There are 2 primary portions of the adrenal glands Adrenal Glands The adrenal glands are a pair of retroperitoneal endocrine glands located above the kidneys. The outer parenchyma is called the adrenal cortex and has 3 distinct zones, each with its own secretory products. Beneath the cortex lies the adrenal medulla, which secretes catecholamines involved in the fight-or-flight response. Adrenal Glands: Anatomy, the adrenal medulla Adrenal Medulla The inner portion of the adrenal gland. Derived from ectoderm, adrenal medulla consists mainly of chromaffin cells that produces and stores a number of neurotransmitters, mainly adrenaline (epinephrine) and norepinephrine. The activity of the adrenal medulla is regulated by the sympathetic nervous system. Adrenal Glands: Anatomy and the adrenal cortex Adrenal Cortex The outer layer of the adrenal gland. It is derived from mesoderm and comprised of three zones (outer zona glomerulosa, middle zona fasciculata, and inner zona reticularis) with each producing various steroids preferentially, such as aldosterone; hydrocortisone; dehydroepiandrosterone; and androstenedione. Adrenal cortex function is regulated by pituitary adrenocorticotropin. Adrenal Glands: Anatomy. Each of these areas secretes different hormones Hormones Hormones are messenger molecules that are synthesized in one part of the body and move through the bloodstream to exert specific regulatory effects on another part of the body. Hormones play critical roles in coordinating cellular activities throughout the body in response to the constant changes in both the internal and external environments. Hormones: Overview and Types and has different regulatory mechanisms. The adrenal medulla Adrenal Medulla The inner portion of the adrenal gland. Derived from ectoderm, adrenal medulla consists mainly of chromaffin cells that produces and stores a number of neurotransmitters, mainly adrenaline (epinephrine) and norepinephrine. The activity of the adrenal medulla is regulated by the sympathetic nervous system. Adrenal Glands: Anatomy is the inner portion of the gland, secreting epinephrine Epinephrine The active sympathomimetic hormone from the adrenal medulla. It stimulates both the alpha- and beta- adrenergic systems, causes systemic vasoconstriction and gastrointestinal relaxation, stimulates the heart, and dilates bronchi and cerebral vessels. Sympathomimetic Drugs and, to a lesser degree, norepinephrine Norepinephrine Precursor of epinephrine that is secreted by the adrenal medulla and is a widespread central and autonomic neurotransmitter. Norepinephrine is the principal transmitter of most postganglionic sympathetic fibers, and of the diffuse projection system in the brain that arises from the locus ceruleus. Receptors and Neurotransmitters of the CNS. These hormones Hormones Hormones are messenger molecules that are synthesized in one part of the body and move through the bloodstream to exert specific regulatory effects on another part of the body. Hormones play critical roles in coordinating cellular activities throughout the body in response to the constant changes in both the internal and external environments. Hormones: Overview and Types function in conjunction with the sympathetic nervous system Nervous system The nervous system is a small and complex system that consists of an intricate network of neural cells (or neurons) and even more glial cells (for support and insulation). It is divided according to its anatomical components as well as its functional characteristics. The brain and spinal cord are referred to as the central nervous system, and the branches of nerves from these structures are referred to as the peripheral nervous system. Nervous System: Anatomy, Structure, and Classification and contribute to the fight-or-flight response. The adrenal cortex Adrenal Cortex The outer layer of the adrenal gland. It is derived from mesoderm and comprised of three zones (outer zona glomerulosa, middle zona fasciculata, and inner zona reticularis) with each producing various steroids preferentially, such as aldosterone; hydrocortisone; dehydroepiandrosterone; and androstenedione. Adrenal cortex function is regulated by pituitary adrenocorticotropin. Adrenal Glands: Anatomy is the outer portion of the gland and is part of the hypothalamic- pituitary Pituitary A small, unpaired gland situated in the sella turcica. It is connected to the hypothalamus by a short stalk which is called