More Related Content Similar to Endocrine a p s2010 1 Similar to Endocrine a p s2010 1 (20) Endocrine a p s2010 11. Hormonal Regulation
Reference: Pathophysiology by Kathryn
McCance
Mindy Milton, MPA, PA-C
July 29, 2010
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2. Hormones
General characteristics
Specific rates and rhythms of secretion
Diurnal, pulsatile and cyclic, and patterns depending
on circulating substances
Operate within feedback systems
Most common negative feedback
Affect only cells with appropriate receptors
Endocrine communication
The liver inactivates hormones, rendering the
hormones more water soluble for renal excretion
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3. The Endocrine System
Hypothalamus
Pituitary
Adenohypophysis
Neurohypophysis
Thyroid
Parathyroid
Adrenals
Pancreas
Ovaries
Testes
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4. Regulation of Hormone Release
Hormones are released:
In response to an alteration in the cellular
environment
To maintain a regulated level of certain
substances or other hormones
Hormones are regulated by chemical,
hormonal, or neural factors
Negative feedback
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5. Feedback
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6. Hormone Transport
Hormones are released into the circulatory
system by endocrine glands
Water-soluble hormones circulate in free,
unbound forms
short half life
Peptides, glucoproteins, polypeptides
Insulin
PTH
Pituitary hormones
Hypothalamic hormones
Lipid soluble hormones are primarily circulating
bound to a carrier
Circulate on protein carrier – longer half life
Steroid hormones
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7. Cellular Mechanism of Hormone
Action
Target cell
Up-regulation
Down-regulation
Hormone effects
Direct effects
Permissive effects
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8. Cellular Mechanism of Hormone
Action
Hormone receptors
Located in or on the plasma membrane or in the
intracellular compartment of the target cell
Water-soluble hormones
High molecular weight
Cannot diffuse across the plasma membrane
Lipid-soluble hormones
Easily diffuse across the plasma membrane and
bind to cytosolic or nuclear receptors
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9. Cellular Mechanism of Hormone
Action
Water-soluble hormones
First messenger
Signal transduction
Second-messenger molecules
Calcium
Cyclic adenosine monophosphate (cAMP)
Cyclic guanosine monophosphate (cGMP)
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11. Cellular Mechanism of Hormone
Action
Lipid-soluble hormones
Steroid hormones
Androgens, estrogens, progestins, glucocorticoids,
mineralocorticoids, and thyroid hormones
Diffuse across the plasma membrane
Bind to cytoplasmic or nuclear receptors
Activate
RNA polymerase
DNA transcription and translation
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13. Structure and Function of the
Endocrine Glands
Hypothalamic-pituitary axis
Hypothalamus
Secretes regulatory hormones
Releasing and inhibiting
Autonomic center neural control
Endocrine organ
Pituitary gland
Anterior pituitary (adenohypophysis)
Posterior pituitary (neurohypophysis) neuro-
attachments to adrenal medulla. Has trophic hormones
too.
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15. Posterior Pituitary Hormones
Synthesized with their
binding proteins in the
supraoptic and
paraventricular nuclei of
the hypothalamus
Secreted by the posterior
pituitary
Antidiuretic hormone
(ADH)
Controls plasma osmolality
Oxytocin
Uterine contractions and
milk ejection in lactating
women
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16. Anterior Pituitary Hormones
Adrenocorticotropic hormone (ACTH)
Melanocyte-stimulating hormone (MSH)
Growth hormone (GH)<-- GHRH
Prolactin (has “releasing” and
“inhibiting”(Dopamine).
