EXAM#1 Anatomy and Physiology

Adrenal medulla

>Adrenaline and noradrenaline: increase heart rate and blood pressure (targets heart, blood vessel)

Pancreas

>Insulin: regulates glucose metabolism islets of Langerhans beta cells (beta cells in the pancreatic islets secrete he hormone insulin in response to a high concentration of glucose in the blood) >Glucagon: raises blood sugar levels (targets liver and muscle) made by islet of Langerhans alpha cells. >Digestive Enzymes made by acinar cells

Adipose tissue

>Leptin

Thyrotropin-releasing hormone (TRH)

A hypothalamic hormone that regulates the release of thyroid-stimulating hormone from the anterior pituitary. The hypothalamus releases thyrotropin-releasing hormone (TRH) into the hypothalamic-hypophyseal portal system to the anterior pituitary gland. TRH stimulates thyrotropin cells in the anterior pituitary to release thyroid-stimulating hormone (TSH). Thyrotropin-releasing hormone is the master regulator of thyroid gland growth and function (including the secretion of the thyroid hormones thyroxine and triiodothyronine). These hormones control the body's metabolic rate, heat generation, neuromuscular function and heart rate, among other things.

Downregulation

An decrease in the number of receptors on the surface of target cells, making the cells less sensitive to a hormone or another agent. For example, insulin receptors may be downregulated in type 2 diabetes. Development of a refractory or tolerant state consequent upon repeated administration of a pharmacologically or physiologically active substance.

Dehydroepiandrosterone (DHEA)

Dehydroepiandrosterone (DHEA) is a hormone that your body naturally produces in the adrenal gland. DHEA helps produce other hormones, including testosterone and estrogen. Natural DHEA levels peak in early adulthood and then slowly fall as you age. The body uses DHEA to make androgens and estrogens, the male and female sex hormones.

What is diabetes insipidus?

Diabetes insipidus is usually caused by problems with a hormone called vasopressin that helps your kidneys balance the amount of fluid in your body. Problems with a part of your brain that controls thirst can also cause diabetes insipidus. Diabetes insipidus occurs when the body can't regulate how it handles fluids. The condition is caused by a hormonal abnormality and isn't related to diabetes. In addition to extreme thirst and heavy urination, other symptoms may include getting up at night to urinate or bed-wetting.

What is the difference between the anterior and posterior pituitary?

One secretes chemical signals from endocrine cells (anterior), and the other secretes chemical signals from neural cells. The anterior pituitary gland is connected to the brain by short blood vessels. The posterior pituitary gland forms part of the brain and secretes hormones directly into the bloodstream under the command of the brain.

Thyroid-stimulating hormone

Organ that secretes: anterior pituitary gland Target tissue: thyroid gland Main effects: growth & secretion of thyroid hormone

Alpha islet cells

The pancreatic islets of Langerhans consist of several hormone-secreting cell types important for blood glucose control. The alpha cells secrete glucagon as a response to low blood glucose. They are located in the endocrine part of the pancreas.

Humoral

Relating to or being the part of immunity or the immune response that involves antibodies secreted by B cells and circulating in bodily fluids.

Adrenal cortex

>Cortisol: regulates stress response (target: liver, muscle, and adipose tissue) (zona fasciculata) >Dehydroepiandrosterone (DHEA): precursor hormone to sex hormones (targets ovaries and testes) (zona reticularis) >Aldosterone: regulates electrolyte (sodium, magnesium, potassium, & calcium) balance and blood pressure (targets distal convoluted tubules of nephron) (zona glomerulosa)

What is the role of negative feedback in the endocrine system?

A negative feedback loop is one way that the endocrine system tries to keep homeostasis (stability) in the body. If an endocrine gland senses that there is too much of one hormone in the body, it will initiate changes to decrease production of that hormone.

Renin

Hormone secreted by the kidney; it raises blood pressure by influencing vasoconstriction (narrowing of blood vessels) ie. raising blood pressure.

Erythropoietin

Interstitial cells in the kidneys secrete erythropoietin "red-maker" a glycoprotein hormone that signals the bone marrow to increase production of red blood cells (erythrocytes). Secreted in response to hypoxia (an absence of enough oxygen in the tissues to sustain bodily functions.)

Thymosin and thymopoietin

Promote development and maturation of T-lymphocytes within the thymus. Organ that secretes: thymus. Target tissue: T lymphocytes in thymus. Main effects: stimulates the development of T lympocytes within the thymus.

Parathyriod glands

>Parathyroid Hormone (PTH): released in response to low calcium to raise levels. Release of calcium by bones into the bloodstream, reabsorption of calcium from the food by the intestines, conservation of calcium by the kidneys.

