1. © 2016 Pearson Education, Inc.

2. I. Introduction
A. Endocrine system acts with nervous system to coordinate and integrate activity of body cells 1. Influences metabolic activities via hormones transported in blood 2. Responses slower but longer lasting than nervous system responses
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3. B. Endocrinology: study of hormones and endocrine organs
1. Endocrine system controls and integrates:
a. Reproduction
b. Growth and development
c. Maintenance of electrolyte, water, and nutrient balance of blood
d. Regulation of cellular metabolism and energy balance
e. Mobilization of body defenses
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4. C. Glands and Other Organs 1. Exocrine glands
a. Produce nonhormonal substances (examples: sweat, saliva)
b. Have ducts to carry secretion to membrane surface
2. Endocrine glands
a. Produce hormones
b. Lack ducts
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5. 3. Hypothalamus is neuroendocrine organ
4. Some have exocrine and endocrine functions
a. Pancreas, gonads, placenta
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6. Figure 16.1 Location of selected endocrine organs of the body.
Pineal gland
Hypothalamus
Pituitary gland
Thyroid gland
Parathyroid glands
(on dorsal aspect
of thyroid gland)
Thymus
Adrenal glands
Pancreas
Gonads
• Ovary (female)
• Testis (male)
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7. D. Chemical messengers of endocrine system:
Hormones: long-distance chemical signals; travel in blood or lymph
Autocrines and paracrines are local chemical messengers; not considered part of endocrine system
a. Autocrines: chemicals that exert effects on same cells that secrete them
b. Paracrines: locally acting chemicals that affect cells other than those that secrete them
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8. Bell Ringer
7.01 Identify at least 2 things the endocrine system controls 7.02 What are the long distance chemical messengers called?
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9. II. Hormones
A. Though hormones circulate systemically, only cells with receptors for that hormone are affected 1. Target cells: tissues with receptors for a specific hormone a. Hormones alter target cell activity
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10. 2. Hormone action on target cells may be to:
a. Alter plasma membrane permeability and/or membrane potential by opening or closing ion channels
b. Stimulate synthesis of enzymes or other proteins
c. Activate or deactivate enzymes
d. Induce secretory activity
e. Stimulate mitosis
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11. B. Hormones act in one of two ways, depending on their chemical nature and receptor location
Water-soluble hormones
a. Act on plasma membrane receptors
b. Cannot enter cell
Lipid-soluble hormones
a. Act on intracellular receptors that directly activate genes
b. Can enter cell
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12. C. Hormone Release 1. Controlled by negative feedback systems
a. Increased hormone effects on target organs can inhibit further hormone release
b. Levels vary only within narrow, desirable range
2. Hormone release is triggered by:
a. Endocrine gland stimuli
b. Nervous system modulation
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13. 3. Endocrine Gland Stimuli
a. Endocrine glands are stimulated to synthesize and release hormones in response to one of three stimuli:
i. Humoral stimuli
ii. Neural stimuli
iii. Hormonal stimuli
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14. b. Humoral stimuli
i. Changing blood levels of ions and nutrients directly stimulate secretion of hormones
ii. Example: Ca2+ in blood
Declining blood Ca2+ concentration stimulates parathyroid glands to secrete PTH (parathyroid hormone)
PTH causes Ca2+ concentrations to rise, and stimulus is removed
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15. Figure 16.4a Three types of endocrine gland stimuli.
Humoral Stimulus
Hormone release caused by
altered levels of certain critical
ions or nutrients.
Capillary (low Ca2
in blood)
Thyroid gland
(posterior view)
Parathyroid
glands
Parathyroid
glands
PTH
Stimulus: Low concentration of Ca2+
in capillary blood.
Response: Parathyroid glands secrete
parathyroid hormone (PTH), which
increases blood Ca2+.
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16. c. Neural stimuli i. Nerve fibers stimulate hormone release
ii. Sympathetic nervous system fibers stimulate adrenal medulla to secrete catecholamines
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17. Figure 16.4b Three types of endocrine gland stimuli.
Neural Stimulus
Hormone release caused by
neural input.
CNS (spinal cord)
Preganglionic
sympathetic
fibers
Medulla of
adrenal gland
Capillary
Stimulus: Action potentials in preganglionic
sympathetic fibers to adrenal medulla.
Response: Adrenal medulla cells secrete
epinephrine and norepinephrine.
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18. d. Hormonal stimuli
i. Hormones stimulate other endocrine organs to release their hormones
Hypothalamic hormones stimulate release of most anterior pituitary hormones
Anterior pituitary hormones stimulate targets to secrete still more hormones
Hypothalamic–pituitary–target endocrine organ feedback loop
Hormones from final target organs inhibit release of anterior pituitary hormones
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19. Figure 16.4c Three types of endocrine gland stimuli.
