Organs Adrenal Cross Section
Estrogens are present in significant amounts in both men and women. They are present in significantly higher amounts in women after menarche (onset of menstrual periods at puberty) until menopause (cessation of menstrual periods after completion of reproductive age). The primary function of estrogens is development of female secondary sexual characteristics. These includes breasts, endometrium, regulation of the menstrual cycle etc. In males estrogen helps in maturation of the sperm and maintenance of a healthy libido. Estrogen is responsible for development of the female body and the secondary sexual characters. It helps decelerate height increase in females during puberty, accelerates burning of body fat and reduces muscle bulk. It also stimulates growth of the inner lining of the uterus (endometrium) during the menstrual cycle, increases uterine growth, improves lubrication of the vagina, and thickens the vaginal wall while increasing blood vessels to the skin. Estrogens increase cortisol and Sex hormone binding globulin. Estrogens increase melanin and pheomelanin and reduce eumelanin. Estrogen helps in causing physical differentiation of the fetus to either males or females as per their genetic code. While androgens like testosterone lead to masculinizing the fetus, estrogen feminizes the fetus. Prenatal androgens act on behavior and other tissues, with the possible exception of effects on bone via androgen receptors. Estradiol has been found to be responsible for initiating spermatogenesis or formation and maturation of sperms in men. It helps in bone strength, sexual maturation and cholesterol metabolism. https://www.news-medical.net/health/What-Does-Estrogen-Do.aspx ;
Testosterone is the key male sex hormone that regulates fertility, muscle mass, fat distribution, and red blood cell production. Testosterone is the hormone responsible for the development of male sexual characteristics. Hormones are chemical messengers that trigger necessary changes in the body. Females also produce testosterone, but usually in smaller amounts. In men, testosterone is thought to regulate a number of functions alongside sperm production like sex drive, bone mass, fat distribution, muscle size and strength, red blood cell production. Without adequate amounts of testosterone, men become infertile. This is because testosterone assists the development of mature sperm. Testosterone levels are controlled by the brain and pituitary gland. Once produced, the hormone moves through the blood to carry out its various important functions. When a man has low testosterone, or hypogonadism, he may experience reduced sex drive, erectile dysfunction, low sperm count, enlarged or swollen breast tissue Over time, these symptoms may develop in loss of body hair, loss of muscle bulk, loss of strength, increased body fat. Chronic, or ongoing, low testosterone may lead to osteoporosis, mood swings, reduced energy, and testicular shrinkage. Too much testosterone, on the other hand, can lead to the triggering of puberty before the age of 9 years. This condition would mainly affect younger men and is much rarer. In women, however, high testosterone levels can lead to male pattern baldness, a deep voice, and menstrual irregularities, as well as growth and swelling of the clitoris, changes in body shape, reduction in breast size, facial hair growth around the body, lips, and chin. Source
Stress on the body has profound effects on all of our systems. When we are under stress, our bodies responds by releasing a hormone called cortisol. Cortisol is made by our adrenal glands — two small glands that sit on top of your kidneys (the adrenal cortex of the adrenal gland). Along with helping us respond to stress, it also plays a key role in other functions, including how your body breaks down carbohydrates, lipids, and proteins. Cortisol belongs to a group of hormones called glucocorticoids. As a group, these hormones are involved in the regulation of metabolism in the cells, and they also help us regulate various stressors on the body. Cortisol, also known as hydrocortisone, cortisone and corticosterone are all glucocorticoids. Cortisol is a steroid-based hormone and is synthesized from cholesterol. Cortisol, like all steroid-based hormones, is a powerful chemical. Steroid-based hormones have a common mechanism of action in that they enter cells and modify the gene activity in the DNA. The amount of cortisol in our bodies is driven by our eating patterns and how much physical activity we get. As a general rule, our highest level of cortisol occurs just after you get up in the morning and the lowest level is in the evening as we are falling asleep. Cortisol’s main function is to provoke the cell to manufacture glucose from proteins and fatty acids. This process is known as gluconeogenesis. What cortisol is doing is saving glucose for the brain and forcing the body to use fatty acids from stored fat as energy. Cortisol also forces the breakdown of stored proteins into amino acids so that the body can use them for making enzymes