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Trouble brewing? . Trouble brewing? 2 choices…. Trouble brewing? 2 choices…. OR. © 2011 Pearson Education, Inc. Two systems coordinate communication throughout the body: the endocrine system and the nervous system
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© 2011 Pearson Education, Inc. Two systems coordinate communication throughout the body: the endocrine system and the nervous system • The endocrine system secretes hormones that coordinate slower but longer-acting responses including reproduction, development, energy metabolism, growth, and behavior • The nervous system conveys high-speed electrical signals along specialized cells called neurons; these signals regulate other cells
Figure 45.1What signals caused this butterfly to grow within the body of a caterpillar?
Chapter 45 Hormones and the Endocrine System
Andre the Giant had acromegaly: HGH secreted in adulthood To what would hyposecretion of HGH in childhood lead?
Methods of intercellular communication by secreted molecules Bloodvessel Response (a) Endocrine signaling Response (b) Paracrine signaling – short distances Response (c) Autocrine signaling – short distances Synapse Neuron Response (d) Synaptic signaling Neurosecretorycell Bloodvessel Response (e) Neuroendocrine signaling
© 2011 Pearson Education, Inc. Synaptic and Neuroendocrine Signaling • In synaptic signaling, neurons form specialized junctions with target cells, called synapses • At synapses, neurons secrete molecules called neurotransmitters that diffuse short distances and bind to receptors on target cells • In neuroendocrine signaling, specialized neurosecretory cells secrete molecules called neurohormones that travel to target cells via the bloodstream
© 2011 Pearson Education, Inc. Signaling by Pheromones, hormones outside the self • Members of the same animal species sometimes communicate with pheromones, chemicals that are released into the environment • Pheromones serve many functions, including marking trails leading to food, defining territories, warning of predators, and attracting potential mates
Major endocrine glands: Hypothalamus Figure 45.4 Pineal gland Pituitary gland Organs containingendocrine cells: Thyroid gland Thymus Parathyroid glands(behind thyroid) Heart Liver Adrenal glands(atop kidneys) Stomach Kidneys Pancreas Smallintestine Ovaries (female) Testes (male) • Endocrine glands secrete hormones directly into surrounding fluid • Vs. exocrine glands, which have ducts and which secrete substances onto body surfaces or into cavities
Example Pathway A simple endocrine pathway Low pH in duodenum Stimulus S cells of duodenumsecrete the hormonesecretin ( ). Endocrinecell Hormone Negative feedback Bloodvessel Targetcells Pancreas Response Bicarbonate release
Example Pathway A simple neuroendocrine pathway Stimulus Suckling Sensoryneuron Hypothalamus/posterior pituitary Posterior pituitarysecretes theneurohormoneoxytocin ( ). Neurosecretory cell Neurohormone Positive feedback Blood vessel Targetcells Smooth muscle inbreasts Response Milk release
Water-soluble (hydrophilic) Lipid-soluble (hydrophobic) Polypeptides Steroids 3 Chemical classes of hormones 0.8 nm Insulin Cortisol Amines Epinephrine Thyroxine
SECRETORYCELL Receptor location varies with hormone type. Lipid-solublehormone Water-solublehormone VIABLOOD Transportprotein Signal receptor TARGETCELL Signalreceptor NUCLEUS (a) (b)
SECRETORYCELL Figure 45.6-2 Lipid-solublehormone Water-solublehormone VIABLOOD Transportprotein Signal receptor TARGETCELL OR Signalreceptor Cytoplasmicresponse Generegulation Cytoplasmicresponse Generegulation NUCLEUS (a) (b)
© 2011 Pearson Education, Inc. Animation: Water-Soluble Hormone Right-click slide / select”Play”
