* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Animal Science 434 Reproductive Physiology
Survey
Document related concepts
Triclocarban wikipedia , lookup
Menstrual cycle wikipedia , lookup
Endocrine disruptor wikipedia , lookup
Neuroendocrine tumor wikipedia , lookup
Xenoestrogen wikipedia , lookup
Mammary gland wikipedia , lookup
Breast development wikipedia , lookup
Hormone replacement therapy (male-to-female) wikipedia , lookup
Bioidentical hormone replacement therapy wikipedia , lookup
Hyperandrogenism wikipedia , lookup
Hyperthyroidism wikipedia , lookup
Transcript
The endocrine system Major Endocrine Glands 15.1 Endocrine glands What is a target cell? Circulating and local hormones • • • Circulating hormones enter the blood. Paracrine hormones act on neighboring cells. Autocrine hormones act on the secreting cell. Hormones Receptors Long Distance Communication: Endocrine Hormones • • • • Signal Chemicals Made in endocrine cells Transported via blood Receptors on target cells Figure 6-2a: Long distance cell-to-cell communication Paracrine and Autocrine Hormones • • • Local communication Signal chemicals diffuse to target Example: Cytokines » Autocrine–receptor on same cell » Paracrine–neighboring cells Figure 6-1c: Direct and local cell-to-cell communication Mechanisms of Hormone Action • Endocrine – hormones • Paracrine – hormones • Autocrine secreted into the blood acting on downstream target tissues. secreted into the interstitial space acting at nearby cells. – hormones secreted into the interstitial space acting back on same cell. Figure 6-2b, c: Long distance cell-to-cell communication 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 Hormones are Extremely Powerful ACAT: acyl CoA;cholesterol acyl transferase; ACTH: adrenocorticotropic hormone AT: angiotensin II; LH: luteinizing hormone Acetyl CoA biosynthesis LDL Cholesterol from plasma outer membrane Cholesterol Cholesterol esters ACAT inhibited by: AT, ACTH , LH AT (ZG) ACTH (ZF) LH (gonads) StAR storage vacuole Fatty acids cholesterol esterase: activated by AT in ZG (IP3-DAG) ACTH in ZF (cAMP) LH in gonads (cAMP) Cholesterol Steroidogenic acute regulatory protein Pregnenolone SER MITOCHONDRION matrix inner membrane P-450scc: ACTH-activated: ZF AT-activated: ZG LH-activated: gonads Figure 2. Initial events common to the biosynthesis of steroid hormones Ca2+ Microfilaments ........ . 7 6 Secretory granules 5 Microtubules 4 Golgi Glucose Transfer uptake vesicles Figure 5. Structural components Endoplasmic reticulum (italicized) of the pancreatic -cell involved in glucose-induced biosynthesis and Biological structures Nucleus release of insulin. Granule fusion with membrane; Exocytosis of insulin Ca2+ contraction Of microfilaments Insulin storage Proinsulin to insulin; Packaging of insulin Transport of proinsulin to Golgi 3 2 1 Synthesis of preproinsul Uptake into ER; Excision of signal peptid Disulfide bonds formed mRNA production; Preproinsulin gene transcription Mechanism of Hormone Action Protein Hormones (cAMP second messenger) LH Receptor G Plasma Membrane Adenylate Cyclase R C S-ER Protein Kinase A (PKA) Steroid Synthesis Mitochondria Nucleus Protein Synthesis (Enzymes) Synthesis R-ER Protein DNA Mechanism of Hormone Action Protein Hormones (cAMP second messenger) LH G Receptor Plasma Membrane Adenylate Cyclase ATP cAMP S-ER cAMP R C Protein Kinase A (PKA) Steroid Synthesis Mitochondria Nucleus Protein Synthesis (Enzymes) Synthesis R-ER Protein DNA Mechanism of Hormone Action Protein Hormones (cAMP second messenger) LH G Receptor Plasma Membrane Adenylate Cyclase cAMP ATP R cAMP Protein Kinase A (PKA) S-ER Steroid Synthesis C (+ PO4) Mitochondria Histones Nucleus Protein Synthesis (Enzymes) Synthesis R-ER Protein mRNA DNA Mechanism of Hormone Action Protein Hormones (cAMP second messenger) LH G Receptor Plasma Membrane Adenylate Cyclase cAMP Testosterone ATP R cAMP Protein Kinase A (PKA) S-ER Steroid Synthesis C (+ PO4) Mitochondria Cholesterol Pregnenolone Histones Cholesterol