The document provides an overview of the endocrine system and its major glands and hormones. It discusses how the endocrine system works with the nervous system to regulate bodily functions through the release of hormones into the bloodstream. The main endocrine glands discussed are the pituitary gland, thyroid gland, parathyroid glands, thymus gland, adrenal glands, pancreas, and reproductive glands. For each gland, its location in the body, cellular structure, and major hormones produced are described. The hypothalamus and its role in controlling the pituitary gland is also summarized.

1. © 2012 Pearson Education, Inc.
19
The Endocrine System
PowerPoint®
Lecture Presentations prepared by
Steven Bassett
Southeast Community College
Lincoln, Nebraska

2. © 2012 Pearson Education, Inc.
Introduction
• The nervous system and the endocrine
system work together to monitor the
body’s activities
• The nervous system: produces short-term,
very specific responses
• The endocrine system: many times it produces
long-term, general responses

3. © 2012 Pearson Education, Inc.
Introduction
• The endocrine system releases chemicals
called hormones
• Hormones leave a gland or gland-like structure
• The hormone enters into the bloodstream
• Hormones are organized into four groups
based on chemical structure:
• Amino acid derivatives
• Peptide hormones
• Steroid hormones
• Eicosanoids

4. © 2012 Pearson Education, Inc.
An Overview of the Endocrine System
• The main endocrine organs are:
• Pituitary gland
• Hypothalamus
• Thyroid gland
• Thymus gland
• Suprarenal glands
• Pineal gland
• Parathyroid glands
• Pancreas
• Reproductive glands

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Endocrine activity
Endocrine activity is controlled by endocrine
reflexes that are triggered by:
 Humoral stimuli
 Hormonal stimuli
 Neural stimuli

6. © 2012 Pearson Education, Inc.
Figure 19.1 The Endocrine System
KEY TO PITUITARY HORMONES
ACTH
TSH
GH
PRL
FSH
LH
MSH
ADH
Adrenocorticotropic hormone
Thyroid-stimulating hormone
Growth hormone
Prolactin
Follicle-stimulating hormone
Luteinizing hormone
Melanocyte-stimulating hormone
Antidiuretic hormone
Each suprarenal gland is
subdivided into:
Medulla:
Epinephrine (E)
Norepinephrine (NE)
Cortex:
Cortisol, corticosterone,
aldosterone, androgens
Thymosins
Testis
Thyroxine (T4)
Triiodothyronine (T3)
Calcitonin (CT)
Pars distalis (anterior lobe):
ACTH, TSH, GH, PRL,
FSH, LH, and MSH
Neurohypophysis
(posterior lobe):
Release of oxytocin
and ADH
Suprarenal Glands
Thymus
(Undergoes atrophy
during adulthood)
Thyroid Gland
Pituitary Gland
Hypothalamus
Production of ADH,
oxytocin, and regulatory
hormones
Pineal Gland
Melatonin
Parathyroid Glands
(on posterior surface of
thyroid gland)
Parathyroid hormone (PTH)
Heart
Natriuretic peptides:
Atrial natriuretic
peptide (ANP)
Brain natriuretic
peptide (BNP)
Erythropoietin (EPO)
Calcitriol
(Chapters 19 and 26)
Kidney
Adipose Tissue
Digestive Tract
Pancreatic Islets
Gonads
Leptin
Resistin
Numerous hormones
(detailed in Chapter 25)
Insulin, glucagon
Testes (male):
Androgens (especially
testosterone), inhibin
Ovaries (female):
Estrogens, progestins,
inhibinOvary

7. © 2012 Pearson Education, Inc.
An Overview of the Endocrine System
• The Hypothalamus and Endocrine
Regulation
• Hypothalamus functions via three mechanisms
• Secretes regulatory hormones
• Secretes releasing hormones (RH)
• Secretes inhibiting hormones (IH)
• Acts as an endocrine organ
• Releases antidiuretic hormone and oxytocin to
the pituitary gland
• Contains autonomic nervous system centers
• Exerts control over the suprarenal medulla

8. © 2012 Pearson Education, Inc.
Figure 19.2 Hypothalamic Control over Endocrine Organs
HYPOTHALAMUS
Secretion of
regulatory hormones
to control activity of
pars distalis (anterior
lobe) of pituitary gland
Production
of ADH and
oxytocin
Control of sympathetic
output to suprarenal
medullae
Pars distalis
(anterior lobe)
of pituitary gland
Neurohypophysis
(posterior lobe)
of pituitary gland
Medulla
Hormones secreted
by pars distalis of
pituitary gland
control other
endocrine organs
Release of
ADH and
oxytocin
Secretion of
epinephrine and
norepinephrine
Suprarenal gland
Preganglionic
motor fibers