Liver

>Thrombopoietin: stimulates platelet production

Thymus

>Thymosin >Thymopoietin

Antagonist

Antagonistic hormones are a pair of hormones that have opposing effects on one another. Insulin and glucagon, for example, are antagonistic hormones because insulin works to lower blood glucose levels while glucagon works to raise blood glucose levels.

Upregulation

Increase in receptor number in response to low concentration of hormone. An increase in the number of receptors on the surface of target cells, making the cells more sensitive to a hormone or another agent. For example, there is an increase in uterine oxytocin receptors in the third trimester of pregnancy, promoting the contraction of the smooth muscle of the uterus.

Bone

Osteocalcin

How do polar hormones act on a cell?

Polar hormones = polar hormones do not enter their target cells but instead bind to receptors on the plasma membrane. These hormones then exert their effects through second-messenger systems. Hormones are delivered by the blood to every cell in the body, but only the target cells are able to respond to these hormones.

Paracrine

Referring to a secreted molecule that acts on a neighboring cell. A local hormone produced at one site but active at a different site in the body.

Ovaries

>Estrogen >Progesterone

Precursors

>Growth hormone (GH): produced from a precursor molecule called somatomedin C. >Adrenocorticotropic hormone (ACTH): produced from a precursor molecule called proopiomelanocortin (POMC) >Thyroid hormones (T3) triidothyronine and (T4) thyroxine: tyrosine-based (phenylalanine) produced from precursor molecule, thyroglobulin >Testosterone: produced from precursor molecule, cholesterol >Estrogen: produced from precursor molecule, cholesterol DHEA: produced from precursor molecule, cholesterol Melatonin: produced from precursor molecule, serotonin Insulin: produced by precursor molecule proinsulin

Anterior Pituitary (produces)

>Growth hormone (GH): stimulates growth and cell reproduction. >Prolactin (PRL): stimulates milk production in lactating women. & tropic hormones (tropic hormones are a group of hormones that stimulate other endocrine glands so as to produce their particular hormones.) >Adrenocorticotropic hormone (ACTH): stimulates adrenal gland to produce steroid hormones. >Thyroid-stimulating hormone (TSH): stimulates thyroid gland to produce thyroid hormones. >Follicle-stimulating hormone (FSH): regulates development of ovarian follicle and production of estrogen in females, and sperm production in males. Luteinizing hormone (LH): regulates ovulation and production of progesterone in females, and testosterone production in males.

Hypothalamus (produces)

>Oxytocin. (secreted into the bloodstream by the posterior pituitary gland) >Antidiuretic Hormone >Thyrotropin-Releasing Hormone (TRH) >> Release of TSH from anterior pituitary >Corticotropin-Releasing Hormone (CRH) >> release of ACTH from anterior pituitary >Gonadotropin-Releasing Hormone (GnRH) >> release of LH and FSH from anterior pituitary >Growth-Hormone-Releasing Hormone (GHRH) >Growth-Hormone-Inhibiting Hormone (GHIH or somatostatin) >Prolactin-Releasing Hormone (PRLH) >Prolactin-Inhibiting Hormone (PIH or dopamine)

Posterior Pituitary (stores and secretes)

>Oxytocin: regulates contractions during childbirth and stimulated milk let-down (a response from your body that causes breastmilk to flow) *(targets uterus, mammary glands)* >Antidiuretic hormone (ADH): regulates water balance in body (production of aquaporins (defintion: they transport water across cell membranes in response to osmotic gradients created by active solute transport) in collecting ducts and distal convoluted tubule of nephron)

Water-Soluble Hormones

>Peptide hormones: produced by pituitary gland and pancreas >Growth hormone (GH), prolactin (PRL), adrencorticotropic hormone (ACTH), thyroid-stimulating hormone (TSH), follicle-stimulating (FSH), luteinizing hormone (LH), insulin, glucagon, oxytocin, antidiuretic hormone (ADH) >Precursor hormones: >DHEA (produced by adrenal gland) is a precursor hormone that can be converted to other steriod hormones such as estrogen and testosterone.

Kidney

>Renin: released by granular cells in response to a drop in blood pressure. >Erythropoietin: stimulates erythropoietin production >Thrombopoietin: stimulates platelet production

Lipid-Soluble Hormones

>Steroid hormones: produced by adrenal glands, ovaries, and testes >Cortisol, estrogen, progesterone, testosterone, DHEA >Thyroid hormones: produced by the thyroid gland >Triiodothyronine (T3), thyroxine (T4)

Thyroid Gland

>Triiodothyronine (T3) and thyroxine (T4): regulate metabolism (targets liver, muscle, and adipose tissue) made by follicular cells or C cells. >Calcitonin: made by parafollicular cells (synthesize, store, and secrete)

Agonist

A chemical substance which binds to specific hormone receptors activating the function of the endocrine glands, the biosynthesis of their secreted hormones, or the action of hormones upon their specific sites. Agonist is a drug that mimics a natural molecule. These drugs "pick the lock." Examples of full agonists are heroin, oxycodone, methadone, hydrocodone, morphine, opium

Melatonin

A hormone manufactured by the pineal gland that produces sleepiness. The target organ of the melatonin hormone is SCN (suprachiasmatic nucleus) in the lower brain. SCN plays an important in regulating circadian rhythms in the body. It is responsible for proper sleeping patterns in human beings. Melatonin secretion is increased during nighttime and inhibited during daylight. Overproduction of the melatonin hormone can cause sleepiness, tiredness, and fatigue in the body. The underproduction of the melatonin hormone can cause sleep deprivation and sleep disturbances in the body.