Figure 45.7-1 Epinephrine (aka) adrenaline, has multiple effects Epinephrine Adenylylcyclase G protein GTP G protein-coupledreceptor ATP Secondmessenger cAMP
Figure 45.7-2 Epinephrine Adenylylcyclase G protein GTP G protein-coupledreceptor ATP Secondmessenger cAMP Proteinkinase A Inhibition ofglycogen synthesis Promotion ofglycogen breakdown
© 2011 Pearson Education, Inc. Animation: Lipid-Soluble HormoneRight-click slide / select”Play”
EXTRACELLULARFLUID Hormone(estradiol) Steroid hormone receptors directly regulate gene expression Estradiol(estrogen)receptor Plasmamembrane Hormone-receptorcomplex
EXTRACELLULARFLUID Hormone(estradiol) Figure 45.8-2 Estradiol(estrogen)receptor Plasmamembrane Hormone-receptorcomplex NUCLEUS CYTOPLASM DNA Vitellogenin mRNAfor vitellogenin
© 2011 Pearson Education, Inc. Multiple Effects of Hormones • The same hormone may have different effects on target cells that have for two reasons:
© 2011 Pearson Education, Inc. Multiple Effects of Hormones • The same hormone may have different effects on target cells that have for two reasons: • Different receptors for the hormone • Different signal transduction pathways
© 2011 Pearson Education, Inc. Multiple Effects of Hormones • The same hormone may have different effects on target cells that have for two reasons: • Different receptors for the hormone • Different signal transduction pathways Also…… 3. “Love on a bridge study”
(b) Skeletal muscleblood vessel (c) Intestinal bloodvessel Same receptors but differentintracellular proteins (not shown) Different receptors One hormone, different effects Different cellularresponses Different cellularresponses Epinephrine Epinephrine Epinephrine receptor receptor receptor Glycogendeposits Vesseldilates. Vesselconstricts. Glycogenbreaks downand glucoseis releasedfrom cell. (a) Liver cell
Brain Neurosecretory cells Regulation of insect development and metamorphosis Corpora cardiaca Corpora allata PTTH Prothoracicgland Juvenilehormone (JH) Ecdysteroid EARLYLARVA
Brain Neurosecretory cells Regulation of insect development requires multiple hormones Corpora cardiaca Corpora allata PTTH Prothoracicgland Juvenilehormone (JH) Ecdysteroid EARLYLARVA LATERLARVA
Brain Neurosecretory cells Figure 45.10-3 Corpora cardiaca Corpora allata PTTH Prothoracicgland Juvenilehormone (JH) LowJH Ecdysteroid EARLYLARVA LATERLARVA PUPA ADULT
Maintenance of glucose homeostasis is done by paired hormones, insulin and glucagon Insulin Beta cells ofpancreasrelease insulininto the blood. STIMULUS:Blood glucose level rises (for instance, after eating acarbohydrate-rich meal). Homeostasis:Blood glucose level(70–110 mg/100 mL)
Figure 45.13a-2 Insulin Body cellstake up moreglucose. Beta cells ofpancreasrelease insulininto the blood. Liver takesup glucose and stores itas glycogen. STIMULUS:Blood glucose level rises (for instance, after eating acarbohydrate-rich meal). Blood glucoselevel declines. Homeostasis:Blood glucose level(70–110 mg/100 mL)
Figure 45.13b-1 Homeostasis:Blood glucose level(70–110 mg/100 mL) STIMULUS:Blood glucose level falls (for instance, afterskipping a meal). Alpha cells of pancreasrelease glucagon intothe blood. Glucagon
Figure 45.13b-2 Homeostasis:Blood glucose level(70–110 mg/100 mL) STIMULUS:Blood glucose level falls (for instance, afterskipping a meal). Blood glucoselevel rises. Alpha cells of pancreasrelease glucagon intothe blood. Liver breaksdown glycogenand releasesglucose intothe blood. Glucagon
© 2011 Pearson Education, Inc. Diabetes Mellitus • Diabetes mellitus is perhaps the best-known endocrine disorder • It is caused by a deficiency of insulin or a decreased response to insulin in target tissues • It is marked by elevated blood glucose levels