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The Pituitary Gland
The pituitary gland, or hypophysis
 Neurohypophysis (posterior lobe)
 ADH: is secreted in response to low blood volume or high electrolyte
concentration in blood. It will raise the blood pressure and lower the
electrolyte concentration.
 Lack of ADH secretion will cause diabetes insipidus.
 Oxytocin
 Adenohypophysis (anterior lobe)
 ACTH — adrenocorticotropic hormone
 TSH — thyroid-stimulating hormone
 GH — growth hormone
 PRL — prolactin
 FSH — follicle-stimulating hormone: stimulates egg development
and estrogen production in female.
 LH — luteinizing hormone

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Figure 19.3a Gross Anatomy and Histological Organization of the Pituitary Gland and Its Subdivisions
Relationship of the pituitary
gland to the hypothalamus
Median
eminence
Third
ventricle
Mamillary
body
HYPOTHALAMUS
Optic chiasm
Infundibulum
Diaphragma
sellae
Pars
tuberalis
Pars
distalis
Pars
intermedia
Neurohypophysis
(posterior lobe)
Sphenoid
(sella turcica)
Adenohypophysis
(anterior lobe)

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Figure 19.5 The Pituitary Gland and the Hypophyseal Portal System
ADENOHYPOPHYSIS
OF PITUITARY GLAND
NEUROHYPOPHYSIS
OF PITUITARY GLAND
MEDIAN
EMINENCE
HYPOTHALAMUS
Hypophyseal veins
Endocrine cells
Inferior hypophyseal artery
Infundibulum
Superior hypophyseal artery
Portal veins
Mamillary
body
Paraventricular
nuclei
Supraoptic
nuclei
Optic
chiasm
Capillary
Beds

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Table 19.1 The Pituitary Hormones

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Figure 19.4 Pituitary Hormones and Their Targets
Hypothalamus
Direct Release
of Hormones
Indirect Control Through Release
of Regulatory Hormones
Direct Control
by Nervous
System Sensory
stimulation
Osmoreceptor
stimulationRegulatory hormones are released into
the hypophyseal portal system for delivery
to the anterior lobe of the pituitary
Posterior lobe
of pituitary gland
Adenohypophysis of
pituitary glandMedulla
Cortex
Suprarenal
gland
Thyroid
gland
Epinephrine and
norepinephrine
Liver
Glucocorticoids
(cortisol,
corticosterone)
Thyroid
hormones (T3, T4)
Bone, muscle,
other tissues Mammary
glands
Testes
of male
Ovaries
of female
TestosteroneInhibin Estrogen Progesterone Inhibin
Melanocytes (uncertain
significance in healthy
adults)
Females: Uterine
smooth muscle and
mammary glands
Males: Smooth
muscle in ductus
deferens and
prostate gland
Kidneys
KEY TO PITUITARY HORMONES
ACTH
TSH
GH
PRL
FSH
LH
MSH
ADH
Adrenocorticotropic hormone
Thyroid-stimulating hormone
Growth hormone
Prolactin
Follicle-stimulating hormone
Luteinizing hormone
Melanocyte-stimulating hormone
Antidiuretic hormone
ADH
Oxytocin
MSH
LHFSH
PRL
GH
TSH
ACTH
Somatomedins

14. © 2012 Pearson Education, Inc.
The Thyroid Gland
Sits on thyroid cartilage of larynx
 Butterfly-like appearance
 Consists of two main lobes connected by
the isthmus
The only endocrine gland that stores its hormone
extracellularly.
 Controls metabolism
 Thyroxine (T4)
 Triiodothyronine (T3)
 Involved in calcium homeostasis
 Calcitonin: decreases the concentration of
calcium in blood.

15. © 2012 Pearson Education, Inc.
Figure 19.6a Anatomy and Histological Organization of the Thyroid Gland
Location and anatomy of the thyroid gland
Isthmus of
thyroid gland
Left lobe of
thyroid gland
Internal
jugular vein
Cricoid cartilage
of larynx
Inferior
thyroid artery
Inferior
thyroid
veins
Superior
thyroid artery
Hyoid bone
Middle thyroid vein
Thyrocervical trunk
Trachea
Outline of clavicle
Outline of sternum
Thyroid cartilage
of larynx
Superior
thyroid vein
Common
carotid artery
Right lobe of
thyroid gland

16. © 2012 Pearson Education, Inc.
Table 19.2 Hormones of the Thyroid Gland, Parathyroid Glands, and Thymus (Part 1 of 2)

17. © 2012 Pearson Education, Inc.
Figure 19.7 The Regulation of Thyroid Secretion
Hypothalamus
releases TRH
Pituitary
gland
Anterior
lobe
Anterior
lobe
TRH
TSH
Thyroid
gland
Adenohypophysis
releases TSH
Thyroid follicles
release T3 and T4
Normal T3 and T4
concentrations,
normal body
temperature
Decreased T3 and
T4 concentrations
in blood or low
body temperature
Increased T3 and
T4 concentrations
in blood
Homeostasis
Disturbed
Homeostasis
Restored
HOMEOSTASIS

