How do endocrine glands regulate body processes. What are the key differences between endocrine and exocrine glands. Which historical events shaped our understanding of the endocrine system. How does the endocrine system maintain homeostasis in the human body.

The Fundamentals of the Endocrine System

The human endocrine system is a complex network of ductless glands that play a crucial role in regulating various bodily functions. These glands secrete chemical substances called hormones directly into the bloodstream, which then travel to specific target organs and tissues to exert their effects. This intricate system works in tandem with the nervous system and immune system to maintain homeostasis, the body’s internal balance.

Understanding the endocrine system is essential for comprehending how our bodies function and respond to various stimuli. Let’s delve deeper into the components and functions of this remarkable system.

Endocrine vs. Exocrine Glands: Understanding the Distinction

To fully grasp the concept of the endocrine system, it’s crucial to differentiate between endocrine and exocrine glands:

• Endocrine glands: These glands release hormones directly into the bloodstream, allowing them to reach distant target organs.
• Exocrine glands: These glands secrete substances through ducts onto external or internal body surfaces, acting on local tissues.

Examples of exocrine glands include salivary glands and sweat glands. The saliva produced by salivary glands and the sweat secreted by sweat glands act on nearby tissues. In contrast, endocrine glands, such as the thyroid or pituitary gland, release hormones that can affect tissues far from their point of origin.

Key Differences Between Endocrine and Exocrine Glands

1. Secretion method: Endocrine glands secrete directly into the bloodstream, while exocrine glands use ducts.
2. Target area: Endocrine glands affect distant tissues, while exocrine glands typically act locally.
3. Type of secretion: Endocrine glands produce hormones, while exocrine glands secrete various substances like sweat, saliva, or digestive enzymes.
4. Response time: Endocrine effects are often slower but longer-lasting, while exocrine effects are typically more immediate.

Historical Milestones in Endocrinology

The field of endocrinology has a rich history dating back thousands of years. Ancient civilizations, such as the Chinese, recognized and treated endocrine disorders as early as 3000 BCE. For instance, they prescribed iodine-rich seaweed to treat goiter, an enlargement of the thyroid gland.

Throughout history, various observations and experiments have contributed to our understanding of the endocrine system:

• Castration experiments in humans and animals revealed the testes as the source of male characteristics.
• In 1849, German physiologist Arnold Adolph Berthold demonstrated the endocrine function of testes by transplanting them into castrated roosters.
• Charles-Édouard Brown-Séquard’s self-experimentation with animal testicular extracts in the 19th century led to the widespread use of organ extracts to treat endocrine conditions (organotherapy).

The Birth of Modern Endocrinology

Modern endocrinology emerged in the 20th century, building upon the foundational work of earlier scientists. Two key figures in this development were:

1. Claude Bernard (1813-1878): A French physiologist who introduced the concept of the “milieu intérieur” or internal environment, emphasizing the importance of maintaining a stable internal state.
2. Walter Bradford Cannon (1871-1945): An American physiologist who coined the term “homeostasis” to describe the body’s ability to maintain internal stability in response to external changes.

These concepts laid the groundwork for our current understanding of how the endocrine system, along with the nervous and immune systems, regulates the body’s internal activities and interactions with the external environment.

Major Endocrine Glands and Their Functions

The human endocrine system consists of several glands located throughout the body. Each gland produces specific hormones that regulate various physiological processes. Here are some of the major endocrine glands and their primary functions:

1. Pituitary Gland

Often called the “master gland,” the pituitary gland is located at the base of the brain and produces hormones that control other endocrine glands. It secretes growth hormone, prolactin, and hormones that stimulate the thyroid, adrenal glands, and reproductive organs.

2. Thyroid Gland

The thyroid gland, located in the neck, produces thyroid hormones that regulate metabolism, growth, and development. It also produces calcitonin, which helps regulate calcium levels in the body.

3. Parathyroid Glands

These small glands, located behind the thyroid, produce parathyroid hormone, which regulates calcium and phosphate levels in the blood and bones.

4. Adrenal Glands

Situated atop the kidneys, the adrenal glands produce hormones such as cortisol, aldosterone, and adrenaline, which help regulate metabolism, blood pressure, and the body’s stress response.