Oxytocin

A hormone released by the posterior pituitary that stimulates uterine contractions during childbirth and milk ejection during breastfeeding. Target organ/tissue; Uterine smooth muscle Mammary gland.

Relaxin

A hormone secreted by the placenta that causes the cervix to dilate and prepares the uterus for the action of oxytocin during labor. Hormone produced during pregnancy that loosens and softens ligaments.

How does aldosterone increased blood volume and pressure?

Aldosterone signals certain organs, like your kidneys and colon, to increase the amount of sodium they send into your bloodstream or the amount of potassium released in your urine (pee). Aldosterone's effect on sodium increase causes your body to retain water in your blood, which increases blood volume. Figure: Regulating Blood Pressure: The Renin-Angiotensin ... Aldosterone and vasopressin cause the kidneys to retain sodium (salt). Aldosterone also causes the kidneys to excrete potassium. The increased sodium causes water to be retained, thus increasing blood volume and blood pressure.

What is the 2nd messenger system and what are the general steps?

Second messengers are intracellular signaling molecules that transfer the extracellular signal inherent to a first messenger (hormone or neurotransmitter) to the cytosol. Second messengers are molecules that relay signals received at receptors on the cell surface 1. Hormone binds to the receptor 2. the receptor changes shape which allows an inactive G protein to bind 3. when the inactive G-protein binds to it, it will kick out the GDP so that the GTP can bind to it. The G-protein now becomes active 4. when the G-protein becomes active, it will activate an enzyme that is present on the cell membrane (Adenylate Cyclase) 5. when adenylate cyclase activates, it will take the ATP and convert them into cAMP. Your second-messenger system cAMP has been created 6. the level of cAMP elevates in the intracellular fluid, and they go through the cascade chemical effects where they communicate with the nucleus so that the nucleus can respond to whatever that hormone is asking them to do. 7. Phosphodiestarase: when the cAMP level elevates, it will break the cAMP into a different chemical (Turn off mechanism) or control system.

estrogen and progesterone

In female bodies, the ovaries mainly produce estrogen. Fat tissue, adrenal glands, and the brain can make it too. In males, fatty tissues typically produce estrogen. Enzymes can also convert it from excess testosterone. Estrogen has several functions but is best known for its essential role in female growth and reproductive development. It helps maintain the menstrual cycle and facilitates the preparation of the uterus for anticipated and actual pregnancy. Estrogen is also necessary for all human bodies to ensure proper bone growth and health, optimize brain function, and regulate mood. Progesterone is a steroid hormone that plays a key role in preparing all human bodies for reproduction. In females and some intersex people, most progesterone is produced by the corpus luteum. It's a temporary gland that emerges in the second half of the menstrual cycle after ovulation. progesterone down-regulates estrogen receptors in the uterus, thus antagonizing estrogens' actions. The ovaries produce estrogen and progesterone. Estrogens have multiple effects on the growth and development of cells in their target tissues, including the uterus, ovary, breast, bone marrow and brain

Follicle-stimulating hormone (FSH)

In women, FSH helps control the menstrual cycle and stimulates the growth of eggs in the ovaries. FSH levels in women change throughout the menstrual cycle, with the highest levels happening just before an egg is released by the ovary. This is known as ovulation. In men, FSH helps control the production of sperm. Target tissue; Ovaries / testes (tubules). Follicle stimulating hormone (FSH) is produced by the pituitary gland in the brain.

What is the action of insulin?

Insulin helps control blood glucose levels by signaling the liver and muscle and fat cells to take in glucose from the blood. Insulin therefore helps cells to take in glucose to be used for energy. If the body has sufficient energy, insulin signals the liver to take up glucose and store it as glycogen.

