Adrenal glands - RightDiagnosis.com Adrenal glands Article Excerpts about Adrenal glands Cortisol is normally produced by the adrenal glands, located just above the kidneys. It belongs to a class of hormones called glucocorticoids, which affect almost every organ and tissue in the body. Scientists think that cortisol has possibly hundreds of effects in the body. Cortisol's most important job is to help the body respond to stress. Among its other vital tasks, cortisol: helps maintain blood pressure and cardiovascular function; helps slow the immune system's inflammatory response; helps balance the effects of insulin in breaking down sugar for energy; and helps regulate the metabolism of proteins, carbohydrates, and fats. Because cortisol is so vital to health, the amount of cortisol produced by the adrenals is precisely balanced. Like many other hormones, cortisol is regulated by the brain's hypothalamus and the pituitary gland, a bean-sized organ at the base of the brain. (Source: excerpt from Addison's Disease: NIDDK ) Summary Information: Adrenal glands Adrenal glands: The adrenal glands are a pair of endocrine glands, one located on the top of each kidney.

The adrenal glands produce a variety of hormones, chemical substances that help to regulate a wide variety of the body's processes. The adrenal glands and the hormones they produce play a big role in such processes as metabolism, water and electrolyte balance, sexual development and function, the immune system, and the stress response. The adrenal glands include two regions, the adrenal cortex and the adrenal medulla, which each produce different hormones. Adrenal hormones include the catecholamines epinephrine and norepinephrine, and the adrenal steroid hormones: adrenal androgen hormones, mineralocorticoids, and glucocorticoids. Conditions that can afflict the adrenal glands include Addison's disease, Cushing's syndrome, pheochromocytoma, hyperaldosteronism, adrenal tumors, adrenal cancer, and trauma. Closely Related Organs: Adrenal glands The following organs are closely related to the organ: Adrenal glands: Endocrine System: Discover the Anatomy and Function of Glands Oxytocin Antidiuretic hormone (ADH) All of the releasing and inhibiting hormones affect the function of the anterior pituitary gland. TRH stimulates the anterior pituitary gland to release thyroid-stimulating hormone.

GHRH and GHIH work to regulate the release of growth hormone—GHRH stimulates growth hormone release, GHIH inhibits its release. GnRH stimulates the release of follicle stimulating hormone and luteinizing hormone while CRH stimulates the release of adrenocorticotropic hormone. The last two hormones—oxytocin and antidiuretic hormone—are produced by the hypothalamus and transported to the posterior pituitary, where they are stored and later released. Pituitary Gland The pituitary gland , also known as the hypophysis, is a small pea-sized lump of tissue connected to the inferior portion of the hypothalamus of the brain. Many blood vessels surround the pituitary gland to carry the hormones it releases throughout the body. Situated in a small depression in the sphenoid bone called the sella turcica, the pituitary gland is actually made of 2 completely separate structures: the posterior and anterior pituitary glands. Posterior Pituitary: The posterior pituitary gland is actually not glandular tissue at all, but nervous tissue instead.

The posterior pituitary is a small extension of the hypothalamus through which the axons of some of the neurosecretory cells of the hypothalamus extend. These neurosecretory cells create 2 hormones in the hypothalamus that are stored and released by the posterior pituitary: Oxytocin triggers uterine contractions during childbirth and the release of milk during breastfeeding. Antidiuretic hormone (ADH) prevents water loss in the body by increasing the re-uptake of water in the kidneys and reducing blood flow to sweat glands. Anterior Pituitary: The anterior pituitary gland is the true glandular part of the pituitary gland. The function of the anterior pituitary gland is controlled by the releasing and inhibiting hormones of the hypothalamus. The anterior pituitary produces 6 important hormones: Thyroid stimulating hormone (TSH), as its name suggests, is a tropic hormone responsible for the stimulation of the thyroid gland. Adrenocorticotropic hormone (ACTH) stimulates the adrenal cortex, the outer part of the adrenal gland, to produce its hormones.

Follicle stimulating hormone (FSH) stimulates the follicle cells of the gonads to produce gametes—ova in females and sperm in males. Luteinizing hormone (LH) stimulates the gonads to produce the sex hormones—estrogens in females and testosterone in males. Human growth hormone (HGH) affects many target cells throughout the body by stimulating their growth, repair, and reproduction. Prolactin (PRL) has many effects on the body, chief of which is that it stimulates the mammary glands of the breast to produce milk. Pineal Gland The pineal gland is a small pinecone-shaped mass of glandular tissue found just posterior to the thalamus of the brain. The pineal gland produces the hormone melatonin that helps to regulate the human sleep-wake cycle known as the circadian rhythm. The activity of the pineal gland is inhibited by stimulation from the photoreceptors of the retina. This light sensitivity causes melatonin to be produced only in low light or darkness. Increased melatonin production causes humans to feel drowsy at nighttime when the pineal gland is active.

