Transcript CHAPTER 11 OBJECTIVES AFTER YOU HAVE COMPLETED THIS CHAPTER, YOU SHOULD BE ABLE TO: 1. Distinguish between endocrine and exocrine glands and define the terms.

CHAPTER 11
OBJECTIVES
AFTER YOU HAVE COMPLETED THIS CHAPTER, YOU SHOULD BE ABLE TO:
1.
Distinguish between endocrine and exocrine glands and define the
terms hormone and prostaglandin.
2.
Identify and locate the primary endocrine glands and list the major
hormones produced by each gland.
3.
Describe the mechanisms of steroid and non-steroid hormone
action.
4.
Explain how negative and positive feedback mechanisms regulate
the secretion of endocrine hormones.
5.
6.
Explain the primary mechanisms of endocrine disorders.
7.
Define diabetes insipidus, diabetes mellitus, gigantism, goiter,
cretinism, and glycosuria.
identify the principal functions of each major endocrine hormone
and describe the conditions that may result from hyposecretion or
hypersecretion.
QUICK OUTLINE
In this presentation we will discuss the following:
A.
MECHANISMS OF HORMONE
ACTION
 Nonsteroid Hormones
 Steroid Hormones
B. REGULATION OF HOFIMONE
SECRETION
H.
PARATHYROID GLANDS
I.
ADRENAL GLANDS
 Adrenal Cortex
 Adrenal Medulla
 Adrenal Abnormalities
J.
PANCFIEATIC ISLETS
C.
MECHANISMS OF ENDOCFIINE
DISEASE
K.
FEMALE SEX GLANDS
D.
PROSTAGLANDINS
L.
MALE SEX GLANDS
E.
PITUITAFIY GLAND
M.
THYMUS
 Anterior Pituitary Gland
Hormones
 Posterior Pituitary Gland
Hormones
F.
HYPOTHALAMUS
N.
PLACENTA
O.
PINEAL GLAND
P.
OTHER ENDOCRINE STRUCTURES
G.
THYROID GLAND
MECHANISMS OF
HORMONE ACTION
A. Endocrine glands secrete
chemicals (hormones) into
the blood (Figure 11-1)
B. Hormones perform
general functions of
communication and
control but a slower,
longer-lasting type of
control than that provided
by nerve impulses
C. Cells acted on by
hormones are called
target organ cells
Page(s) 343-344
Page(s) 344
MECHANISMS OF
HORMONE ACTION
D. Nonsteroid
hormones
(first
messengers)
bind to
receptors on
the target
cell
membrane,
triggering
second
messengers
to affect the
cell’s
activities
(Figure 11-2)
Page(s) 344-349
MECHANISMS OF
HORMONE ACTION
E. Steroid
hormones
bind to
receptors
within the
target cell
nucleus
and
influence
cell
activity by
acting on
DNA
(Figure 113)
Page(s) 348-349
REGULATION OF
HORMONE SECRETION
A. Hormone secretion is controlled by homeostatic
feedback
B. Negative feedback—mechanisms that reverse
the direction of a change in a physiological
system (Figure 11-4)
C. Positive feedback—(uncommon) mechanisms
that amplify physiological changes
Page(s) 348-351
Page(s) 350
MECHANISMS OF
ENDOCRINE DISEASE
(Table 11-1)
A. Hypersecretion—secretion of an excess of
hormone
B. Hyposecretion—insufficient hormone secretion
C. Target cell insensitivity produces results similar
to hyposecretion
D. Endocrinologists have developed many different
strategies for treatment (e.g., surgery and
hormone therapy)
Page(s) 351
Page(s) 345
Page(s) 346
Page(s) 347
PROSTAGLANDINS
A. Prostaglandins (PGs) are powerful
substances found in a wide variety of body
tissues
B. PGs are often produced in a tissue and
diffuse only a short distance to act on cells in
that tissue
C. Several classes of PGs include prostaglandin