Insulin

Insulin is a hormone that's involved in lowering the blood sugar levels or glycemia after a meal. Insulin comes from the latin insula, which means island, because this hormone is produced by some small islands of cells scattered throughout the pancreas that are called pancreatic islets or islets of Langerhans. The primary function of insulin is to facilitate the uptake of glucose into body cells. Red blood cells, as well as cells of the brain, liver, kidneys, and the lining of the small intestine, do not have insulin receptors on their cell membranes and do not require insulin for glucose uptake. Although all other body cells do require insulin if they are to take glucose from the bloodstream, skeletal muscle cells and adipose cells are the primary targets of insulin. Insulin also reduces blood glucose levels by stimulating glycolysis, the metabolism of glucose for generation of ATP. while beta cells produce insulin. Insulin and glucagon are involved in the regulation of glucose metabolism. Insulin is produced by the beta cells in response to high blood glucose levels. It enhances glucose uptake and utilization by target cells, as well as the storage of excess glucose for later use. Dysfunction of the production of insulin or target cell resistance to the effects of insulin causes diabetes mellitus, a disorder characterized by high blood glucose levels. The hormone glucagon is produced and secreted by the alpha cells of the pancreas in response to low blood glucose levels. Glucagon stimulates mechanisms that increase blood glucose levels, such as the catabolism of glycogen into glucose.

Autocrine

Local chemical messengers, not generally considered part of the endocrine system, include autocrines, which act on the cells that secrete them, and paracrines, which act on a different celltype nearby. Autocrines are short-distance chemical signals that exert their effects o n the same cells that secrete them. For example, certain prostaglandins released by smooth muscle cells cause those smooth muscle cells to contract. Acting on the same surface receptors of the same cell.

Luteinizing hormone (LH)

Luteinising hormone is produced by the pituitary gland and is one of the main hormones that control the reproductive system. Produced and released by cells in the anterior pituitary gland. It is crucial in regulating the function of the testes in men and ovaries in women. Target organ; ovaries / testes (Leydig cells)

Thyroxine and triiodothyronine

Major hormones produced by the thyroid: stimulate metabolism, growth, and development. Once in the bloodstream, thyroxine travels to the organs, like the liver and kidneys, where it is converted to its active form of triiodothyronine. Thyroxine plays a crucial role in heart and digestive function, metabolism, brain development, bone health, and muscle control.

Which hormones are amino acid based?

Most hormones are amino acid based hormones. The hormones derived from amino acids include catecholamines, serotonin, melatonin, and the thyroid hormones thyroxine and triiodothyronine. If a hormone is amino acid-derived, its chemical name will end in "-ine". Examples of amino acid-derived hormones include epinephrine and norepinephrine, which are synthesized in the medulla of the adrenal glands, and thyroxine, which is produced by the thyroid gland. The pineal gland in the brain makes and secretes melatonin, which regulates sleep cycles.

Corticotropin-releasing hormone (CRH)

Stressors cause hypothalamic neurons to release corticotropin-releasing hormone (CRH). Adrenocorticotropic hormone (ACTH) stimulates the adrenal cortex to release corticosteroids. Corticotropin-releasing hormone (CRH) triggers ACTH release; rising glucocorticoid levels inhibit it. Involved in stress response. Central driver of the stress hormone system, known as the hypothalamic-pituitary-adrenal axis. Secreted by the paraventricular nucleus of the hypothalamus. CRH causes release of adrenocorticotropic hormone from the pituitary gland. ACTH in turn travels in the bloodstream to the adrenal glands where it causes the secretion of the stress hormone cortisol. CRH acts on many other areas in the brain where it suppresses appetite, increases anxiety, and improves memory and selective attention. These effects coordinate behaviour to develop and fine tune the body's response to a stressful experience. Thought to start labour in pregnant women.

What is SIADH?

Syndrome of inappropriate antidiuretic hormone secretion. A condition defined by the unsuppressed release of antidiuretic hormone (ADH) from the pituitary gland or nonpituitary sources or its continued action on vasopressin receptors.

Synergist

Synergism occurs when two or more hormones produce the same effects in a target cell and their results are amplified. Antagonism occurs when a hormone opposes or reverses the effect of another hormone. Example; Production and secretion of milk by the mammary glands require the effect of estrogen, cortisol, prolactin, oxytocin, etc. The increase of the cardiac rate of the heart requires the action of two hormones, epinephrine, and norepinephrine.

How do non-polar hormones act on a cell?

Non polar hormones = Nonpolar hormones can easily pass through plasma membranes and so bind to receptor proteins within their target cells. Polar hormones = polar hormones do not enter their target cells but instead bind to receptors on the plasma membrane. These hormones then exert their effects through second-messenger systems.

Norepinephrine

Norepinephrine also called noradrenaline is both a hormone, produced by the adrenal glands, and a neurotransmitter, a chemical messenger which transmits signals across nerve endings in the body. Norepinephrine is produced in the inner part of the adrenal glands, also called the adrenal medulla. As a neurotransmitter, norepinephrine is made from dopamine. Norepinephrine is made from nerve cells in the brainstem area of your brain and in an area near your spinal cord. Norepinephrine is a metabolite of dopamine that primarily acts on the alpha-adrenoreceptors in the blood vessels. Together with adrenaline, norepinephrine increases heart rate and blood pumping from the heart. It also increases blood pressure and helps break down fat and increase blood sugar levels to provide more energy to the body.

acinar cells

located in the pancreas, acinar cells form the bulk of the gland produce an enzyme-rich juice that is carried by ducts to the small intestine during digestion. Pancreatic acinar cells are highly specialized exocrine factories that produce copious amounts of digestive enzymes. Pancreatic acinar cells are the major cell type in the pancreas. Synthesizes, stores, and secretes digestive enzymes.

