Endocrine System
Hormone
is a chemical messenger secreted by one
endocrine gland or cell into the bloodstream and
targeted toward cells in another organ.
- specificity
- receptor
- distribution
Chemical Identity of Hormones
1) Steroid hormones
2) Biogenic amines
3) Peptide hormones
1) Steroid hormones
Estrogens
Progesterone
Androgens
glucocorticoids
aldosterone
- derived from cholesterol
2) Biogenic amines
Epinephrine
Norepinephrine
Dopamine
Serotonin
Melatonin
thyroid hormones
- Synthesized from amino acids
3) Peptide hormones
Hypothalamic hormones
Pituitary hormones
Pancreatic hormones
GI hormones
- are peptides
Water Solubility and Membrane Permeability
Steroid + thyroid hormones
All other hormones
Hydrophobic
Membrane-permeable
Hydrophilic
Membrane-impermeable
Effects after hormones bind to their receptors
1) Synthesis of new proteins (enzymes)
2) Alterations of activities of proteins that are
already present
Effects of Hormone Concentration
Effects of Hormone Concentration
Hormone Deactivation
Hormones have short half-life (< 2 min) in the plasma.
Hormone Interactions
Synergistic effects
Two hormones act together to produce an effect
that is greater than the sum of their separate
effects.
Permissive effects
Only in the presence of one hormone, the target
organ responds to a second hormone.
Antagonistic effects
One hormone opposes the action of another
hormone.
Posterior Pituitary
Hormone
Target Organ
Principal Effects
1) ADH
Kidneys
blood vessels
reducing urine output
vasoconstriction
2) Oxytocin
Uterus,
Labor contractions
mammary glands, milk ejection
Anterior Pituitary
Hormone
Target Organ
Ovaries and Testes
follicle/egg or sperm
development
Ovaries and testes
Ovulation/growth of
corpus luteum
1) FSH
(Follicle-Stimulating
Hormone)
2) LH
(Luteinizing Hormone)
3) TSH
(Thyroid-Stimulating
Hormone)
Principal Effects
Thyroid gland
Growth of thyroid gland
Secretion of thyroid
hormone
Anterior Pituitary
Hormone
4) ACTH
Target Organ
Adrenal cortex
(Adrenocorticotropic
Hormone)
5) PRL
(Prolactin)
Mammary gland
Testes
Principal Effects
Growth of adrenal cortex
secretion of
glucocorticoids
milk synthesis
enhance secretion
of testosterone
Anterior Pituitary
Hormone
Target Organ
6) GH
Most tissues
(Growth hormone
or somatotropin)
Principal Effects
tissue/organ growth,
cell mitosis and
differentiation
Hypothalamus
hormones
Hypothalamus
Hormone
1) TRH
Target Organ
Pituitary
Thyrotropin-releasing
hormone
2) CRH
Promotes ACTH
secretion
Pituitary
Promotes FSH/LH
secretion
Gonadotropin-releasing
hormone
4) PRF
Prolactin-releasing factor
Promotes TSH and PRL
secretion
Pituitary
Corticotropin-releasing
hormone
3) GnRH
Principal Effects
Pituitary
Promotes PRL secretion
Hypothalamus
Hormone
Target Organ
5) PIF
Principal Effects
Pituitary
Inhibits PRL secretion
Pituitary
Promotes GH secretion
Pituitary
Inhibits GH/TSH secretion
Prolactin-inhibiting factor
Dopamine
6) GHRH
Growth hormone-releasing
hormone
7) GHIH
Growth hormone-inhibiting
hormone
somatostatin
Pineal Gland
Hormone
Target Organ
Principal Effects
1) Melatonin
Brain
Regulate timing of puberty;
influence mood
2) Serotonin
Brain
Regulate timing of puberty;
influence mood
Thymus
Hormone
Target Organ
Thymopoietin/
Thymosins
T lymphocytes
Principal Effects
Promote T lymphocyte
development/activation
Thyroid Gland
Hormone
1) Triiodothyronin
(T3)
Target Organ
Most tissues
2) Throxin (T4)
3) Calcitonin
Osteoblasts
Principal Effects
Stimulate Na+-K+ pumps,
metabolic rate,
heat production,
alertness, protein
synthesis, fetal and
childhood growth, and
CNS development
Stimulates calcium
deposition and
ossification; reduces
blood calcium
concentration
Parathyroid Gland
Hormone
PTH
Parathyroid
hormone
Target Organ
Small intestine,
Kidneys, and
Osteoclasts
Principal Effects
Stimulates calcium
absorption and