5. Pancreas

The pancreas functions as both an endocrine and exocrine gland. Its endocrine function involves producing insulin and glucagon, hormones that regulate blood sugar levels.

6. Reproductive Glands

The ovaries in females and testes in males produce sex hormones (estrogen, progesterone, and testosterone) that regulate sexual development, reproduction, and secondary sex characteristics.

Hormones: The Chemical Messengers of the Endocrine System

Hormones are the primary means by which the endocrine system exerts its influence on the body. These chemical messengers are released by endocrine glands and travel through the bloodstream to reach their target tissues. Upon reaching their destination, hormones bind to specific receptors on or within cells, triggering a cascade of biochemical reactions that ultimately lead to changes in cellular function.

Types of Hormones

Hormones can be classified into several categories based on their chemical structure:

• Peptide hormones: Made up of amino acid chains (e.g., insulin, growth hormone)
• Steroid hormones: Derived from cholesterol (e.g., cortisol, testosterone, estrogen)
• Amino acid-derived hormones: Synthesized from modified amino acids (e.g., thyroid hormones, epinephrine)

Each type of hormone has unique properties that influence how it is produced, transported, and acts on target cells.

Hormone Action Mechanisms

Hormones typically act through one of two main mechanisms:

1. Direct gene activation: Some hormones, particularly steroid hormones, can enter cells and bind to receptors in the nucleus, directly influencing gene expression.
2. Second messenger systems: Many hormones bind to receptors on the cell surface, triggering intracellular signaling cascades that lead to changes in cell function.

The specific action of a hormone depends on the presence of appropriate receptors on target cells. This selectivity ensures that hormones only affect the intended tissues, even though they circulate throughout the body.

Homeostasis and the Endocrine System

One of the primary functions of the endocrine system is to maintain homeostasis, the state of internal balance within the body. This complex process involves constant monitoring and adjustment of various physiological parameters, such as body temperature, blood glucose levels, and blood pressure.

The endocrine system achieves homeostasis through feedback mechanisms, which can be either negative or positive:

• Negative feedback: This is the most common type of feedback in the body. When a parameter deviates from its normal range, the body initiates responses to bring it back to the desired level. For example, when blood glucose levels rise, the pancreas secretes insulin to lower them.
• Positive feedback: In some cases, the body uses positive feedback to amplify a response. This is less common but can be seen in processes like childbirth, where contractions stimulate the release of oxytocin, which in turn increases contractions.

Examples of Endocrine-Mediated Homeostasis

1. Blood glucose regulation: Insulin and glucagon work antagonistically to maintain blood sugar levels within a narrow range.
2. Calcium homeostasis: Parathyroid hormone and calcitonin regulate calcium levels in the blood and bones.
3. Stress response: The hypothalamic-pituitary-adrenal (HPA) axis coordinates the body’s response to stress through the release of cortisol and other hormones.
4. Thermoregulation: Thyroid hormones play a crucial role in regulating metabolism and body temperature.

By maintaining homeostasis, the endocrine system ensures that the body’s internal environment remains stable, allowing for optimal functioning of all physiological processes.

Endocrine Disorders: When the System Malfunctions

While the endocrine system is remarkably efficient, it can sometimes malfunction, leading to various disorders. Endocrine disorders can result from several factors:

• Oversecretion of hormones
• Undersecretion of hormones
• Inability of target organs or tissues to respond effectively to hormones

These disturbances can have wide-ranging effects on the body, given the crucial role hormones play in regulating numerous physiological processes.

Common Endocrine Disorders

1. Diabetes mellitus: A group of metabolic disorders characterized by high blood glucose levels, typically due to insufficient insulin production or insulin resistance.
2. Thyroid disorders: Conditions such as hypothyroidism (underactive thyroid) and hyperthyroidism (overactive thyroid) can affect metabolism, growth, and development.
3. Adrenal insufficiency: Also known as Addison’s disease, this condition occurs when the adrenal glands don’t produce enough cortisol and aldosterone.
4. Growth hormone deficiency: Can lead to short stature and other developmental issues in children.
5. Polycystic ovary syndrome (PCOS): A hormonal disorder in women that can cause irregular menstrual cycles, fertility issues, and metabolic problems.