the infundibulum. Hormones: Overview and Types-adrenal axis Axis The second cervical vertebra. Vertebral Column: Anatomy. The cortex secretes mineralocorticoids Mineralocorticoids Mineralocorticoids are a drug class within the corticosteroid family and fludrocortisone is the primary medication within this class. Fludrocortisone is a fluorinated analog of cortisone. The fluorine moiety protects the drug from isoenzyme inactivation in the kidney, allowing it to exert its mineralocorticoid effect. Mineralocorticoids, glucocorticoids Glucocorticoids Glucocorticoids are a class within the corticosteroid family. Glucocorticoids are chemically and functionally similar to endogenous cortisol. There are a wide array of indications, which primarily benefit from the antiinflammatory and immunosuppressive effects of this class of drugs. Glucocorticoids, and androgens Androgens Androgens are naturally occurring steroid hormones responsible for development and maintenance of the male sex characteristics, including penile, scrotal, and clitoral growth, development of sexual hair, deepening of the voice, and musculoskeletal growth. Androgens and Antiandrogens. The mineralocorticoid aldosterone Aldosterone A hormone secreted by the adrenal cortex that regulates electrolyte and water balance by increasing the renal retention of sodium and the excretion of potassium. Hyperkalemia is primarily involved in fluid volume and potassium Potassium An element in the alkali group of metals with an atomic symbol k, atomic number 19, and atomic weight 39. 10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the water-electrolyte balance. Hyperkalemia regulation. The glucocorticoids Glucocorticoids Glucocorticoids are a class within the corticosteroid family. Glucocorticoids are chemically and functionally similar to endogenous cortisol. There are a wide array of indications, which primarily benefit from the antiinflammatory and immunosuppressive effects of this class of drugs. Glucocorticoids (e.g., cortisol Cortisol Glucocorticoids) provide the body with immediate energy and have antiinflammatory properties. The androgens Androgens Androgens are naturally occurring steroid hormones responsible for development and maintenance of the male sex characteristics, including penile, scrotal, and clitoral growth, development of sexual hair, deepening of the voice, and musculoskeletal growth. Androgens and Antiandrogens stimulate secondary sex characteristics Secondary sex characteristics Gonadal Hormones.
Last updated: 13 Apr, 2022
The adrenal glands Adrenal Glands The adrenal glands are a pair of retroperitoneal endocrine glands located above the kidneys. The outer parenchyma is called the adrenal cortex and has 3 distinct zones, each with its own secretory products. Beneath the cortex lies the adrenal medulla, which secretes catecholamines involved in the fight-or-flight response. Adrenal Glands: Anatomy have 2 primary areas with separate functions and regulatory mechanisms.
Zones of the adrenal cortex Adrenal Cortex The outer layer of the adrenal gland. It is derived from mesoderm and comprised of three zones (outer zona glomerulosa, middle zona fasciculata, and inner zona reticularis) with each producing various steroids preferentially, such as aldosterone; hydrocortisone; dehydroepiandrosterone; and androstenedione. Adrenal cortex function is regulated by pituitary adrenocorticotropin. Adrenal Glands: Anatomy and medulla and their hormonal products
Image by Lecturio.Hormones Hormones Hormones are messenger molecules that are synthesized in one part of the body and move through the bloodstream to exert specific regulatory effects on another part of the body. Hormones play critical roles in coordinating cellular activities throughout the body in response to the constant changes in both the internal and external environments. Hormones: Overview and Types secreted by the adrenal cortex Adrenal Cortex The outer layer of the adrenal gland. It is derived from mesoderm and comprised of three zones (outer zona glomerulosa, middle zona fasciculata, and inner zona reticularis) with each producing various steroids preferentially, such as aldosterone; hydrocortisone; dehydroepiandrosterone; and androstenedione. Adrenal cortex function is regulated by pituitary adrenocorticotropin. Adrenal Glands: Anatomy (not the medulla) are controlled by, and help regulate, the HPA axis Axis The second cervical vertebra. Vertebral Column: Anatomy.