or repairing cells. Cortisol increases blood pressure, which increases blood flow and distributes the glucose and other nutrients as quickly as possible to the cells. Finally, cortisol helps the body resist stress and reduces the inflammatory response as well as overall immune response in the body. When too much cortisol is made by the body itself, it is called Cushing’s syndrome, regardless of the cause. Some patients have Cushing’s syndrome because the adrenal glands have a tumor(s) making too much cortisol. Other patients have Cushing’s syndrome because they make too much of the hormone ACTH (adrenocorticotropic hormone), which causes the adrenal glands to make cortisol. When the ACTH comes from the pituitary gland it is called Cushing’s disease. Cushing’s syndrome is fairly rare. It is more often found in women than in men and often occurs between the ages of 20 and 40. Cortisol deficiency occurs when the adrenal glands do not produce enough cortisol. This can happen for four main reasons, like when the pituitary gland is unable to produce the chemicals needed to tell the adrenal glands to ‘switch on’ their cortisol production. The pituitary gland is the ‘master gland’ which controls other glands in the body. When there is a defect in the adrenal glands, so they do not allow cortisol to be produced, If the adrenal gland itself fails or is removed, or If adrenal glands stop producing cortisol because there are additional steroids in the body. The replacement steroid medicines should be withdrawn slowly to give the adrenal glands a chance to ‘wake up’ and start producing cortisol again. Also, if you become deficient in cortisol you can possible find yourself with Addison’s disease. Addison’s disease is caused by damage to the adrenal cortex. This condition can lead to the hyposecretion of cortisol. Not enough cortisol affects the function of many systems in the body. Persons affected by Addison’s disease have low glucose and sodium levels in their blood and increased potassium. They also tend to lose weight. Addison’s disease can also cause low blood pressure and dehydration. Cortisol deficiency is usually treated by corticosteroid replacement therapy to return cortisol to normal levels in the body. Source
This also known as 17α,21-dihydroxypregn-4-ene-3,11,20-trione, is a pregnane (21-carbon) steroid hormone. It is one of the main hormones released by the adrenal gland in response to stress. Cortisone, a glucocorticoid, and adrenaline are the main hormones released by the body as a reaction to stress. They elevate blood pressure and prepare the body for a fight or flight response.
Somatostatin is a hormone that inhibits the secretion of several other hormones, including growth hormone, thyroid stimulating hormone, cholecystokinin and insulin. Somatostatin is a hormone produced by many tissues in the body, principally in the nervous and digestive systems. It regulates a wide variety of physiological functions and inhibits the secretion of other hormones, the activity of the gastrointestinal tract and the rapid reproduction of normal and tumour cells. Somatostatin may also act as a neurotransmitter in the nervous system. somatostatin is produced in the pancreas and inhibits the secretion of other pancreatic hormones such as insulin and glucagon. Somatostatin is also produced in the gastrointestinal tract where it acts locally to reduce gastric secretion, gastrointestinal motility and to inhibit the secretion of gastrointestinal hormones, including gastrin and secretin. In the same way that somatostatin controls the production of several hormones, these hormones feedback to control the production of somatostatin. This is increased by raised levels of these other hormones and reduced by low levels. Excessive somatostatin levels in the bloodstream may be caused by a rare endocrine tumour that produces somatostatin, called a ‘somatostatinoma’. Too much somatostatin results in extreme reduction in secretion of many endocrine hormones. An example of this is suppression of insulin secretion from the pancreas leading to raised blood glucose levels (diabetes). As somatostatin inhibits many functions of the gastrointestinal tract, its overproduction may also result in the formation of gallstones, intolerance to fat in the diet and diarrhoea. However, since somatostatin regulates many physiological processes, too little somatostatin production would lead to a variety of problems, including too much secretion of growth hormone. However, there are very few reports of somatostatin deficiency. Source
This is an undecapeptide (a peptide composed of a chain of 11 amino acid residues) member of the tachykinin neuropeptide family. It is a neuropeptide, acting as a neurotransmitter and as a neuromodulator. Substance P and its closely related neurokinin A (NKA) are produced from a polyprotein precursor after differential splicing of the preprotachykinin A gene. Substance P is released from the terminals of specific sensory nerves. It is found in the brain and spinal cord and is associated with inflammatory processes and pain.