Thyroid Gland The thyroid gland is a butterfly-shaped gland located at the base of the neck and wrapped around the lateral sides of the trachea. The thyroid gland produces 3 major hormones: Calcitonin Triiodothyronine (T3) Thyroxine (T4) Calcitonin is released when calcium ion levels in the blood rise above a certain set point. Calcitonin functions to reduce the concentration of calcium ions in the blood by aiding the absorption of calcium into the matrix of bones. The hormones T3 and T4 work together to regulate the body’s metabolic rate. Increased levels of T3 and T4 lead to increased cellular activity and energy usage in the body. Parathyroid Glands The parathyroid glands are 4 small masses of glandular tissue found on the posterior side of the thyroid gland. The parathyroid glands produce the hormone parathyroid hormone (PTH), which is involved in calcium ion homeostasis. PTH is released from the parathyroid glands when calcium ion levels in the blood drop below a set point. PTH stimulates the osteoclasts to break down the calcium containing bone matrix to release free calcium ions into the bloodstream.

PTH also triggers the kidneys to return calcium ions filtered out of the blood back to the bloodstream so that it is conserved. Adrenal Glands The adrenal glands are a pair of roughly triangular glands found immediately superior to the kidneys. The adrenal glands are each made of 2 distinct layers, each with their own unique functions: the outer adrenal cortex and inner adrenal medulla. Adrenal cortex: The adrenal cortex produces many cortical hormones in 3 classes: glucocorticoids, mineralocorticoids, and androgens. Glucocorticoids have many diverse functions, including the breakdown of proteins and lipids to produce glucose. Glucocorticoids also function to reduce inflammation and immune response. Mineralocorticoids, as their name suggests, are a group of hormones that help to regulate the concentration of mineral ions in the body. Androgens, such as testosterone, are produced at low levels in the adrenal cortex to regulate the growth and activity of cells that are receptive to male hormones. In adult males, the amount of androgens produced by the testes is many times greater than the amount produced by the adrenal cortex, leading to the appearance of male secondary sex characteristics.

Adrenal medulla: The adrenal medulla produces the hormones epinephrine and norepinephrine under stimulation by the sympathetic division of the autonomic nervous system. Both of these hormones help to increase the flow of blood to the brain and muscles to improve the “fight-or-flight” response to stress. These hormones also work to increase heart rate, breathing rate, and blood pressure while decreasing the flow of blood to and function of organs that are not involved in responding to emergencies. Pancreas The pancreas is a large gland located in the abdominal cavity just inferior and posterior to the stomach . The pancreas is considered to be a heterocrine gland as it contains both endocrine and exocrine tissue. The endocrine cells of the pancreas make up just about 1% of the total mass of the pancreas and are found in small groups throughout the pancreas called islets of Langerhans. Within these islets are 2 types of cells—alpha and beta cells. The alpha cells produce the hormone glucagon, which is responsible for raising blood glucose levels. Glucagon triggers muscle and liver cells to break down the polysaccharide glycogen to release glucose into the bloodstream.

The beta cells produce the hormone insulin, which is responsible for lowering blood glucose levels after a meal. Insulin triggers the absorption of glucose from the blood into cells, where it is added to glycogen molecules for storage. Gonads The gonads—ovaries in females and testes in males—are responsible for producing the sex hormones of the body. These sex hormones determine the secondary sex characteristics of adult females and adult males. Testes: The testes are a pair of ellipsoid organs found in the scrotum of males that produce the androgen testosterone in males after the start of puberty. Testosterone has effects on many parts of the body, including the muscles, bones, sex organs, and hair follicles. This hormone causes growth and increases in strength of the bones and muscles, including the accelerated growth of long bones during adolescence. During puberty, testosterone controls the growth and development of the sex organs and body hair of males, including pubic, chest, and facial hair. In men who have inherited genes for baldness testosterone triggers the onset of androgenic alopecia, commonly known as male pattern baldness. Ovaries: The ovaries are a pair of almond-shaped glands located in the pelvic body cavity lateral and superior to the uterus in females.

The ovaries produce the female sex hormones progesterone and estrogens. Progesterone is most active in females during ovulation and pregnancy where it maintains appropriate conditions in the human body to support a developing fetus. Estrogens are a group of related hormones that function as the primary female sex hormones. The release of estrogen during puberty triggers the development of female secondary sex characteristics such as uterine development, breast development, and the growth of pubic hair. Estrogen also triggers the increased growth of bones during adolescence that lead to adult height and proportions. Thymus The thymus is a soft, triangular-shaped organ found in the chest posterior to the sternum. The thymus produces hormones called thymosins that help to train and develop T-lymphocytes during fetal development and childhood. The T-lymphocytes produced in the thymus go on to protect the body from pathogens throughout a person’s entire life. The thymus becomes inactive during puberty and is slowly replaced by adipose tissue throughout a person’s life. Other Hormone Producing Organs In addition to the glands of the endocrine system, many other non-glandular organs and tissues in the body produce hormones as well.

