Ch 16 Lecture review

Chapter 16 – Endocrine System Review

Review Questions

• Amino Acid Based Hormones

  • Virtually all exert their signaling through intracellular receptors.

• Hormones

  • Hormones are chemical messengers produced by glands and secreted into the bloodstream to regulate various bodily functions.

• Hormone Transportation

  • Hormones travel through the bloodstream to reach their target organs or tissues.

• Organs Producing Female Characteristics

  • Hormones that promote the development of female secondary sexual characteristics at puberty are produced by the adrenal glands (not the ovaries).

• Hormones Produced by the Hypothalamus

  • The hypothalamus produces releasing hormones (e.g., TRH, CRH) and inhibitory hormones (e.g., dopamine, somatostatin).

• Organ Involved in Electrolyte Balance

  • The adrenal cortex produces hormones involved in electrolyte balance and stress response.

• Organ Initiating Immune Response

  • The thymus initiates the immune response in early development.

• Positive Feedback Hormones

  • Examples include oxytocin during childbirth and luteinizing hormone (LH) during ovulation.

• Negative Feedback Hormones

  • Examples include insulin and glucagon which regulate blood sugar levels.

• Importance of Receptors

  • Receptors are needed on specific target tissues or organs because they bind hormones specifically, triggering appropriate cellular responses.

• Steroid Hormone Entry into Cells

  • Steroid hormones enter a cell by diffusing across the cell membrane due to their lipid-soluble nature. The effects are generally longer-lasting.

• Second-Messenger Mechanism of Hormone Action

  • Involves steps where the binding of a water-soluble hormone to a receptor on the cell surface activates a G-protein. This leads to the conversion of ATP to cyclic AMP (cAMP), which acts as a second messenger to trigger internal cellular responses.

• Tropic Hormone

  • A tropic hormone is a hormone that stimulates other glands to release their hormones (e.g., TSH stimulates the thyroid).

• Growth Hormone Targets

  • Growth Hormone targets bones and muscles for growth and metabolism.

• Calcium Regulation

  • Calcium levels are increased by parathyroid hormone (PTH) from the parathyroid gland and decreased by calcitonin from the thyroid gland.

• Hypophyseal Portal System

  • The hypophyseal portal system is a network of blood vessels connecting the hypothalamus to the anterior pituitary gland, allowing hormones like CRH and TRH to quickly reach the anterior pituitary.

• Parathyroid Hormone

  • Released by the parathyroid gland, its function is to increase blood calcium levels. It inhibits calcitonin synthesis.

• Graves Disease Cause

  • Caused by autoimmune stimulation of the thyroid, leading to excessive thyroid hormone production.

• Atrial Natriuretic Peptide (ANP)

  • Synthesized by the heart and regulates blood pressure by promoting the excretion of sodium and water, decreasing blood volume.

• Most Important Mineralocorticoid

  • Aldosterone is the most important mineralocorticoid, regulating electrolyte concentrations in extracellular fluids.

• Function of Aldosterone

  • Aldosterone functions to increase sodium reabsorption in the kidneys and is synthesized by the adrenal cortex.

• Regulation of Aldosterone from Hypothalamus

  • Hormones like angiotensin II from the hypothalamus regulate Aldosterone by signaling its release.

• Regulation of Aldosterone from Pituitary

  • Adrenocorticotropic hormone (ACTH) from the pituitary gland regulates Aldosterone by stimulating its release.

• Other Hormone-Producing Organs

  • Other organs such as the heart and kidneys also produce hormones (e.g., ANP, erythropoietin respectively).

• Function of Glucagon

  • Glucagon increases blood glucose levels and is produced by the alpha cells of the pancreas.

• Hormone Regulating Sleep Cycles

  • Melatonin regulates sleep cycles and is produced by the pineal gland.

• Organ Producing Hormones Regulating Glucose

  • The pancreas produces hormones that regulate glucose levels (insulin and glucagon).

• Organ Making Metabolic Hormones

  • The thyroid gland makes metabolic hormones, including thyroxine and triiodothyronine.

• Causes of Diabetes Mellitus

  • Causes include lack of insulin production (Type 1) or insulin resistance (Type 2).

• Alpha Cells of Pancreas

  • Produce glucagon, which increases blood glucose levels.

• Beta Cells of Pancreas

  • Produce insulin, which decreases blood glucose levels.

• Definition of Glycogenolysis

  • The process of breaking down glycogen into glucose, increasing blood sugar levels.

• Definition of Gluconeogenesis

  • The creation of glucose from non-carbohydrate sources, important during fasting.

• Insulin Release Timing

  • Insulin should be released immediately after you eat to promote glucose uptake.

• Glucagon Release Timing

  • Glucagon should be released between meals or when you haven't eaten to maintain glucose levels.

• Causes of Addison's Disease

  • Caused by the insufficient production of adrenal hormones, often due to autoimmune disorders.

• Three Cardinal Signs of Diabetes Mellitus

  • Polyuria (increased urination), polydipsia (increased thirst), and polyphagia (increased hunger).

• Hormone Produced by Skin

  • The skin produces vitamin D (calcitriol) which is important for calcium metabolism.

• Organ Making Leptin

  • Leptin is made by adipose (fat) tissue; it functions to suppress appetite and increase energy expenditure.

• Hormones Produced in Gastrointestinal Tract

  • Hormones such as gastrin (promotes secretion of gastric acid) and ghrelin (stimulates hunger) are produced in the GI tract.

• Appetite Suppressing Hormone

  • Leptin suppresses appetite and increases energy expenditure.

• EPO (Erythropoietin)

  • EPO is a hormone that stimulates the production of red blood cells, made primarily by the kidneys.