Protein Synthesis (Enzymes) Synthesis R-ER Protein mRNA Nucleus DNA Nonsteroid Hormone Action Figure 9.1b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 9.9 Steroid Hormone Action Figure 9.1a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 9.7 Action of a steroid hormone HYPOTHALAMUS Master control Master integrator hypothalamus infundibulum PITUITARY GLAND AKA = hypophysis Infundibulum Sella turcica pituitary gland sella turcica in sphenoid bone Location of the Pituitary Sella turcica of the sphlenoid bone 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) Hypothalamic Hormones Hypothalamic Hormones: Gondotropin RF Corticotropin RF Thyrotropin RF Growth Hor RF Prolactin RF (CRF) Pituitary Hormones: Follicle SH & Lutenizing Hor. Adrenocorticoptropin Thyrotropin SH Growth Hormone Hormone (ACTH) Prolactin Target Gland or Structure: Ovaries & Testes (androgens, estrogen) Adrenal Gland Thyroid Gland (cortisol) (thyroxine) Cells of body Bones, breasts & cells of body Endocrine Feedback Loops • • Negative » gonadal steriods – Testosterone, Progesterone, Estradiol » Protein hormones – inhibin Positive » Gonadal steroids – estradiol Control of Hormonal Secretions • primarily controlled by negative feedback mechanism Positive/Negative Feedback loop Neural input Hypothalamus Inhibiting factors + Releasing factors Pituitary gland + Hormone A Target organ + Hormone B Important Point: Secretions are pulsatile vs. continuous Thyrotrophs (5%) Neural input Hypothalamus + Thyrotropin RH via dorsomedial nucleus Pituitary gland + TSH Thyroid Gland + T3(inhibitory) T4 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 Hypothalamus TRH Somatostatin Anterior Pituitary Estrogen Feedback inhibition on hypothalamus TRH secretion Thyrotropin (TSH) Growth hormone (GH) Glucocorticoids Thyroid gland Thyroid hormones (T4 and T3) Feedback inhibition on pituitary TSH secretion Complex negative feedback Controlling centers of the CNS Neural pathways Hypothalamus Hypothalamic hormones Adenohypophysis Adenohypophysal hormones Peripheral glands Hormones of peripheral glands Tissue 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) 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 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). 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. PARS INTERMEDIA: rudimentary in humans, lies between the pars distalis and pars nervosa. BE ABLE TO IDENTIFY THE STRUCTURES WITH HYPERLINKS Hormones of the Anterior Pituitary Figure 9.4 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 9.17 Anterior pituitary Regulation Hormone Target organ Action Pathology GHRH and GHIH Growth hormone (GH) Many cells (bones..) Stimulate cell growth and cell division - not enough: children pituitary dwarfism too much: gigantism (children) – acromegaly (adult) PRH - PIH Prolactin (PL) Breast secretory cells - milk secretion -- TRH Thyroid stimulating hormone (TSH) Thyroid gland - promote thyroid gland secretion (T3 and T4) - not enough: hypothyroidism (cretinism in children) - too much: hyperthyroidism CRH Adrenocorticotropic hormone (ACTH) Adrenal cortex (3 layers) - stimulates secretion of adrenal cortex - not enough: Addison's disease - too much: Cushing syndrome GnRH Gonadotropin - Follicle stimulating hormone (FSH) - Luteinizing hormone (LH) Stimulate gamete maturation Stimulate gonadal gland secretion and gamete formation - infertility Figure 6.8 Higher centers Stress Suckling stimulus Dopamine Ant Pituitary PRL Breast Milk production PRL Afferent Stimulatory pathway I I TRH + Control of Prolactin + + + Hypothalamus Stress + Ant Pituitary ACTH + Adrenal Gland Cortisol ACTH I Cortisol + CRH I Control of ACTH I I Hypothalamus Higher centres I + Dopamine Somatostatin I Ant Pituitary TSH + Thyroid Gland T3 + T4 TSH TRH I Control of TSH I I Hypothalamus + GnRH I I Ant Pituitary LH FSH + + Control of LH & FSH In Male I I Hypothalamus Testes Leydig Cells Sertoli cells + Testosterone Inhibin + GnRH I I+ Ant Pituitary LH FSH + + Control of LH & FSH In