Heart: The cardiac muscle tissue of the heart is capable of producing the hormone atrial natriuretic peptide (ANP) in response to high blood pressure levels. ANP works to reduce blood pressure by triggering vasodilation to provide more space for the blood to travel through. ANP also reduces blood volume and pressure by causing water and salt to be excreted out of the blood by the kidneys. Kidneys: The kidneys produce the hormone erythropoietin (EPO) in response to low levels of oxygen in the blood. EPO released by the kidneys travels to the red bone marrow where it stimulates an increased production of red blood cells. The number of red blood cells increases the oxygen carrying capacity of the blood, eventually ending the production of EPO. Digestive System: The hormones cholecystokinin (CCK), secretin, and gastrin are all produced by the organs of the gastrointestinal tract. CCK, secretin, and gastrin all help to regulate the secretion of pancreatic juice, bile, and gastric juice in response to the presence of food in the stomach. CCK is also instrumental in the sensation of satiety or “fullness” after eating a meal.

Adipose: Adipose tissue produces the hormone leptin that is involved in the management of appetite and energy usage by the body. Leptin is produced at levels relative to the amount of adipose tissue in the body, allowing the brain to monitor the body’s energy storage condition. When the body contains a sufficient level of adipose for energy storage, the level of leptin in the blood tells the brain that the body is not starving and may work normally. If the level of adipose or leptin decreases below a certain threshold, the body enters starvation mode and attempts to conserve energy through increased hunger and food intake and decreased energy usage. Adipose tissue also produces very low levels of estrogens in both men and women. In obese people the large volume of adipose tissue may lead to abnormal estrogen levels. Placenta: In pregnant women, the placenta produces several hormones that help to maintain pregnancy. Progesterone is produced to relax the uterus, protect the fetus from the mother’s immune system , and prevent premature delivery of the fetus. Human chorionic gonadotropin (HCG) assists progesterone by signaling the ovaries to maintain the production of estrogen and progesterone throughout pregnancy.

Local Hormones: Prostaglandins and leukotrienes are produced by every tissue in the body (except for blood tissue) in response to damaging stimuli. These two hormones mainly affect the cells that are local to the source of damage, leaving the rest of the body free to function normally. Prostaglandins cause swelling, inflammation, increased pain sensitivity, and increased local body temperature to help block damaged regions of the body from infection or further damage. They act as the body’s natural bandages to keep pathogens out and swell around damaged joints like a natural cast to limit movement. Leukotrienes help the body heal after prostaglandins have taken effect by reducing inflammation while helping white blood cells to move into the region to clean up pathogens and damaged tissues. Physiology of the Endocrine System Endocrine System vs. Nervous System Function The endocrine system works alongside of the nervous system to form the control systems of the body. The nervous system provides a very fast and narrowly targeted system to turn on specific glands and muscles throughout the body. The endocrine system, on the other hand, is much slower acting, but has very widespread, long lasting, and powerful effects.

Hormones are distributed by glands through the bloodstream to the entire body, affecting any cell with a receptor for a particular hormone. Most hormones affect cells in several organs or throughout the entire body, leading to many diverse and powerful responses. Hormone Properties Once hormones have been produced by glands, they are distributed through the body via the bloodstream. As hormones travel through the body, they pass through cells or along the plasma membranes of cells until they encounter a receptor for that particular hormone. Hormones can only affect target cells that have the appropriate receptors. This property of hormones is known as specificity. Hormone specificity explains how each hormone can have specific effects in widespread parts of the body. Many hormones produced by the endocrine system are classified as tropic hormones. A tropic hormone is a hormone that is able to trigger the release of another hormone in another gland. Tropic hormones provide a pathway of control for hormone production as well as a way for glands to be controlled in distant regions of the body. Many of the hormones produced by the pituitary gland, such as TSH, ACTH, and FSH are tropic hormones. Hormonal Regulation The levels of hormones in the body can be regulated by several factors.

The nervous system can control hormone levels through the action of the hypothalamus and its releasing and inhibiting hormones. For example, TRH produced by the hypothalamus stimulates the anterior pituitary to produce TSH. Tropic hormones provide another level of control for the release of hormones. For example, TSH is a tropic hormone that stimulates the thyroid gland to produce T3 and T4. Nutrition can also control the levels of hormones in the body. For example, the thyroid hormones T3 and T4 require 3 or 4 iodine atoms, respectively, to be produced. In people lacking iodine in their diet, they will fail to produce sufficient levels of thyroid hormones to maintain a healthy metabolic rate. Finally, the number of receptors present in cells can be varied by cells in response to hormones. Cells that are exposed to high levels of hormones for extended periods of time can begin to reduce the number of receptors that they produce, leading to reduced hormonal control of the cell. Classes of Hormones Hormones are classified into 2 categories depending on their chemical make-up and solubility: water-soluble and lipid-soluble hormones.

