* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download INTEGUMENTARY SYSTEM
Survey
Document related concepts
Breast development wikipedia , lookup
Hormonal contraception wikipedia , lookup
Xenoestrogen wikipedia , lookup
Menstrual cycle wikipedia , lookup
Triclocarban wikipedia , lookup
History of catecholamine research wikipedia , lookup
Neuroendocrine tumor wikipedia , lookup
Hyperthyroidism wikipedia , lookup
Hormone replacement therapy (male-to-female) wikipedia , lookup
Mammary gland wikipedia , lookup
Bioidentical hormone replacement therapy wikipedia , lookup
Hyperandrogenism wikipedia , lookup
Endocrine disruptor wikipedia , lookup
Transcript
ENDOCRINE SYSTEM Endocrine - General Major Control System of Homeostasis Negative Feedback Ductless Glands; Produce Hormones Diffuse into Blood Slow Initial Effects, but Effects Persist much longer Hormones act on specific Targets Classification of Glands Endocrine – ductless glands that secrete hormones into the blood stream Exocrine – ducted glands that secrete their products onto a surface Hormones – Definition Definitions - Literal: To spur on, to set in motion - Physiological: A chemical messenger that affects another tissue or organ (the target) Hormones - General Function Modify activity of target cells Targets have specific receptors for the particular hormone Distributed by blood Location of Receptors Cell Surface - cell membrane Intracellular - Cytoplasm - Nucleus Mechanisms of Hormone Action Steroids (Synthesized from Cholesterol) - Hormone enters cell Hormone forms complex with receptor Hormone/receptor complex enters nucleus Complex binds to DNA Protein synthesis occurs Protein alters cell function (i.e. produces the effect) - E.g. Testosterone Mechanisms of Hormone Action continued Non-Steroids (Proteins/Peptides/Amine) Hormones - Hormone does not enter cell - Hormone is 1st messenger - Hormone binds to receptor on cell membrane - Triggers formation of 2nd messenger (cyclic AMP) - 2nd messenger alters cellular activities (i.e. produce the effect) - E.g. Pituitary hormones Regulation by Receptors Changeable Number of receptors on target - Up Regulation * Low hormone levels * Number of receptors increases * Target’s responsiveness increases - Down Regulation * Excess hormone levels * Number of receptors decreases * Target’s responsiveness decreases Secretion Stimuli Hormonal - Tropic hormones regulate activity of other endocrine glands - Most common Humoral - Changing levels of ion or nutrients trigger release of hormones Neural - Stimulated by nerve fibers Hormonal Stimuli of Endocrine Glands Endocrine glands are activated by other hormones Figure 9.2a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 9.11 Humoral Stimuli of Endocrine Glands Changing blood levels of certain ions or nutrients stimulate hormone release Figure 9.2b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 9.12 Neural Stimuli of Endocrine Glands Nerve impulses stimulate hormone release Most are under control of the sympathetic nervous system Figure 9.2c Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 9.13 Endocrine Organs Hypothalamus Pituitary - Anterior - Posterior Thyroid Gland Parathyroid Glands Adrenal Glands - Cortex - Medulla Pancreas Pineal Gland Thymus Gonads Hypothalamus Integrates Nervous System & Endocrine Portal Circulation carries hormones to Anterior Pituitary Releasing Factors (hormones) stimulate secretion by Anterior Pituitary Inhibiting Factors (hormones) are antagonistic to Releasing Nervous tissue carries hormones to Posterior Pituitary Pituitary Gland Attached to Hypothalamus via infundibulum Protected by sella turcica of sphenoid Divided into 2 lobes: - Anterior (glandular) - Posterior (neuroendocrine) Anterior Pituitary (Adenohypophysis) “Master Gland” (makes & secretes various tropic hormones) Tropic Hormones - Act on other Endocrine Glands - Serve as Hormonal Stimuli - Stimulate release of another hormone Anterior Pituitary (Adenohypophysis) - Human Growth Hormone (GH): *Target: All/Most Body Cells (esp. Bone & Muscle) *Action: Promotes Growth & Repair, *Increases Blood Glucose - Prolactin (PRL): *Target: Mammary Tissue *Action: Promotes milk secretion Anterior Pituitary continued Thyroid Stimulating Hormone (TSH) - Target: Thyroid Gland - Action: Stimulates production of Thyroxine Anterior Pituitary continued Adrenocorticotropic Hormones (ACTH) - Target: Adrenal Cortex - Action: Controls production/secretion adrenal cortex hormones Gonadotropic Hormones - Follicle Stimulating Hormone (FSH) * Target: Gonads (Ovaries/Testes) * Action: Production of gametes & sex hormones Anterior Pituitary continued - Luteinizing Hormone (LH/ICSH) *Target: Gonads *Functions: Production of sex hormones Prepare uterus for implantation Develop corpus luteum Hormones of the Anterior Pituitary Figure 9.4 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 9.17 Posterior Pituitary (Neurohypophysis) Does NOT synthesize Hormones Neural rather than glandular Stores & Releases two hormones produced by hypothalamus - Oxytocin *Target: Uterus & Mammary Glands *Action: Stimulates Contractions to eject fetus & milk Posterior Pituitary continued - Antidiuretic Hormone (ADH) also called vasopressin *Target: Kidneys *Action: Conserve Water (decrease urine volume) Increase BP Hormones of the Posterior Pituitary Figure 9.5 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 9.22b Thyroid Gland Thyroid Hormone - T3 (Triiodothyronine), T4 (Thyroxine) - Target: Most body cells - Action: Increase metabolic rate, regulate body temperature Calcitonin - Target: Bone/Osteoclast Inhibition - Action: Decrease blood Ca2+ (Hypocalcemia if excessive) Parathyroid Glands Parathyroid Hormone - Target: Bone/Stimulation of Osteoclasts - Action: Increase blood Ca2+ (Hypercalcemia if excessive) Parathyroid Glands Tiny masses on the posterior of the thyroid Secrete parathyroid hormone (PTH) Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 9.26 Adrenal Glands Adrenal Cortex (outer/glandular) - Cortisol * Target: Many tissues * Action: make glucose, decrease inflammation - Aldosterone * Target: Kidneys * Action: Maintain Na+/K+ blood levels Adrenal Glands continued Adrenal Medulla (inner/nervous) - Epinephrine/Adrenalin (Fear/Flight) - Norepinephrine/Noradrenalin (Anger/Fight) - Targets:Heart, Liver, Muscles, Blood Vessels, etc. - Functions: Prepare for sudden threat Pancreas Endocrine (Islets of Langerhans) & Exocrine Glucagon (from Alpha Cells) - Target: Liver - Action: Release glucose from glycogen (increases blood glucose) Insulin (from Beta Cells) - Target: Most/All Cells - Action: Promotes glucose transport into cells (decreases blood glucose) Pineal & Thymus Glands Pineal Gland (Endocrine & CNS) - Melatonin * Target: Hypothalamus * Action: Sets Diurnal Clock/Circadian rhythm & promotes sleep Thymus (atrophies at puberty) - Thymosins * Target: T cells of immune system * Action: T cell maturation (immunocompetence) Gonads Ovaries - Estrogen * Target: Uterus, Ovaries, other * Action: prepare for fetus, secondary sexual characteristics - Progesterone * Target: Uterus * Action: maintains pregnancy, prevents uterine contractions Gonads continued Testes - Testosterone *Target: Various body parts *Action: Secondary sexual characteristics