retention; promotes
bone resorption;
elevates blood
calcium
concentration
Adrenal Gland
Adrenal Medulla
Hormone
Target Organ
1) Epinephrin
2) Norepinephrin
3) Dopamine
Most tissues
Principal Effects
Complement action
of sympathetic
nervous system
Adrenal Cortex
Hormone
Target Organ
1) Aldosterone
2) Glucocorticoids
Cortisol/Corticosterone
Kidneys
Most tissues
Principal Effects
Promotes Na+
retention and K+
excretion; maintains
blood pressure and
volume
Promote fat and
protein catabolism,
gluconeogesis,
stress resistance,
and tissue repair;
inhibit inflammation
Adrenal Cortex
Hormone
Target Organ
Principal Effects
3) Androgen
Bone, muscle,
Integument,
many other
organs
Stimulate growth of
pubic and axillary
hair in both sexes;
stimulate libido;
negligible effcts in
males compared to
teststerone from
testes
Pancreatic Islets
Hormone
Target Organ
Principal Effects
1) Glucagon
Primarily liver
Stimulates glycogen
and fat hydrolysis,
mobilization of glucose
and fatty acids, and
gluconeogenesis
2) Insulin
Most tissues
Promotes glucose and
amino acid uptake and
synthesis of glycogen,
fat, and protein
The Ovaries
Hormone
Estradiol
Estragen
Target Organ
Ovaries, uterus,
mammary glands,
brain, many other
tissues
Principal Effects
Regulates egg
production; stimulates
adolescent growth;
promotes development of
female secondary sex
characteristics; prepares
mammary glands for
lactation; prepares uterus
for pregnancy
The Ovaries
Hormone
Progesterone
Inhibin
Target Organ
Principal Effects
Ovaries,
uterus,
mammary
glands, many
other tissues
Stimulates mammary
development in puberty
and pregnancy; prepares
uterus for pregnancy
Anterior pituitary
Suppresses FSH
secretion
The Testes
Hormone
Testosterone
Target Organ
Most Tissues
Principal Effects
Regulates sperm
production; promotes
development of male
reproductive system and
physique; stimulates
adolescent growth,
libido, and sexual
behavior
Heart
Hormone
ANF
Target Organ
Kidneys
Principal Effects
Increases Na+
excretion and urine
output; lowers blood
pressure
Kidneys
Hormone
Target Organ
Calcitriol
Intestines
Increase
absorption of
calcium
Red
Bone
marrow
Stimulate RBC
production
Erythropoietin
Renin
angiotensinogen
Principal Effects
Stimulate
production of
angiotensin I
Liver
Hormone
Target Organ
Angiotensinogen
Erythropoietin
Blood vessels,
adrenal cortex,
hypothalamus
Principal Effects
Stimulates
vasoconstriction,
aldosterone
secretion, and thirst
GI tract
Hormone
Gastrin
Secretin
Target Organ
GI tract and its
accessory
glands
CCK
(cholecystokinin)
GIP
(gastric inhibitory peptide)
Principal Effects
Coordinate secretion
and motility in
digestion
Placenta
Hormone
Estrogen
Progesterone
Target Organ
Maternal and
fetal tissues
Principal Effects
Promotes fetal growth;
regulate pregnancy;
prepare mammary
glands for lactation
Exercise
11. Digestion is a process to ___.
A. take food into the mouth
B. take absorbable nutrients into blood
stream
C. break ingested food into absorbable
forms
D store food in the digestive tract
W2. Which of the following forms of nutrients
cannot be directly absorbed into blood
without digestion?
A. Proteins
B. fatty acids
C. vitamin A
D. glucose
33. The primary dietary carbohydrates
are starch, which are ____.
A. Monosaccharides
B. polymers of glucose
C. polymers of amino acids
D. polymers of fatty acids
44. Fats or triglycerides ___.
A. can be absorbed without
digestion
B. are digested into monoglycerides
and fatty acids, then absorbed in the
small intestine
C. are digested into glucose, then
absorbed in the small intestine
D. are digested into amino acids,
then absorbed in the small intestine
55. Which of the following is not
secreted by gastric glands?
A. pepsinogen
B. trypsinogen
C. HCl
D. intrinsic factor
66. Which of the following is not a function of
gastric acid?
