to Seiferle, 1992) a left, a’ right adrenal gland; b left, b" right kidney; c ureter; d oesophagus; e ventral leg, e' lateral leg of the right part of the diaphragm. f left side diaphragms; g pars costalis musculature of the diaphragm; h v cava caudaiis; i. i" diaphragm mirror; k m. psoas minor; l m. psoas major; IX. -XIII. 9- 13. ribs
1 aorta abdominalis; 2 a. hepatica, 7 a. gastrica sinistra, 2" splenic artery a. coeliaca; 3 a. mesenterica cranialis 4 a. phrenica caudaiis; 5 a. und v. renalis, 6 a. mesenterica caudaiis; 7 a. tcsticularis; 8 vv. phrenicac, 8" common trunk v. phrenica caudaiis and v. abdominalis cranialis; 9 truncus vagalis ventralis, 9" his rami gastrici parietales; 10 truncus vagalis dorsalis, 10" his rami gastrici viscrales, 10" his rami cocliaci; 11 ganglion cocliacum; 12 ganglion mesentericum craniale; 13 branches of plexus suprarenalis; 14 ganglion renale and plexus renalis ; 15 plexus aorticus abdominalis; 17 left and right n. hypogastricus; 19 branch n. iliohypogastricus lateralis;
Table 2
Numerous autonomic nerve fibers to the adrenal glands arise either directly from nearby n. splanchnicus major, or from ganglion coeliacum and ganglion mesentericum craniale. In the form of plexus suprarenalis, they reach the adrenal glands directly or with blood vessels and enter the organ with them. The nerve fibers form a plexus in the capsule, from which numerous bundles of nerve fibers extend into the cortex and adrenal medulla.
O lines of the pancreas
Inside the pancreas, between the exocrine cells of the terminal sections of the gland, endocrine cells of the pancreas, endocrinocyti pancreatici, are united into small groups, the islets of the pancreas or islets of Langerhans, insulae pancreaticae. Individual islands of unequal size, including a large number of vessels, consist of 10-100 endocrinocytes. The number of islets varies significantly in dogs and cats, reaching several thousand. In the lobus sinister of the pancreas, the islets of Langerhans are larger and more numerous than in the lobus dexter. The capillary region of the endocrine and exocrine parts of the pancreas are connected to each other, and the lumen of the capillaries in the islets is larger and the capillaries are more numerous than in the exocrine part of the pancreas. The transition to the boundary surface between the two parts is very pronounced.
Upon microscopic examination, 3 types of cells are distinguished in the islets. A cells make up a total of 10 - 20% endocrine cells, however, are absent in the islets of the caudal part of the lobus dexter of the pancreas. This may be due to the fact that the caudal part of the lobus dexter and the remaining parts have different origins. A-cells produce glucathone and regulate carbohydrate metabolism with insulin-producing B-cells. B cells make up 80-90% of endocrine gland cells. In addition to somatostatin-producing D cells, which make up 1% of all islet cells, there are also other, individually occurring cells that, for example, can produce gastrin and serotonin. These cells are compared to the cells of the enteroendocrine system (Mosimann/Kohler, 1990). Electron microscopy revealed the presence in A-cells of electron-dense granules with a diameter of up to 0.5 μt. In B cells, the granules are larger than in A cells, have lower electron density, but contain crystalline inclusions. In D cells, the granules are smaller and have less electron density than the granules in A cells.
PARAGANGLIA
There is no precise definition of what paraganglia are. Most often, paraganglia are large or small clusters of devoid of processes, catecholamine-containing, chromaffin cells, which are located in close proximity to the ganglia of the autonomic nervous system or from large arteries. Most often, these clusters are distinguished only using macro-microscopic research methods. Since these cells, as well as the cells of the adrenal medulla, have common origin, it has long been believed that paraganglion cells have endocrine activity. Today it is known that the adrenal medulla, as the largest paraganglia, according to this definition, actively produces hormones, but the carotid glomerulus, glomus caroticum, as well as the aortic glomerulus, glomus aorticum, function as chemoreceptors and record the partial pressure of CO 2 in the blood.
