Download Principles of Anatomy and Physiology

Principles of Anatomy
and Physiology
Thirteenth Edition
Gerard J. Tortora • Bryan H. Derrickson
Chapter 18
The Endocrine System
Copyright © 2012 by John Wiley & Sons, Inc.
PINEAL GLAND
HYPOTHALAMUS
Thyroid gland
PARATHYROID
GLANDS
PITUITARY GLAND
Trachea
THYROID GLAND
Trachea
PARATHYROID GLANDS
(behind thyroid glands)
SKIN
THYMUS
Lung
HEART
LIVER
STOMACH
ADRENAL
GLANDS
KIDNEY
Uterus
PANCREAS
OVARY
SMALL
INTESTINE
Female
Scrotum
TESTES
Male
Endocrine
cell
Circulating hormone
Blood
capillary
Hormone
receptor
Distant target cells
(a) Circulating hormones
Paracrine receptor
Paracrine
Paracrine cell
Nearby target cell
Autocrine
cell
Autocrine
(b) Local hormones (paracrines and autocrines)
Autocrine
receptor
Steroid hormones
Aldosterone
Thyroid hormones
Triiodothyronine (T3)
Amines
Norepinephrine
Peptides and proteins
Oxytocin
Eicosanoids
A leukotriene (LTB4)
Free hormone
Transport protein
2 Activated receptor–
hormone
complex alters gene
expression
Cytosol
Blood capillary
1 Lipid-soluble hormone
diffuses into cell
Nucleus
Receptor
DNA
mRNA
Ribosome
3 Newly
Formed mRNA
directs synthesis of
specific proteins on
ribosomes
New
protein
4 New proteins alter
cell's activity
Target cell
Blood capillary
Binding of hormone (first messenger) to its receptor activates
G protein, which activates adenylate cyclase
1
Water-soluble
hormone
Adenylate cyclase
Receptor
Second messenger
G protein
ATP
cAMP
2 Activated adenylate
cyclase converts
ATP to cAMP
6 Phosphodiesterase
Protein kinases
3 cAMP serves as a Activated inactivates cAMP
second messenger protein
to activate protein kinases
kinases
4 Activated protein
Protein
kinases
phosphorylate
ATP
cellular proteins
ADP
Protein - P
5 Millions of phosphorylated
proteins cause reactions that
produce physiological responses
Target cell
Infundibulum
Hypothalamus
POSTERIOR
PITUITARY
ANTERIOR
PITUITARY
Pituitary gland
Sagittal section of pituitary gland
Primary plexus of
hypophyseal portal system
Infundibulum
HYPOTHALAMUS
Median eminence
Superior hypophyseal
artery
Posterior hypophyseal
veins
Hypophyseal portal veins
Sphenoid bone
POSTERIOR
PITUITARY
ANTERIOR PITUITARY
Capillary plexus of
infundibular process
Secondary plexus of
hypophyseal portal system
Hypophyseal
fossa
Anterior hypophyseal
veins
POSTERIOR
ANTERIOR
Inferior hypophyseal artery
(a) Relationship of hypothalamus to pituitary gland
Hypothalamic
neurosecretory
cell
Primary plexus of
hypophyseal portal system
Hypophyseal
portal veins
(b) Path of releasing and inhibiting hormones
Corticotroph
Somatotroph
Thyrotroph
Lactotroph
Gonadotroph
LM all about 65x
(c) Histology of anterior pituitary
Corticotropin-releasing
hormone (CRH)
Hypothalamus
CRH stimulates release of
corticotropin (ACTH)
Anterior pituitary
Corticotropin stimulates
secretion of cortisol by
adrenal cortex
Adrenal
cortex
Cortisol
Corticotropin
(ACTH)
Elevated cortisol
inhibits release
of CRH by
hypothalamic
neurosecretory
cells
Elevated cortisol
inhibits release
of corticotropin
by anterior
pituitary
corticotrophs
1 Low blood glucose
6 High blood glucose
(hypoglycemia)
stimulates release of
(hyperglycemia)
stimulates release of
GHRH GHIH
2 GHRH stimulates
7
secretion
of hGH by
somatotrophs
GHIH inhibits
secretion of
hGH by
somatotrophs
hGH
Anterior
pituitary
3 hGH and IGFs speed
8 A low level of hGH and
up breakdown of liver
glycogen into glucose,
which enters the blood
more rapidly
4 Blood glucose level
rises to normal
(about 90 mg/100 mL)
5 If blood glucose
continues to increase,
hyperglycemia inhibits
release of GHRH
IGFs decreases the rate
of glycogen breakdown
in the liver and glucose
enters the blood more
slowly
9 Blood glucose level
falls to normal
(about 90 mg/100 mL)
10
If blood glucose
continues to decrease,
hypoglycemia inhibits
release of GHIH
Human growth hormone (hGH),
also known as somatotropin
Luteinizing hormone (LH)
Ovaries
Testes
Liver (and other tissues)
Prolactin (PRL)
Thyroid-stimulating hormone (TSH),
also known as thyrotropin
Mammary glands
Adrenocorticotropic hormone (ACTH),