A (PGA), prostaglandin E (PGE), and
prostaglandin F (PGF)
D. PGs influence many body functions,
including respiration, blood pressure,
gastrointestinal secretions, and reproduction
Page(s) 351
PITUITARY GLAND
(FIGURE 11-6)
Page(s) 354
PITUITARY GLAND
A. Anterior pituitary gland
(adenohypophysis)
1. Names of major
hormones
a. Thyroid-stimulating
hormone (TSH)
b. Adrenocorticotropic
hormone (ACTH)
c. Follicle-stimulating
hormone (FSH)
d. Luteinizing hormone
(LH)
e. Growth hormone
(GH)
f. Prolactin (lactogenic
hormone)
Page(s) 352-354
PITUITARY GLAND
2. Functions of major
hormones
a. TSH—stimulates growth of
the thyroid gland; also
stimulates it to secrete
thyroid hormone
b. ACTH—stimulates growth of
the adrenal cortex and
stimulates it to secrete
glucocorticoids (mainly
cortisol)
c. FSH—initiates growth of
ovarian follicles each month
in the ovary and stimulates
one or more follicles to
develop to the stage of
maturity and ovulation; FSH
also stimulates estrogen
secretion by developing
follicles; stimulates sperm
production in the male
Page(s) 352-354
PITUITARY GLAND
2.Functions of major
hormones
d. LH—acts with FSH
to stimulate
estrogen secretion
and follicle growth
to maturity; causes
ovulation; causes
luteinization of the
ruptured follicle and
stimulates
progesterone
secretion by corpus
luteum; causes
interstitial cells in
the testes to secrete
testosterone in the
male
Page(s) 352-354
PITUITARY GLAND
2.Functions of major
hormones
d. LH—acts with FSH
to stimulate
estrogen secretion
and follicle growth
to maturity; causes
ovulation; causes
luteinization of the
ruptured follicle and
stimulates
progesterone
secretion by corpus
luteum; causes
interstitial cells in
the testes to secrete
testosterone in the
male
Page(s) 352-354
PITUITARY GLAND
2. Functions of major
hormones
e. GH—stimulates growth by
accelerating protein
anabolism; also accelerates
fat catabolism and slows
glucose catabolism; by
slowing glucose catabolism,
tends to increase blood
glucose to higher than
normal level
(hyperglycemia)
1) Hypersecretion during
childhood results in
gigantism and during
adulthood results in
acromegaly
2) Hyposecretion during
childhood results in
pituitary dwarfism
Page(s) 352-354
Page(s) 353
Page(s) 353
PITUITARY GLAND
2. Functions of major
hormones
f. Prolactin or lactogenic
hormone—stimulates
breast development
during pregnancy and
secretion of milk after
the delivery of the baby
Page(s) 352-354
PITUITARY GLAND
B. Posterior pituitary
gland (neurohypophysis)
1.
Names of
hormones
a.Antidiuretic
hormone (ADH)
1) Hyposecretion
causes diabetes
insipidus,
characterized by
excessive
volume of urine
b.Oxytocin
Page(s) 352-354
PITUITARY GLAND
2. Functions of hormones
a. ADH—accelerates
water reabsorption
from urine in the
kidney tubules into the
blood, thereby
decreasing urine
secretion
b. Oxytocin—stimulates
the pregnant uterus to
contract; may initiate
labor; causes glandular
cells of the breast to
release milk into ducts
Page(s) 352-354
HYPOTHALAMUS
A. Actual production of ADH and oxytocin occurs in
the hypothalamus
B. After production in the hypothalamus, hormones
pass along axons into the pituitary gland
C.