Each of these classes of hormones has specific mechanisms for their function that dictate how they affect their target cells. Water-soluble hormones: Water-soluble hormones include the peptide and amino-acid hormones such as insulin, epinephrine, HGH, and oxytocin. As their name indicates, these hormones are soluble in water. Water-soluble hormones are unable to pass through the phospholipid bilayer of the plasma membrane and are therefore dependent upon receptor molecules on the surface of cells. When a water-soluble hormone binds to a receptor molecule on the surface of a cell, it triggers a reaction inside of the cell. This reaction may change a factor inside of the cell such as the permeability of the membrane or the activation of another molecule. A common reaction is to cause molecules of cyclic adenosine monophosphate (cAMP) to be synthesized from adenosine triphosphate (ATP) present in the cell. cAMP acts as a second messenger within the cell where it binds to a second receptor to change the function of the cell’s physiology.

Lipid-soluble hormones: Lipid-soluble hormones include the steroid hormones such as testosterone, estrogens, glucocorticoids, and mineralocorticoids. Because they are soluble in lipids, these hormones are able to pass directly through the phospholipid bilayer of the plasma membrane and bind directly to receptors inside the cell nucleus. Lipid-soluble hormones are able to directly control the function of a cell from these receptors, often triggering the transcription of particular genes in the DNA to produce "messenger RNAs (mRNAs)" that are used to make proteins that affect the cell’s growth and function. Prepared by Tim Taylor, Anatomy and Physiology Instructor An Overview of the Adrenal Glands - Beyond Fight or Flight An Overview of the Adrenal Glands Beyond Fight or Flight Written by Robert M. Sargis MD, PhD Adrenal Gland Essentials The adrenal glands are two glands that sit on top of your kidneys that are made up of two distinct parts. The adrenal cortex—the outer part of the gland—produces hormones that are vital to life, such as cortisol (which helps regulate metabolism and helps your body respond to stress) and aldosterone (which helps control blood pressure).

The adrenal medulla—the inner part of the gland—produces nonessential (that is, you don’t need them to live) hormones, such as adrenaline (which helps your body react to stress). When you think of the adrenal glands (also known as suprarenal glands), stress might come to mind. And rightly so—the adrenal glands are arguably best known for secreting the hormone adrenaline, which rapidly prepares your body to spring into action in a stressful situation. But the adrenal glands contribute to your health even at times when your body isn’t under extreme stress. In fact, they release hormones that are essential for you to live. Anatomy of the Adrenal Glands The adrenal glands are two, triangular-shaped organs that measure about 1.5 inches in height and 3 inches in length. They are located on top of each kidney. Their name directly relates to their location (ad—near or at; renes—kidneys). Each adrenal gland is comprised of two distinct structures—the outer part of the adrenal glands is called the adrenal cortex. The inner region is known as the adrenal medulla. Hormones of the Adrenal Glands The adrenal cortex and the adrenal medulla have very different functions.

One of the main distinctions between them is that the hormones released by the adrenal cortex are necessary for life; those secreted by the adrenal medulla are not. Adrenal Cortex Hormones The adrenal cortex produces two main groups of corticosteroid hormones—glucocorticoids and mineralcorticoids. The release of glucocorticoids is triggered by the hypothalamus and pituitary gland . Mineralcorticoids are mediated by signals triggered by the kidney. When the hypothalamus produces corticotrophin-releasing hormone (CRH), it stimulates the pituitary gland to release adrenal corticotrophic hormone (ACTH). These hormones, in turn, alert the adrenal glands to produce corticosteroid hormones. Glucocorticoids released by the adrenal cortex include: Hydrocortisone: Commonly known as cortisol, it regulates how the body converts fats, proteins, and carbohydrates to energy. It also helps regulate blood pressure and cardiovascular function. Corticosterone: This hormone works with hydrocortisone to regulate immune response and suppress inflammatory reactions. The principle mineralcorticoid is aldosterone, which maintains the right balance of salt and water while helping control blood pressure.

There is a third class of hormone released by the adrenal cortex, known as sex steroids or sex hormones. The adrenal cortex releases small amounts of male and female sex hormones. However, their impact is usually overshadowed by the greater amounts of hormones (such as estrogen and testosterone) released by the ovaries or testes . Adrenal Medulla Hormones Unlike the adrenal cortex, the adrenal medulla does not perform any vital functions. That is, you don’t need it to live. But that hardly means the adrenal medulla is useless. The hormones of the adrenal medulla are released after the sympathetic nervous system is stimulated, which occurs when you’re stressed. As such, the adrenal medulla helps you deal with physical and emotional stress. You can learn more by reading a SpineUniverse article about the sympathetic nervous system . You may be familiar with the fight-or-flight response—a process initiated by the sympathetic nervous system when your body encounters a threatening (stressful) situation. The hormones of the adrenal medulla contribute to this response. Hormones secreted by the adrenal medulla are: Epinephrine: Most people know epinephrine by its other name—adrenaline.

