Endocrine system review key:

Describe the endocrine system?

Endocrine system includes endocrine glands: adrenal, pineal, ovary, testis that secret chemicals (hormones) directly into the blood stream. Hormones that signal and regulate body functions that affect emotions, thought, growth, reproduction, use of nutrients, minerals, energy, balance of fluids, and other body changes.

Descriibe functions of the endocrine system.

Glands

  • Thyroid gland produces hormones that regulate metabolism, body temperature, and bone growth. [Hormones such as Thyroid-stimulating hormone (TSH, thyrotropin, thyrotropic hormone), thyroxine (T4), and triiodothyronine (T3).]
  • Parathyroid glands produce hormones that balance calcium and phosphorus in the body.
  • Ovaries produce hormones that regulate growth and produce egg cells for reproduction.
  • Testes produce hormones that regulate growth and produce sperm for reproduction.
  • Hypothalamus connects the endocrine system and nervous system and stimulates the pituitary gland to release certain hormones.
  • Pineal gland secretes the hormone melatonin that regulates the sleep cycle and onset of puberty.
  • Pituitary gland regulates and controls all endocrine glands.
  • Thymus gland regulates the immune system.
  • Adrenal glands produce hormones that regulate stress, salt and water balance. Secretions are from the adrenal cortex and adrenal medulla for emergency responses and other important functions.
  • Pancreas provides functions for both digestive system and endocrine system. Hormones glucagon and insulin to regulate blood sugar (glucose) levels.

Hormones

  • Estrogen is produced in the ovaries and adrenal glands. It determines if cells use carbohydrates or fats for energy during intense exercise sessions. Women tend to burn fat for fuel because they have higher levels or estrogen, while men tend to burn carbohydrates.
  • Testosterone contributes to muscle repair, building cells, and growth in both men and women. It is produced in the ovaries, testes, and adrenal gland. Intense exercise increases testosterone production.
  • Anti-diuretic hormone (ADH) also called arginine vasopressin (AVP). It is made in the hypothalamus and stored in the pituitary. It signals the kidneys to regulate the amount of water in the blood stream. It also helps maintain blood pressure, constrict blood vessels (increasing ADH constricts blood vessels), regulate blood volume, and the concentration of urine excreted by the kidney.
  • Endorphins are created in the pituitary gland. They make you feel exhilarated, happy, and block pain.
  • Oxytocin - released by the pituitary gland in stressful situations. Urges you to seek others for support and help, anti inflammation, helps regenerate and strengthen heart cells. In women during birth it stimulates the contraction of the uterus and production of breast milk. It cements a bond between mother and child. Seems to increase social information processed in the brain.
  • Adrenocorticotropic hormone (ACTH.) is produced in and released from the pituitary gland. It stimulates the production and secretion of cortisol (helps body manage stress) from the adrenal cortex. Its release is a responses to the release of corticotropin-releasing hormone (CRH), by the hypothalamus. Cortisol is necessary for life, so its levels in the blood must be closely controlled. When cortisol levels rise, ACTH levels normally fall. When cortisol levels fall, ACTH levels normally rise. Therefore, testing to measure the level of adrenocorticotropic hormone (ACTH) in the blood is used to monitor the health of the pituitary and adrenal glands.
  • Thyroid-stimulating hormone (TSH, thyrotropin, thyrotropic hormone) is made in the pituitary and stimulates the thyroid gland. See thyroid gland.
  • Growth hormone is a complex chain of amino acids secreted by your anterior pituitary gland. It is needed for muscle growth, collagen repair, joint health, immune system function, and healthy skin. Requires intense exercise and short rest intervals. Other Growth factors are similar to hormones and are also produced in the pituitary and most cells. Growth factors hepatocyte, fibroblast, and insulin like growth factor (IGF 1) sends signals to satellite cells to regulate the repair, rebuilding, and growth of muscle mass. IGF-1, for example, signals new muscle cells to fuse to existing muscle fibers to repair muscle cells damaged by exercise. Intense exercise and weight training can increase human growth factor by as much as 200%. Just be careful and have a spotter.
  • Melanocyte-stimulating hormone (MSH) is a group of hormones produced by the pituitary gland, hypothalamus and skin cells. Melanocytes are cells in the basal (base) layer of the epidermis that produces melanin when signaled by MSH (melanocyte-stimulating hormone).
  • Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) are synthesized and secreted by the gonadotropic cells in the anterior pituitary gland. It is a gonadotropin, a glycoprotein polypeptide hormone and regulates development, growth, pubertal maturation, and stimulate the testes in males and ovaries in females which is necessary for reproductive. FSH stimulates the production of estrogen which stimulates egg cell production. LH causes ovulation and stimulates the ovarian cells to produce progesterone. LH stimulates the testes to produce testosterone. FSH controls the production of sperm.
  • Prolactin stimulates production of milk in females after they give birth.
  • Adrenaline and noradrenaline also called epinephrine and norepinephrine are produced in the medulla. They regulate constriction of blood vessels (tension of blood vessels), heart rate, breathing, and metabolism (use of energy or use of glycogen and fat and muscle in the absence of sufficient sugar and fat). Sugar and fat are stored mostly in the liver and skeletal muscles, but also in smaller amounts in all other tissues and organs. The production or epinephrine and norepinephrine increases proportional to increased exercise intensity and duration.
  • Norepinephrine is released into the blood stream from the medulla in the adrenal glands and in parts of the brain. It improves cognitive function dulled by stress by elevating mood and learning, whose production is increased with exercise. Exercise can make you smarter.
  • Aldosterone is made in the adrenal cortex in the adrenal gland. It regulates sodium excretion important to maintain electrolyte balance.
  • Cortisol is know as the chronic (long term) stress hormone, though there are others. The release of adrenocorticotropic hormone from the pituitary gland promotes the production and secretion of cortisol from the adrenal cortex. It maintains blood glucose for long periods of exercise by signaling the body to start breaking down proteins and triglycerides. Excessive physical activity and exercise without providing sufficient time to rest will increase cortisol, which is associated with inflammation, lowered immunity, reduced short-term memory, constipation, weight gain especially in the abdominal region, loss of muscle tone, osteoporosis, and reduced production of hormones: growth hormone, testosterone, DHEA and estrogen.
  • Estrogen is produced in the ovaries and adrenal glands. It determines if carbohydrates or fat are used to fuel the body during an intense exercise session. Women tend to burn fat for fuel because they have higher levels or estrogen, while men tend to burn carbs.
  • Insulin is a hormone secreted by the pancreas and regulates blood sugar levels. More insulin decreases blood sugar faster. After a hard work out blood sugar is low and insulin levels high. To reduce insulin levels after a workout take simple sugars or simple proteins, such as dextrose and whey.
  • Glucagon is a hormone that stimulates the liver to release glucose. Glucagon is released when blood glucose levels are low and more glucose is needed, such as with exercise and stressful situations. If too low it can cause the release of glycogen, a concentrated stored form of glucose stored in the liver and muscles. Insulin brakes it down into glucose for energy when blood glucose levels are low. Glycogen has an important role to fuel muscles during exercise. When we exercise, muscles will use their stored glycogen. When we rest the muscles replenish their glycogen stores in a few hours or in several days depending on the intensity of the work-out. When glycogen is used up, gluconeogenesis (the conversion of glucose from non carbohydrate substances, amino acids and fatty acids, in the liver and kidneys) begins. Turning stored fat (triglycerides and fatty acids) and muscle protein (amino acids) into glucose to use as fuel. This fat and protein metabolism is less efficient, so performance declines and fatigue occurs.