also known as corticotropin
Thyroid gland
Adrenal
cortex
Follicle-stimulating hormone (FSH)
Melanocyte-stimulating hormone (MSH)
Ovaries
Testes
Brain
Hypothalamus
Neurosecretory cells
Pituitary gland
HYPOTHALAMUS
Optic
chiasm
Capillary plexus
of the posterior
pituitary
Infundibulum
Axons of neurosecretory cells
Axon terminal
POSTERIOR
PITUITARY
ANTERIOR
PITUITARY
1 High blood osmotic pressure
5 Low blood osmotic pressure
stimulates hypothalamic
osmoreceptors
inhibits hypothalamic
osmoreceptors
Osmoreceptors
2 Osmoreceptors
activate neurosecretory
cells that synthesize
and release ADH
6 Inhibition of osmoreceptors
reduces or stops ADH secretion
Hypothalamus
3 Nerve impulses
liberate ADH from
axon terminals in
posterior pituitary into
bloodstream
ADH
Target tissues
4 Kidneys retain
more water,
which decreases
urine output
Sudoriferous (sweat)
glands decrease water
loss by perspiration
from skin
Arterioles constrict,
which increases
blood pressure
Oxytocin (OT)
Uterus
Mammary glands
Antidiuretic hormone (ADH)
or vasopressin
Kidneys
Sudoriferous
(sweat) glands
Arterioles
Hyoid bone
Superior thyroid artery
Thyroid
gland
Trachea
Superior thyroid vein
Pyramidal lobe of
thyroid gland
Thyroid cartilage of larynx
RIGHT LATERAL LOBE
OF THYROID GLAND
LEFT LATERAL LOBE
OF THYROID GLAND
Middle thyroid vein
Common carotid artery
Inferior thyroid artery
ISTHMUS OF THYROID
GLAND
Vagus (X) nerve
Internal jugular vein
Subclavian artery
Trachea
Inferior thyroid veins
Sternum
(a) Anterior view of thyroid gland
Parafollicular (C) cell
Follicular cell
Thyroid follicle
Thyroglobulin (TGB)
(colloid)
Basement membrane
LM 500x
(b) Thyroid follicles
LEFT LATERAL
LOBE
RIGHT LATERAL
LOBE
ISTHMUS
(c) Anterior view of thyroid gland
Thyroid cartilage of larynx
Cricoid cartilage of larynx
RIGHT LATERAL LOBE OF THYROID GLAND
LEFT LATERAL LOBE OF THYROID GLAND
ISTHMUS OF THYROID GLAND
Trachea
Right lung
Arch of aorta
(d) Anterior view
Portion of thyroid follicle
Follicular
cell
Colloid
4 Iodination
of tyrosine
Blood capillary
5 Coupling
of T1 and T2
Tyrosine
T1
T2
T4
3 Oxidation
of iodide
T3
Colloid
I2
TGB
6 Pinocytosis
and digestion
of colloid
Secretory
vesicles
Lysosome
Golgi complex
I–
I–
I–
I–
I–
I–
I–
I–
2 Synthesis
of TGB
Rough ER
1 Iodide
I–
I–
Key:
T3 T
4
7 Secretion
of thyroid
hormones
trapping
I–
T3
T4
T3 TBG
Blood T TBG
4
plasma
I– = Iodide; I2 = Iodine
TGB = thyroglobulin
TBG = thyroxine-binding globulin
8 Transport
in blood
Blood capillary
1 Low blood levels of T3 and
T4 or low metabolic rate
stimulates release of
Hypothalamus
TRH
2 TRH, carried
by hypophyseal
portal veins to
anterior pituitary,
stimulates
release of TSH
by thyrotrophs
5 Elevated T3 inhibits release of TRH
and TSH (negative feedback)
TSH
3 TSH released into
blood stimulates
thyroid follicular cells
Anterior
pituitary
4 T3 and T4 released into
Thyroid
follicle
blood by follicular
cells
T3 (triiodothyronine) and T4 (thyroxine) or
thyroid hormones from follicular cells
Thyroid
follicle
Follicular
cells
Blood
vessel
Calcitonin (CT) from parafollicular cells
Thyroid
follicle
Parafollicular cells
Parathyroid
glands (behind
thyroid gland)
Trachea
Right internal jugular vein
Right common carotid artery
Middle cervical
sympathetic ganglion
Thyroid gland
LEFT SUPERIOR
PARATHYROID GLAND
RIGHT SUPERIOR
PARATHYROID GLAND
Esophagus
Inferior cervical
sympathetic ganglion
LEFT INFERIOR
PARATHYROID GLAND
RIGHT INFERIOR
PARATHYROID GLAND
Left inferior thyroid artery
Vagus (X) nerve
Left subclavian artery
Right brachiocephalic vein
Brachiocephalic trunk
Left subclavian vein
Left common carotid artery
Trachea
(a) Posterior view
Venule
Capillary
Arteriole
Chief cell
Oxyphil cell
(b) Parathyroid gland
LM
240x
Capsule
Parathyroid
Thyroid
Follicular cell
Parafollicular cell
Chief cell
Oxyphil cell
Thyroid gland
Parathyroid gland
Blood vessel
(c) Portion of thyroid gland (left) and parathyroid gland (right)
PARATHYROID
GLAND
Thyroid gland
PARATHYROID
GLAND
(d) Posterior view of parathyroid glands
1 High level of Ca2+ in blood
stimulates thyroid gland
parafollicular cells to release
more CT.