Testes

Testosterone

Growth hormone-inhibiting hormone

Also known as somatostatin. Origin: hypothalamus. Effect: inhibit release of hGH, TSH. It is produced in many locations, which include the gastrointestinal (GI) tract, pancreas, hypothalamus, and central nervous system (CNS). The hormone source organ/tissue is the hypothalamus. The hormone target organ/tissue is the anterior pituitary. The hormone targets GH. Inhibits anterior pituitary from releasing GHRH; released in cases of hyperglycemia; identical to somatostatin

From what are steroid hormones derived?

The steroid hormones are synthesized in the adrenal cortex, the gonads, and the placenta; are all derived from cholesterol and many are of clinical importance.

What is the antagonist of aldosterone?

Aldosterone antagonists are diuretics or "water pills." They may also be called aldosterone receptor blockers. Aldosterone antagonists include: Eplerenone (Inspra) Spirinolactone (Aldactone)

Aldosterone

Aldosterone helps to regulate salt and water balance of the body by targeting the kidneys. Aldosterone released in response to low Na• or high K+blood levels. The release of aldosterone is from adrenal glands.

What hormones are made by the anterior pituitary?

Adrenocorticotrophic hormone (ACTH) Thyroid-stimulating hormone (TSH) Luteinising hormone (LH) Follicle-stimulating hormone (FSH) Prolactin (PRL) Growth hormone (GH) Melanocyte-stimulating hormone (MSH)

Brain Natriuretic Peptide (BNP)

BNP is a neurohormone released in response to volume expansion and increased pressure. It is commonly used to assist in the diagnosis and management of heart failure. When you have heart failure, your heart makes two proteins, one of those, BNP, will rise in your blood when heart failure gets worse.

Leptin

Adipose cells release leptin, which serves to tell your body how much stored energy (as fat) you have. The more fat you have the more leptin there will be in your blood. Leptin binds to CNS neurons concerned with appetite control, producing a sensation of satiety. It also appears to stimulate increased energy expenditure.

What is upregulation?

An increase in the number of receptors on the surface of target cells, making the cells more sensitive to a hormone or another agent. For example, there is an increase in uterine oxytocin receptors in the third trimester of pregnancy, promoting the contraction of the smooth muscle of the uterus.

How does ADH increased blood volume and pressure?

Anti-diuretic hormone acts to maintain blood pressure, blood volume and tissue water content by controlling the amount of water and hence the concentration of urine excreted by the kidney. Higher concentrations of anti-diuretic hormone cause blood vessels to constrict (become narrower) and this increases blood pressure. A deficiency of body fluid (dehydration) can only be finally restored by increasing water intake. ADH Stimulates the tubules to add water pores, also known as aquaporins, to surface membranes thus, increasing permeability of the kidney tubules to water. This increases the reabsorption of water and increases blood volume.

Antidiuretic hormone (ADH)

Antidiuretic hormone is made by special nerve cells found in an area at the base of the brain known as the hypothalamus. Antidiuretic hormone acts to maintain blood pressure, blood volume, and tissue water content by controlling the amount of water and hence the concentration of urine excreted by the kidney. The nerve cells transport the hormone down their nerve fibres (axons) to the posterior pituitary gland where the hormone is released into the bloodstream. It helps to control blood pressure by acting on the kidneys and the blood vessels. Most important role is to conserve the fluid volume of your body by reducing the amount of water passed out in urine. Water in urine can be taken back into the body in a specific area of the kidney; more water returning to bloodstream, urine concentrate rises and water loss is reduced. Higher concentrations of ADH cause blood vessels to constrict (become narrower) and this increases blood pressure. Controlled by a decrease in blood volume or low blood pressure, ie, dehydration or if concentration of salts in the bloodstream increases.

Beta islet cell

Beta cells are cells that make insulin, a hormone that controls the level of glucose in the blood. Beta cells are found in the pancreas within clusters of cells known as islets. In type 1 diabetes the body's immune system mistakenly destroys the beta cells.

Cortisol

Body's main stress hormone. Produced by the 2 adrenal glands that sit on top of each kidney. When stressed, increased cortisol is released into the bloodstream. Regulated by the pituitary gland. Regulates your body's stress response, helps control your body's use of fats, proteins, and carbohydrates (metabolism), suppresses inflammation, regulates blood pressure and blood sugar, and helps control your sleep/wake cycle.

