1. Chapter 10 Endocrine System
Endocrine glands are ductless
releases hormones
hormones released to target organs
Exocrine glands have ducts
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2. Chemistry of Hormones Steroid Hormones Nonsteroid Hormones
derived from cholesterol
sex hormones
adrenal cortex hormones
Nonsteroid Hormones
amines
proteins
peptides
glycoproteins
most hormones
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3. Actions of Steroid Hormones
hormone crosses membranes
hormone combines with receptor in nucleus
synthesis of mRNA activated
mRNA enters cytoplasm to direct synthesis of protein
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4. Actions of Nonsteroid Hormones
hormone binds to receptor on cell membrane
adenylate cyclase activated
ATP converted to cAMP
cAMP promotes a series of reactions leading to cellular changes
second messenger
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5. Control of Hormonal Secretions
primarily controlled by negative feedback mechanism
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6. Negative Feedback
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7. Major Endocrine Glands
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8. Pituitary Gland Two distinct portions
anterior pituitary (adenohypophysis)
posterior pituitary (neurohypophysis)
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9. Pituitary Gland Control
Hypothalamic releasing hormones stimulate cells of anterior pituitary to release hormones
Nerve impulses from hypothalamus stimulate nerve endings in the posterior pituitary gland to release hormones
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10. Hypothalamic Hormones
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11. Anterior Pituitary Hormones
Growth Hormone (GH)
stimulates increase in size and rate of body cells
enhances movement of amino acids through membranes
promotes growth of long bones
secretion stimulated by growth hormone-releasing hormone
slows carbohydrate catabolism; increases blood glucose levels
Prolactin (PRL)
sustains milk production after birth
secretion inhibited by prolactin release-inhibiting hormone
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12. Anterior Pituitary Hormones
Thyroid Stimulating Hormone (TSH)
controls secretions of hormones from the thyroid gland
controlled by thyrotropin-releasing hormone
Adrenocorticotropic Hormone
controls secretions of some hormones of adrenal cortex
controlled by corticotropin-releasing hormone
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13. Anterior Pituitary Hormones
Follicle-Stimulating Hormone (FSH)
stimulates development of egg-containing follicles in ovaries
stimulates follicular cells to secrete estrogen
stimulates production of sperm cells
controlled by gonadotropin-releasing hormone
Luteinizing Hormone (LH)
promotes secretions of sex hormones
stimulates release of egg from ovary (ovulation)
stimulates corpus luteum to produce progesterone
controlled by gonadotropin-releasing hormone
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14. Posterior Pituitary Hormones
Antidiuretic Hormone (ADH)
causes kidneys to reduce water excretion
in high concentration, raises blood pressure
controlled by hypothalamus in response to changes in blood water concentration and blood volume
Oxytocin (OT)
stimulates uterine contractions
stimulates mammary glands to release milk
controlled by hypothalamus in response to stretch in uterine and vaginal walls and stimulation of breasts
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15. Thyroid Gland
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16. Thyroid Gland Hormones
Thyroxine (T4) and Triiodothyronine (T3)
increases rate of energy release from carbohydrates
accelerates growth
stimulates activity in the nervous system
controlled by TSH
Calcitonin
lowers blood calcium concentrations by inhibiting release of calcium from bones
increases rate at which calcium isdeposited in bones
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17. Thyroid Gland Disorders
General Hyperthyroidism
high metabolic rate
hyperactivity
weight loss
protruding eyes
Simple Goiter
deficiency of iodine
leads to deficiency of thyroid hormones
gland enlarges
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18. Parathyroid Glands
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19. Parathyroid Hormone PTH increases blood calcium levels
stimulates bone resorption by osteoclasts
inhibits osteoblasts
stimulates kidneys to retain calcium
promotes calcium absorption into intestine
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20. Adrenal Glands
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21. Adrenal Cortex Hormones
Aldosterone
increases blood volume and pressure by promoting conservation of sodium ions and water
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22. Adrenal Cortex Hormones
Cortisol
decreases protein synthesis
increases fatty acid release
stimulates glucose synthesis from noncarbohydrates
controlled by CRH from hypothalamus and ACTH from anterior pituitary
maintain normal blood pressure
anti-inflammatory effect
released during long term stress
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23. Adrenal Medulla Hormones
Epinephrine and Norepinephrine
release controlled by sympathetic nervous system
increases heart rate and blood pressure
dilates respiratory airways
promotes breakdown of glycogen
increases metabolic rates
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24. Adrenal Cortex Hormones
Adrenal androgens
supplement sex hormones from the gonads
may be converted to estrogen
female sexual drive
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25. Pancreas
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26. Pancreatic Hormones Glucagon
secreted by alpha cells of pancreatic islets
stimulates liver to break down glycogen
stimulates liver to convert noncarbohydrates into glucose
controlled by blood glucose concentrations
Insulin
secreted by beta cells of pancreatic islets
promotes formation of glycogen from glucose
enhances movement of glucose into adipose and muscle cells
decreases blood glucose concentrations
controlled by blood glucose concentrations
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27. Other Endocrine Glands
Reproductive Glands
ovaries secrete estrogen and progesterone
testes secrete testosterone
placenta secretes estrogen, progesterone, and gonadotropins
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28. Other Endocrine Glands
Pineal Gland
secretes melatonin
regulates sleep/wake cycles
may control onset of puberty
helps regulate female reproductive cycle
Thymus Gland
secretes thymosins
promotes development of certain lymphocytes
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29. Clinical Application Growth Hormone Ups and Downs
Gigantism - hypersecretion of GH in children
Acromegaly – hypersecretion of GH in adults
Dwarfism – hyposecretion of GH in children
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30. Clinical Application Diabetes Mellitus 3 Cardinal signs polyuria
polyphagia
polydipsia
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