Hormonal Stimulus
Hormone release caused by another
hormone (a tropic hormone).
Hypothalamus
Anterior
pituitary
gland
Thyroid
gland
Adrenal
cortex
Gonad
(Testis)
Stimulus: Hormones from hypothalamus.
Response: Anterior pituitary gland secretes
hormones that stimulate other endocrine glands
to secrete hormones.
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20. 4. Nervous System Modulaiton
a. Nervous system can make adjustments to hormone levels when needed
i. Can modify stimulation or inhibition of endocrine glands
b. Nervous system can override normal endocrine controls
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21. Bell Ringer
7.03 Identify the two types of hormones based on chemical nature 7.04 What two things cause the release of hormones?
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22. III. The Hypothalamus
A. Hypothalamus is connected to pituitary gland 1. Pituitary secretes at least 8 major hormones 2. It has two major lobes: a. Posterior pituitary: composed of neural tissue that secretes neurohormones b. Anterior pituitary:consists of glandular tissue
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23. B. Pituitary-Hypothalamic Relationships 1
B. Pituitary-Hypothalamic Relationships 1. Posterior lobe is neural tissue derived from a downgrowth of brain a. Maintains neural connection to hypothalamus b. Secretes two neurohormones (oxytocin and ADH)
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24. Slide 5
Posterior Pituitary: Action potentials travel down the axons of hypothalamic neurons,
causing hormone release from their axon terminals in the posterior pituitary.
Paraventricular nucleus
Hypothalamus
Hypothalamic neurons synthesize
oxytocin or antidiuretic hormone
(ADH). 1
Posterior lobe
of pituitary
Optic chiasma
Supraoptic
nucleus
Infundibulum
(connecting stalk) 2
Oxytocin and ADH are
transported down the axons of the
hypothalamic-hypophyseal tract
to the posterior pituitary.
Inferior
hypophyseal
artery
Hypothalamic-
hypophyseal
tract
Oxytocin and ADH are stored in
axon terminals in the posterior
pituitary. 3
Axon terminals 4
When associated hypothalamic
neurons fire, action potentials
arriving at the axon terminals cause
oxytocin or ADH to be released into
the blood.
Posterior lobe
of pituitary
Oxytocin
Antidiuretic hormone (ADH)
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25. 2. Anterior lobe is glandular tissue derived from an outpocketing of oral mucosa a. Vascularly connected to hypothalamus (through blood vessels) b. Hypothalamus secretes releasing and inhibiting hormones to anterior pituitary to regulate hormone secretion
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26. Anterior Pituitary: Hypothalamic hormones released into special blood vessels
(the hypophyseal portal system) control the release of anterior pituitary hormones.
Hypothalamus
Hypothalamic neurons
synthesize releasing
and inhibiting hormones
(GHRH, GHIH, TRH,
CRH, GnRH, PIH).
Anterior lobe
of pituitary
When appropriately stimulated, hypothalamic
neurons secrete releasing or inhibiting
hormones into the primary capillary plexus. 1
Hypophyseal
portal system
Superior
hypophyseal
artery
Hypothalamic hormones travel
through portal veins to the anterior
pituitary where they stimulate or inhibit
release of hormones made
in the anterior pituitary. 2
• Primary capillary
plexus
• Hypophyseal
portal veins
• Secondary
capillary plexus
A portal system is two
capillary plexuses
(beds) connected by
veins.
In response to releasing
hormones, the anterior pituitary
secretes hormones into the
secondary capillary plexus. This in
turn empties into the general
circulation. 3
Growth hormone (GH)
Thyroid-stimulating hormone (TSH)
Adrenocorticotropic hormone (ACTH)
Follicle-stimulating hormone (FSH)
Luteinizing hormone (LH)
Prolactin (PRL)
Anterior lobe
of pituitary
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27. C. Posterior Pituitary and Hypothalamic Hormones 1. Oxytocin
a. Strong stimulant of uterine contractions released during childbirth
b. Also acts as hormonal trigger for milk release
c. Both are positive feedback mechanisms
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28. 2. Antidiuretic hormone (ADH)
a. Hypothalamus monitors solute/water concentrations
b. If concentration too high, posterior pituitary triggered to secrete ADH
i. Targets kidney tubules to reabsorb more water to inhibit or prevent urine formation
c. Release also triggered by pain, low blood pressure, and drugs
d. Inhibited by alcohol, diuretics
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29. Table 16.2-1 Pituitary Hormones: Summary of Regulation and Effects
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30. On your own sheet of paper, draw a chart that is 4 columns across and 9 rows down. Use the chart on the next slide as an example and copy the information that is on it. Fill in the information for ADH using your notes and/or the textbook. You will fill in the rest of the information later.