How does the body respond to low calcium? Describe the three mechanisms to raise calcium?

Calcium homeostasis is maintained by actions of hormones that regulate calcium transport in the gut, kidneys, and bone. The 3 primary hormones are parathyroid hormone (PTH) 1,25-dihydroxyvitamin D-3 (Vitamin D3), and calcitonin. 1. parathyroid hormone (PTH) is released by the parathyroid gland when the body detects low blood calcium 2. PTH increases blood calcium by stimulating osteoclasts to break down bone to release calcium into the bloodstream 3. the response of the decrease of calcium in the bones brings the blood calcium levels back in balance

Calcitroil

Calcium is absorbed from the intestine under the control of the active form of vitamin D, called calcitriol. The active form of vitamin D3, calcitriol, is an essential regulator of the carrier sys- tem that intestinal cells use to absorb Ca2+ from food. Activated by the kidneys to active vitamin D3 (calcitriol) in response to parathyroid hormone. Target organs/effects; Intestine: stimulates active transport of dietary calcium across cell membranes o f small intestine.

What tropic hormones are made by the hypothalamus?

Corticotropin-releasing hormone (CRH) is released from the hypothalamus, which stimulates the anterior pituitary to release adrenocorticotropic hormone (ACTH). ACTH then acts on its target organ, the adrenal cortex.

Pancreatic enzymes

Digestive proteins found in pancreatic secretions that breakdown all organic nutrients. Lipase. This enzyme works together with bile, which your liver produces, to break down fat in your diet. Protease. This enzyme breaks down proteins in your diet. Amylase. This enzyme helps break down starches into sugar, which your body can use for energy.

Catecholamines

Stimulated by preganglionic fibers of the sympathetic nervous system. Target organ/effetcs; Sympathetic nervous system target organs: effects mimic sympathetic nervous system activation; increase heart rate and metabolic rat e; increase blood pressure by promoting vasoconstriction. The adrenal medulla produces catecholamines (epinephrine and norepi nephrine) in response to sympathetic nervous system stimulation. Catecholamines enhance and prolong the fight-or- flight response to short-tenn stressors. Hypersecretion leads to symptoms typical of sympathetic nervous system overactivity. Epinephrine, norepinephrine, and dopamine; a class of amines that act as chemical messengers.

Thrombopoietin

Stimulates production of platelets, made in liver, kidney, smooth muscle, and bone marrow. It stimulates the production and differentiation of megakaryocytes, the bone marrow cells that bud off large numbers of platelets. TPO is produced primarily in liver parenchymal cells with much smaller amounts being made in the kidney and bone marrow.

What is the role of the hypothalamus in the endocrine system?

The hypothalamus has a significant role in maintaining homeostasis. As a part of the nervous system, the hypothalamus collects information about the state of our body. As a part of the endocrine system, it controls the secretion of the hormones from the pituitary gland.

Epinephrine

Epinephrine, also known as adrenaline, is both a neurotransmitter and a hormone. It plays an important role in your body's "fight-or-flight" response. It's also used as a medication to treat many life-threatening conditions. Made and released by your adrenal glands. Functions primarily to increase cardiac output and to raise glucose levels in the blood.

What is downregulation?

Fewer receptors are left on the cell membrane and therefore the less notice is being given to that specific message. So a decrease in the number of receptors to a message sited on the cell membrane reduces the cell's sensitivity to the message.

What is the action of glucagon?

Glucagon is a naturally occurring hormone that promotes the breakdown of glycogen in the liver to glucose to increase blood glucose levels. Glucagon's role in the body is to prevent blood glucose levels dropping too low. To do this, it acts on the liver in several ways: It stimulates the conversion of stored glycogen (stored in the liver) to glucose, which can be released into the bloodstream.

Glucagon

Glucagon is a peptide hormone secreted from the alpha cells of the pancreatic islets of Langerhans. Glucagon prevents your blood sugar from dropping too low. The alpha cells in your pancreas make glucagon and release it in response to a drop in blood sugar, prolonged fasting, exercise and protein-rich meals. Glucagon triggers your liver to convert stored glucose (glycogen) into a usable form and then release it into your bloodstream. This process is called glycogenolysis.

Hormone

Hormones are chemicals that coordinate different functions in your body by carrying messages through your blood to your organs, skin, muscles and other tissues. These signals tell your body what to do and when to do it. After being made in one part of the body, they travel to other parts of the body where they help control how cells and organs do their work. For example, insulin is a hormone that's made by the beta cells in the pancreas.