18. © 2012 Pearson Education, Inc.
The Parathyroid Glands
Located on the back of the thyroid gland
Two types of cells:
 Parathyroid cells, or principal cells (Chief Cells)—
glandular cells that produce the hormone PTH, which
raises the blood calcium
 Oxyphil cells and transitional cells— likely immature or
inactive principal cells
Regulates calcium homeostasis
 PTH— parathyroid hormone

19. © 2012 Pearson Education, Inc.
Figure 19.8 Anatomy and Histological Organization of the Parathyroid Glands
The location and size of the parathyroid
glands on the posterior surface of the
thyroid lobes
The histology of the parathyroid
and thyroid glands
A histological section showing parathyroid cells
and oxyphil cells of the parathyroid gland
LM × 600Parathyroid gland
Oxyphil
cells
Parathyroid
(chief) cells
LM × 100Parathyroid and thyroid gland
Connective
tissue capsule
of parathyroid
gland
Thyroid
follicles
Blood vessel
Left lobe of
thyroid gland
Parathyroid
glands

20. © 2012 Pearson Education, Inc.
Table 19.2 Hormones of the Thyroid Gland, Parathyroid Glands, and Thymus (Part 1 of 2)

21. © 2012 Pearson Education, Inc.
The Thymus Gland
 Located on top of the heart
 Secretes many chemicals that help T
cells of the immune system develop
 Thymosins
 Atrophies as one ages

22. © 2012 Pearson Education, Inc.
Figure 19.1 The Endocrine System
KEY TO PITUITARY HORMONES
ACTH
TSH
GH
PRL
FSH
LH
MSH
ADH
Adrenocorticotropic hormone
Thyroid-stimulating hormone
Growth hormone
Prolactin
Follicle-stimulating hormone
Luteinizing hormone
Melanocyte-stimulating hormone
Antidiuretic hormone
Each suprarenal gland is
subdivided into:
Medulla:
Epinephrine (E)
Norepinephrine (NE)
Cortex:
Cortisol, corticosterone,
aldosterone, androgens
Thymosins
Testis
Thyroxine (T4)
Triiodothyronine (T3)
Calcitonin (CT)
Pars distalis (anterior lobe):
ACTH, TSH, GH, PRL,
FSH, LH, and MSH
Neurohypophysis
(posterior lobe):
Release of oxytocin
and ADH
Suprarenal Glands
Thymus
(Undergoes atrophy
during adulthood)
Thyroid Gland
Pituitary Gland
Hypothalamus
Production of ADH,
oxytocin, and regulatory
hormones
Pineal Gland
Melatonin
Parathyroid Glands
(on posterior surface of
thyroid gland)
Parathyroid hormone (PTH)
Heart
Natriuretic peptides:
Atrial natriuretic
peptide (ANP)
Brain natriuretic
peptide (BNP)
Erythropoietin (EPO)
Calcitriol
(Chapters 19 and 26)
Kidney
Adipose Tissue
Digestive Tract
Pancreatic Islets
Gonads
Leptin
Resistin
Numerous hormones
(detailed in Chapter 25)
Insulin, glucagon
Testes (male):
Androgens (especially
testosterone), inhibin
Ovaries (female):
Estrogens, progestins,
inhibinOvary

23. © 2012 Pearson Education, Inc.
The Suprarenal Glands
 Located on top of kidneys
 Manages stress levels
 Can be divided into two regions:
 Suprarenal cortex. Yellow in color due to
presence of steroid lipids.
 The Zona Glomerulosa produces
mineralocorticoids.
 The Zona Fasciculata produces glucocorticoids.
 The Zona Reticularis produces androgens.
 Suprarenal medulla
 Chromaffin cells produce epinephrine (adrenaline)
and norephinephrine (noradrenaline).

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Figure 19. 9ab Anatomy and Histological Organization of the Suprarenal Gland
A suprarenal gland
cut to show both the
cortex and the
medulla. Note the
orientation of the
section for part (c).
Medulla
Cortex
Sectional plane
for part (b)
Left suprarenal
(adrenal) gland
Left middle
suprarenal artery
Left inferior
suprarenal arteries
Left suprarenal vein
Superior mesenteric
artery
Left renal vein
Left renal artery
Right and left inferior
phrenic arteries
Inferior
vena cava
Abdominal
aorta
Anterior view of the kidney and suprarenal
gland. Note the sectional plane for part (b).
Right superior
suprarenal arteries
Celiac trunk
Right suprarenal
(adrenal) gland
Right middle
suprarenal artery
Right inferior
suprarenal artery
Right renal
artery
Right renal
vein

