POWERPOINT LECTURE SLIDE PRESENTATION by ZARA OAKES MS
POWERPOINT® LECTURE SLIDE PRESENTATION by ZARA OAKES, MS, The University of Texas at Austin UNIT 2 7 PART A Introduction to the Endocrine System HUMAN PHYSIOLOGY AN INTEGRATED APPROACH DEE UNGLAUB SILVERTHORN Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings FOURTH EDITION
About this Chapter § Function and purpose of hormones § Classification, structure, and synthesis of hormones § Pathways of nervous to endocrine regulation § Effects of hormone interactions § Pathologies of the endocrine system § Hormone evolution Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings
Anatomy Summary: Hormones Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 7 -2 (1 of 4)
Anatomy Summary: Hormones Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 7 -2 (2 of 4)
Anatomy Summary: Hormones Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 7 -2 (3 of 4)
Anatomy Summary: Hormones PLAY Animation: Endocrine System Review Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 7 -2 (4 of 4)
General Information on Hormones Chemical Regulating Systems § Hormones § § § Depend on cell to cell communication molecules Made in gland(s) or cells Transported by blood Distant target tissue receptors Activates physiological response § Pheromones: organism to organism communication Hormone Function § Control rates of enzymatic reactions, transport of ions or molecules across cell membranes, and gene expression and protein synthesis § Exert effects at very low concentrations § Bind to target cell receptors § Half-life indicates length of activity Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings
Hormones: Classification § Peptide or protein hormones § Molecular structure includes amino acid chains § Water soluble and lipophobic = bind cell receptor § short life-time but triggers rapid respondses § Steroid hormones § § Molecular structure includes a cholesterol molecule. Made only in few organs (adrenal gland, gonads, placenta) Not water soluble, lipophobic Enters the nucleus, affects transcription= genomic effect § Amine hormones § Small hormone derived from tryptophan and tyrosine § Catecholamines- epinephrine, norepinephrine, and dopamine are neurohormones that are lipophobic § Thyroid hormones – T 3, T 4, Thyroxine, are lipophilic and bind intracellular receptors Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings
Hormones: Peptides or Proteins § Preprohormone § Large, inactive- before being processed they may have multiple copies of a peptide hormone § Prohormone § Post-translational modification - inactive prehormones are cleaved by proteolytic enzymes § Peptide hormone-receptor complex § Signal transduction system - Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings
Peptide Hormone Synthesis, Packaging, and Release 1 Messenger RNA on the 2 Enzymes in the 3 The prohormone 4 Secretory vesicles containing 5 The secretory 6 The hormone ribosomes binds amino acids into a peptide chain called a preprohormone. The chain is directed into the ER lumen by a signal sequence of amino acids. ER chop off the signal sequence, creating an inactive prohormone. passes from the ER through the Golgi complex. enzymes and prohormone bud off the Golgi. The enzymes chop the prohormone into one or more active peptides plus additional peptide fragments. vesicle releases its contents by exocytosis into the extracellular space. Golgi complex Endoplasmic reticulum (ER) To target Ribosome Active hormone Transport vesicle Peptide fragment 3 4 Prohormone 6 Secretory vesicle Release signal 5 Capillary endothelium 2 1 m. RNA moves into the circulation for transport to its target. Signal sequence Cytoplasm ECF Plasma Preprohormone Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 7 -3
Peptide Hormone-Receptor Complex Membrane receptors and signal transduction for peptide hormones Surface receptor Hormone binds Enzyme activation Open channels Second messenger systems Cellular response Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 7 -5
Steroid Hormones: Features § Cholesterol-derived- made only in a few organs, synthesized as needed, not stored. § Lipophilic and can enter target cell - § Cytoplasmic or nuclear receptors (mostly) – binds receptors intracellularly § Activate DNA for protein synthesis – receptorhormone complexes act as transcription factors. § Slower acting, longer half-life – because of it’s slow rate of activation they do not mediate reflex pathways. § Examples§ Cortisol, estrogen, and testosterone Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings
Steroid Hormones: Structure Steroid hormones are derived from cholesterol Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 7 -6
Steroid Hormones: Action 1 Most hydrophobic steroids are bound to plasma protein carriers. Only unbound hormones can diffuse into the target cell. 2 Steroid hormone receptors are typically in the cytoplasm or nucleus. 2 a Some steroid hormones also bind to membrane receptors that use second messenger systems to create rapid cellular responses. 3 The receptorhormone complex binds to DNA and activates or represses one or more genes. Blood vessel Steroid hormone Cell surface receptor 2 a Rapid responses 1 2 Protein carrier Nucleus Cytoplasmic receptor Nuclear receptor DNA Interstitial fluid Cell membrane 3 Endoplasmic reticulum 5 New proteins 4 Activated genes create new m. RNA that moves into the cytoplasm. Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Transcription produces m. RNA 4 Translation 5 Translation produces new proteins for cell processes. Figure 7 -7