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31. Hormone Name
Origin Organ
Target Organ(s)
Effects
Oxytocin
Posterior Pituitary
Uterus
Breast
Stimulates contractions; initiates labor
Initiates milk production (ejection)
Antidiuretic Hormone (ADH)
Thyroid Stimulating Hormone (TSH)
Adrenocorticotropic Hormone (ACTH)
Follicle Stimulating Hormone (FSH)
Luteinizing Hormone (LH)
Prolactin (PRL)
Growth Hormone (GH)

32. Bell Ringer
7.05 What gland is the Hypothalamus connected with? 7.06 What hormone initiates labor?
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33. D. Anterior Pituitary Hormones
1. All but two are tropic hormones (tropins) that regulate secretion of other hormones
a. Thyroid-stimulating hormone (TSH) i. tropic
ii. Stimulates normal development and secretory activity of thyroid
b. Adrenocorticotropic hormone (ACTH) i. tropic
ii. ACTH stimulates adrenal cortex to release corticosteroids
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34. c. Follicle-stimulating hormone (FSH) i. tropic
ii. FSH stimulates production of gametes (egg or sperm)
d. Luteinizing hormone (LH)
ii. In females, LH helps mature follicles of egg, triggers ovulation and release of estrogen and progesterone
iii. In males, LH stimulates production of testosterone
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35. i. Stimulates milk production in females
e. Prolactin (PRL)
i. Stimulates milk production in females
ii. Role in males not well understood
f. Growth hormone (GH)
i. Has direct actions on metabolism
ii. Has indirect growth-promoting actions
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36. © 2016 Pearson Education, Inc.

37. Table 16.2-2 Pituitary Hormones: Summary of Regulation and Effects (continued)
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38. IV. Thyroid and Parathyroid Gland
1. Location and Structure
a. Butterfly-shaped gland in anterior neck on the trachea, just inferior to larynx, that consists of:
i. Isthmus
ii. Follicles
iii. Colloid
iv. Parafollicular cells
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39. Gross anatomy of the thyroid gland, anterior view
Hyoid bone
Thyroid
cartilage
Epiglottis
Superior
thyroid
artery
Common
carotid
artery
Inferior
thyroid
artery
Isthmus of
thyroid gland
Trachea
Left subclavian
artery
Left lateral
lobe of
thyroid
gland
Aorta
Gross anatomy of the thyroid gland,
anterior view
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40. a. Body’s major metabolic hormone b. Found in two forms
2. Thyroid Hormone (TH)
a. Body’s major metabolic hormone
b. Found in two forms
i. T4 (thyroxine): major form
ii. T3 (triiodothyronine)
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41. c. TH affects virtually every cell in body
i. Increases basal metabolic rate and heat production
ii. Regulates tissue growth and development
iii. Maintains blood pressure
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42. © 2016 Pearson Education, Inc.

43. 3. Calcitonin a. Produced by parafollicular (C) cells in response to high Ca2+ levels b. Antagonist to parathyroid hormone (PTH)
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44. a. Contain cells that secrete parathyroid hormone (PTH)
B. Parathyroid Gland
1. Four to eight tiny yellow-brown glands embedded in posterior aspect of thyroid
a. Contain cells that secrete parathyroid hormone (PTH)
b. PTH is most important hormone in Ca2+ homeostasis
i. Target organs are skeleton, kidneys, and intestine
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45. Figure 16.11 The parathyroid glands.
Pharynx
(posterior
aspect)
Capillary
Thyroid
gland
Parathyroid
cells
(secrete
parathyroid
hormone)
Parathyroid
glands
Esophagus
Trachea
Oxyphil
cells
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46. 2. Functions to:
a. Stimulate osteoclasts to digest bone matrix and release Ca2+ to blood
b. Enhances reabsorption of Ca2+ and secretion of phosphate (PO43-) by kidneys
c. Promotes activation of vitamin D by kidneys, which leads to increased absorption of Ca2+ by intestinal mucosa
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47. Hypocalcemia (low blood Ca2+) PTH release from parathyroid gland