Diagnosing and treating endocrine disorders often requires a multidisciplinary approach, involving endocrinologists, specialized tests, and tailored treatment plans.

The Future of Endocrinology: Emerging Research and Therapies

As our understanding of the endocrine system continues to evolve, new avenues for research and treatment are emerging. Some exciting areas of development include:

1. Precision Medicine

Advances in genomics and molecular biology are paving the way for more personalized approaches to diagnosing and treating endocrine disorders. By analyzing an individual’s genetic makeup and hormone profiles, doctors may be able to tailor treatments more effectively.

2. Artificial Endocrine Systems

Researchers are working on developing artificial endocrine systems, such as closed-loop insulin delivery systems for diabetes management. These systems aim to mimic the body’s natural hormone regulation more closely.

3. Endocrine Disruptors

There is growing interest in understanding the impact of environmental endocrine disruptors – chemicals that can interfere with hormone function. This research could lead to new public health initiatives and regulations.

4. Hormone Replacement Therapies

Ongoing research is focused on developing more effective and safer hormone replacement therapies for conditions such as menopause, andropause, and various endocrine deficiencies.

5. Neuroendocrinology

The field of neuroendocrinology, which explores the interactions between the nervous and endocrine systems, is advancing rapidly. This research could lead to new treatments for disorders that involve both systems, such as stress-related conditions.

As we continue to unravel the complexities of the endocrine system, we can expect to see significant advancements in our ability to diagnose, treat, and prevent endocrine disorders. This progress will undoubtedly contribute to improved health outcomes and quality of life for millions of people worldwide.

Human endocrine system | Description, Function, Glands, & Hormones

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human endocrine system, group of ductless glands that regulate body processes by secreting chemical substances called hormones. Hormones act on nearby tissues or are carried in the bloodstream to act on specific target organs and distant tissues. Diseases of the endocrine system can result from the oversecretion or undersecretion of hormones or from the inability of target organs or tissues to respond to hormones effectively.

Follow hormones of the endocrine system from glands to their chemical receptors on or in a cell

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It is important to distinguish between an endocrine gland, which discharges hormones into the bloodstream, and an exocrine gland, which secretes substances through a duct opening in a gland onto an external or internal body surface. Salivary glands and sweat glands are examples of exocrine glands. Both saliva, secreted by the salivary glands, and sweat, secreted by the sweat glands, act on local tissues near the duct openings. In contrast, the hormones secreted by endocrine glands are carried by the circulation to exert their actions on tissues remote from the site of their secretion.

As far back as 3000 bce, the ancient Chinese were able to diagnose and provide effective treatments for some endocrinologic disorders. For example, seaweed, which is rich in iodine, was prescribed for the treatment of goitre (enlargement of the thyroid gland). Perhaps the earliest demonstration of direct endocrinologic intervention in humans was the castration of men who could then be relied upon, more or less, to safeguard the chastity of women living in harems. During the Middle Ages and later, the practice persisting well into the 19th century, prepubertal boys were sometimes castrated to preserve the purity of their treble voices. Castration established the testes (testicles) as the source of substances responsible for the development and maintenance of “maleness.”

This knowledge led to an abiding interest in restoring or enhancing male sexual powers. In the 18th century, London-based Scottish surgeon, anatomist, and physiologist John Hunter successfully transplanted the testis of a rooster into the abdomen of a hen. The transplanted organ developed a blood supply in the hen, though whether masculinization occurred was unclear. In 1849 German physiologist Arnold Adolph Berthold performed a similar experiment, except, instead of hens, he transplanted rooster testes into capons (castrated roosters). The capons subsequently regained secondary sex characteristics, demonstrating that the testes were the source of a masculinizing substance. Also in the 19th century, French neurologist and physiologist Charles-Édouard Brown-Séquard asserted that the testes contained an invigorating, rejuvenating substance. His conclusions were based in part on observations obtained after he had injected himself with an extract of the testicle of a dog or of a guinea pig. These experiments resulted in the widespread use of organ extracts to treat endocrine conditions (organotherapy).