Flowchart showing the hypothalamic-
pituitary
Pituitary
A small, unpaired gland situated in the sella turcica. It is connected to the hypothalamus by a short stalk which is called the infundibulum.
Hormones: Overview and Types–
adrenal cortex
Adrenal Cortex
The outer layer of the adrenal gland. It is derived from mesoderm and comprised of three zones (outer zona glomerulosa, middle zona fasciculata, and inner zona reticularis) with each producing various steroids preferentially, such as aldosterone; hydrocortisone; dehydroepiandrosterone; and androstenedione. Adrenal cortex function is regulated by pituitary adrenocorticotropin.
Adrenal Glands: Anatomy
axis
Axis
The second cervical vertebra.
Vertebral Column: Anatomy
ACTH: adrenocorticotropic hormone
CRH:
corticotropin-releasing hormone
Corticotropin-releasing hormone
A peptide of about 41 amino acids that stimulates the release of adrenocorticotropic hormone. Crh is synthesized by neurons in the paraventricular nucleus of the hypothalamus. After being released into the pituitary portal circulation, crh stimulates the release of acth from the pituitary gland. Crh can also be synthesized in other tissues, such as placenta; adrenal medulla; and testis.
Hypothalamic and Pituitary Hormones
The RAAS is one of the primary regulators of blood pressure, total body water Total body water Body Fluid Compartments, serum sodium Sodium A member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23. Hyponatremia levels, and pH pH The quantitative measurement of the acidity or basicity of a solution. Acid-Base Balance balance in the body.
Diagram of the
RAAS:
Angiotensinogen is secreted by
hepatocytes
Hepatocytes
The main structural component of the liver. They are specialized epithelial cells that are organized into interconnected plates called lobules.
Liver: Anatomy.
Renin
Renin
A highly specific (leu-leu) endopeptidase that generates angiotensin I from its precursor angiotensinogen, leading to a cascade of reactions which elevate blood pressure and increase sodium retention by the kidney in the renin-angiotensin system.
Renal Sodium and Water Regulation is secreted by juxtaglomerular (JG) cells in the kidney, and converts the angiotensinogen to angiotensin I.
Renin
Renin
A highly specific (leu-leu) endopeptidase that generates angiotensin I from its precursor angiotensinogen, leading to a cascade of reactions which elevate blood pressure and increase sodium retention by the kidney in the renin-angiotensin system.
Renal Sodium and Water Regulation
secretion
Secretion
Coagulation Studies is stimulated by a decrease in blood pressure (BP) which is sensed by the JG cells in the kidney, decreased
sodium
Sodium
A member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23.
Hyponatremia delivery to the kidney which is sensed by the
macula
Macula
An oval area in the retina, 3 to 5 mm in diameter, usually located temporal to the posterior pole of the eye and slightly below the level of the optic disk. It is characterized by the presence of a yellow pigment diffusely permeating the inner layers, contains the fovea centralis in its center, and provides the best phototropic visual acuity. It is devoid of retinal blood vessels, except in its periphery, and receives nourishment from the choriocapillaris of the choroid.
Eye: Anatomy densa (MD) cells, and an increase in sympathetic tone. Angiotensin-converting enzyme (ACE) is secreted by the
lungs
Lungs
Lungs are the main organs of the respiratory system. Lungs are paired viscera located in the thoracic cavity and are composed of spongy tissue. The primary function of the lungs is to oxygenate blood and eliminate CO2.
Lungs: Anatomy, and converts the angiotensin I to
angiotensin II
Angiotensin II
An octapeptide that is a potent but labile vasoconstrictor. It is produced from angiotensin I after the removal of two amino acids at the c-terminal by angiotensin converting enzyme. The amino acid in position 5 varies in different species. To block vasoconstriction and hypertension effect of angiotensin II, patients are often treated with ace inhibitors or with angiotensin II type 1 receptor blockers.
Renal Sodium and Water Regulation.
Actions of
aldosterone
Aldosterone
A hormone secreted by the adrenal cortex that regulates electrolyte and water balance by increasing the renal retention of sodium and the excretion of potassium.
