Lecture Outline - Chapter 14

14.1 How Hormones Work (p. 288)
	1.	Hormones, chemical messengers that travel in the bloodstream, can be either peptides or steroids. Organs wait for the arrival of hormones.
	2.	Steroid Hormones Activate DNA (p. 288, Fig. 14.2)
		a.	Steroids are lipid soluble and pass through the plasma membranes of target cells and combine with receptors in the nucleus.
		b.	Certain genes are activated, and cell changes, such as altered protein synthesis, follow.
	3.	Peptide Hormones Activate Enzymes (p. 289, Fig. 14.3)
		a.	Peptide hormones bind to receptors in the target plasma membrane and then initiate a cascade of biochemical changes within the cell.
		b.	Binding with a membrane receptor activates an enzyme that produces cyclic AMP (cAMP), which serves as a second messenger (the peptide hormone is the first messenger).
		c.	cAMP sets the enzyme cascade into motion by activating the first enzyme in a sequence. Each enzyme then begins the next reaction and in the process amplifies the hormone's effect.
	4.	Endocrine Glands (p. 291, Fig. 14.4, Table 14.1)
		a.	Two mechanisms control hormone release: negative feedback and hormones working in opposition to each other.
		b.	In negative feedback, an endocrine gland is sensitive to the condition it regulates or to blood levels of the hormone itself. When the product increases, the gland slows the release of the hormone.
		c.	In some cases, hormone secretion slows the release of another hormone, thus regulating the release of that substance.
14.2 Hypothalamus and Pituitary Gland (p. 292)
	1.	The hypothalamus produces hormones that control the activities of the pituitary gland.
	2.	Posterior Pituitary Stores Two Hormones (p. 292, Fig. 14.5)
		a.	The posterior pituitary stores antidiuretic hormone (ADH) and oxytocin, both of which the hypothalamus produces.
		b.	ADH promotes the reabsorption of water from the collecting ducts of the kidney. When the blood becomes too concentrated, the hypothalamus senses this and triggers the posterior pituitary to release ADH.
		c.	Oxytocin causes uterine contractions during labor and stimulates milk release from mammary glands during nursing.
	3.	Anterior Pituitary Is the Master Gland (p. 293, Fig. 14.6)
		a.	The anterior pituitary is controlled by hypothalamic-releasing and release-inhibiting hormones. It produces six different hormones.
		b.	Growth hormone (GH) influences growth rate and stimulates bone growth (Fig. 14.7). 
		c.	Prolactin causes the mammary glands to produce milk after childbirth.
		d.	Thyroid-stimulating hormone (TSH) triggers the production and release of thyroid hormones (Fig. 14.8).
		e.	Adrenocorticotropic hormone (ACTH) stimulates the adrenal cortex to release hormones.
		f.	Gonadotropic hormones (FSH and LH) stimulate the gonads in both males and females.
14.3 Thyroid and Parathyroid Glands (p. 295, Fig. 14.13)
	1. Thyroid Gland (p. 295, Figs. 14.9, 14.10)
		a.	Thyroxin Speeds Metabolic Rate (p. 295, Fig. 14.11)
			i.	Thyroxin is usually secreted as T4, which is converted to T3, the active form. Iodine is a necessary component of thyroxin.
			ii.	Thyroxin increases metabolic rate and stimulates all organs to metabolize faster.
			iii.	Simple goiter is caused by insufficient iodine in the diet. TSH from the anterior pituitary overstimulates the thyroid, causing it to enlarge when iodine is absent.
			iv.	Cretinism results when the thyroid fails to develop normally.
			v.	Myxedema is hypothyroidism in adults.
			vi.	Hyperthyroidism is caused by an overactive thyroid in Graves' disease.
		b.	Calcitonin Lowers Blood Calcium (p. 296, Fig. 14.12)
			The thyroid also secretes calcitonin, which promotes calcium absorption by bones.
	2.	Parathyroid Glands Are Embedded in Thyroid (p. 296, Fig. 14.13)
		a.	Parathyroid Hormone Raises Blood Calcium (p. 296, Fig. 14.12)
			i.	Parathyroid hormone causes the blood phosphate level to decrease and the blood calcium level to increase by demineralizing bones and increasing calcium retention by kidneys and intestines.
			ii.	Parathyroid hormone is controlled by a negative feedback mechanism involving blood calcium levels.