Other body areas that produce hormones or hormone like chemicals

  • Neuroendocrine cells are cells that receive nerve inputs as nerves and release hormones like endocrine cells into the blood stream.
  • Thyroxine, or T4, increases metabolism and hence caloric use during exercise. This will allow the body to burn excess sugar and fat faster. However, if you lack sufficient sugar or fat to burn, your body will begin to use muscle for energy and result in the lose muscle mass.
  • Vasopressin is released by the brain and regulates the amount of water in the blood stream. Related to sweat when you exercise, staying hydrated, and urine production.

Parts and functions

Match the words in the word bank to the function and label the diagram.

  1. ___ adrenal _______ glands produce hormones that regulate stress, salt and water balance.
  2. ___ pituitary ______ pituitary gland regulates and controls all endocrine glands.
  3. ___ testes ________ glands that produce hormones that regulate growth and produce sperm for reproduction.
  4. ___ adrenaline _____ also called epinephrine and norepinephrine produced in the medulla regulates blood vessels tension, heart rate, breathing, and metabolism.
  5. ___ estrogen ______ hormone produced in the ovaries and adrenal glands. Regulates use of carbohydrates or fat during an intense exercise.
  6. ___ testosterone ____ hormone for muscle repair, build cells, and growth in both men and women. Produced in the ovaries, testes, and adrenal gland.
  7. ___ thyroid _______ gland produces hormones that regulate metabolism, body temperature, and bone growth.
  8. ___ parathyroid ____ gland produces hormones that balance calcium and phosphorus.
  9. ___ pancreas ______ provides hormones, glucagon and insulin, to regulate blood sugar (glucose) levels.
  10. ___ diabetes ______ is caused by an imbalance of sugar in the body..
  11. ___ thymus ______ gland regulates the immune system.
  12. ___ ovaries _______ produce hormones that regulate growth and produce egg cells for reproduction.
  13. ___ cortisol _______ the stress hormone.
  14. ___ pineal ________ gland secretes the hormone melatonin that regulates the sleep cycle and onset of puberty.

Label parts on the diagram

Endocrine system diagram

Adapted from By Governmenst [Public do teh main], via Wikimedia Commons

Word bank

adrenaline, pancreas, pineal, diabetes, epidermis, blood vessels, estrogen, cortisol, adrenal, thymus, ovaries, parathyroid, pituitary, testes, testosterone, thyroid,

Describe ways to care for the endocrine system.

  • Eat balanced meals and drink sufficient water
  • Exercise
  • Manage stress
  • Get sufficient sleep (eight and one-half - nine hours a night)
  • Avoid infections through proper care or medical treatment.
  • Keep a balance of minerals or vitamins in your diet.
  • Have regular medical check-ups

Describe health related care issues for the endocrine system.

  • Diabetes is caused by an imbalance of sugar in the body. There are two types: Type 1. and Type 2.
    • Type 1: is when the pancreas doesn't produce enough insulin for the body to function well. (see pancreas)
    • Type 2 diabetes is when the pancreas produces insulin, but not enough for the body to function well based on the food and lifestyle choices made.
  • Thyroid problems related to too much or not enough production of the hormones it makes.
  • Goiter often caused by lack of dietary iodine but if iodine is provided in table salt and other foods, then a goiter may also develo when the thyroid gland produces too much thyroid hormone (hyperthyroidism).
  • Adrenal functions that make too much of its hormones.

 

Dr. Robert Sweetland's notes
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