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Facts You Should Know: The Human Body Quiz

Modern endocrinology largely originated in the 20th century, however. Its scientific origin is rooted in the studies of French physiologist Claude Bernard (1813–78), who made the key observation that complex organisms such as humans go to great lengths to preserve the constancy of what he called the “milieu intérieur” (internal environment). Later, American physiologist Walter Bradford Cannon (1871–1945) used the term homeostasis to describe this inner constancy.

The endocrine system, in association with the nervous system and the immune system, regulates the body’s internal activities and the body’s interactions with the external environment to preserve the internal environment. This control system permits the prime functions of living organisms—growth, development, and reproduction—to proceed in an orderly, stable fashion; it is exquisitely self-regulating, so that any disruption of the normal internal environment by internal or external events is resisted by powerful countermeasures. When this resistance is overcome, illness ensues.

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Observations against the recent discovery of a new pair of salivary glands in humans

by Chiman Kumari, Ravi K. Narayan and Ashutosh Kumar , Medical Xpress

The tubal glands shown at the nasopharyngeal end of the auditory tube were claimed to be a new salivary gland by a recent study by Valstar et al. Credit: Kumari et al., 2022, Journal of Anatomy.

Human anatomy has been studied for centuries, and its intricacies are still not entirely understood. Discoveries, particularly microstructural details, keep adding to the known anatomy of the human body. However, discovery of a new body part or human organ raises eyebrows and invites scrutiny from the scholarly community considering the rarity of the situation.

Recently, the health science community was rocked by the claim of the discovery of a new human organ, a pair of salivary glands in the head and neck. These glands are located at the nasopharyngeal end of the auditory tube in the throat. The auditory tube connects the nasopharynx with the middle ear cavity and works as a decompression valve, balancing sound wave effects and evacuating mucosal secretions, thus facilitating optimum hearing. This tube is in continuity with the respiratory tract, a passage carrying air from the nose to the lung via the throat. The classic anatomy textbooks described the auditory tube as a component of the respiratory tract.

Further, similar to the respiratory tract, there are seromucous glands beneath the luminal mucosa of the auditory tube. These glands are more condensed at the nasopharyngeal end of the tube. The secretions from these glands help flush the middle ear secretions to the throat. (1)

A group of cancer scientists from the Netherlands, under the leadership of Matthijs H. Valstar, claimed that the seromucous collections at the nasopharyngeal end of the auditory tube, as a new pair of salivary glands, may have a significant role in radiotherapy-induced xerostomias and consequent dysphagia in patients with head and neck cancers following radiotherapy treatment. (2)

Valstar and colleagues mainly used PET/CT, a combination of positron emission tomography (PET) and computed tomography (CT), using a radioactive tracer that binds to a prostate-specific membrane antigen (PSMA). Although PSMA PET/CT is commonly used for diagnosing prostate cancer, it can easily detect the presence of seromucous glands in other tissues. The authors published their findings in Radiotherapy and Oncology. The claim of discovering a new human organ and a previously unknown body part received extensive media coverage and appraisal around the globe.

The general public viewed the claimed discovery as an outstanding achievement and remarkable addition to human anatomy knowledge. Still, scholars around the globe, more specifically anatomists, questioned the claim of discovering a body part that is already structurally and functionally known. The declaration that the structures are salivary glands was also striking, as the earlier known salivary glands are present along the mouth cavity, and their secretions effectively contribute to digestive functions. In contrast, the anatomists opined that the auditory tube glands are located very high up in the throat, toward the rear end of the nasal cavity, and fall along the respiratory passage. (4)

We were pioneers among the anatomists who voiced objections against the claims of Valstar et al. (4) Our fundamental objections were that structure and function of the glandular conglomerates are not entirely unknown as were claimed in defending a discovery. The existing literature considers them part of the respiratory tract and an integral component of the auditory tube. (1, 4-5) For classification as salivary, we considered it essential that the glands be located along the digestive tract and contribute significantly to the saliva and thus to the digestive functions. Further, these glandular conglomerates don’t present as an isolated mass and don’t have the independent blood supply, innervation or lymphatic drainage that characterize an organ.