Female I I+ Hypothalamus Ovary Oestradiol Progesterone Inhibin Pituitary & Hypothalamus Hormones of the Posterior Pituitary Figure 9.5 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 9.22b Stretch receptors Stretch receptors Hypothalamus Post Pituitary Oxytocin Mammary gland + + Control of Oxytocin Higher Centers Uterus Higher Centers Hypothalamus Osmoreceptors Post Pituitary H2O Vasopressin Kidney Blood Vessel Stretch receptors Control of Vasopressin Baroreceptors ANTI-DIURETIC HORMONE AKA = vasopressin Hypothalamic osmoreceptors Water reabsorption dehydration increased interstitial fluid osmotic pressure stimulation of hypothalamic osmoreceptors ( -) secretion of ADH from posterior pituitary gland 1. WATER REABSORPTION BY KIDNEYS 2. decreased perspiration increased water in blood increased interstitial fluid osmotic pressure Hormones of Adenohypophysis • Somatotropes – human growth hormone (hGH) • Corticotropes – adrenocorticotropin (ACTH) » Melanocyte stimulating hormone (MSH) • Thyrotropes – Thyroid stimulating hormone (TSH) • Gonadotropes – gonadotropic hormones » Luteinizing hormone (LH) » Follicle stimulating hormone (FSH) • Lactotropes – prolactin (PRL) Hormonal Stimuli Figure 16.5c Figure 58-1 Hormones and releasing factors of the hypothalamus and pituitary. Hypothalamus Somatostatin - + GHRH Anterior pituitary gland GH Liver Cartilage and bone growth Muscle and other organs: -Protein synthesis and growth Adipose Tissue -lipolysis - release of FFAs Most Tissues glucose utilization - blood glucose Hypothalamus GHRH Somatostatin Anterior Pituitary Growth Hormone (GH) Liver Adipose Tissue IGF-1 synthesis and release Gluconeogenesis Glycogen synthesis -Oxidation of fatty acids Lipolysis Bone Bone and cartilage growth Muscle Glucose uptake Protein synthesis Amino acid uptake GROWTH HORMONE Promotion of secretion Regulation of secretion 1. HYPOGLYCEMIA (low blood sugar) 2. decreased blood fatty acids 3. increased blood amino acids 4. deep sleep hypoglycemia hyperglycemia inhibits GH-IF secretion Inhibits GH-RF secretion HYPOTHALAMUS Inhibition of secretion 1. HYPERGLYCEMIA (high blood sugar) 2. 3. 4. 5. 6. increased blood fatty acids decreased blood amino acids REM sleep obesity severe emotional states GH-RF GH-IF secretion on ANTERIOR PITUITARY GLAND growth hormone Actions 1. increased cellular uptake of amino acids = increased protein synthesis = growth/maintenance 2. increased lipolysis and gluconeogenesis for energy, leading to hyperglycemia = diabetogenic effect secretion off Growth hormone Growth factors http://www.maniacworld.com/worlds_tallest_man.htm People with this disease can also live a normal life like us. They too can get married and have kids. This is a picture of two dwarfs who are happily married with each other. PiCtUrEs This is a picture of two dwarfs that are at work. Dwarfs can also make friends. They have friends who aren’t dwarfs too. Back to Description Regulating blood osmolarity If amount of dissolved material in blood too high, need to dilute blood Dehydration Osmotic concentration of blood increases Negative feedback Lowers blood volume & pressure Osmoreceptors Negative feedback ADH synthesized in hypothalamus ADH Increased water retention Reduced urine volume ADH released from posterior pituitary into blood Increased vasoconstriction leading to higher blood pressure Antidiuretic Hormone Oxytocin • Two target tissues both involved in neuroendocrine reflexes Pituitary Gland Growth Hormone (GH) Too much Growth Hormone • • • Acromegaly: (↑ GH) irreversible enlarged cranium and jaw, bulging forehead, thick lips, big tongue enlarged cranium and jaw, Acromegaly Effect of growth hormone Dwarfism By Amy Evans PeDiGrEe AnD cHaRt BaCk To InHeRiTaNcE Control of ADH release …cont. 3. arterial blood pressure, due to blood volume ADH. 4. Age: ADH secretion water retention & hyponatremia. 5. Pain, emotional stress & physical trauma ADH secretion. 6. Drugs, e.g. morphine, barbiturates, & nicotine ADH secretion. 7. Alcohol ADH secretion.