This hormone rapidly responds to stress by increasing your heart rate and rushing blood to the muscles and brain. It also spikes your blood sugar level by helping convert glycogen to glucose in the liver. (Glycogen is the liver’s storage form of glucose.) Norepinephrine: Also known as noradrenaline, this hormone works with epinephrine in responding to stress. However, it can cause vasoconstriction (the narrowing of blood vessels). This results in high blood pressure. Disorders and Diseases of the Adrenal Glands There are multiple reasons why the adrenal glands might not work as they should. The problem could be with the adrenal gland itself, or the root cause may be due to a defect in another gland. Below are the most common disorders and diseases of the adrenal glands: Addison’s disease: This rare disorder may affect anyone at any age. It develops when the adrenal cortex fails to produce enough cortisol and aldosterone. To learn more, read our article about Addison's Disease . Adrenal cancer: Adrenal cancer is an aggressive cancer, but it’s very rare. Malignant adrenal tumors are rarely confined to the adrenal glands—they tend to spread to other organs and cause adverse changes within the body because of the excess hormones they produce.

To learn more, read our article about adrenal cancer . Cushing’s syndrome: Cushing’s syndrome is an uncommon condition that is essentially the opposite of Addison’s disease. It is caused by overproduction of the hormone cortisol. There are a variety of causes of this disorder—a tumor in the adrenal gland or pituitary gland could be to blame. To learn more, read our article about Cushing's syndrome . Congenital adrenal hyperplasia: This genetic disorder is characterized by low levels of cortisol. It’s common for people with congenital adrenal hyperplasia to have additional hormone problems such as low levels of aldosterone (which maintains a balance of water and salt). The adrenal glands have a multi-functional role in the endocrine system. The two very different parts of these glands, the medulla and cortex, regulate and maintain many of your internal processes—from metabolism to the fight-or-flight response. Adrenal glands - human anatomy organs Adrenal glands Tweet ADRENAL GLANDS ANATOMY The adrenal cortex and the adrenal medulla are often considered to be of similar function. However, both in structure and in function, these two structures are unique unto themselves.

The adrenal medulla primarily secretes catecholamine hormones which are vital in the sympathetic actions of the autonomic nervous system . Corticosteroids are secreted by the adrenal cortex. These hormones are designed to regulate the balance of minerals, provide a balanced energy for human action, and have a significant role in the reproductive cycle. ADRENAL GLANDS DEFINITION The adrenal glands, also known as suprarenal glands, can be located along the superior edges of the kidneys . The adrenal glands are literally encased by the muscles of the back, protected by the pad of fat that surrounds them, just as the kidneys. This makes them retroperitoneal. The two adrenal glands are formed in the shape of a pyramid. Each one measures about 2 inches in length and just over an inch wide, with a depth of only 10 millimeters. The outer layer, which is the adrenal cortex, covers the inner layer, which is the adrenal medulla. Each layer is a separate gland. The adrenal cortex is by far the largest portion of the gland, and in fact is determined in three subdivisions. The outer division, or “zone” is known as the zona glomerulosa.

The inner division is known as the zona reticularis, and the middle zone is referred to as the zona fasciculata. ADRENAL GLANDS FUNCTIONS Special cells know as chromaffin cells are tightly packed in small clusters to comprise the adrenal medulla. These clusters are situated appropriately around the blood vessels . Each individual cluster of packed cells is specifically autonomically innervated. The adrenal glands demand a high level of vascular supply, just as the entire endocrine system . To meet the excessive demands, there are three individual suprarenal arteries that maintain the blood supply to the adrenal glands. The first one is derived from a branch of the inferior phrenic artery. The second branches from the renal artery. The third artery is a branch directly from the aorta. The venous return from this high demand released from the right adrenal gland flows into the suprarenal vein and directly into inferior vena cava. The left adrenal gland flows back through the suprarenal vein and then into the left renal vein. Preganglionic neurons derived from the splanchnic nerves which innervate the adrenal glands along with the celiac fibers and the associated sympathetic plexus.