Although Valstar et al issued a reply to the set of letters to editors sent to the original journal against their radical claims, it couldn’t sufficiently dispel our apprehensions. They clarified in the reply that they never claimed to have discovered an organ, but proposed “a potential new organ at risk of radiotherapy,” and the global media misinterpreted this. We might have no objection to accepting this clarification. However, their manuscript at large argued for considering the tubal gland conglomerates as a new organ. Notably, they issued no rectifications against the media reports, which had already spread the claim of discovering a new human organ far enough to be accepted as truth.

Interestingly, Valstar et al still insisted that they had discovered a new pair of salivary glands. They presented further evidence supporting their claim that injecting cyanine dye around the auditory tube opening in living humans reached the palatopharyngeal arch, thus the oropharynx (a part of the digestive tract).

As experts in anatomy, we were not convinced by the evidence presented by Valstar et al in the original paper nor their reply to the letters. (2-3) The tubal glands have been known for centuries through classic texts. (1, 4-5) Moreover, the early anatomical studies presented a detailed histological characterization of these glands, although they lacked immunohistological validation as these techniques were not yet established.

Interestingly, another group of anatomists from India, under the leadership of N.B. Pushpa, corroborated the claim of Valstar et al, showing myoepithelial cells in the acini of tubal glands via an immunohistochemical marker. Notably, pathology laboratories often use myoepithelial cells to identify salivary gland lesions. Although this new evidence appeared convincing, it was again not sufficient to prove the tubal glands as salivary, as myoepithelial cells are not exclusive to salivary glands; their presence is well known in the breast and sweat glands. Moreover, any clear evidence that tubal glands secreted saliva was still lacking.

The contesting views and differences of opinions, including among the anatomists, necessitated that we examine the tubal glands in greater detail using the updated histological methods. We performed gross dissections of human cadavers and microscopic analyses of the obtained tissue samples using routine and special staining methods and immunohistochemical markers for myoepithelial cells and salivary amylase. Of note, amylase is a crucial enzyme in salivary secretions.

We used the control tissue samples from the known salivary glands (submandibular for major and soft palate glands for minor) and the respiratory tract (trachea) to make valid comparisons. We also performed a biochemical analysis of the salivary amylase in the tubal glandular secretions received through nasopharyngeal swab sampling from the living human volunteers.

The collective findings strongly indicate that these glands are taxonomically very different from the salivary glands: summarily, the anatomical location of the tubal glands along the respiratory tract, the presence of respiratory epithelium in the overlying mucosa, their continuity with the seromucous glands within the auditory tube, the morphological and functional similarity to the seromucous glands in the respiratory tract, and the absence of salivary amylase.

We showed that myoepithelial cells are not unique to the salivary glands but are also present in the seromucous acini of the submucosal glands in the respiratory tract; hence, their presence in tubal glands does not disqualify them from their existing taxonomic recognition. Due to a lack of capsular covering, lobular organization, ductal complexity and the conspicuous absence of salivary amylase, the tubal glands are located far from the major salivary glands.

Although the minor salivary glands bore some similarities with the tubal gland conglomerates, being predominantly mucous and lacking salivary amylase, these glands are dispersed, are present along the mouth cavity, and their collective secretion contributes significantly to the mucous content of the saliva. Of note, the mucous content of the saliva has the specific purpose of creating a slippery surface that facilitates the smooth passage of the food bolus along the digestive tract. Moreover, the minor salivary glands are not exclusively mucous but vary widely in their seromucous proportions. Exceptionally, certain minor salivary glands are serous and secrete salivary amylase, such as the von Ebner’s glands, which are present in the parenchyma of the back of the tongue.

The high anatomical location of the tubal glands in the nasopharynx makes it very unlikely that their mucous content will reach the mouth cavity and make any significant contribution to the total saliva. Valstar et al later presented supportive evidence that dye injected around the opening of the auditory tube trickled to the oropharynx could be due to the mucosal surface tension and pull of gravity, and can’t be taken as the vital operational mechanisms explaining the physiological functions of a gland.