Osteoclast activity
in bone causes Ca2+
and PO43– release
into blood
Ca2+ reabsorption
in kidney tubule
Activation of
vitamin D by kidney
Ca2+ absorption
from food in small
intestine
Initial stimulus
Physiological response
Ca2+ in blood
Result
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48. Bell Ringer
7.07 What does Tropic mean? 7.08 What is the body’s major metabolic hormone?
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49. Hormone Name
Origin Organ
Target Organ(s)
Effects
Thyroid Hormone (TH)
Thyroid
All Organs
Metabolic Rate, Growth and Developent
Calcitonin
Parathyroid Hormone (PTH)
Mineralocorticoids
Glucocorticoids
Gonadocorticoids
Catecholamines
Insulin
Glucagon

50. V. Adrenal Gland A. Paired, pyramid-shaped organs atop kidneys
1. Structurally and functionally it is two glands in one
a. Adrenal cortex: three layers of glandular tissue that synthesize and secrete several different hormones
b. Adrenal medulla: nervous tissue that is part of sympathetic nervous system
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51. a. Steroid hormones are not stored in cells
B. Adrenal Cortex
1. This area of adrenal gland produces over 24 different hormones collectively called corticosteroids
a. Steroid hormones are not stored in cells
b. Three layers of cortical cells produce the different corticosteroids
i. Zona glomerulosa—Mineralocorticoids
ii. Zona fasciculata—Glucocorticoids
iii. Zona reticularis—Gonadocorticoids
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52. Figure 16.13 Microscopic structure of the adrenal gland.
Hormones
secreted
Capsule
Zona
glomerulosa
Aldosterone
Zona
fasciculata
Adrenal gland
• Medulla
Cortex
• Cortex
Cortisol
and
androgens
Kidney
Zona
reticularis
Medulla
Adrenal
medulla
Epinephrine and
norepinephrine
Drawing of the
histology of the
adrenal cortex and
a portion of the
adrenal medulla
Photomicrograph
(115×)
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53. 2. Mineralocorticoids 3. Glucocorticoids
a. Regulate electrolyte concentrations in ECF
3. Glucocorticoids
a. Influence metabolism of most cells and help us resist stressors
b. Keep blood glucose levels relatively constant
c. Maintain blood pressure by increasing action of vasoconstrictors
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54. 4. Gonadocorticoids (adrenal sex hormone)
a. May contribute to:
i. Onset of puberty and appearance of secondary sex characteristics
ii. Sex drive in women
iii. Source of estrogens in postmenopausal women
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55. 1. Medullary chromaffin cells synthesize catecholamines
C. Adrenal Medulla
1. Medullary chromaffin cells synthesize catecholamines
a. epinephrine (80%)
b. norepinephrine (20%)
2. Effects of catecholamines:
a. Vasoconstriction
b. Increased heart rate
c. Increased blood glucose levels
d. Blood diverted to brain, heart, and skeletal muscle
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56. Figure 16.16 Stress and the adrenal gland.
Short-term stress
Prolonged stress
Stress
Nerve impulses
Hypothalamus
CRH (corticotropin-
releasing hormone)
Spinal cord
Corticotropic cells
of anterior pituitary
Preganglionic
sympathetic
fibers
To target via blood
Adrenal cortex
(secretes steroid
hormones)
Adrenal medulla
(secretes amino acid–
based hormones)
ACTH
Norepinephrine
and epinephrine
(catecholamines)
Mineralocorticoids
Glucocorticoids
Short-term stress response
Long-term stress response
Heart rate increases
Blood pressure increases
Bronchioles dilate
Liver converts glycogen to glucose and releases glucose to blood
Blood flow changes, reducing digestive system activity and urine output
Metabolic rate increases
Kidneys retain sodium and water
Blood volume and blood pressure rise
Proteins and fats converted to glucose or broken down for energy
Blood glucose increases
Immune system supressed
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57. Table 16.4 Adrenal Gland Hormones: Summary of Regulation and Effects
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58. Bell Ringer
7.09 Where are the adrenal glands located? 7.10 Which part of the medulla releases catecholamines?
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59. VI. Other Endocrine Organs
Pancreas
1. Alpha () cells produce glucagon
a. Triggered by decreased blood glucose levels
b. Release glucose into blood
2. Beta () cells produce insulin
a. Secreted when blood glucose levels increase
b. Insulin lowers blood glucose levels
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60. Figure 16.17 Photomicrograph of differentially stained pancreatic tissue.
Pancreatic islet
•  (Glucagon-
producing)
cells
•  (Insulin-
producing)
cells
Pancreatic acinar
cells (exocrine)
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61. Figure 16.18 Insulin and glucagon from the pancreas regulate blood glucose levels.
Stimulates glucose
uptake by cells
Insulin
Tissue cells
Stimulates
glycogen
formation
Pancreas
Glucose
Glycogen
Blood
glucose
falls to
normal
range.
Liver
IMBALANCE
Stimulus
Blood
glucose level
BALANCE:
Normal blood glucose level (about 90 mg/100 ml)
Stimulus
Blood
glucose level
IMBALANCE
Blood
glucose
rises to
normal
range.
Pancreas
Glucose
Glycogen
Liver
Stimulates
glycogen
breakdown
Glucagon
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62. B. The Gonads and Placenta 1
B. The Gonads and Placenta 1. Gonads produce same steroid sex hormones as those of adrenal cortex, just lesser amounts a. Ovaries produce estrogens and progesterone b. Testes produce testosterone 2. Placenta secretes estrogens, progesterone, and human chorionic gonadotropin (hCG)
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