Thyroid-stimulating hormone (TSH)
Luteinizing hormone (LH) <-- GRH
Follicle-stimulating hormone (FSH)<-- GRH
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18. Thyroid and Parathyroid Glands
Thyroid gland
Two lobes lateral to the trachea
Isthmus
Follicles (follicle cells surrounding colloid)
Parafollicular cells (C cells)
Secrete calcitonin
Stimulus is high serum ionized calcium
Regulation of thyroid hormone secretion
Thyrotropin-releasing hormone and thyroid stimulating hormone
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19. Thyroid and Parathyroid Glands
Thyroid hormones
90% T4 and 10% T3
T4 converted to T3 in the liver, kidneys, and peripheral tissues
T3 has greatest metabolic effects
Bound to thyroxine-binding globulin, thyroxine-
binding prealbumin, or albumin
Affect growth and maturation of tissues, cell
metabolism, heat production, and oxygen
consumption
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21. Thyroid and Parathyroid Glands
Parathyroid glands
Small glands located behind the upper and lower
poles of the thyroid gland
Produce parathyroid hormone
Regulator of serum calcium
Stimulus is low serum ionized calcium level
Antagonist of calcitonin
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22. Endocrine Pancreas
The pancreas is both an endocrine and an exocrine
gland
Islets of Langerhans
Secretion of glucagon and insulin
Cells
Alpha—glucagon
Beta—insulin
Delta—somatostatin and gastrin
F cells—pancreatic polypeptide
ANS innervation
PNS +
SNS –
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24. Endocrine Pancreas
Insulin
Synthesized from proinsulin
Secretion is promoted by increased blood glucose
levels
Facilitates the rate of glucose uptake into the cells
of the body
Anabolic hormone
Synthesis of proteins, lipids, and nucleic acids
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25. Endocrine Pancreas
Glucagon
Secretion is promoted by decreased blood glucose
levels
Stimulates glycogenolysis, gluconeogenesis, and
lipolysis
Somatostatin
Possible involvement in regulating alpha and beta
cell secretions
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27. Adrenal Glands
Adrenal cortex
80% of an adrenal
gland’s total weight
Zona glomerulosa
Zona fasciculata
Zona reticularis
Adrenal medulla
20% of total weight
Innervated by ANS
Pre-ganglionic
cholinergic fibers
SNS and PNS
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28. Adrenal Glands
Adrenal cortex
Stimulated by adrenocorticotropic hormone
(ACTH)
Glucocorticoid hormones
Direct effects on carbohydrate metabolism
Anti-inflammatory and growth-suppressing effects
Influence awareness and sleep habits
Most potent naturally occurring glucocorticoid is
cortisol
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29. Adrenal Glands
Adrenal cortex
Mineralocorticoid hormones
Affect ion transport by epithelial cells
Increase the activity of the sodium pump of the epithelial
cells
Cause sodium retention and potassium and hydrogen loss
Most potent naturally occurring mineralocorticoid is
aldosterone
Regulated by the renin-angiotensin system
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30. Aldosterone
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31. Adrenal Glands
Adrenal cortex
Adrenal estrogens and androgens
Estrogen secretion by the adrenal cortex is minimal
The adrenal cortex secretes weak androgens
Androgens are converted by peripheral tissues to stronger
androgens such as testosterone
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32. Adrenal Glands
Adrenal medulla
Chromaffin cells (pheochromocytes)
Chromaffin cells secrete the catecholamine
epinephrine (majority) and norepinephrine
Release of catecholamine has been characterized
as a “fight or flight” response
Catecholamines promote hyperglycemia
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33. Tests of Endocrine Function
Radioimmunoassay
Measures minute quantities of hormone in blood
Enzyme-linked immunosorbent assay
(ELISA)
Similar to RIA but less expensive
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34. Aging and the Endocrine System
Thyroid gland
Glandular atrophy, fibrosis, nodularity, and increased
inflammatory infiltrates
TSH and TH secretion diminished
Hypothyroidism
Parathyroid glands
Related to alterations in calcium balance
Inadequate intake, malabsorption, or renal changes
Adrenal glands
Decreased clearance of cortisol
Secondary to decline in liver and renal functions
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35. Hormones from other tissues
Erythropoietin
Released by kidney
Stimulus is low oxygen levels
Increases RBC production in bone marrow
Renin
Released by Kidney
Stimulus is low volume, hypotension, low GFR
Angiotensin II and Aldosterone – retains sodium, water, and
vasoconstriction increases blood pressure
ANP
Released by atrium
Stimulus is increased wall stretch due to increased blood volume
Promotes loss of Na+ and water
Decreases release of Renin, aldosterone, ADH
Suppresses thirst
Thysosin
Released by Thymus
Maturation of lymphocytes
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36. The End
Questions?
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Editor's Notes \n \n \n \n \n LIpid based hormones --> arachadonic acid, and cholesterol based. Sex hormones, Leuk and prostiglandins. Mostly autocrin, peracrin, vs endocrin. \n Permssive effect -- Insulin makes the mamery glands more sensitive to prolactin. \n\nn biology, permissiveness is a certain relationship between hormones and the target cell. It can be applied to describe situations in which the presence of one hormone, at a certain concentration, is required in order to allow a second hormone to fully affect the target cell. For example, thyroid hormone increases the number of receptors available for epinephrine at the latter's target cell, thereby increasing epinephrine's effect at that cell. Without the thyroid hormone, epinephrine would only have a weak effect.[1]\n \n \n \n \n More rapid response with a PM protien and machinery already to go inside the cell. \nWater soluble hormones cannot! So Fat soluble can go fast and slow. \n \n Close to optic chiasm. \n \n CRH --> MSH --> melanin production\n Portal system - Vein connecting two capillary beds.\n T4- 4 iodines on tyrosine. Most produces.\nT3 - Thyroxin, predominate in the body.\nT4 is turned into T3. \nIodide is what we consume, Iodine is what is in our bodies. \n \n \n \n \n \n brain does not need insulin\n \n \n \n \n \n \n \n \n \n \n \n \n