The secretion and
release of posterior
pituitary hormones
is controlled by
nervous stimulation
D. The hypothalamus
controls many body
functions related to
homeostasis
(temperature,
appetite, and thirst)
Page(s) 344, 355
THYROID GLAND
(FIGURE 11-7)
Page(s) 356
THYROID GLAND
A. Names of hormones
1.Thyroid hormone—thyroxine (T4) and
triiodothyronine (T3)
2.Calcitonin
B. Functions of hormones
1.Thyroid hormones—accelerate catabolism
(increase the body’s metabolic rate)
2.Calcitonin—decreases the blood calcium
concentration by inhibiting breakdown of
bone, which would release calcium into the
blood
Page(s) 355-357
THYROID GLAND
Thyroid Hormones are stored in colloid in thyroid follicles
Page(s) 356
THYROID GLAND
C. Hyperthyroidism
(hypersecretion of
thyroid hormones)
increases metabolic rate
1. Characterized by
restlessness and
exophthalmos
(protruding eyes)
2. Graves’ disease is
an inherited form
of hyperthyroidism
Page(s) 357
THYROID GLAND
D. Hypothyroidism
(hyposecretion of
thyroid hormones)
1. May result from
different conditions
2. Simple goiter—
painless enlargement
of thyroid caused by
dietary deficiency of
iodine
Page(s) 357
THYROID GLAND
D. Hypothyroidism
(hyposecretion of
thyroid hormones)
3. Hyposecretion
during early
development may
result in cretinism
(retardation) and
during adulthood in
myxedema
(characterized by
edema and
sluggishness)
Page(s) 358
PARATHYROID GLANDS
(FIGURE 11-7)
A. Name of
hormone—
parathyroid
hormone (PTH)
B. Function of
hormone—
increases blood
calcium
concentration
by increasing
the breakdown
of bone with
the release of
calcium into
the blood
Page(s) 356, 358
Page(s) 359
ADRENAL GLANDS
(FIGURE 11-13)
Page(s) 359
ADRENAL GLANDS
A. Adrenal cortex
1. Names of hormones (corticoids)
a. Glucocorticoids (GCs)—chiefly cortisol
b. Mineralocorticoids
(MCs)—chiefly
aldosterone
c. Sex hormones—
small amounts of
male hormones
(androgens)
secreted by adrenal
cortex of both
sexes
Page(s) 358-360
ADRENAL GLANDS
2.
Three cell layers (zones)
a. Outer layer—secretes mineralocorticoids
b. Middle layer—secretes glucocorticoids
c. Inner layer—secretes sex hormones
3.
Mineralocorticoids—
increase blood
sodium and decrease
body potassium
concentrations by
accelerating kidney
tubule reabsorption
of sodium and
excretion of
potassium
Page(s) 359-360
ADRENAL GLANDS
4. Functions of glucocorticoids
a.
b.
Page(s) 360
Help maintain normal blood glucose concentration
by increasing gluconeogenesis—the formation of
“new” glucose from amino acids produced by the
breakdown of proteins, mainly those in muscle
tissue cells; also the conversion to glucose of fatty
acids produced by the breakdown of fats stored in
adipose tissue cells
Play an essential part in maintaining normal blood
pressure—make it possible for epinephrine and
norepinephrine to maintain a normal degree of
vasoconstriction, a condition necessary for
maintaining normal blood pressure
ADRENAL GLANDS
c.