Steroid Hormones: Action 1 Most hydrophobic steroids are bound to plasma protein carriers. Only unbound hormones can diffuse into the target cell. 2 Steroid hormone receptors are typically in the cytoplasm or nucleus. 2 a Some steroid hormones also bind to membrane receptors that use second messenger systems to create rapid cellular responses. Blood vessel Steroid hormone Cell surface receptor 2 a Rapid responses 1 2 Protein carrier Nucleus Cytoplasmic receptor Nuclear receptor Interstitial fluid Cell membrane Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 7 -7, steps 1– 2 a
Steroid Hormones: Action 1 Most hydrophobic steroids are bound to plasma protein carriers. Only unbound hormones can diffuse into the target cell. 2 Steroid hormone receptors are typically in the cytoplasm or nucleus. 2 a Some steroid hormones also bind to membrane receptors that use second messenger systems to create rapid cellular responses. 3 The receptorhormone complex binds to DNA and activates or represses one or more genes. Blood vessel Steroid hormone Cell surface receptor 2 a Rapid responses 1 2 Protein carrier Nucleus Cytoplasmic receptor Nuclear receptor DNA Interstitial fluid 3 Transcription produces m. RNA Cell membrane 4 4 Activated genes create new m. RNA that moves into the cytoplasm. Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 7 -7, steps 1– 4
Steroid Hormones: Action 1 Most hydrophobic steroids are bound to plasma protein carriers. Only unbound hormones can diffuse into the target cell. 2 Steroid hormone receptors are typically in the cytoplasm or nucleus. 2 a Some steroid hormones also bind to membrane receptors that use second messenger systems to create rapid cellular responses. 3 The receptorhormone complex binds to DNA and activates or represses one or more genes. Blood vessel Steroid hormone Cell surface receptor 2 a Rapid responses 1 2 Protein carrier Nucleus Cytoplasmic receptor Nuclear receptor DNA Interstitial fluid Cell membrane 3 Endoplasmic reticulum 5 New proteins 4 Activated genes create new m. RNA that moves into the cytoplasm. Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Transcription produces m. RNA 4 Translation 5 Translation produces new proteins for cell processes. Figure 7 -7, steps 1– 5
Amine Hormones: Features § Derived from one of two amino acids § Tryptophan – double ring amino acid § Tyrosine-single ring amino acid § Ring structure§ Thyroid hormones- bind intracellular receptors. § Catecholaminesneurohormones that bind cell membrane receptors § Epinephrine § Norepinephrine § Dopamine Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings
Endocrine Reflex Pathways § Stimulus Hormones may have multiple stimuli for their release and endocrine cells act as the receptor § Afferent signal input signal § Integration The cells that make the hormone must interpret the various signals and decide how much to produce. § Efferent signal Out put signal=hormone § Physiological action § Negative feedback Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings
The Pituitary Gland Anatomy Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 7 -11
The Pituitary Gland: Two Fused Posterior pituitary produces 1. Vasopressin (also called ADH) 2. Oxytocin Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 7 -12
The Hypothalamic-Hypophyseal Portal System Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 7 -16
The Pituitary Gland: Two Fused Hormones of the hypothalamic-anterior pituitary pathway Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 7 -13
Endocrine Control § Three levels § Hypothalamic stimulation —from CNS § Pituitary stimulation—from hypothalamic trophic hormones § Endocrine gland stimulation—from pituitary trophic hormones § Long-loop feedback § Short-loop feedback Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings
Comparing two control Pathways Two types of Neuro hormones: 1. Adrenal medulla 2. Catecholamin es 2. Hypothalamus Anterior pituitary Posterior pituitary Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 7 -15
Hormone Interactions § Synergism § Multiple stimuli—more than additive § Permissiveness § Need second hormone to get full expression § Antagonism § Glucagons opposes insulin Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings
Endocrine Pathologies § Hormone disease is caused by an imbalance due to either excess or deficiency or abnormal responsiveness § Hypersecretion: excess hormone causes exaggerated effects § Tumors (benign or cancerous) of glandular tissues § Exogenous sources- most sources are medications or suppliments, can cause gland atrophy § Grave’s disease—high secretion of thyroxin§ Hyposecretion: deficient hormone § Most often low levels cause increased tropic hormone levels § Goiter— low secretion of thyroxin § Diabetes—low secretion of insulin § Abnormalities related to hormone response § Target tissues do not respond to the hormone correctly § Downregulation- high hormone levels may result in a decrease of receptors as it happens in Hyperinsulinemia § Receptor abnormalities- the receptors may not function due to a genetic mutation as it happens in Testicular feminization syndrome Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings
Endocrine Pathologies § Exogenous medication § Replaces and exceeds normal § Cause atrophy of gland Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 7 -19
Primary and Secondary Pathologies Primary and Secondary hypersecreti ons are caused by abnormalitie s of different glands along the hormone release path Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 7 -20
Pineal Gland Melatonin § Influences body clock- sets sleep-wake cycles § Antioxidant activity- neutralizes free radicals § Other roles need research § SAAD - seasonal affective depressive disorder § sexual behavior- sexual function and the onset of puberty Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings
Pineal Gland Melatonin Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 7 -22 (1 of 3)
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