ADRENAL GLANDS DIAGRAM Image: Adrenal Glands ADRENAL CORTEX The adrenal cortex delivers over 30 previously identified hormones into the body’s bloodstream. The hormones released and secreted by the adrenal cortex are known as corticosteroids (corticoids) and are segregated into three functionally varying divisions. Mineralocorticoids, glucocorticoids, and gonadocorticoids all serve a basic function via different secretions. The zona glomerulosa is responsible for the secretions known as mineralocorticoids. These hormones basically regulate the varying levels of extracellular electrolytes within the cell structures. This layer is known to administer three different hormones, yet by far, the most vital of these three hormones is considered to be the aldosterone hormone . Aldosterone target the kidneys and initiates the organ’s ability to reabsorb sodium and to emit potassium into the body. It also encourages absorption of excess water and influences urine output, often initiating lower levels of urine excretion. The zona fasciculata is responsible for administering glucocortoids. These hormones target the metabolic rate in reference to fats, proteins, and carbohydrates.

Additionally, these hormones are known to initiate constriction of the blood vessels when necessary as well as assist the body in alleviate the various stress it finds itself under. There are numerous hormones that contain anti-inflammatory agents to help provide relief of pain in injury and deformation sites. Hydrocortisone (cortisol) has been determined to be the most vital of the hormones administered from the zona fasciculata. It is not only the most vital to the body physiological health, it is also the most abundant of the hormones secreted by this region of the adrenal cortex. The final division, the zona reticularis, is responsible for administering the hormones known as gonadocorticoids. These hormones target the reproductive regions of the human body. While the vast majority of hormones secreted by this layer are deemed to be adrenal androgens, a small percentage of adrenal estrogens and progesterones have been discovered. These hormones work cohesively with other hormones to initiate the libido as well as initiate the production and maturation of the gonads in both the male and female body. ADRENAL MEDULLA The cells of the adrenal medulla are known to produce two essential and closely related hormones.

Epinephrine and norepinephrine are similar in both function and structure, and are technically classified as amines. They most specifically belong to the group of hormones referred to as catecholamines. These two hormones are known to sort of mimic the sympathetic division of the autonomic nervous system. Their effects are much longer lasting than the initial impulses sent by the autonomic nervous system. The chromaffin cells release hormones which can increase heart rhythm, enhance mental awareness, dilate the coronary blood vessels, enhance the metabolic rate, and elevate the respiratory rate. Naturally, sympathetic neurons innervate the adrenal medulla. Stress initiates a response from the spinal cord which in turn initiated reaction from the hypothalamus . Stress can be a single determining factor in initiating reactions from both the adrenal cortex and the adrenal medulla. The adrenal medulla is designed to initiate the body into a flight or fight response, and can keep the body in a state of preparedness for an indefinite amount of time.

Major endocrine glands and other organs | The Pituitary Foundation Major endocrine glands and other organs Major endocrine glands Function Hypothamlus (1) The hypothalamus is situated in the brain, at the base of the optic chiasm and is attached to the pituitary via a stalk-like structure. It acts as a collecting centre for information concerned with the internal well being of the body and uses much of this information to regulate the secretion of the hormones produced by the pituitary. Pituitary (1) The pituitary gland is an important gland and it is often referred to as the 'master gland', because it controls several of the other hormone glands. It is usually about the size of a pea and is situated in a bony hollow beneath the base of the brain and just behind the bridge of your nose. The gland consists of two parts (often called lobes) each of which has different functions. The pituitary gland is also sometimes called the Hypophysis. Thyroid (1) & parathyroid (4) The thyroid gland is situated in the front part of the neck, near the windpipe. Embedded in the rear surface of this gland are four parathyroid glands.

The thyroid gland controls many body functions, including heart rate, temperature and metabolism. Both these glands play a role in the metabolism of calcium in the body. Adrenals (2) The adrenal glands (each of which weighs about 4 grams and is about the size of your thumb) are situated just above the kidneys and consist of two parts, the adrenal medulla and the adrenal cortex. These glands produce hormones which are essential for life and help us cope with stress. Pineal (1) The pineal gland is a tiny body located at the base of the brain. It produces the hormone melatonin. Other organs in the body containing endocrine tissue Gland Function Kidneys (2) The kidneys are situated near the middle of the back, just below the rib cage. These glands control the blood fluid and mineral levels within the body by processing the blood to remove waste products and any excess fluid. Ovaries (2) The ovaries are situated either side of the uterus. In addition to containing the egg cells necessary for reproduction, they produce the hormones Oestrogen and Progesterone which are necessary for menstruation and producing the other female sexual characteristics.

Testes (2) The testes are situated in a pouch that hangs outside the male body. They produce the hormones necessary for the production of sperm and the other male sexual characteristics. Pancreas (1) In addition to its digestive functions, cells in the pancreas regulate the blood sugar that provides the body with energy. * ( ) indicates the number of glands in the body Support our work! Donate or become a member! A-Z of downloads The Adrenal Gland | HowStuffWorks The Adrenal Gland NEXT PAGENEXT For years the adrenal gland remained a behind-the-scenes player in the development of several chronic conditions, like fibromyalgia (for more common questions and expert answers on Fibromyalgia, visit Sharecare.com ) and chronic fatigue. Few patients know about or understand this gland. In fact, many doctors do not really focus much attention on it during the process of treating chronic illness. Advertisements are now targeting how to lose weight and fight fatigue by treating the adrenal gland. Unfortunately, products of this quick-fix nature won't work with this organ. The health of the adrenal gland is of primary importance to help prevent and treat chronic disease. The adrenal gland is a small organ that comes in pairs.

