the endocrine system. major endocrine glands what is a target cell? 15.1 endocrine glands

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  • Slide 1
  • The endocrine system
  • Slide 2
  • Major Endocrine Glands
  • Slide 3
  • What is a target cell? 15.1 Endocrine glands
  • Slide 4
  • Circulating and local hormones Circulating hormones enter the blood. Paracrine hormones act on neighboring cells. Autocrine hormones act on the secreting cell.
  • Slide 5
  • Hormones Receptors
  • Slide 6
  • Signal Chemicals Made in endocrine cells Transported via blood Receptors on target cells Long Distance Communication: Endocrine Hormones Figure 6-2a: Long distance cell-to-cell communication
  • Slide 7
  • Paracrine and Autocrine Hormones Local communication Signal chemicals diffuse to target Example: Cytokines Autocrinereceptor on same cell Paracrineneighboring cells Figure 6-1c: Direct and local cell-to-cell communication
  • Slide 8
  • Mechanisms of Hormone Action Endocrine hormones secreted into the blood acting on downstream target tissues. Paracrine hormones secreted into the interstitial space acting at nearby cells. Autocrine hormones secreted into the interstitial space acting back on same cell.
  • Slide 9
  • Figure 6-2b, c: Long distance cell-to-cell communication
  • Slide 10
  • Comparison of Nervous System and Endocrine System Neurons release neurotransmitters into a synapse, affecting postsynaptic cells Glands release hormones into the bloodstream Only target cells of hormone responds
  • Slide 11
  • Hormones are Extremely Powerful
  • Slide 12
  • ACAT: acyl CoA;cholesterol acyl transferase; ACTH: adrenocorticotropic hormone AT: angiotensin II; LH: luteinizing hormone Fatty acids Cholesterol cholesterol esterase: activated by AT in ZG (IP 3 -DAG) ACTH in ZF (cAMP) LH in gonads (cAMP) MITOCHONDRION matrix Pregnenolone SER Cholesterol esters storage vacuole Cholesterol Acetyl CoA LDL Cholesterol from plasma ACAT biosynthesis AT (ZG) ACTH (ZF) LH (gonads) StAR outer membrane inner membrane Steroidogenic acute regulatory protein P-450 scc : ACTH-activated: ZF AT-activated: ZG LH-activated: gonads Figure 2. Initial events common to the biosyn- thesis of steroid hormones inhibited by: AT, ACTH, LH
  • Slide 13
  • mRNA production; Preproinsulin gene transcription 1 Figure 5. Structural components (italicized) of the pancreatic -cell involved in glucose-induced biosynthesis and release of insulin. Glucose uptake Transport of proinsulin to Golgi 3 vesicles Transfer Synthesis of preproinsulin; Uptake into ER; Excision of signal peptide; Disulfide bonds formed 2 Endoplasmic reticulum Microfilaments Golgi Proinsulin to insulin; Packaging of insulin 4 Insulin storage 5 Microtubules Secretory granules Ca 2+ contraction Of microfilaments 6......... Granule fusion with membrane; Exocytosis of insulin 7 Ca 2+ Biological structures Nucleus
  • Slide 14
  • Mechanism of Hormone Action Receptor Protein Kinase A (PKA) Nucleus DNA Protein Synthesis (Enzymes) Plasma Membrane Protein Hormones (cAMP second messenger) Protein Hormones (cAMP second messenger) C R R-ER Protein Synthesis Mitochondria S-ER Steroid Synthesis LH G Adenylate Cyclase
  • Slide 15
  • Mechanism of Hormone Action Receptor Protein Kinase A (PKA) Nucleus DNA Protein Synthesis (Enzymes) Plasma Membrane Protein Hormones (cAMP second messenger) Protein Hormones (cAMP second messenger) G Adenylate Cyclase C R cAMP LH ATP cAMP C R R-ER Protein Synthesis Mitochondria S-ER Steroid Synthesis
  • Slide 16
  • C R cAMP Mechanism of Hormone Action Receptor Protein Kinase A (PKA) Nucleus DNA Histones Protein Synthesis (Enzymes) Plasma Membrane Protein Hormones (cAMP second messenger) Protein Hormones (cAMP second messenger) G Adenylate Cyclase LH ATP cAMP (+ PO 4 ) R-ER Protein Synthesis Mitochondria S-ER Steroid Synthesis mRNA
  • Slide 17
  • Mechanism of Hormone Action Receptor Protein Kinase A (PKA) Nucleus DNA Histones Protein Synthesis (Enzymes) mRNA Plasma Membrane Protein Hormones (cAMP second messenger) Protein Hormones (cAMP second messenger) Cholesterol G Adenylate Cyclase C R cAMP LH ATP cAMP (+ PO 4 ) R-ER Protein Synthesis Mitochondria Cholesterol Pregnenolone S-ER Steroid Synthesis Testosterone
  • Slide 18
  • Nonsteroid Hormone Action Slide 9.9 Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 9.1b
  • Slide 19
  • Steroid Hormone Action Slide 9.7 Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 9.1a