A. activating pepsinogen.
B. digesting connective tissues in the ingested
food
C. destroying ingested pathogens
D. activating pancreatic enzymes
77. Intrinsic factor has the function of
___?
A. activating pepsinogen
B. helping absorb vitamin B12
C. helping absorb vitamin B6
D. activating pancreatic enzymes
88. Pepsinogen is able to digest
___.
A. proteins
B. fats
C. starch
D. none of the above
99. Food digestion is completed primarily in ____.
A. stomach
B. small intestine
C. large intestine
110. Gastric motility and secretion is ____.
A. inhibited when food is ingested into the mouth
B. stimulated when food enters the stomach
C. strongly stimulated after chyme have entered
the small intestine
111. Bile is produced by ____.
A. hepatocytes
B. gallbladder
C. pancreas
D. small intestine
112. Bile salts are needed for digestion
and absorption of ____.
A. carbohydrates
B. proteins
C. fats
D. minerals
113. Which component of bile is reabsorbed via
enterohepatic circulation?
A. bile salts
B. bile pigments
C. cholesterol
D. minerals
114. Pancreatic juice is ____.
A. acidic (low pH)
B. basic (high pH)
C. neutral
115. Which of the following cannot be
digested and absorbed by human
pancreatic enzymes?
A. starch
B. proteins
C. fats
D. cellulose
116. Bile and pancreatic juice are released into
duodenum when ___.
A. chyme is not present in duodenum
B. cholecystokinin is secreted by duodenal
mucosa
C. hepatopancreatic sphincter constricts
D. gallbladder relaxes
117. Pancreatic zymogens are ___.
A. active when stored in pancreatic duct
B. activated after being released into duodenum
118. Proteins and carbohydrates can be digested
into amino acids and glucose by ___.
A. pancreatic enzymes alone
B. pancreatic enzymes plus brush border enzymes
C. brush border enzymes alone
119. Which of the following is not a
hormone?
A. gastrin
B. cholecystokinin
C. secretin
D. intrinsic factor
220. Which type of the movement of the
small intestine can push chyme towards
the large intestine?
A. peristalsis
B. segmentation
C. both peristalsis and segmentation
221. Which of the following is a function of
gastrin?
A. to stimulate the secretion of HCl and
pepsinogen
B. to inhibit gastric motility
C. to inhibit motility of the large intestine
222. The functions of cholecystokinin include ___.
A. to stimulate constriction of gallbladder
B. to stimulate relaxation of hepatopanreatic
sphincter
C. to inhibit gastric secretion of motility
D. all of the above
223. Bacterial flora ____.
A. are present primarily in small
intestine
B. synthesize vitamins
C. are harmful to human health
224. The large intestine primarily absorbs
___.
A. glucose
B. fatty acids
C. amino acids
D. water
225. Glucose is taken into intestinal
epithelial cells directly by ____.
A. Na+-K+ ATPase
B. sodium-dependent glucose transporters
C. potassium-dependent glucose
transporters
D. all of the above
226. Emulsification is required to complete
digestion of ___.
A. fats
B. proteins
C. carbohydrates
D. water
227. Hunger and satiety are regulated by ____.
A. the feeding center and satiety center at
hypothalamus
B. cholecystokinin
C. appetite-stimulating hormones released by
adipocytes
D. all of the above
228. Which of the following nutrients is
more often used to produce ATP?
A. glucose
B. fats
C. proteins
D. vitamins
229. Which of the following can be stored
in human body?
A. ATP
B. Glucose
C. Glycogen and fats
D. All of the above
330. Which of the following fuel do neurons
normally use?
A. glucose
B. amino acids
C. fatty acids
31. Absorption of blood glucose by most
tissue cells depends on ____.
A. insulin
B. insulin receptors
C. both of the above
332. During absorptive state, ____.
A. blood glucose is absorbed by all tissue cells
B. excessive blood glucose is converted to
glycogen or fat
C. both of the above take place
333. Glycogen is synthesized and stored
primarily in ____.
A. liver
B. kidneys
C. neurons
34. Gluconeogenesis is a process that
____.
A. glucose is synthesized from fats or amino
acids
B. occurs normally during absorptive state
when blood glucose is abundant
C. glycogen is hydrolyzed into glucose
335. During postabsorptive state, ____.
A. blood glucose comes from glycogen and
fats.
B. blood insulin level is high
C. blood glucagon is low
D. all of the above take place
336. In which temporal order (first to last), are the following
nutrients used to produce ATP when food is not available.