3 Low level of Ca2+ in blood stimulates
parathyroid gland chief cells to
release more PTH.
6 CALCITRIOL stimulates
increased absorption of
Ca2+ from foods, which
increases blood Ca2+ level.
5 PTH also stimulates
the kidneys to release
CALCITRIOL.
4 PARATHYROID HORMONE (PTH)
Ca2+ from
promotes release of
bone extracellular matrix into
blood and slows loss of Ca2+
in urine, thus increasing blood
Ca2+ level.
2 CALCITONIN inhibits
osteoclasts, thus decreasing
blood Ca2+ level.
Parathyroid hormone (PTH)
from chief cells
Chief cell
Adrenal
glands
Inferior phrenic arteries
Kidney
Right superior
suprarenal arteries
LEFT ADRENAL GLAND
Celiac trunk
RIGHT ADRENAL
GLAND
Left middle suprarenal artery
Right middle
suprarenal artery
Left inferior suprarenal artery
Right inferior
suprarenal artery
Left suprarenal vein
Right renal artery
Left renal vein
Left renal artery
Right renal vein
Superior
mesenteric artery
Inferior vena cava
Abdominal aorta
(a) Anterior view
CAPSULE
ADRENAL
CORTEX
ADRENAL
MEDULLA
(b) Section through left adrenal gland
ADRENAL GLAND
Kidney
(c) Anterior view of adrenal gland and kidney
Capsule
Adrenal cortex:
Zona glomerulosa
secretes
mineralocorticoids,
mainly aldosterone
Zona fasciculata
secretes
glucocorticoids,
mainly cortisol
Zona reticularis
secretes androgens
Adrenal medulla
chromaffin cells secrete
epinephrine and
norepinephrine (NE)
LM 50x
(d) Subdivisions of adrenal gland
1
Dehydration,
Na+ deficiency,
or hemorrhage
2
Decrease in
blood volume
14
4
3
Juxtaglomerular
cells of kidneys
Decrease in
blood volume
15
5
Liver 6
10
7
Adrenal
cortex
Increased
angiotensin I
16
9
12
Increased
angiotensin II
Increased
aldosterone
Increased blood
volume
Increased
K+ in
extracellular
fluid
11
ACE
Lungs (ACE = angiotensin
converting enzyme)
13
Vasoconstriction
of arterioles
Increased renin
Angiotensinogen
8
Blood pressure
increases until
it returns to normal
In kidneys, increased Na+
and water reabsorption
and increased secretion of
K+ and H+ into urine
Some stimulus disrupts
homeostasis by
Decreasing
Glucocorticoid level
in blood
Receptors
Neurosecretory
cells in
hypothalamus
Input
Increased CRH and
decreased cortisol
Control center
Corticotrophs in
anterior pituitary
Output
Increased ACTH
Effectors
Cells of zona
fasciculata in
adrenal cortex
secrete glucocorticoids
Increased glucocorticoid
level in blood
Return to homeostasis
when response brings
glucocorticoid level in
blood back to normal
Androgens (mainly dehydroepiandrosterone, or DHEA) from zona reticularis cells
Adrenal
cortex
Epinephrine and norepinephrine from chromaffin cells
Adrenal
medulla
Common hepatic artery
Pancreas
Kidney
Abdominal aorta
Celiac trunk
Splenic artery
Gastroduodenal artery
Dorsal pancreatic artery
Anterior pancreaticoduodenal
artery
Spleen
(elevated)
Duodenum of small
intestine
TAIL OF PANCREAS
BODY OF PANCREAS
Inferior pancreatic artery
Superior mesenteric artery
Inferior pancreaticoduodenal artery
HEAD OF PANCREAS
(a) Anterior view
Blood capillary
Exocrine acini
Alpha cell
(secretes glucagon)
Beta cell
(secretes insulin)
Delta cell
(secretes somatostatin)
F cell (secretes
pancreatic polypeptide)
(b) Pancreatic islet and surrounding acini
Exocrine
acinus
Pancreatic
islet
Beta
cell
Alpha
cell
LM 200x
Pancreatic
duct
LM 40x
(c) Pancreatic islet and surrounding acini