  • Slide 20
  • Slide 21
  • Action of a steroid hormone
  • Slide 22
  • Master control Master integrator HYPOTHALAMUS PITUITARY GLAND AKA = hypophysis Infundibulum Sella turcica hypothalamus infundibulum pituitary gland sella turcica in sphenoid bone
  • Slide 23
  • Sella turcica of the sphlenoid bone Location of the Pituitary
  • Slide 24
  • Slide 25
  • Hypothalamic releasing & inhibiting hormones Thyrotropin releasing hormone (TRH) Corticotropin releasing hormone (CRH) Growth hormone releasing hormone (GHRH) Growth hormone inhibitory hormone (GHIH) (Somatostatin) Gonadotropin releasing hormone (GnRH) Prolactin inhibitory hormone (PIH) Prolactin releasing hormone (PRH)
  • Slide 26
  • Hypothalamic Hormones
  • Slide 27
  • Slide 28
  • Hypothalamic Hormones: Gondotropin RFCorticotropin RF (CRF) Thyrotropin RFGrowth Hor RFProlactin RF Pituitary Hormones: Follicle SH & Lutenizing Hor. Thyrotropin SHAdrenocorticoptropin Hormone (ACTH) ProlactinGrowth Hormone Target Gland or Structure: Ovaries & Testes (androgens, estrogen) Adrenal Gland (cortisol) Cells of body Thyroid Gland (thyroxine) Bones, breasts & cells of body
  • Slide 29
  • Endocrine Feedback Loops Negative gonadal steriods Testosterone, Progesterone, Estradiol Protein hormones inhibin Positive Gonadal steroids estradiol
  • Slide 30
  • Slide 31
  • Control of Hormonal Secretions primarily controlled by negative feedback mechanism
  • Slide 32
  • Hypothalamus Pituitary gland Target organ Hormone A Hormone B Releasing factors Inhibiting factors Neural input + + + Positive/Negative Feedback loop Important Point: Secretions are pulsatile vs. continuous
  • Slide 33
  • Hypothalamus Pituitary gland Thyroid Gland TSH T3( inhibitory) T4 Thyrotropin RH via dorsomedial nucleus Neural input + + + Thyrotrophs (5%) Defects? Hypothyroidism - At the level of the pituitary gland results in low levels of TSH and T3/T4 - At the level of the thyroid gland results in normal levels of TSH and low levels of T3/T4
  • Slide 34
  • Hypothalamus Anterior Pituitary TRH Somatostatin Thyrotropin (TSH) Thyroid gland Estrogen Growth hormone (GH) Glucocorticoids Thyroid hormones (T 4 and T 3 ) Feedback inhibition on hypothalamus TRH secretion Feedback inhibition on pituitary TSH secretion
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Complex negative feedback Controlling centers of the CNS Neural pathways Hypothalamus Hypothalamic hormones Adenohypophysis Adenohypophysal hormones Peripheral glands Hormones of peripheral glands Tissue
  • Slide 39
  • Negative Feedback Regulation of Spermatogenesis both testosterone and inhibin feed back to hypothalamus and pituitary to inhibit FSH and LH secretion sperm production maintained at a relatively constant level (note: testosterone also needed for sperm production)
  • Slide 40
  • Slide 41
  • Pituitary gland Be able to identify which hormone comes from the anterior and posterior pituitary Hormones: FSH, LH, ACTH, TSH, GH, PRL, MSH, OT, ADH
  • Slide 42
  • Pituitary gland (the hyperlinks work on this page) PARS DISTALIS: chromophils (50%) and chromophobes (50%). The chromophils can be further subdivided into acidophils (40%) and basophils (10%). The acidophils secrete GH (somatotropes) and prolactin (mammotropes). Basophils secrete TSH (thyrotropes), LH (gonadotropes), FSH (gonadotropes), and ACTH (corticotropes). chromophobesacidophils basophils PARS NERVOSA: main cell type here is a glial or supporting cell called a pituicyte. The bulk of the pars nervosa consists of axons from neurons in the supraoptic and paraventricular nuclei of the hypothalamus.pituicyteaxons PARS INTERMEDIA: rudimentary in humans, lies between the pars distalis and pars nervosa. BE ABLE TO IDENTIFY THE STRUCTURES WITH HYPERLINKS
  • Slide 43
  • Slide 44
  • Hormones of the Anterior Pituitary Slide 9.17 Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 9.4
  • Slide 45
  • Figure 6.8 Anterior pituitary RegulationHormoneTarget organActionPathology GHRH and GHIHGrowth hormone (GH)Many cells (bones..)Stimulate cell growth and cell division - not enough: children pituitary dwarfism too much: gigantism (children) acromegaly (adult) PRH - PIHProlactin (PL)Breast secretory cells - milk secretion-- TRHThyroid stimulating hormone (TSH) Thyroid gland- promote thyroid gland secretion (T3 and T4) - not enough: hypothyroidism (cretinism in children) - too much: hyperthyroidism CRHA