14.4 Adrenal Glands Have Two Parts (p. 297)
	1.	The adrenal glands sit atop each kidney and have two parts: a glandular cortex and a neurotransmitter-storing medulla.
	2.	Adrenal Medulla Responds to Stress (p. 297, Fig. 14.14)
		a.	The adrenal medulla stores epinephrine and norepinephrine produced by postganglionic fibers of the sympathetic nervous system.
		b.	Hormones from the adrenal medulla increase metabolic and breathing rate, blood pressure, and heart output, and prepare the body to act in an emergency.
	3.	Adrenal Cortex Also Responds to Stress (p. 298)
		a.	The adrenal cortex produces glucocorticoids, which help regulate blood glucose, and mineralocorticoids, which regulate levels of minerals in the blood.
		b.	Glucocorticoids Raise Blood Glucose (p. 298)
			Cortisol is primarily responsible for increasing blood glucose by mobilizing any available energy sources. It also counteracts the inflammatory response and reduces swelling.
		c.	Mineralocorticoids Regulate Blood Na+ and K+ Levels (p. 298, Fig. 14.15)
			i.	Aldosterone targets the kidneys, where it promotes reabsorption of sodium and excretion of potassium.
			ii.	When blood volume is low, the kidneys secrete renin, which converts angiotensin in plasma to angiotensin I. Angiotensin I is converted to angiotensin II by a lung enzyme. Angiotensin II promotes aldosterone secretion, which helps to raise blood volume.
	4.	Adrenal Cortex Can Malfunction (p. 299, Figs. 14.16, 14.17)
		In Addison disease, the adrenal cortex slows its release of hormones, and in Cushing syndrome, hormone release is increased.
14.5 Pancreas Produces Two Hormones (p. 300, Fig. 14.18)
	1.	The pancreas secretes digestive enzymes. Its pancreatic islets produce and secrete the hormones insulin and glucagon into the bloodstream.
		a.	When blood sugar is high, insulin causes cells to take up glucose and stimulates the liver to store glucose as glycogen.
		b.	Glucagon promotes glucose release from the liver, raising blood glucose.
	2.	Diabetes Mellitus: Two Types (p. 300, Table 14.2)
		a.	Diabetes is characterized by sugar in the urine, excessive thirst, weight loss, weakness and fatigue, visual disturbances, and other symptoms.
		b.	Type I (insulin-dependent) diabetes is caused by immune system destruction of insulin- producing cells of the pancreas. It is most likely initiated by the viral activity. The deficiency of insulin is absolute.
		c.	Type II (noninsulin-dependent) diabetes is caused by a failure of target cells to respond to insulin, which is present in normal quantities.
14.6 Other Endocrine Glands (p. 301)
	1.	Testes Are in Males and Ovaries Are in Females (p. 301)
		a.	The testes secrete testosterone, the hormone responsible for male characteristics. The anterior pituitary controls testosterone release.
		b.	The ovaries secrete estrogen and progesterone, which are responsible for female characteristics and the uterine cycle. 
			HEALTH FOCUS: Dangers of Anabolic Steroids (p. 302, Fig. 14A)
			i.	Anabolic steroids are synthetic forms of testosterone that are taken in large doses to promote muscle development and athletic performance.
			ii.	Anabolic steroids have many adverse side effects.
	2.	Thymus: Most Active in Children (p. 303)
		The thymus secretes thymosins, hormones that trigger the maturation of T lymphocytes. Thy thymus is largest in children and virtually disappears in old age.
	3.	Pineal Gland: Hormone at Night (p. 303)
		The pineal gland secretes melatonin, a hormone involved in the body's circadian rhythm.
	4.	Nontraditional Sources (p. 303)
		a.	The heart produces atrial natriuretic hormone, which helps regulate sodium and water balance.
		b.	Prostaglandins are local hormones that are produced and act locally. They have diverse functions.
14.7 Working Together (p. 303)
	The Working Together box on page 304 illustrates how the endocrine system works with the other body systems to maintain homeostasis.
14.8 Environmental Signals (p. 305, Fig. 14.19)
	The three categories of environmental signals are: those that act at a distance between different individuals, such as pheromones; those that act at a distance within an organism (hormones); and those that act locally between adjacent cells within an organism (prostaglandins and neurotransmitters.)