25. © 2012 Pearson Education, Inc.
Figure 19. 9bc Anatomy and Histological Organization of the Suprarenal Gland
A suprarenal gland
cut to show both the
cortex and the
medulla. Note the
orientation of the
section for part (c).
Medulla
Cortex
Histology of the suprarenal gland showing
identification of the major regions
Capsule
Zona
glomerulosa
Zona
fasciculata
Zona
reticularis
Cortex
Medulla
Suprarenal gland LM × 140

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Table19.3 The Suprarenal Hormones

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Endocrine Functions of the Kidneys and Heart
 The kidneys
 Renin, an enzyme that regulates the blood pressure
and blood volume.
 Erythropoietin, a peptide hormone that stimulates the
RBC production in red bone marrow.
 Calcitriol, a steroid hormone
 The heart
 Atrial natriuretic peptide (ANP)
 Brain natriuretic peptide (BNP)
 Both produce hormones involved with
the regulation of blood pressure and blood
volume

28. © 2012 Pearson Education, Inc.
The Pancreas and Other Endocrine Tissues
The Pancreas — located under stomach
 Alpha cells — glucagon
 Beta cells — insulin
 Delta cells — somatostatin (growth-hormone
inhibiting hormone)
 F cells — pancreatic polypeptide (PP)
 Other digestive hormones discussed
in digestive chapter

29. © 2012 Pearson Education, Inc.
Figure 19.1 The Endocrine System
KEY TO PITUITARY HORMONES
ACTH
TSH
GH
PRL
FSH
LH
MSH
ADH
Adrenocorticotropic hormone
Thyroid-stimulating hormone
Growth hormone
Prolactin
Follicle-stimulating hormone
Luteinizing hormone
Melanocyte-stimulating hormone
Antidiuretic hormone
Each suprarenal gland is
subdivided into:
Medulla:
Epinephrine (E)
Norepinephrine (NE)
Cortex:
Cortisol, corticosterone,
aldosterone, androgens
Thymosins
Testis
Thyroxine (T4)
Triiodothyronine (T3)
Calcitonin (CT)
Pars distalis (anterior lobe):
ACTH, TSH, GH, PRL,
FSH, LH, and MSH
Neurohypophysis
(posterior lobe):
Release of oxytocin
and ADH
Suprarenal Glands
Thymus
(Undergoes atrophy
during adulthood)
Thyroid Gland
Pituitary Gland
Hypothalamus
Production of ADH,
oxytocin, and regulatory
hormones
Pineal Gland
Melatonin
Parathyroid Glands
(on posterior surface of
thyroid gland)
Parathyroid hormone (PTH)
Heart
Natriuretic peptides:
Atrial natriuretic
peptide (ANP)
Brain natriuretic
peptide (BNP)
Erythropoietin (EPO)
Calcitriol
(Chapters 19 and 26)
Kidney
Adipose Tissue
Digestive Tract
Pancreatic Islets
Gonads
Leptin
Resistin
Numerous hormones
(detailed in Chapter 25)
Insulin, glucagon
Testes (male):
Androgens (especially
testosterone), inhibin
Ovaries (female):
Estrogens, progestins,
inhibinOvary

30. © 2012 Pearson Education, Inc.
Figure 19.10a Anatomy and Histological Organization of the Pancreas
The gross anatomy of the pancreas
Pancreatic
duct
Body of
pancreas
Lobule Tail
Accessory
pancreatic
duct
Head of
pancreas
Small
intestine
(duodenum)
Common
bile duct

31. © 2012 Pearson Education, Inc.
Table 19.4 Hormones of the Pancreas

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Endocrine Tissues of the Reproductive System
Testes
 Interstitial cells produce androgens (testosterone)
 Promotes production of functional sperms, maintains secretory
glands, influences secondary sexual characteristics, and
stimultes muscle growth
 Nurse cells (or sustentabular cells) secrete inhibin
 Ovaries
 Follicular cells produce estrogens and secrete inhibin
 Corpus luteum releases progestins and relaxin

33. © 2012 Pearson Education, Inc.
Table 19.6 Hormones of the Reproductive System

34. © 2012 Pearson Education, Inc.
The Pineal Gland
 Part of the epithalamus
 Contains neurons, glial cells, and special
secretary cells called pinealocytes
 Pinealocytes synthesizes the hormone,
melatonin
 Melatonin
 Slows the maturation of sperm, oocytes, and
reproductive organs
 Production rate rises at night and declines
during the day

35. © 2012 Pearson Education, Inc.
Hormones and Aging
Exhibits relatively few changes with advancing age
One can expect
 The changes in reproduction hormone levels
at puberty
 The decline in the concentration of
reproductive hormones at menopause in
women

36. © 2012 Pearson Education, Inc.