Most individuals have never heard about this particular hormone, yet it plays an important role in cardiovascular health. Aldosterone is produced in the cortex of the adrenal glands, which are located above the kidneys. Aldosterone affects the body’s ability to regulate blood pressure. It sends the signal to organs, like the kidney and colon, that can increase the amount of sodium the body sends into the bloodstream or the amount of potassium released in the urine. The hormone also causes the bloodstream to re-absorb water with the sodium to increase blood volume. All of these actions are integral to increasing and lowering blood vessels. Indirectly, the hormone also helps maintain the blood’s pH and electrolyte levels. Aldosterone is closely linked to two other hormones: renin and angiotensin, which create the renin-angiotensin-aldosterone system. This system is activated when the body experiences a decrease in blood flow to the kidneys, such as after a drop in blood pressure, or a significant drop in blood volume after a hemorrhage or serious injury. Renin is responsible for the production of angiotensin, which then causes the release of aldosterone. Once the body is rehydrated and has proper salt levels in the blood, renin levels fall, and aldosterone levels lower as a result. In a healthy individual, the renin-angiotensin-aldosterone system functions without interference, helping to regulate and control blood pressure levels naturally. However, individuals can have too-high or too-low amounts of aldosterone, and both of these can impact aldosterone function. Individuals with high levels of aldosterone have a condition known as hyperaldosteronism, and this is typically caused by small, benign tumors on the adrenal glands. Hyperaldosteronism can cause high blood pressure, low potassium levels and an abnormal increase in blood volume because of the way the hormone affects the body. It’s also possible to have low levels of aldosterone. Primary adrenal insufficiency, a disease that causes a general loss of adrenal function, can be a cause. Patients with primary adrenal insufficiency causing low levels of aldosterone may experience low blood pressure, increased potassium levels, and lethargy. Source
This is a steroid hormone, produced by the adrenal cortex, its involved in regulating the water in our bodies and for electrolyte balance. A corticosteroid, C21H30O4, that is secreted into the bloodstream by the adrenal cortex in response to stress and stimulates many metabolic pathways, such as the production of glucose. Corticosterone has multiple effects on memory. The main effects are seen through the impact of stress on emotional memories as well as long term memory (LTM). With emotional memories, corticosterone is largely associated with fear memory recognition. Studies have shown that when fear memories are reactivated or consolidated, levels of corticosterone increased. The increase in corticosterone is linked to anxiety relief. Source
Epinephrine, also called adrenaline, hormone that is secreted mainly by the medulla of the adrenal glands and that functions primarily to increase cardiac output and to raise glucose levels in the blood. Epinephrine typically is released during acute stress, and its stimulatory effects fortify and prepare an individual for either “fight or flight”. Epinephrine is produced specifically in the adrenal medulla, where the amino acid tyrosine is transformed through a series of reactions to norepinephrine. An enzyme known as phenylethanolamine N-methyltransferase, which is found in the chromaffin cells of the adrenal medulla, catalyzes the methylation of norepinephrine to epinephrine. In addition to the release of epinephrine from the adrenal glands, small amounts of the hormone are also released from the ends of sympathetic nerves. The actions of epinephrine are complex, owing to its stimulatory effects on α- and β-adrenergic receptors (or adrenoceptors, so named for their reaction to the adrenal hormones), which produce various responses, depending on the specific receptor and the tissue in which it occurs. Hence, epinephrine causes constriction in many networks of minute blood vessels but dilates the blood vessels in the skeletal muscles and the liver. In the heart, it increases the rate and force of contraction, thus increasing the output of blood and raising blood pressure. In the liver, epinephrine stimulates the breakdown of glycogen to glucose, resulting in an increase in glucose levels in the blood. It also acts to increase the level of circulating free fatty acids. The extra amounts of glucose and fatty acids can be used by the body as fuel in times of stress or danger, when increased alertness and exertion are required. Epinephrine may be injected into the heart during cardiac arrest to stimulate heart activity. Epinephrine is also used to treat anaphylaxis (acute systemic allergic reaction), which can occur in response to exposure to certain drugs, insect venoms, and foods. Source