Human chorionic gonadotropin (hCG)

Human chorionic gonadotropin (hCG) is a chemical created by trophoblast tissue, tissue typically found in early embryos and which will eventually be part of the placenta. Measuring hCG levels can be helpful in identifying a normal pregnancy, pathologic pregnancy, and can also be useful following an aborted pregnancy. It's sometimes called the pregnancy hormone because of its unique role in supporting a pregnancy. Once your placenta begins making hCG, it triggers your body to create more estrogen and progesterone. Together with hCG, these hormones help thicken your uterine lining and tell your body to stop menstruating (or releasing eggs). The correct balance of these three hormones sustains and supports the pregnancy.

What is humoral stimulus?

Humoral stimuli refer to the control of hormone release in response to changes in extracellular fluids such as blood or the ion concentration in the blood. For example, a rise in blood glucose levels triggers the pancreatic release of insulin.

Parathyroid hormone

Parathyroid hormone (PTH) is a hormone your parathyroid glands release to control calcium levels in your blood. It also controls phosphorus and vitamin D levels. If your body has too much or too little parathyroid hormone, it can cause symptoms related to abnormal blood calcium levels. The main target organs where parathyroid hormone exerts its effects are the bones and the kidneys. When calcium levels are low, parathyroid hormone is released by the parathyroid glands into the blood and causes the bones to release calcium and increase levels in the bloodstream.

Calcitonin

Produced by parafollicular cells of the thyroid gland, has been thought to regulate blood Ca2+ levels as well. However, in humans, calcitonin appears to be a hormone in search of a function. At normal levels, its effects on calcium homeostasis are negligible. When administered at pharmacological (abnormally high) doses, it does lower blood calcium levels temporarily. A polypeptide hormone released by the parafolli- cnlar, or C, cells of the thyroid gland in response to a rise in blood Ca2• levels. It is not normally important in calcium homeostasis. At pharmacological levels, it inhibits bone matrix resorption and enhances calcium deposit in bone.

Prolactin

Prolactin is a polypeptide hormone that is responsible for lactation, breast development, and hundreds of other actions needed to maintain homeostasis. Prolactin is synthesized by lactotrophs in the anterior pituitary gland. Target; mammory gland.

Prostaglandin

Prostaglandins are hormone-like substances (group of lipids) that affect several bodily functions, including inflammation, pain and uterine contractions. They control processes such as inflammation, blood flow, the formation of blood clots and the induction of labour. Unlike most hormones, which are produced by glands and transported in the bloodstream to act on distant areas of the body, the prostaglandins are produced at the site where they are needed. Prostaglandins are produced in nearly all cells and are part of the body's way of dealing with injury and illness. Target; made at sites of tissue damage or infection that are involved in dealing with injury and illness.

Somatostatin

Somatostatin is a cyclic peptide well known for its strong regulatory effects throughout the body. Also known by the name of growth hormone inhibiting hormone, it is produced in many locations, which include the gastrointestinal (GI) tract, pancreas, hypothalamus, and central nervous system (CNS). In your pancreas, somatostatin prevents (inhibits) the release of pancreatic hormones, including insulin, glucagon and gastrin, and pancreatic enzymes that aid in digestion. In your gastrointestinal (GI) tract, somatostatin reduces gastric secretion, which is stimulated by the act of eating.

What is the interaction between the hypothalamus, anterior pituitary, and endocrine organs (adrenal cortex, gonads, thyroid)?

The hypothalamus produces hormones that travel to the anterior pituitary and stimulate the anterior pituitary to produce specific hormones that control the thyroid, adrenal cortex, and gonads.

Gastrin

The hormone gastrin stimulates stomach smooth muscle to contract so it can churn foodstuffs more efficiently. Produced in stomach mucosa (G cells). General action; food (particularly partially digested proteins) in stomach (chemical stimulation); acetylcholine released by nerve fibers. Target organ; Stomach (parietal cells), small intestine, lleocecal valve, large intestine.

Growth hormone-releasing hormone

The hormone source organ/tissue is the hypothalamus.The hormone target organ/tissue is the anterior pituitary. The hormone targets GH. Stimulates release of Thyroid Hormones. Dependent on levels of thyroxine (T4) and triiodothyronine (T3) - which will inhibit release of Thyroid-Stimulating Hormone; releasing hormone for Thyroid-Stimulating Hormone

What's the difference between prolactin and oxytocin?

The key difference between prolactin and oxytocin hormone is that prolactin hormone is a protein hormone responsible for milk production, while oxytocin hormone is a protein hormone responsible for milk ejection reflex and uterine contraction during childbirth.

Adrenocorticotropic hormone (ACTH)

The main function of ACTH is to regulate the glucocorticoid (steroid) hormone cortisol. Cortisol is released by the adrenal gland. It regulates blood pressure, blood sugar, the immune system, and the response to stress. Corticotropin-releasing hormone (CRH) is released from the hypothalamus, which stimulates the anterior pituitary to release adrenocorticotropic hormone (ACTH). ACTH then acts on its target organ, the adrenal cortex.