There is one on top of each kidney. Like the ovaries, testicles and thyroid, it is a hormone-producing gland. It makes several hormones that encompass a vast array of functions. To emphasize how important this gland is, consider that the gonads (testicles or ovaries) of a man or woman could be removed and without any further medication that person would live. Without critical medical care, a patient would die shortly after the removal of the adrenal glands. Unfortunately, conventional medicine has traditionally taught that in most circumstances the adrenal glands are either healthy or essentially absent. Addison’s disease is the term used to describe very poor adrenal gland function. Patients with Addison’s disease need medication every day to provide the necessary hormone treatment that their body no longer provides. Doctors are now seeing that the adrenal gland is neither on nor completely off, but that there is a spectrum of how well it functions. Up Next Testosterone The health of the adrenal gland can and will dictate the health and recovery of many types of chronic illness, though the topic can get confusing. The adrenal gland should make the necessary amount of hormones in a balance, without producing too much or too little. One of the major hormones made by the adrenal gland is cortisol.

Too much cortisol can cause symptoms of weight gain around the waist, poor sleep, fatigue, elevated blood sugars, menstrual irregularities, increased thirst, higher blood pressure and even more frequent infections. One of the biggest causes of an overactive adrenal gland is stress. The adrenal gland is needed to respond to stress. It was designed to deal with stress in small spurts rather than in periods of days or months (or even years). Chronic stress will overwork the adrenal gland to the point of exhaustion and eventually they become too fatigued to meet the needs of the body. Low cortisol symptoms include fatigue, sugar or salt cravings, low blood sugar, a history of low blood pressure, skin rashes, allergies, poor sleep, depression and anxiety. Cortisol production is usually highest in the morning before we eat, with levels gradually tapering throughout the day. Some patients will be just the opposite, low in the morning when they have terrible fatigue and high at night, not allowing them to get their much needed rest. Any major or chronic stress will affect the adrenal gland. Quite frankly, it is not a gland that deals well with the modern-day lifestyle. A few thousand years ago, our stress responses were not asked to last days and months.

If we encountered a lion, we would need to fight the lion, flee from it or be eaten. This type of stress would be decided in a matter of seconds or minutes. This is much different from the daily attacks of an impatient boss, a terrible commute, a rocky relationship or a chronic illness. While our mind knows that a bad boss at work does not threaten our lives, from the neck down the adrenal glands and the other organs respond by hearing the same instinctive alarms. So the stress encountered day in and day out at work is sending the message, “Lion!” The body can run from a lion for short distances, but it was not made to outrun the lion every hour of the day. 1 Adrenal Glands Function, Location & Definition | Body Maps Your message has been sent. OK We're sorry, an error occurred. We are unable to collect your feedback at this time. However, your feedback is important to us. Please try again later. Close Suprarenal gland (adrenal gland) The suprarenal gland (adrenal gland) is located at the top of each kidney; therefore each person has two suprarenal glands. The suprarenal glands are divided into two parts.

The outer portion of the gland is called the adrenal cortex. The adrenal cortex is responsible for creating three different types of hormones: mineralocorticoids which conserve sodium in the body, glucocorticoids which increase blood glucose levels, and gonadocorticoids which regulate sex hormones such as estrogen. Death would result if the adrenal cortex were to stop functioning as it controls metabolic processes that are essential to life. The adrenal medulla is the inner portion of the suprarenal gland (adrenal gland). This portion secretes epinephrine and norepinephrine in times of stress. There are several diseases that may impact the functionality of the suprarenal gland (adrenal gland). Two notable examples are Cushing disease, which is the creation of too much cortisol, and Addison's disease which occurs when not enough cortisol is created. Both may be treated with medications. The Adrenal Glands - locations, hormones, and functions of hormones The Adrenal Glands Fracking threat to most important wildlife locations in Britain, University study - 15 Oct 2016 Human Adrenal Glands (part of the Endocrine System) Here is a simple summary of information about the adrenal glands.

