7 Introduction to the Endocrine System About this Chapter Function in addition to purpose o

7 Introduction to the Endocrine System About this Chapter Function in addition to purpose o www.phwiki.com

7 Introduction to the Endocrine System About this Chapter Function in addition to purpose o

Peters, Brian, Meteorologist has reference to this Academic Journal, PHwiki organized this Journal 7 Introduction to the Endocrine System About this Chapter Function in addition to purpose of hormones Classification, structure, in addition to synthesis of hormones Pathways of nervous to endocrine regulation Effects of hormone interactions Pathologies of the endocrine system Hormone evolution Anatomy Summary: Hormones Figure 7-2 (1 of 4)

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Anatomy Summary: Hormones Figure 7-2 (2 of 4) Anatomy Summary: Hormones Figure 7-2 (3 of 4) Anatomy Summary: Hormones Figure 7-2 (4 of 4) Animation: Endocrine System: Endocrine System Review PLAY

General In as long as mation on Hormones Chemical Regulating Systems Hormones Depend on cell to cell communication molecules Made in gl in addition to (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, in addition to gene expression in addition to protein synthesis Exert effects at very low concentrations Bind to target cell receptors Half-life indicates length of activity Hormones: Classification Peptide or protein hormones Molecular structure includes amino acid chains Water soluble in addition to 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 gl in addition to , gonads, placenta) Not water soluble, lipophobic Enters the nucleus, affects transcription= genomic effect Amine hormones Small hormone derived from tryptophan in addition to tyrosine Catecholamines- epinephrine, norepinephrine, in addition to dopamine are neurohormones that are lipophobic Thyroid hormones – T3, T4, Thyroxine, are lipophilic in addition to bind intracellular receptors PLAY Hormones: Peptides or Proteins Preprohormone Large, inactive- be as long as e 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 –

Peptide Hormone Synthesis, Packaging, in addition to Release Figure 7-3 Peptide Hormone-Receptor Complex Membrane receptors in addition to signal transduction as long as peptide hormones Figure 7-5 Surface receptor Hormone binds Enzyme activation Open channels Second messenger systems Cellular response Steroid Hormones: Features Cholesterol-derived- made only in a few organs, synthesized as needed, not stored. Lipophilic in addition to can enter target cell – Cytoplasmic or nuclear receptors (mostly) – binds receptors intracellularly Activate DNA as long as protein synthesis – receptor-hormone 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, in addition to testosterone

Steroid Hormones: Structure Steroid hormones are derived from cholesterol Figure 7-6 Steroid Hormones: Action Figure 7-7 Steroid Hormones: Action Figure 7-7, steps 1–2a

Steroid Hormones: Action Figure 7-7, steps 1–4 Steroid Hormones: Action 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. Catecholamines- neurohormones that bind cell membrane receptors Epinephrine – Norepinephrine – Dopamine –

Endocrine Reflex Pathways Stimulus Hormones may have multiple stimuli as long as their release in addition to endocrine cells act as the receptor Afferent signal input signal Integration The cells that make the hormone must interpret the various signals in addition to decide how much to produce. Efferent signal Out put signal=hormone Physiological action Negative feedback PLAY The Pituitary Gl in addition to Anatomy Figure 7-11 The Pituitary Gl in addition to : Two Fused Figure 7-12 Posterior pituitary produces 1. Vasopressin (also called ADH) 2. Oxytocin

The Hypothalamic-Hypophyseal Portal System Figure 7-16 The Pituitary Gl in addition to : Two Fused Hormones of the hypothalamic-anterior pituitary pathway Figure 7-13 Endocrine Control Three levels Hypothalamic stimulation—from CNS Pituitary stimulation—from hypothalamic trophic hormones Endocrine gl in addition to stimulation—from pituitary trophic hormones Long-loop feedback Short-loop feedback

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Comparing two control Pathways Figure 7-15 Two types of Neuro hormones: Adrenal medulla Catecholamines 2. Hypothalamus Anterior pituitary Posterior pituitary Hormone Interactions Synergism Multiple stimuli—more than additive Permissiveness Need second hormone to get full expression Antagonism Glucagons opposes insulin 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 gl in addition to ular tissues Exogenous sources- most sources are medications or suppliments, can cause gl in addition to 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

Endocrine Pathologies Exogenous medication Replaces in addition to exceeds normal Cause atrophy of gl in addition to Figure 7-19 Primary in addition to Secondary Pathologies Figure 7-20 PLAY Primary in addition to Secondary hypersecretions are caused by abnormalities of different gl in addition to s along the hormone release path Pineal Gl in addition to in addition to 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 in addition to the onset of puberty

Pineal Gl in addition to in addition to Melatonin Figure 7-22 (1 of 3)

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