As we categorically established that the overall evidence presented by Valstar et al (2-3) and Pushpa et al (6) was insufficiently robust to prove that tubal glands conglomerates are salivary, we suggested maintaining their existing taxonomic recognition as part of the respiratory tract and an integral component of the auditory tube. Moreover, we also expressed reservations regarding the clinical importance of the tubal glands proposed by Valstar et al (2), considering secretions of these glands are predominantly mucous.

In our view, their assumed association with physician-rated, post-treatment xerostomia and dysphagia may have other likely explanations, such as collateral damage to the other mucosal and submucosal glands in the surrounding area of the auditory tube opening in the nasopharynx. However, as our study was limited to investigating the morpho-functional details of the tubal gland conglomerates, we recommend further studies to get a clear view of the clinical importance of these glands in radiotherapy-induced xerostomia and dysphagia.

This story is part of Science X Dialog, where researchers can report findings from their published research articles. Visit this page for information about ScienceX Dialog and how to participate.

More information:

1. Chiman Kumari et al, Morpho‐functional characterization of the submucosal glands at the nasopharyngeal end of the auditory tube in humans, Journal of Anatomy (2022). DOI: 10.1111/joa.13816
2. Matthijs H. Valstar et al, The tubarial salivary glands: A potential new organ at risk for radiotherapy, Radiotherapy and Oncology (2020). DOI: 10.1016/j.radonc.2020.09.034
3. Matthijs H. Valstar et al, The tubarial glands paper: A starting point. A reply to comments. Radiotherapy and Oncology (2021). doi.org/10.1016/J. RADONC.2020.12.001
4. Ravi K. Narayan et al, A macroscopic salivary gland and a potential organ or simply tubarial sero-mucinous glands?, Radiotherapy and Oncology (2020). DOI: 10.1016/j.radonc.2020.12.016
5. José J.C. Nascimento et al, Letter to the Editor regarding ‘The tubarial salivary glands: A potential new organ at risk for radiotherapy’, Radiotherapy and Oncology (2020). DOI: 10.1016/j.radonc.2020.12.014
6. Pushpa N.B. et al, Discovery of new salivary gland—A substantial histological analysis, Radiotherapy and Oncology (2021). DOI: 10.1016/j.radonc.2021.06.004

Dr. Chiman Kumari and Dr. Ashutosh Kumar are associate professors in the Department of Anatomy, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India, and All India Institute of Medical Sciences (AIIMS)- Patna, Bihar, India. Dr. Ravi K. Narayan is an assistant professor in the Department of Anatomy, Dr. B.C. Roy Multi-Specialty Medical Research Centre, Indian Institute of Technology, Kharagpur, India.

Citation:
Observations against the recent discovery of a new pair of salivary glands in humans (2023, January 5)
retrieved 8 June 2023
from https://medicalxpress.com/news/2023-01-discovery-pair-salivary-glands-humans.html

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What human sweat consists of and how it is formed

It is as natural to sweat as it is to shed a tear when an eyelash is caught in the eye, or to react to a delicious dinner by secreting gastric juice. At the same time, many prejudices are associated with sweating. In the words “work hard” or work out in the gym “up to a sweat” is worthy of praise. In reality, wet stains on a T-shirt and a characteristic smell are perceived by others as a lack of hygiene. Let’s try to figure out how sweat is formed and is it possible to “tame” this physiological process?

Why would a person sweat?

Everyone sweats. Nature has rewarded each person with 2-4 million sweat glands – they are scattered over the entire surface of the body, with the exception of the mucous membranes. The eccrine glands “turn on” as early as 3-4 weeks after birth and work non-stop throughout life. Their main task is to prevent the body from overheating. In the heat, during sports or illness, the process of sweating is more active. Evaporating, moisture cools the surface of the skin and internal organs. Even at rest, we continue to produce 400-600 ml of sweat per day, but we do it unnoticed by ourselves and others.

Apocrine sweat glands come into play during puberty. They are concentrated in the armpits, groin, on the head. Their work largely depends on the level of hormones. Adolescents, as well as women during pregnancy and menopause, often complain of profuse sweating. In old age, this problem goes away by itself. Eccrine and apocrine sweat have a different chemical composition, their smell will also be different – but we will return to this.