Hyperkalemia at the principal cell:
Aldosterone
Aldosterone
A hormone secreted by the adrenal cortex that regulates electrolyte and water balance by increasing the renal retention of sodium and the excretion of potassium.
Hyperkalemia stimulates the production of epithelial
sodium
Sodium
A member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23.
Hyponatremia
channels
Channels
The Cell: Cell Membrane (
ENaC
ENaC
Sodium channels found on salt-reabsorbing epithelial cells that line the distal nephron; the distal colon; salivary ducts; sweat glands; and the lung. They are amiloride-sensitive and play a critical role in the control of sodium balance, blood volume, and blood pressure.
Liddle Syndrome), renal outer medullary
potassium
Potassium
An element in the alkali group of metals with an atomic symbol k, atomic number 19, and atomic weight 39. 10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the water-electrolyte balance.
Hyperkalemia (ROMK)
channels
Channels
The Cell: Cell Membrane, and Na+/K+ ATPases. The Na+K+ ATPase creates a chemical gradient for Na+ (allowing for increased reabsorption of Na+ through the ENaCs) and a chemical gradient for K+ (allowing for increased K+
secretion
Secretion
Coagulation Studies through the ROMK
channels
Channels
The Cell: Cell Membrane).
ROMK:
renal outer medullary potassium channel
Renal outer medullary potassium channel
Renal Potassium Regulation
Differences between the nerve and hormone pathways used for sympathetic signaling:
The
adrenal medulla
Adrenal Medulla
The inner portion of the adrenal gland. Derived from ectoderm, adrenal medulla consists mainly of chromaffin cells that produces and stores a number of neurotransmitters, mainly adrenaline (epinephrine) and norepinephrine. The activity of the adrenal medulla is regulated by the sympathetic nervous system.
Adrenal Glands: Anatomy is considered a modified sympathetic ganglion because it secretes catecholamines just like postganglionic nerves of the sympathetic
nervous system
Nervous system
The nervous system is a small and complex system that consists of an intricate network of neural cells (or neurons) and even more glial cells (for support and insulation). It is divided according to its anatomical components as well as its functional characteristics. The brain and spinal cord are referred to as the central nervous system, and the branches of nerves from these structures are referred to as the peripheral nervous system.
Nervous System: Anatomy, Structure, and Classification. The chromaffin cells of the
adrenal medulla
Adrenal Medulla
The inner portion of the adrenal gland. Derived from ectoderm, adrenal medulla consists mainly of chromaffin cells that produces and stores a number of neurotransmitters, mainly adrenaline (epinephrine) and norepinephrine. The activity of the adrenal medulla is regulated by the sympathetic nervous system.
Adrenal Glands: Anatomy are unique due to their ability to convert nerve stimuli into endocrine signals.
The primary purpose of the medullary catecholamines is to supplement the effects of the sympathetic nervous system Nervous system The nervous system is a small and complex system that consists of an intricate network of neural cells (or neurons) and even more glial cells (for support and insulation). It is divided according to its anatomical components as well as its functional characteristics. The brain and spinal cord are referred to as the central nervous system, and the branches of nerves from these structures are referred to as the peripheral nervous system. Nervous System: Anatomy, Structure, and Classification. Because these substances are released directly into the bloodstream as hormones Hormones Hormones are messenger molecules that are synthesized in one part of the body and move through the bloodstream to exert specific regulatory effects on another part of the body. Hormones play critical roles in coordinating cellular activities throughout the body in response to the constant changes in both the internal and external environments. Hormones: Overview and Types, their effects last longer than when catecholamines are released as neurotransmitters. These effects include characteristics of the fight-or-flight response:
There are a number of clinical conditions that result from abnormalities of the adrenal hormones Hormones Hormones are messenger molecules that are synthesized in one part of the body and move through the bloodstream to exert specific regulatory effects on another part of the body. Hormones play critical roles in coordinating cellular activities throughout the body in response to the constant changes in both the internal and external environments. Hormones: Overview and Types. Some of the most clinically important include: