chapter 42 ~ the endocrine system Flashcards
Long-distance signaling molecules
Hormones
Hormones are secreted into the ECF by the cells of endocrine glands
Classical endocrine signaling
Ductless secretory organs
Endocrine glands
Release their secretions into ducts that lead outside the body or into the cavity of the digestive tract
Exocrine glands
Specialized neurons called neurosecretory neurons release a hormone called neurohormone into the circulatory system when appropriately stimulated
Neuroendocrine signaling
A cell releases a signaling molecule that diffuses through the ECF and acts on nearby cells
Paracrine regulation
When a local regulator acts on the same cells that produced it
Autocrine regulation
Involved in classical endocrine and neuroendocrine signaling. Most are based on tyrosine. With one exception (thyroxine, which passes through the plasma membrane and binds to a receptor inside the target cell), they are hydrophilic and diffuse readily into the blood and ECF. They bind to receptors at the cell surface. Include dopamine, epinephrine, and norepinephrine
Amine hormones
Consist of amino acid chains ranging in length from three to more than two hundred. Some have carbohydrate groups attained to the chain. Involved in classical endocrine and neuroendocrine signaling, as well as act in paracrine and autocrine manners. Released into the ECF and enter the blood. Include insulin, gonadotropin releasing hormone, and growth hormones.
Peptide hormones
A large group of peptide hormones that regulate the division and differentiation of many cell types in body. Act in both paracrine and autocrine manners, as well as in classical endocrine signaling
Growth factors
Involved in classical endocrine signaling. Hydrophobic molecules derived from cholesterol. Combine with hydrophilic carrier proteins to form water soluble complexes that can diffuse through the ECF and enter the bloodstream. On contacting a cell they are released from the carrier proteins and pass through the plasma membrane of the target cell and bind to internal receptors in the nucleus or cytoplasm. Include aldosterone, cortisol, and sex hormones
Steroid hormones
Involved in paracrine and autocrine regulation. Include prostaglandins
Fatty acid derived molecules
A fatty acid derived molecule and important local regulator that can be secreted by virtually every cell and is present essentially at all times. They generally induce contraction or relaxation of smooth muscle cells, and also may intensify pain and inflammation
Prostaglandins
A product of the pathway inhibits an earlier step in the pathway
Negative feedback
A region of the brain located in the floor of the cerebrum
Hypothalamus
Consisting mostly of two fused lobes, is suspended just below the hypothalamus by a slender stalk of tissue that contains both neurons and blood vessels
Pituitary gland
Contains axons and nerve endings of neurosecretory neurons that originated in the hypothalamus
Posterior pituitary
Contains non neuronal endrocine cells that form a distinct gland
Anterior pituitary
Peptide neurohormones from the hypothalamus that control the secretion of hormones from the anterior pituitary, are carried in the blood from the hypothalamus to the anterior pituitary in a portal vein, secretion is controlled by neurons containing receptors that monitor the blood to defect changes in body chemistry and temperature, negative feedback pathways regulate secretion
Releasing hormones and inhibiting hormones
A special vein that connects the capillaries of the hypomalamus and anterior pituitary. it provides a critical link between the brain and the endocrine system, ensuring that most of the blood reaching the anterior pituitary first passes through the hypothalamus
Portal vein
Secreted by the anterior pituitary, influences reproductive activities and parental care in vertebrates, in mammals stimulates development of the secretory cells of mammary glands during late pregnancy and stimulates milk synthesis after a female mammal gives birth
Prolactin PRL
Secreted by the anterior pituitary, stimulates cell division, protein synthesis, and bone growth in children and adolescents, causing body growth, stimulates protein synthesis and cell division in adults by binding to target tissues, mostly liver cells, causing them to release insulin like growth factor, controls many metabolic processes in mammals of all ages including the conversion of glycogen to glucose and fats to fatty acids, stimulates body cells to take up fatty acids and amino acids and limits the rate at which muscle cells take up glucose
Growth hormones GH
Secreted by liver cells, a peptide that directly stimulates growth processes
Insulin-like growth factor
A deficiency in GH secretion during childhood, those affected remain small in saltire through the childhood into adulthood
Pituitary dwarfs
Overproduction of GH during childhood of adolescence, often due to a tumor of the anterior pituitary, those affected may grow above 8 ft in height
Pituitary giants
Secreted by the anterior pituitary, stimulates the thyroid gland to grow size and secrete thyroid hormones
Thyroid stimulating hormone TSH
Secreted by the anterior pituitary, triggers hormone secretion by cells in the adrenal cortex
Adrenocorticotropic hormone ACTH
Secreted by the anterior pituitary, controls egg development and the secretion of sex hormones in female mammals, and sperm production in males
Follicle stimulating hormone FSH
Secreted by the anterior pituitary, regulates part of menstrual cycle in human females and secretion of sex hormones in males
Luteinizing hormone LH
FSH and LH, regulate the activity of the gonads
Gonadotropins
Produced by the anterior pituitary but is secreted little to none adult humans, effects skin cells that contain the black pigment melanin
Melanocyte-stimulating hormone MSH
Peptide hormones produced by the hypothalamus and pituitary, are released by the anterior pituitary, act as neurotransmitters in the PNS in pathways that control pain, inhibiting the perception of pain
Endorphins