Act with epinephrine and norepinephrine to
produce an antiinflammatory effect, to bring
about normal recovery from inflammations of
various kinds
d. Produce anti-immunity, anti-allergy effect;
bring about a decrease in the number of
lymphocytes and plasma cells and therefore a
decrease in the amount of antibodies formed
e. Secretion of glucocorticoid quickly increases
when the body is thrown into a condition of
stress; high blood concentration of
glucocorticoids, in turn, brings about many
other stress responses (Figure 11-14)
Page(s) 360
Page(s) 361
ADRENAL GLANDS
B. Adrenal medulla
1. Names of hormones—epinephrine (adrenaline) and
norepinephrine
2. Functions of
hormones—help the
body resist stress by
intensifying and
prolonging the effects
of sympathetic
stimulation; increased
epinephrine secretion
is the first endocrine
response to stress
Page(s) 359-362
ADRENAL GLANDS
C. Adrenal abnormalities
1. Hypersecretion of glucocorticoids causes Cushing
syndrome: moon face, hump on back, elevated blood
sugar levels, frequent infections
Page(s) 362-363
ADRENAL GLANDS
C. Adrenal abnormalities
2. Hypersecretion of
adrenal androgens may
result from a virilizing
tumor and cause
masculinization of
affected women
3. Hyposecretion of
cortical hormones may
result in Addison
disease: muscle
weakness, reduced
blood sugar, nausea,
loss of appetite, and
weight loss
Page(s) 362-363
PANCREATIC ISLETS
(FIGURE 11-17)
Page(s) 364
PANCREATIC ISLETS
A. Names of hormones
1. Glucagon—
secreted by
alpha cells
2. Insulin—
secreted by
beta cells
Page(s) 363-364
PANCREATIC ISLETS
B. Functions of hormones
1. Glucagon increases the blood glucose level
by accelerating liver glycogenolysis
(conversion of glycogen to glucose)
2. Insulin decreases the blood glucose by
accelerating the movement of glucose out
of the blood into cells, which increases
glucose metabolism by cells
Page(s) 363
PANCREATIC ISLETS
C. Diabetes mellitus (Figure 11-18)
1. Type 1 results from hyposecretion of insulin
2. Type 2 results from target cell insensitivity
to insulin
3. Glucose cannot enter cells and thus blood
glucose levels rise, producing glycosuria
(glucose in the urine)
Page(s) 363-364
Page(s) 365
FEMALE SEX GLANDS
A. The ovaries contain two structures that secrete
hormones—the ovarian follicles and the corpus
luteum; see Chapter 22
1.
Effects of estrogen
(feminizing
hormone)
a. Development
and maturation
of breasts and
external genitals
b. Development of
adult female
body contours
c. Initiation of
menstrual cycle
Page(s) 344, 366
MALE SEX GLANDS
A. The interstitial cells of testes secrete the male
hormone testosterone; see Chapter 22
1. Effects of
testosterone
(masculinizing
hormone)
a.Maturation of
external genitals
c. Beard growth
d.Voice changes at
puberty
e.Development of
musculature and
body contours
typical of the
male
Page(s) 344, 366
THYMUS
A. Name of
hormone—
thymosin
B. Function of
hormone—plays
an important role
in the
development and
function of the
body’s immune
system
Page(s) 344, 366-367
PLACENTA
A. Name of hormones—chorionic gonadotropins,
estrogens, and progesterone
B. Functions of hormones—maintain the corpus
luteum during pregnancy
Page(s) 367
PINEAL GLAND
A. A small gland near the roof of the third
ventricle of the brain
1. Glandular tissue predominates in children
and young adults
2. Becomes fibrous and calcified with age
B. Called third eye
because its
influence on
secretory activity is
related to the
amount of light
entering the eyes
Page(s) 344, 367
PINEAL GLAND
C. Secretes melatonin, which:
1. Inhibits ovarian activity
2. Regulates the body’s internal clock
D. Abnormal secretion of (or sensitivity to)
melatonin may produce seasonal affective
disorder (SAD) or winter depression, a form of
depression that occurs when exposure to
sunlight is low and melatonin levels are high
Page(s) 367
OTHER ENDOCRINE
STRUCTURES
A. Many organs (for example, the stomach,
intestines, and kidney) produce endocrine
hormones
B. The atrial wall of the heart secretes atrial
natriuretic hormone (ANH), which stimulates
sodium loss from the kidneys
C. Fat-storing cells secrete leptin, which controls
how full or hungry we feel
Page(s) 367-368
CREDITS
A. All photos and references are taken from:
Thibodeau, Gary, & Patton, Kevin. (2005).
The Human body in health & disease.
Mosby.
ISBN: 0-323-03161-7