Glomus caroticum in dogs has a very thin capsule of loose connective tissue, which passes into the surrounding tissues without a clear boundary. Therefore, the boundaries between the glomus and surrounding tissues are little noticeable when viewed through a magnifying glass. It is located, most often, craniomedial from the terminal division of a. carotis communis in the area where a. pharyngea ascendens or a. occipitalis, less often - in the area of origin of a. carotis interna. Glomus caroticum is spherical or elongated, sometimes covering, like a ring or semiring, the area of origin of one of the named arteries (Cantieni/Frewein, 1982). Accurate data on the size of glomus caroticum can be obtained from histomorphometric studies. The volume of the glomus caroticum in an adult German Shepherd and an adult Boxer is 3-16 mm 3 . A dense network of voluminous capillaries contacts parenchymal cells (Type I and Type II). On average, dogs have 3.3% Type I cells and 2.2% Type II cells (Frei-Kuchen, 1981; Pallot, 1987).
Rice. 5. Topography of the right glomus caroticum, view from the medial side. A - German shepherd (according to Cantieni/Frewein, 1982) and B - cat (modified, according to Pallot, 1987)
1 glomus caroticum; 2 a. carotis communis; 3 a. carotis externa; 4 a. carotis interna; 5 sinus carotis; 6 a. occipitalis; 7 a. pharyngea ascendens; 8 a. larvngea cranialis; 9 ramus sinus carotici glossopharyngeal nerve; 10 branch n. vagus; 11th branch from ganglion cervicale craniale; 12 plexus caroticus externus
Rice. 6. a. Schematic representation of the paraganglia of the head, neck and thoracic region (after Seiferle, 1992)
1 aorta descensens; 2 arcus aortae; aorta thoracica; 4 a. subclavia sinistra; 5 truncus brachiocephalicus; 6 a. subclavia dextra; 7 a. carotis communis dextra; 8 a. carotis communis sinistra; 9 a. carotis interna; 10 a.m. carotis externa;
11 sinus caroticus; 12 glomus caroticum; 13 glomus aorticum; 14 ramus sinus carotici; 15 ganglion distale vagus nerve; 16 no. laryngeus cranialis; 17 no. depressor; 18 ganglion cervicale craniale; 19 sympathetic part
IX n. glossopharyngeus; X n. vagus
Rice. 6. b. Schematic representation of the large abdominal paraganglia of a dog at 24 weeks of age. Ventral view (after Mascorro/Yates, from Seiferle/Bohme, 1992)
1 aorta abdominalis; 2 a. renalis; 3 a. testicularis (ovarica); 4 a. mesenterica caudalis; 5 adrenal gland; 6 paraganglion aorticum abdominale
In cats, glomus caroticum, due to its powerful connective tissue capsule, is separated from surrounding tissues more easily than in dogs. In general, glomus caroticum is spherical in diameter, 2 mm and is located at the site of origin of either a. pharyngea ascendens, or a. occipitalis. Components, according to Seiferleet al. (1977), include: vessels 22.3%, specific tissue 16.9% and remaining tissue 60.8%.
In dogs and cats, the glomus caroticum is innervated by branches from the ramus sinus carotici of the glossopharyngeal nerve, as well as branches of the ganglion cervicale craniale. In dogs, in addition, thin branches come directly from n. vagus or its rami pharyngei. All named branches are connected to each other, and in dogs they are attached to the part of the plexus caroticus externus, with significant variations.
Glomus aorticum includes groups of chromaffin cells that lie on the aortic arch and are not clearly demarcated from surrounding tissues. These cells, like the cells of glomus caroticum, record CO2 pressure in the blood and transmit information along the branches of n. vagus to nuclei medulla oblongata. The meaning and functions of the efferent fibers that end in the glomus caroticum and glomus aorticum are not yet precisely known.
Paraganglion aorticum abdominale is located near the ventral surface of the aorta abdominalis and the place of origin of a. mesenterica caudalis, and is better developed in newborn animals than in adults. Its functions, as well as those of small groups of chromaffin cells, for example near n. tympanicus or in a. subclavia are unknown.
Literature used: Anatomy of a dog and a cat (Coll, authors) / Transl. with him. E. Boldyreva, I. Kravets. - M.: “AQUARIUM BUK”, 2003. 580 pp., ill. color on
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