A. Glycogen --- fats --- skeletal muscle proteins --- cardiac muscle
proteins
B.
skeletal muscle proteins --- glycogen --- fats --- cardiac muscle
proteins
C.
fats --- skeletal muscle proteins --- glycogen --- cardiac muscle
proteins
D.
cardiac muscle proteins --- skeletal muscle proteins --- fats --glycogen
337. Body heat is produced during
___.
A. synthesis of ATP
B. consumption of ATP
C. both of the above
338. Thermoregulation center is located in
___.
A. medulla oblongata
B. hypothalamus
C. spinal cord
D. cerebral cortex
339. The body heat can be lost via ___.
A. conduction
B. radiation
C. evaporation
D. all of the above
440. The sex of an individual is determined by
____.
A. sex chromosomes
B. primary sex organs
C. secondary sex organs
D. secondary sex characteristics
441. Sperm cells are produced in ____.
A. seminiferous tubules
B. epididymus
C. seminal vesicles
D. vas differens
442. Sperm cells are stored in
____.
A. seminiferous tubules
B. epididymus
C. seminal vesicles
D. vas defferens
443. Semen contains ___.
A. spermatozoan
B. fructose
C. prostaglandins
D. all of the above
444. Sperm cells ___.
A. start to migrate towards uterus immediately
after being ejaculated into vagina
B. are not able to fertilize an egg without
capacitation
C. can all find the egg
445. In which part of the female reproductive tract is
an egg usually fertilized by a sperm cell?
A. uterus
B. vagina
C. one third of uterine tube that is proximal to the
uterus
D. one third of uterine tube that is distal to the uterus
446. During which of the following period does a
sexual intercourse have the maximum chance of
resulting in pregnancy?
A.
starting at 48 hours before ovulation and ending at 14
hours after ovulation
B.
starting at 48 hours before ovulation and ending at 24
hours after ovulation
C.
starting at 48 hours before ovulation and ending at 48
hours after ovulation
D.
starting at 48 hours before ovulation and ending at 72
hours after ovulation
447. Which of the following statement is
incorrect?
A. Only one egg is released by two ovaries in
each ovarian cycle
B. Ovulation is triggered by a sudden
increase of blood FSH level at day 14
C. FSH stimulates the development of
follicles
448. Which of the following statements about
corpus luteum is incorrect ?
A. Corpus luteum normally secrets progesterone
and estrogen
B. Corpus luteum secrets progesterone and
estrogen for only ~10 days, then undergo
degeneration, no matter if the egg is fertilized or not.
C. Corpus luteum is formed after the oocyte is
ovulated.
449. Which of the following statement about
uterus is incorrect?
A. The growth and secretion of uterus depends
on progesterone
B. The uterus harbors embryo
C. The uterus secrets nutrients
D. The uterus does not contract at labor.
550. The pH of vagina is usually
___.
A. low (acidic)
B. high (basic)
C. neutral
551. Which of the following statements about
HCG is correct?
A. HCG is secreted by ovaries.
B. HCG is found in blood 8-10 days after
fertilization
C. HCG inhibits the secretion of progesterone
from corpus luteum
D. HCG stimulates the development of follicles.
552. In which of the following events, are
the chemical messengers transported by the
blood?
A. endocrine
B. paracrine
C. autocrine
D. synaptic communication
553. Hormones fall into the following
chemical classes except ____.
A. steroids
B. biogenic amines
C. fatty acids
D. peptides
554. Which of the following hormone classes
has their receptors located in the nucleus?
A. steroid hormones
B. peptide hormones
C. biogenic amine hormones (except thyroid
hormones)
555. Which of the following hormone
classes stimulates synthesis of new
proteins?
A. steroid hormones
B. peptide hormones
C. biogenic amine hormones (except thyroid
hormones)
556. Long-term exposure to high levels of
a hormone causes ____ in the number of
receptors and sensitivity to the hormone
A. a decrease
B. an increase
C. no change
557. Which of the following statements is
correct?
A. Most hormones remain active for several
hours after being released into the blood.
B. About 50% of most hormones are deactivated
a couple of minutes after being released into the
blood.
C. Hormones are primarily deactivated in
muscles.
558. Which of the following hormones is
not secreted by pituitary?
A. luteinizing hormone (LH)
B. thyrotropin releasing hormone (TRH)
C. adrenocorticotropic hormone (ACTH)
D. growth hormone (GH)
559. Which of the following hormones is
synthesized in hypothalamus and secreted from
pituitary?
A. antidiuretic hormone
B. prolactin
C. follicle-stimulating hormone
D. growth hormone
660. Which of the following hormones
stimulates gluconeogenesis ?
A. insulin
B. vasopressin
C. glucagon
D. gastrin
661. Which of the following hormones has
the strongest stimulatory effect on
metabolic rate or heat production?
A. thyroid hormone
B. ADH
C. Aldosterone
D. oxytocin
662. Which of the hormone stimulates
uterine labor contractions?
A. thyroid hormone
B. ADH
C. Aldosterone
D. oxytocin
663. Adrenal medulla secrets ____.
A. catecholamines
B. glucocorticoids
C. aldosterone
D. androgen