Endocrine System

• Endocrine System - coordinates and directs the activity of the body's cells
• Endocrine System - second great controlling system of the body
• Nervous system - uses nerve impulses to prod the muscles and glands into immediate action; "built for speed"
• Endocrine System - acts more slowly by using chemical messengers, which are released into blood
• Endocrinology - study of hormones and endocrine organs
• Hormone - comes from a Greek word meaning "to arouse"
• Hormones - chemical substances secreted by endocrine cells into the extracellular fluids
• Hormones - regulates the metabolic activity of other cells in the body
• Target Cells/Organs - a given hormone affects only certain tissue cells or organs
• Receptors - specific proteins attached to the cell's plasma membrane, where hormones attach to influence the activities of the cell
• Steroid hormones - are lipid-soluble molecules; can use the mechanism of direct gene activation, which means that they can diffuse through the plasma membrane
• Amino acid-based hormones - are water-soluble hormone; can only use second-messenger system, which they attach to a receptors to influence the cell's activity
• Hormonal Stimulus - endocrine organs are prodded into actions by other hormones
• Humoral Stimulus - stimulates if changing in blood levels of certain ions and nutrients
• Humoral - comes from an ancient word "humor" to indicate the various body fluids
• Neural Stimulus - a nerve fibers stimulate hormone release, and the endocrine cells are said to respond to it
• Endocrine Glands - are ductless glands that secrete hormones into the bloodstream or lymph
• Exocrine Glands - release their products at the body's surface or into body cavities through ducts
• Pituitary Gland - is the size of a pea; located from the inferior surface of the hypothalamus, where it is surrounded by the sella turcica
• Hypothalamus - control center of the endocrine system
• Anterior Pituitary Glands - often called "master endocrine gland"
• Anterior Pituitary Glands - controls the activity of so many other endocrine glands
• Posterior Pituitary Gland - acts as a storage area for hormones made by hypothalamic neurons
• Oxytocin - stimulates powerful contraction of the uterine muscle
• Oxytocin - causes milk ejection in a nursing woman
• Let-down Reflex - other term for milk ejection
• Oxytocin - to induce labor or to hasten labor
• Antidiuretic hormone - chemical that inhibits or prevents urine production
• Diuresis - term for urine production
• Antidiuretic hormone - causes kidneys to reabsorb more water from the forming urine
• Antidiuretic hormone - also referred to as vasopressin, because it increases pressure by causing constriction of the arterioles
• Edema - water retention in tissue
• Growth hormone - to the growth of skeletal muscles and long bones of the body
• Growth hormone - stimulates most target cells to grow in size and divide
• Pituitary Dwarfism - result of the hyposecretion of GH during childhood
• Gigantism - result of the hypersecretion of the GH during childhood
• Prolactin - stimulates and maintains milk production by the mother's breasts
• Tropic Hormone - stimulates their target organs, which are the endocrine glands, to secrete their hormones
• Gonadotropic hormones - regulate the hormonal activity of the gonads
• Follicle-stimulating hormone - also stimulate sperm development by the testes