Information on this page is likely to be appropriate for first-level courses such as AS and A-Level Human Biology, ITEC Anatomy and Physiology, and other courses in Health Sciences. The location(s) of the Adrenal Glands: The human body normally* includes two adrenal glands. They are located immediately anterior to the kidneys, and are encased in a connective tissue capsule that is usually partially buried in an island of fat. The adrenal glands lie beneath the peritoneum (that is, they are "retroperitoneal"). * In some circumstances (e.g. in the cases of certain types of tumours), one or more of the adrenal glands may be surgically removed. For further information about this see: (Norman Endocrine Surgery Clinic). The Structure of the Adrenal Glands: The most obvious aspect of the structure of the adrenal glands is their partitioning into two distinctive components: the paler medulla (centre), and the darker cortex (surround). Both of these tissues contain many blood vessels , hence they may be described as "richly vascularized". Adrenal Medulla The medulla consists of many large columnar cells called "chromaffin cells". These synthesize and secrete catecholamines.

There are also some Ganglion cells are also observed. Blood from throughout the adrenal gland collects into large medullary veins to exit the gland. Adrenal Cortex The adrenal cortex consists of three concentric zones of steroid-synthesizing cells called the: glomerulosa Adrenal Glands | Definition and Patient Education Read This Next What are your adrenal glands? You have two adrenal glands. They’re located on top of each of your kidneys. They’re part of your endocrine system, a collection of glands that produce hormones. While they’re small in size, your adrenal glands are responsible for numerous hormone-related functions in your body. As a result, disorders that affect your adrenal glands can have a broad impact on your health. If you suspect that you have an adrenal disorder, talk to your doctor. What do your adrenal glands do? You have one triangular-shaped adrenal gland at the top of each kidney. Each adrenal gland contains an outer adrenal cortex. It’s responsible for producing certain steroid hormones, including aldosterone and cortisol. Each gland also contains an inner adrenal medulla, which produces several other hormones, including adrenaline and noradrenaline. Aldosterone helps control your blood pressure by managing the balance of potassium and sodium in your body.

Cortisol works in conjunction with adrenaline and noradrenaline to help regulate your reaction to stress. Cortisol also helps regulate your metabolism, sugar levels, and blood pressure. Your adrenal glands are controlled by your pituitary gland, another part of your endocrine system. Located in your head, your pituitary gland is the main controller of your endocrine glands. Abnormal signals can disrupt the amount of hormones that your pituitary gland tells your adrenal glands to produce. This can cause them to produce too little or too much hormone. Hormonal imbalances can result, causing a variety of symptoms and health problems. Which disorders affect your adrenal glands? Adrenal gland disorders can develop when: your pituitary gland fails to control your hormone production properly benign, or noncancerous, tumors grow in your adrenal glands malignant, or cancerous, tumors grow in your adrenal glands infections develop in your adrenal glands you inherit certain genetic mutations These disorders include the following medical conditions: Addison’s disease: This rare autoimmune disease develops when your adrenal glands don’t produce enough cortisol or aldosterone. This is a self-destructive disease, in which your own immune system may attack your adrenal tissues.

Cushing’s syndrome: This rare disorder occurs when your adrenal glands produce too much cortisol. Long-term steroid use can cause similar symptoms. Pheochromocytoma: In this condition, tumors develop in the medulla of your adrenal glands. These tumors are rarely cancerous. Adrenal cancer: This condition occurs when malignant tumors develop in your adrenal glands. Congenital adrenal hyperplasia (CAH): People who have this inherited hormonal disorder have difficulties producing adrenal hormones. This disorder can affect the development of sex organs in men. What are the symptoms of adrenal gland disorders? Symptoms of adrenal gland disorders may include: dizziness low blood pressure, also known as hypotension irregular periods potassium sodium If they suspect you have an adrenal gland disorder, they might order imaging tests next. They can use ultrasound, MRI, and X-ray imaging to create pictures of your adrenal and pituitary glands. This can help them detect possible tumors, deterioration of your endocrine tissues, and other signs of disease. How are adrenal gland disorders treated? If you’re diagnosed with an adrenal gland disorder, your doctor will prescribe treatment to help your adrenal glands function properly again.

They will likely prescribe hormone replacement therapy if you have low adrenal function, such as that caused by Addison’s disease. They may also recommend medications, as well as radiation treatment, if your glands are producing too much of a hormone. Surgery is another treatment option for certain adrenal disorders. Your doctor may recommend surgery if: you have malignant tumors that can be removed you have tumors on your adrenal or pituitary glands hormone suppressants fail During treatment, your doctor will need to test your blood periodically to check your hormone levels. Since your adrenal glands are related to other organs in your endocrine system, your doctor will likely check for signs of disease in your pancreas, sex organs, thyroid gland, and pituitary gland too. What is the outlook for adrenal gland disorders? Your adrenal glands, and the hormones they produce, are essential for everyday health. If you’re diagnosed with an adrenal gland disorder, it’s important to follow your doctor’s prescribed treatment plan. Your outlook will vary, depending on your diagnosis. Ask your doctor for more information about your specific diagnosis, treatment plan, and long-term outlook.

Question: The adrenal glands are situated above which organs in the human body?
Answer: Kidneys