We cannot tell the body to sweat less. The activity of the sweat glands is regulated by the autonomic nervous system – it is also responsible for hunger, thirst, and sleep. It transmits signals from internal organs and does not obey the will of a person. However, sweating depends on the level of stress. Before an important interview, date, or public speaking, the body produces more norepinephrine and acetylcholine, neurotransmitters that make the palms treacherously wet.

Sweat acts as a natural conditioner, but its functions don’t stop there:

• Sweat protects the skin from drying out. Together with the secret of the sebaceous glands, it forms a hydrolipidic film on the surface of the epidermis: it seals valuable moisture and does not allow bacteria to enter;
• With sweat, the body removes part of the metabolic products and toxins. Therefore, with certain systemic diseases, medication or alcohol abuse, the smell of sweat becomes more pronounced.

What is sweat made of?

Sweat is 98% water. At the same time, the remaining 2% account for about 250 chemical compounds. In the composition of human sweat, scientists have found urea, uric acid, ammonia and creatinine – nitrogenous substances that are formed during the breakdown of proteins. It also contains histamine, steroid hormones, cholesterol, glucose, amino acids, serine and histidine, volatile fatty acid compounds.

Human sweat contains half of the periodic table: sodium, potassium, magnesium, calcium, chlorine, phosphorus, iodine and even vitamins. They are important for maintaining acid-base balance, fluid levels in cells and intercellular space, as well as for the transmission of impulses along nerve fibers. Therefore, with profuse sweating – in the heat, during physical exertion or illness – it is important not only to drink more liquid, but also to replenish the supply of minerals.

Where does the smell come from?

The intensity of the smell depends on where and how sweat is formed in a person. Try to conduct an experiment and “look closely” at sweaty palms: the liquid secreted by the eccrine glands is completely transparent and does not smell of anything. But the apocrine secret can no longer boast of this. Underarm sweat is more viscous. During its production, secretory cells are destroyed, and their particles are removed along with the liquid to the surface of the skin.

It is hard to imagine a more appetizing food for bacteria. Increased humidity and heat do their bit – microorganisms feel like in a resort, actively multiply and cause a characteristic amber. Usually, a persistent smell appears within a couple of hours – only a shower and a change of T-shirt will help get rid of it. But the good news is that bacterial activity is easy to prevent.

Rexona Antiperspirants – No. 1 in sweat protection*

Deodorants and antiperspirants come to the rescue. The former prevent the growth of “odorous” microflora due to antibacterial components: natural oils, alcohol, triclosan. Deodorants also create an invisible film on the skin with a pH unsuitable for bacterial growth, and at the same time allow you to choose a pleasant perfume composition.

Rexona antiperspirant deodorants have a wider effect. Aluminum salts in their composition penetrate into the terminal ducts of the sweat glands: temporarily reduce their activity, narrowing the sweat ducts, but without disturbing the natural process of thermoregulation. Even in the summer heat or after a strenuous workout, the skin remains dry up to 96 hours**, and bacteria lose any chance to reproduce. Motionsense’s micro-capsules expand with every movement for added odor protection – the more active your day goes, the more effective your deodorant will be. It is up to you to decide what your skin will smell like: citrus and eucalyptus, grapefruit and apple, strawberry and apricot, or pristine purity.

* Explanation of product information on website
**Hot room tests Unilever R&D, United Kingdom, 2018

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Diseases of the thyroid gland – KDLmed

Diseases of the thyroid gland are an important branch of endocrinology – a science that deals with the problems of the endocrine glands. The role of the thyroid gland in the body cannot be overestimated. The hormones it produces affect almost all spheres of life: energy metabolism, the state of the nervous system, the development of the musculoskeletal system. Hormonal disorders that occur in diseases of the thyroid gland are quite widespread. In the early stages, they may not cause serious health problems and are mistaken for the effects of overwork or stress. In more severe cases, both too little and too much thyroid hormone can cause life-threatening conditions.

Despite the fact that the laboratory diagnosis of impaired thyroid function is not difficult, the symptoms of its diseases are diverse and can be masked as a large number of pathologies of other organs. This is one of the main reasons for the late treatment of patients for medical care.