Norepinephrine, also called noradrenaline, substance that is released predominantly from the ends of sympathetic nerve fibres and that acts to increase the force of skeletal muscle contraction and the rate and force of contraction of the heart. The actions of norepinephrine are vital to the fight-or-flight response, whereby the body prepares to react to or retreat from an acute threat. Norepinephrine, similar to other catecholamines, is generated from the amino acid tyrosine. Norepinephrine exerts its effects by binding to α- and β-adrenergic receptors in different tissues. In the blood vessels, it triggers vasoconstriction (narrowing of blood vessels), which increases blood pressure. Blood pressure is further raised by norepinephrine as a result of its effects on the heart muscle, which increase the output of blood from the heart. Norepinephrine also acts to increase blood glucose levels and levels of circulating free fatty acids. The substance has also been shown to modulate the function of certain types of immune cells. Norepinephrine activity is efficiently terminated through inactivation by the enzymes catechol-O-methyltransferase (COMT) or monoamine oxidase (MAO), by reuptake into nerve endings, or by diffusion from binding sites. Norepinephrine that diffuses away from local nerve endings can act on adrenergic receptors at distant sites. Norepinephrine is used clinically as a means of maintaining blood pressure in certain types of shock. Source
Facet joint capsules are the fibrous capsule that surround the vertebral facet or zygapophyseal joints. They are particularly thin and loose, attached to the margins of articular facets on adjoining articular processes. The capsules merge medially with the ligamentum flavum. In the cervical region, capsules are longer and looser than the remaining spine, allowing for more range of movement. Source
The outermost of the three layers of the adrenal cortex that consists of round masses of granular epithelial cells that stain deeply, the nuclei stain strongly, and the cytoplasm is less pale than that of the next zone (the zona fasciculata) as there are fewer lipid droplets in these cells. Zona glomerulosa, The outermost zone of the adrenal cortex secretes mineralcorticoids. These hormones are important for fluid homeostasis. These cells produce aldosterone that is important for sodium and water reabsorption and regulates the absorption/uptake of k+ and Na+ Levels (sodium & Potassium) in the kidney. The cells of the zona glomerulosa have distinct round nuclei and a higher nuclear to cytoplasmic ratio than the cells of the adjacent zona fasciculata. The zona glomerulosa is located just beneath the capsule of the adrenal gland and contains cells arranged in clusters separated by trabeculae that are continuous with the capsule. Source
The blood vessels are the part of the circulatory system, and microcirculation, that transports blood throughout the human body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and the tissues, and the veins, which carry blood from the capillaries back toward the heart.
The inner portion of adrenal gland. (The outer portion is the adrenal cortex). The adrenal medulla makes epinephrine (adrenaline) and norepinephrine (noradrenaline). Epinephrine is secreted in response to low blood levels of glucose as well as exercise and stress. it causes the breakdown of the storage product glycogen to the sugar glucose in the liver, facilitates the release of fatty acids from adipose (fat) tissue, causes dilation (widening) of the small arteries within muscle and increases the output of the heart. Norepinephrine secreted by the adrenal gland acts to narrow blood vessels and raise blood pressure. Source
Zona fasciculata, the middle zone of the adrenal cortex secretes glucocorticoids which are important for carbohydrate, protein and lipid metabolism. It is the thickest of the three Zonas, measuring approximately 0.9mm and making up 50% of the mass of the Adrenal Gland.
Its secretion is controlled by a hormone from the pituitary – ACTH. The secretory cells are arranged in cords, often one cell thick, surrounded by fine strands of supporting tissue. The Zona Fasciculata is made up of parenchymal cells known as spongiocytes, arranged into columns (sometimes called fascicles) with venous sinuses in between. Blood flows into the adrenal gland from branches of the phrenic and renal arteries as well as the aorta. From here blood flows through the adrenal tissue from superficial to deep, draining into sinusoids in the adrenal medulla and eventually into a central adrenal vein. The cells of the Zona Fasciculata secrete the glucocorticoids Cortisol and Corticosterone. These hormones regulate carbohydrate metabolism, particularly when an individual is in a time of stress (as part of the “fight-or-flight” response). In an adult human, approximately 10mg of Cortisol and 3mg of Corticosterone are secreted over a 24-hour period. Source .
Zona reticularis, the innermost layer of the cortex, lying just above the adrenal medulla. It secretes sex hormones (androgens). and small amounts of glucocorticoids. These hormones are secreted by the inner zone of the cortex, which is called the zona reticularis. The zona reticularis is the site of biosynthesis of androgen precursors such as dehydroepiandrosterone (DHEA) and androstenedione from cholesterol. These androgens are released into the bloodstream and transported to gonads where they are converted into testosterone or oestrogen. These are largely responsible for the normal development of sexual characteristics during puberty. Further information on the effects of adrenal androgens during puberty can be found here. In postmenopausal women, the conversion of adrenal androgens to oestrogen is the only source of oestrogen synthesis and hence is a significant source. Source