BIOH 113 1st Edition Lecture 6Outline of Last Lecture I. Pituitary-Hypothalamic RelationshipsII. Adenophypophyseal HormonesIII. Thyroid GlandIV. Thyroid HormoneV. CalcitoninVI. Parathyroid GlandsVII. Parathyroid HormonesOutline of Current Lecture I. Adrenal GlandsII. Adrenal CortexIII. MineralocorticoidsIV. GlucocorticoidsV. GonadocorticoidsVI. Adrenal MedullaVII. PancreasVIII. GonadsIX. Pineal GlandX. ThymusXI. Other Hormone Producing StructuresCurrent LectureI. Adrenal Glandsa. Also called suprarenal glandsb. Adrenal glands are paired, pyramid-shaped organs that are located on top of the kidneysc. Structurally and functionally they are two glands clumped into onei. Adrenal medulla- nervous tissue that acts as part of the somatic nervous system (SNS) These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.1. Responds to sympathetic innervationii. Adrenal cortex- glandular tissue derived from embryonic mesoderm1. responds mostly to humoral/tropic hormone cues2. secretes mainly steroid hormonesII. Adrenal Cortexa. Synthesizes and releases steroid hormones called corticosteroidsb. Different corticosteroids are produced in each of the three layers of the adrenal cortexi. Zona glomerulosa- mineralocorticoids (SALT)1. Outermost layer and chiefly aldosterone; globby structureii. Zona fasciculate- glucocorticoids (SUGAR)1. Chiefly cortisol and cortisone; parallel cordlike arrangementsiii. Zona reticularis- gonadocorticoids (SEX)1. Chiefly androgens; netlike structureIII. Mineralocorticoids-regulate the electrolyte concentrations of extracellular fluidsa. Aldosterone- most important mineralocorticoidi. Maintains the sodium balance by reducing excretion of sodium from the bodyii. Stimulates reabsorption of sodium by the kidneysiii. Aldosterone secretion is stimulated by: 1. Rising blood levels of potassium, low blood-sodium, and decreasing blood volume/pressureiv. Aldosterone is the primary driver of potassium secretionv. Mechanism of aldosterone secretion/inhibition:1. Renin-angiotensin mechanism- kidneys release renin, which is converted into angiotensin II that in turn stimulates aldosterone release2. Plasma concentration of sodium and potassium directly influencesthe zona glomerulosa cells3. ACTH causes a small increase of aldosterone during stress4. Atrial natriuretic peptide (ANP) inhibits activity of the zona glomerulosaIV. Glucocorticoids (Cortisol)a. Helps the body to resist stress by: i. Keeping blood sugar levels relatively constantii. Maintaining blood volume and preventing water shift into tissueb. Cortisol provokes:i. Gluconeogenesis, which is the formation of glucose from non-carbohydratesii. Rises in blood glucose, fatty acids, and amino acidsc. Excessive levels of glucocorticoids:i. Depress cartilage and bone formationii. Inhibit inflammationiii. Depress the immune systemiv. Promote changes in cardiovascular, neural, and gastrointestinal functionV. Gonadocorticoids (Sex Hormones)a. Most gonadocorticoids that are secreted are androgens, which are male sex hormonesi. The most important one is testosteroneb. Androgens contribute to:i. The onset of pubertyii. The appearance of secondary sex characteristicsiii. Sex drive in femalesc. Androgens can be converted into estrogens after menopauseVI. Adrenal Medullaa. Made up of chromaffin cells that secrete epinephrine and norepinephrineb. Secretion of these hormones causes:i. Blood glucose levels to riseii. Blood vessels to constrictiii. The heart to beat fasteriv. Blood to be diverted to the brain, heart, and skeletal musclec. Epinephrine is the more potent stimulator of the heart and metabolic activitiesd. Norepinephrine is more influential on peripheral vasoconstriction and blood pressureVII. Pancreasa. The pancreas is a triangular gland that has both exocrine and endocrine cells and is located behind the stomachb. Acinar cells produce an enzyme-rich juice used for digestion (exocrine product)c. Pancreatic islets, or islets of Langerhans, produce hormones (endocrine product)d. The islets contain two major cell types:i. Alpha cells- produce glucagonii. Beta cells- produce insuline. Glucagon- hormone that is a potent hyperglycemic agenti. Glucagon targets the liver where it promotes:1. Glycogenolysis- the breakdown of glycogen to glucose2. Gluconeogenesis- synthesis of glucose from lactic acid and non-carbohydrates3. Release of glucose to the blood from liver cellsf. Insulin- synthesized as part of proinsulin and then excised by enzymes, releasing functional insulini. Functions to: 1. Lower blood glucose levels2. Enhance transport of glucose into body cells3. Counter metabolic activity that would enhance blood glucose levelsg. Regulation of blood-glucose levels:i. The hyperglycemic effects of glucagon and the hypoglycemic effects of insulin work together in a negative feedback system to regulate blood-glucose levelsii. Hypoglycemic hormones:1. Insulin; adiponectiniii. Hyperglycemic hormones: 1. Glucagon; epinephrine/norepinephrine; glucocorticoids; hGH; resistinh. Diabetes Mellitus (DM)i. Results from hyposecretion or hypoactivity of insulinii. The three major signs of DM are:1. Polyuria- excessive urine output2. Polydipsia- excessive thirst3. Polyphagia- excessive hunger and food consumption VIII. Gonadsa. Female Gonads- paired ovaries in the abdominopelvic cavity produce estrogens and progesteronei. They are responsible for:1. Maturation of the reproductive organs2. Appearance of secondary sexual characteristics3. Breast development and cyclic changes in the uterine mucosab. Male Gonads- testes located in the scrotum that produce testosteronei. Testosterone functions to:1. Initiate maturation of male reproductive organs2. Causes appearance of secondary sexual characteristics and sex drive3. Maintains sex organs in their functional, or erect, stateIX. Pineal Glanda. The pineal gland is a small gland that hangs from the roof of the third ventricle ofthe brainb. The pineal gland secretes melatonin which is involved:i. Day/night cyclesii. Physiological processes that show rhythmic variations1. Examples- body temperature, sleep, appetiteX. Thymusa. The thymus is a lobulated gland located deep to the sternum in the thoraxb. Major hormonal products are thymopoietins and thymosinsi. These hormones are essential for the development of the T lymphocytes (T cells) of the immune systemXI. Other Hormone-Producing Structuresa. Heart-