© 2011 Pearson Education, Inc. • Type 1 diabetes mellitus (insulin-dependent) is an autoimmune disorder in which the immune system destroys pancreatic beta cells • Type 2 diabetes mellitus (non-insulin-dependent) involves insulin deficiency or reduced response of target cells due to change in insulin receptors
© 2011 Pearson Education, Inc. 45.3 Coordination of Endocrine and Nervous Systems in Vertebrates • The hypothalamus receives information from the nervous system and initiates responses through the endocrine system • Attached to the hypothalamus is the pituitary gland, composed of the posterior pituitary and anterior pituitary
Cerebrum Pinealgland Figure 45.14 Thalamus Hypothalamus Cerebellum Pituitarygland Spinal cord • The posterior pituitary stores and secretes hormones that are made in the hypothalamus • The anterior pituitary makes and releases hormones under regulation of the hypothalamus Hypothalamus Posteriorpituitary Anteriorpituitary
tropic hormones = target endocrine glands hypothalamus thyroid-stimulating hormone (TSH) antidiuretic hormone (ADH) posterior pituitary Thyroid gland anterior pituitary Kidney tubules adrenocorticotropic hormone (ACTH) oxytocin Muscles of uterus gonadotropic hormones: follicle- stimulating hormone (FSH) & luteinizing hormone (LH) melanocyte-stimulating hormone (MSH) growth hormone (GH) prolactin (PRL) Adrenal cortex Melanocyte in amphibian Mammary glands in mammals Bone and muscle Ovaries Testes
© 2011 Pearson Education, Inc. Thyroid Regulation: A Hormone Cascade Pathway • A hormone can stimulate the release of a series of other hormones, the last of which activates a nonendocrine target cell; this is called a hormone cascade pathway • The release of thyroid hormone results from a hormone cascade pathway involving the hypothalamus, anterior pituitary, and thyroid gland • Hormone cascade pathways typically involve negative feedback
Example Pathway Stimulus Cold A hormone cascade pathway Sensory neuron Hypothalamus secretesthyrotropin-releasinghormone (TRH ). Hypothalamus Neurosecretory cell Releasing hormone Blood vessel Anterior pituitary secretesthyroid-stimulatinghormone (TSH, also knownas thyrotropin ). Anterior pituitary Tropic hormone Negative feedback Thyroid gland secretesthyroid hormone(T3 and T4 ). Endocrine cell Hormone Targetcells Body tissues Increased cellularmetabolism Response
© 2011 Pearson Education, Inc. Evolution of Hormone Function • Over the course of evolution the function of a given hormone may diverge between species • For example, thyroid hormone plays a role in metabolism across many lineages, but in frogs has taken on a unique function: stimulating the resorption of the tadpole tail during metamorphosis
same gene family growthhormone birds fish amphibians fatmetabolism salt &waterbalance metamorphosis& maturation growth& development Hormones as homologous structures What does this tell you about these hormones? How could these hormones have different effects? prolactin gene duplication? mammals milkproduction
© 2011 Pearson Education, Inc. • Melanocyte-stimulating hormone (MSH) regulates skin color in amphibians, fish, and reptiles by controlling pigment distribution in melanocytes • In mammals, MSH plays additional roles in hunger and metabolism in addition to coloration
The roles of parathyroid hormone (PTH) in regulating blood calcium levels in mammals. PTH Parathyroidgland (behindthyroid) STIMULUS:Falling bloodCa2 level Homeostasis:Blood Ca2 level(about 10 mg/100 mL)
Activevitamin D Increases Ca2uptake inintestines Stimulates Ca2uptake in kidneys Figure 45.20-2 PTH Parathyroidgland (behindthyroid) Stimulates Ca2 releasefrom bones STIMULUS:Falling bloodCa2 level Blood Ca2level rises. Homeostasis:Blood Ca2 level(about 10 mg/100 mL)