21 notecards = 6 pages (4 cards per page)
Indicate important differences between hormonal and neural controls of body functioning
The means of control and the speed of the endocrine system are very different from those of the nervous system.
List the major endocrine organs and major hormones in each. Describe their body locations and how their major hormones function.
Pineal Gland: Tiny, pine cone-shaped, hangs from the roof of the third ventricle in the diencephalon in the brain, endocrine function is still a mystery, but releases melatonin(sleep cycle).
Distinguish between hormones, paracrines, and autocrines.
• Hormones are long-distance chemical signals that travel in blood or lymph throughout the body.
Describe how hormones are classified chemically.
•Amino acid based: Most hormones are amino acid based. Molecule size varies widely in this group.
Describe the two major mechanisms by which hormones bring about their effects on their target tissues.
• Water-soluble hormones (all amino acid-based hormones except thyroid hormones) act on receptors in the plasma membrane. These receptors are usually coupled via regulatory molecules called G proteins to one or more intracellular second messengers which mediates the target cell response.
Explain how hormone release is regulated.
The synthesis and release of most hormones are regulated by some type of negative feedback mechanism. Some internal or external stimulus triggers hormone secretion. As levels of hormones rise, it causes target organ effects, which then feedback to inhibit further hormone release. As a result, blood levels of many hormones vary only within a narrow range
List three kinds of interaction of different hormones acting on the same target cell.
• Permissiveness – one hormone cannot exert its full effects without another hormone being present (ex. Reproductive system hormones regulate the development of the reproductive system. However thyroid hormone is also necessary for normal timely development of reproductive structures. Lack of thyroid hormone delays reproductive development.
Describe structural and functional relationships between the hypothalamus and the pituitary gland.
The pituitary gland, also known as the hypophysis, is a roundish organ that lies immediately beneath the hypothalamus, resting in a depression of the base of the skull called the sella turcica.
Discuss the structure of the posterior pituitary, and describe the effects of the two hormones it releases
The posterior pituitary consists largely of axon terminals of hypothalamic neurons. These neurons synthesize one of two neurohormones. Axon terminals in the posterior pituitary release these hormones “on demand” in response to action potentials that travel down the axons of these same hypothalamic neurons
List and describe the chief effects of anterior pituitary hormones.
• Growth Hormone (GH) – Anabolic hormone, stimulates somatic growth, mobilizes fats, spares glucose – target organs liver, muscle, bone, cartilage and other tissue
Describe important effects of the two groups of hormones produced by the thyroid gland.
• Increasing basal metabolic rate and body heat production, by turning on transcription of genes concerned with glucose oxidation. This is the hormone’s calorigenic effect = heat producing
Follow the process of thyroxine formation and release.
• Thyroglobulin is synthesized and discharged into the follicle lumen
Indicate general functions of parathyroid hormone
Controls calcium balance in the blood.
List major hormones produced by the adrenal gland, and cite their physiological effects.
• Aldosterone - mineralcorticoid steroid hormone that regulates the excretion of salt, potassium, and water.
Briefly describe the importance of melatonin.
An amine hormone derived from serotonin. Melatonin concentrates in the blood rise and fall in a daily cycle. Peak levels occur during the night and make us drowsy.
Compare and contrast the effects of the two major pancreatic hormones.
• Glucagon – 29 amino acid polypeptide is a very potent hyperglycemic agent. The major target of glucagon is the liver
Describe the functional roles of hormones of the testes, ovaries, and placenta.
• Estrogen is responsible for maturation of the reproductive organs and the appearance of the secondary sex characteristics of the female at puberty. Acting with progesterone promotes breast development and cyclic changes in the uterine mucosa
Name a hormone produced by the heart.
The heart produces atrial natriuretic peptide (ANP). ANP decreases the amount of sodium in the extracellular fluid thereby reducing blood volume and blood pressure.
State the location of enteroendocrine cells
Enteroendocrine cells are hormone-secreting cells sprinkled in the mucosa of the gastrointestinal tract (GI) These hormones help regulate a wide variety of digestive function.
Briefly explain the hormonal function of the kidneys, skin, adipose tissue, bone and thymus.
• Kidneys – secrets erythropoietin is a glycoprotein hormone that signals bone marrow to increase production of red blood cells.
Describe the effect of aging on endocrine system functioning.
Most endocrine organs operate smoothly until old age. Aging may alter the rate of hormone secretion, breakdown and excretion, or the sensitivity of target cell receptor. It can also be affected by the chronic illnesses common in old age.