Symptoms

Symptoms of thyroid diseases largely depend on whether they are accompanied by insufficient or excessive hormonal levels. A separate group of symptoms are signs associated with an increase in the size of the gland and compression of neighboring organs.

The main symptoms of an underactive thyroid (hypothyroidism) include:

• Lethargy indifference
• Muscle weakness
• Pain in muscles and joints
• Pale, dry skin
• Edema
• Brittle nails and hair
• Unexplained weight gain
• Hypersensitivity to cold, chilliness.

Excess hormonal function (hyperthyroidism) may present:

• Rapid causeless weight loss
• Rapid heartbeat (tachycardia)
• Heart rhythm disorders (arrhythmia)
• Irritability and nervousness
• Increased appetite
• Frequent chair
• Excessive sweating
• Hand trembling
• Poor heat tolerance
• Insomnia
• Fatigue, muscle weakness

An enlarged thyroid gland may cause:

• Thickening neck deformity
• Dyspnea on tilting head back
• Hoarseness of voice
• Swallowing disorders
• Soreness on pressure.

Who is at risk?

An increased risk of thyroid disease is found in areas with high background radiation, as well as in areas where there is an iodine deficiency. There is also a hereditary predisposition.

Other general risk factors include

• Age over 50 years.
• Female
• Previous thyroid surgery
• Previous autoimmune diseases
• Diseases of the thyroid gland in close relatives.
• Constant contact with iodine, especially radioactive.
• Pregnancy and the puerperium
• Smoking
• Taking certain medications (lithium, cordarone), especially those that affect the immune system (immunosuppressants, antivirals)
• Excessive consumption of soy products, raw cabbage, turnips, radishes
• Stress and psycho-emotional overstrain.

General information

The thyroid gland is one of the largest and most superficial of the hormonal (endocrine) glands in the human body. It is located on the front of the neck and is protected only by skin, a thin layer of fat, and several layers of connective tissue. In shape, this gland is usually compared with a butterfly, since it has two lobes covering the anterior wall of the trachea and connected by a thin isthmus.

The thyroid gland produces three hormonally active substances that are involved in the regulation of almost all metabolic processes in the body:

• triiodothyronine (T3)
• thyroxine (tetraiodothyronine or T4)
• calcitonin.

Calcitonin is a hormone involved in calcium and phosphorus metabolism. Its role in the body is relatively small.

Triiodothyronine and thyroxine are of the greatest importance in regulating metabolic processes, maintaining body temperature, ensuring the development and growth of the body. The normal production of these hormones depends on the amount of iodine entering the body, which selectively accumulates in the thyroid gland and is included in their composition. That is why the most widespread diseases of the thyroid gland have received in those areas where there is its natural deficiency.

The thyroid gland regulates many processes, including growth and heart rate, is involved in the metabolism of fats and carbohydrates, thereby affecting body weight and maintaining a constant temperature. A deficiency or excess of thyroid hormones can significantly change a person’s appearance, behavior and emotional background.

The regulation of the thyroid gland is carried out by the pituitary gland, which controls almost all endocrine glands. It is a central endocrine gland located at the base of the brain. The pituitary gland produces thyroid-stimulating hormone (TSH), which stimulates the release of thyroid hormones into the blood. In practice, the following scheme works: a low level of thyroxin activates the production of thyroid-stimulating hormone from the pituitary gland, and that, in turn, causes increased production of thyroid hormones. With an excess of thyroxine and triiodothyronine in the blood, TSH production decreases, and the activity of the thyroid gland decreases. Due to this mechanism, a constant level of thyroid hormones in the blood is maintained. With damage to the pituitary gland, the formation of thyroid-stimulating hormone may be impaired. In these cases, it is customary to talk about secondary disorders of thyroid function.

Depending on the level of hormones, all diseases of the thyroid gland can be divided into three main groups:

• Euthyroid conditions in which the level of hormones remains within the normal range.
• Hyperthyroidism – the level of thyroid hormones is increased. With a significant increase in them, the term thyrotoxicosis is used.
• Hypothyroidism – diseases accompanied by low levels of thyroid hormones.

Impaired production of calcitonin has no independent significance and is usually considered as one of the markers of a malignant tumor of the thyroid gland.