BIOH 113 1st Edition Lecture 4Outline of Last Lecture I. Anatomical TerminologyII. Body CavitiesIII. MembranesIV. Other Body CavitiesOutline of Current Lecture I. Endocrine SystemII. Endocrine System FunctionIII. HormonesIV. Target CellsV. Hormone Blood ConcentrationsVI. Hormone and Target Cell InteractionsVII. Major Endocrine OrgansVIII. OxytocinIX. ADHCurrent LectureI. Endocrine Systema. The body’s second great controlling systemi. Influences metabolic activities of cells by means of hormonesb. Endocrine glands- pituitary, thyroid, parathyroid, adrenal, pineal and thymusc. The pancreas and gonads produce both hormones and exocrine productsd. The hypothalamus has both neural functions and releases hormonese. Other tissues and organs that produce hormones:i. Adipose cells, pockets of cells in the walls of the small intestine, stomach, kidneys, and heartII. Endocrine System Functiona. The endocrine system is able to function all throughout the body through hormonesi. Hormones are chemical substances secreted by cells that act throughout the body and have prolonged effectsThese 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.III. Hormonesa. Regulate metabolic function of other cellsb. Have lag times ranging from seconds to hoursc. Tend to have prolonged effectsd. Are classified as lipid soluble or watersolublee. Types of Hormonesi. Lipid Soluble- steroid, thyroid hormones, and nitric oxideii. Water Soluble- are amino acid based—most hormones belong to this class such as: amines, peptide and protein hormones, and eicosanoidsf. Hormone Action:i. Hormones alter target cell activity by one of two mechanisms1. Amino acid-based hormones use second messenger systems2. Steroid hormones use direct gene activation3. The response depends on the type of target cellii. Mechanism of hormone action:1. Hormones produce one or more of the following changes in targetcellsa. Alter plasma membrane permeabilityb. Stimulate protein synthesisc. Activate or deactivate enzyme systemsd. Induce secretory activitye. Stimulate mitosisIV. Target Cellsa. Target cell specificityi. Hormones circulate to all tissues but only activate their target cellsii. Target cells must have specific receptors for the hormones to bind toiii. These receptors may be intercellular or located on the plasma membraneb. Target cell activationi. Target cell activation depends on three factors1. Blood levels of the hormone2. Relative number of receptors on the target cell3. The affinity of those receptors for the hormonesii. Up-regulation- target cells form more receptors in response to the hormoneiii. Down-regulation- target cells lose receptors in response to the hormoneV. Hormone concentrations in the blooda. Hormones circulate in the blood in two forms—free or boundi. Steroids and thyroid hormone are attached to plasma proteinsii. All others are freeb. Control of hormone release:i. Blood levels of hormones are controlled by negative feedback systems and vary only within a narrow desirable rangec. Hormones are synthesized and released in response to:i. Humoral stimuliii. Neural stimuliiii. Hormonal stimuliVI. Interaction of Hormones at Target Cellsa. There are three types of hormone interaction:i. Permissiveness- one hormone cannot exert its effects without another hormone being presentii. Synergism- more than one hormone produces the same effects on a target celliii. Antagonism- one or more hormones opposes the action of another hormoneVII. Major Endocrine Organsa. Pituitary (Hypophysis):i. Pituitary gland- two-lobed organ that secretes nine major hormonesii. Neurohypophysis- posterior lobe (neural tissue) and the infundibulum1. Receives, stores, and released hormones from the hypothalamusiii. Adenohypophysis- anterior lobe, made up of glandular tissue1. Synthesizes and secretes multiple hormonesiv. Posterior pituitary- made of axons of hypothalamic neurons; also stores antidiuretic hormone (ADH) and oxytocin1. ADH and oxytocin are synthesized in the hypothalamus2. ADH influences water balance3. Oxytocin stimulates smooth muscle contraction in the breasts and uterus4. Both use second-messenger mechanismsv. Posterior Lobe- downgrowth of hypothalamic neural tissue1. Has a neural connection with the hypothalamus (hypothalamic-hypophyseal tract)2. Nuclei of the hypothalamus synthesizes oxytocin and ADH3. These hormones are transported to the posterior pituitaryVIII. Oxytocina. Strong stimulant of uterine contractionsb. Regulated by a positive feedback mechanism to oxytocin in the bloodc. This causes increased intensity of uterine contractions that only end in birthd. Oxytocin triggers milk ejection in women producing milke. In males and females, oxytocin plays a role in sexual arousal and orgasmIX. ADH—Antidiuretic Hormonea. ADH helps to avoid dehydration or water overloadb. Osmoreceptors monitor the solute concentration of the bloodc. With high solutes, ADH is synthesized and released—this preserves waterd. With low solutes, ADH is not released—causing water loss from the body (urination)e. Alcohol inhibits ADH release and causes urine