Testosterone

The most important of the male sex hormones. Both males and females have it, but the additional testosterone in males stimulates the growth of the male sex organs in the fetus and the development of the male sex characteristics during puberty. It is made in the testicles. Testosterone plays an important role in the growth and development of the primary male reproductive tissues and organs such as the testes and prostate.

Gonadotropin-releasing hormone (GnRH)

The pituitary gland in your endocrine system uses gonadotropin-releasing hormone (GnRH) to stimulate the production of follicle-stimulating hormone and luteinizing hormone. These gonadotropins (hormones) make the sex hormones testosterone, estrogen and progesterone. GnRH is vital to your sexual maturity, sex drive and fertility. follicle-stimulating hormone (FSH) and luteinizing hormone (LH) are gonadotropins. Nerve cells (neurons) in your brain's hypothalamus gland make and release GnRH into your blood vessels.

What two hormones are made by the hypothalamus that are stored in the posterior pituitary?

The posterior pituitary does not produce its own hormones; instead, it stores two hormones—vasopressin and oxytocin—that are produced by neurons in the hypothalamus. Both hormones collect at the ends of the neurons, which are located in the hypothalamus and extend to the posterior pituitary.

Growth hormone

The roles of growth hormone include influencing our height, and helping build our bones and muscles. Natural levels of growth hormone fluctuate during the day, seemingly influenced by physical activity. For example, levels rise when we exercise. Growth hormone levels increase during childhood and peak during puberty. A natural hormone your pituitary gland releases, targets all tissues specifically muscles and bones.

What is the difference between the thyroid gland and the parathyroid gland?

The thyroid gland uses iodine from food to make two thyroid hormones that regulate the way the body uses energy. The parathyroid glands are four tiny glands located behind the thyroid gland. The parathyroid glands produce a substance (parathyroid hormone) that helps control the amount of calcium in the blood.

Which hormones are steroid based?

There are five major classes of steroid hormones: testosterone (androgen), estradiol (estrogen), progesterone (progestin), cortisol/corticosterone (glucocorticoid), and aldosterone (mineralocorticoids). All of the hormones in the human body, except the sex hormones and those from the adrenal cortex, are proteins or protein derivatives.

What is the difference between an endocrine and exocrine gland?

Two principal types of glands exist: exocrine and endocrine. The key difference between the two types is that, whereas exocrine glands secrete substances into a ductal system to an epithelial surface, endocrine glands secrete products directly into the bloodstream.

Ketoacidosis

Untreated diabetes mellitus: lack of insulin or inability of tissue cells to respond to insulin, resulting in inability to use glucose; fats are used as primary energy fuel, and ketoacidosis occurs. When ketones build up in the blood, they make it more acidic. They are a warning sign that your diabetes is out of control or that you are getting sick.

What are the signs and symptoms of hyperthyroidism? hypothyroidism?

With hyperthyroidism, you may find yourself with more energy and experience weight loss as opposed to weight gain. You may also feel anxious. Hypothyroidism causes symptoms like slowed metabolism, fatigue and weight gain. Having an underactive thyroid can decrease or slow down your bodily functions. Hyperthyroidism; Skin Manifestations• Diaphoresis (excessive sweating)• Fine, soft, silky body hair• Smooth, warm, moist skin• Thinning of scalp hairNeurologic Manifestations• Blurred or double vision• Eye fatigue• Corneal ulcers or infections• Increased tears• Injected (red) conjunctiva• Photophobia• Eyelid retraction, eyelid lag*• Globe lag*• Hyperactive deep tendon reflexes• Tremors• InsomniaMetabolic Manifestations• Increased basal metabolic rate• Heat intolerance• Low-grade fever• Fatigue. Hypothyroidism; Psychological/Emotional Manifestations• Decreased attention span• Restlessness• Irritability• Emotional lability• Manic behaviorReproductive Manifestations• Amenorrhea• Decreased menstrual flow• Increased libidoOther Manifestations• Goiter• Wide-eyed or startled appearance (exophthalmos)*• Decreased total white blood cell count• Enlarged spleen.

Atrial natriuretic peptide (ANP)

a hormone secreted by the heart when blood pressure rises, fine-tunes blood pressure and sodium-water balance of the body. One of its major effects is to inhibit the renin-angiotensin- aldosterone mechanism. It blocks renin and aldosterone secretion and inhibits other angiotensin-induced mechanisms that enhance water and Na+ reabsorption. Consequently, ANP's overall influence is to decrease blood pressure by allowing Na+ (and water) to flow out of the body in urine (natriuretic = producing salty urine). ANP decreases the amount of sodium in the extracellular fluid, thereby reducing blood volume and blood pressure. Secreted in response to stretching of atria (by rising blood pressure). Target organ/effects; Kidney:inhibits sodium ion reabsorption and renin release Adrenal cortex: inhibits secretion of aldosterone; decreases blood pressure