Pancreas
Duodenum
(cut open)
(d) Anterior view of pancreas dissected to reveal pancreatic duct
1 Low blood
5
High blood glucose
(hyperglycemia) stimulates
beta cells to secrete
glucose(hypoglycemia)
stimulates alpha cells to secrete
GLUCAGON
2 Glucagon acts on
INSULIN
6
hepatocytes (liver
cells) to:
• accelerate facilitated
diffusion of glucose into
cells
• speed conversion of glucose
into glycogen (glycogenesis)
• increase uptake of amino
acids and increase protein
synthesis
• speed synthesis of fatty
acids (lipogenesis)
• slow glycogenolysis
• slow gluconeogenesis
• convert glycogen into
glucose (glycogenolysis)
• form glucose from lactic
acid and certain amino
acids (gluconeogenesis)
3 Glucose released by
hepatocytes raises blood
glucose level to normal
4
If blood glucose
continues to rise,
hyperglycemia inhibits
release of glucagon
Insulin acts on various
body cells to:
7
Blood glucose level falls
8
If blood glucose continues
to fall, hypoglycemia
inhibits release of insulin
Glucagon from alpha
cells of pancreatic islets
Insulin from beta cells
of pancreatic islets
Alpha cell
Beta cell
Somatostatin from delta
cells of pancreatic islets
Pancreatic polypeptide from
F cells of pancreatic islets
Delta cell
F cell
Estrogens and
progesterone
Ovaries
Testosterone
Testes
STRESSORS
stimulate
CRH
GHRH
TRH
Nerve
impulses
Hypothalamus
Sympathetic centers
in spinal cord
Anterior
pituitary
Key:
CRH = Corticotropin-releasing hormone
ACTH = Adrenocorticotropic hormone
GHRH = Growth hormone–releasing hormone
hGH = Human growth hormone
TRH = Thyrotropin-releasing hormone
TSH = Thyroid-stimulating hormone
TSH
hGH
ACTH
Sympathetic nerves
ACTH
Adrenal
medulla
Adrenal
cortex
hGH
Liver
TSH
Thyroid
gland
Visceral effectors
Cortisol
Epinephrine and
norepinephrine
Supplement
and prolong
“fight-orflight”
responses
STRESS RESPONSES
1. Increased heart rate and
force of beat
2. Constriction of blood
vessels of most viscera and
skin
3. Dilation of blood vessels of
heart, lungs, brain, and
skeletal muscles
4. Contraction of spleen
5. Conversion of glycogen
into glucose in liver
6. Sweating
7. Dilation of airways
8. Decrease in digestive
activities
9. Water retention and
elevated blood pressure
(a) Fight-or-flight responses
IGFs
STRESS RESPONSES
Lipolysis
Gluconeogenesis
Protein catabolism
Sensitized blood vessels
Reduced inflammation
Thyroid hormones
(T3 and T4)
STRESS
RESPONSES
STRESS
RESPONSES
Lipolysis
Glycogenolysis
Increased use
of glucose to
produce ATP
(b) Resistance reaction
Pharyngeal pouches
Hypothalamus
Neurohypophyseal bud
4 3
2
1
Hypophyseal
(Rathke’s) pouch
Stomodeum
Esophagus
Respiratory diverticulum
Thyroid diverticulum
(a) Location of neurohypophyseal bud, hypophyseal (Rathke’s) pouch, thyroid
diverticulum, and pharyngeal pouches in 28-day embryo
Neurohypophyseal bud
Hypothalamus
Infundibulum
Infundibulum
Pars intermedia
Infundibulum
Hypophyseal
(Rathke’s)
pouch
Mouth cavity
Mesenchyme
Anterior
pituitary
Posterior pituitary
(b) Development of pituitary gland between 5 and 16 weeks
(a) A 22-year-old man with pituitary giantism
shown beside his identical twin
(b) Acromegaly (excess hGH during adulthood)
(c) Goiter (enlargement of
thyroid gland)
(d) Exophthalmos (excess thyroid hormones, as in
Graves’ disease)
(e) Cushing’s syndrome (excess
glucocorticoids)