Download Chapter 10: Endocrine System

Fig. 10.1
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Pituitary
Thyroid
Thymus
Adrenals
Ovaries
(female)
Pineal
gland
Parathyroids
(posterior
part of
thyroid)
Pancreas
(islets)
Testes
(male)
Fig. 10.4
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Stimulatory
Hypothalamus
Releasing hormone
1
Anterior pituitary
Posterior pituitary
Hormone
2
Target
3
Target
endocrine
cell
Hormone
1 Neurons in the hypothalamus release stimulatory hormones, called
releasing hormones. Releasing hormones travel in the blood to the
anterior pituitary gland.
2 Releasing hormones stimulate the release of hormones from the
anterior pituitary, which travel in the blood to their target endocrine
cell.
3 The target endocrine cell secretes its hormone into the blood, where
it travels to its target and produces a response.
Fig. 10.12
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Hypothalamus
Third
ventricle
Optic
chiasm
Infundibulum
Pituitary
gland
Sella turcica
of sphenoid
bone
Hypothalamic
nerve cell
Bone
Posterior
pituitary
Anterior
pituitary
Antidiuretic
hormone
(ADH)
Growth
hormone (GH)
Adrenocorticotropic
hormone (ACTH)
Kidney
tubules
Thyroidstimulating
hormone (TSH)
Oxytocin
Uterus
smooth
muscle
Adrenal
cortex
Prolactin
Gonadotropic
hormones
Melanocyte- (FSH and LH)
stimulating
hormone
Thyroid
gland
Testis
Ovary
Mammary
glands
Mammary
glands
Skin
Fig. 10.1
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Pituitary
Thyroid
Thymus
Adrenals
Ovaries
(female)
Pineal
gland
Parathyroids
(posterior
part of
thyroid)
Pancreas
(islets)
Testes
(male)
Fig. 10.6
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Hormone 1
Hormone 2
Capillary
Circulating
blood
Hormone 2
cannot bind to
this receptor
Hormone 1
bound to
its receptor
Hormone 1
receptor
Target cell
for hormone 1
Fig. 10.7
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Water-soluble hormone
(glucagon, prolactin)
Lipid-soluble hormone
(thyroid or steroid)
Membrane-bound receptor
G protein
complex
Cellular
responses
ATP
cAMP
Protein
kinase
Nucleus
Hormone
DNA
(a)
Nuclear
receptor
Cellular responses
(b)
Adenylate
cyclase
Fig. 10.2
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
PTH
Ca2+
Osteoclasts
Endocrine cell
when blood
Ca2+ is too low
No PTH secretion
Endocrine cell
when blood
Ca2+ is too high
Ca2+
Fig. 10.3
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Neuron
1 An action potential
(AP) in a neuron
innervating an
endocrine cell
stimulates secretion
of a stimulatory
neurotransmitter.
2
AP
The endocrine cell
secretes its hormone
into the blood where it
will travel to its target.
1
Stimulatory
neurotransmitter
Endocrine cell
2
Hormone
secreted
Capillary
Fig. 10.19
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Hypothalamus
stimulated by
• Stress
• Physical activity
• Low blood glucose
levels
Action potentials travel
through the sympathetic
division of the autonomic
nervous system.
Adrenal
Secretion of
epinephrine and
norepinephrine
increases.
Target tissue
• Increases release of
glucose from the liver
• Increases release of fatty
acids from fat stores
• Increases heart rate
• Decreases blood flow
through blood vessels of
internal organs and skin
• Increases blood flow to
skeletal muscles and the
heart
• Decreases function of
visceral organs
• Increases blood pressure
• Increases metabolic rate
in skeletal muscles
Fig. 8.39
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Preganglionic neuron
Postganglionic neuron
Lacrimal gland
Ciliary ganglion
III
Eye
Nasal
mucosa
Pterygopalatine
ganglion
Sublingualand
submandibular
glands
Submandibular
ganglion
VII
IX
Parotid gland
Sympathetic
nerves
Spinal
cord
Medulla
Otic ganglion
X
Trachea
T1
Lung
Celiac
ganglion
Greater
splanchnic
nerve
Lesser
splanchnic
nerve
Heart
Liver
Superior
mesenteric
ganglion
Stomach
Adrenal
gland
Spleen
Pancreas
Small
intestine
L2
Lumbar
splanchnic
nerves
Sacral
splanchnic
nerves
Kidney
Inferior
mesenteric
ganglion
Large
intestine
S2
S3
S4
Pelvic nerve
Hypogastric
ganglion
Large intestine
Sympathetic
chain
Urinary
system
and genitalia
Sympathetic
Preganglionic neuron
Postganglionic neuron
Parasympathetic
Fig. 10.14
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Stimuli from the
nervous system
Stimulatory
Inhibitory
Hypothalamic
nerve cells
1 Stimuli within the nervous system
stimulate hypothalamic nerve cells to
produce action potentials.
2 Action potentials are carried by axons
of nerve cells to the posterior pituitary.
The axons of nerve cells store
hormones in the posterior pituitary.
1
Optic
chiasm
2
Posterior
pituitary
Hormone
3 In the posterior pituitary gland,
action potentials cause the release
of hormones (red circles) from the
axons into the circulatory system.
Anterior
pituitary
3
Vein
4 The hormones pass through the
circulatory system and influence the
activity of their target tissues (green
arrow).
4
Target tissue
Fig. 10.4-2
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Stimulatory
Hypothalamus
Releasing hormone
1
Anterior pituitary
Posterior pituitary
Hormone
2
Target
Target
endocrine
cell
Hormone
1
Neurons in the hypothalamus release stimulatory hormones, called
releasing hormones. Releasing hormones travel in the blood to the
anterior pituitary gland.
2 Releasing hormones stimulate the release of hormones from the
anterior pituitary, which travel in the blood to their target endocrine
cell.
Fig. 10.16
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Stimulatory
Inhibitory
1
2
3
Neurons within the hypothalamus release TSH-releasing
hormone into the blood. It passes through the
hypothalamic-pituitary portal system to the anterior
pituitary.
TSH-releasing hormone
1
TSH-releasing hormone causes cells of the anterior
pituitary to secrete TSH, which passes through the general
circulation to the thyroid gland.
Hypothalamic-pituitary
portal system
TSH causes increased release of thyroid hormones (T 3 and
T4) into the general circulation.
Anterior
pituitary
TSH
2
4
T3 and T4 act on target tissues to produce a response.
5
T3 and T4
5
T3 and T4 also have an inhibitory effect on the secretion of
TSH-releasing hormone from the hypothalamus and TSH
from the anterior pituitary.
Hypothalamus
4
3
Thyroid gland
Target tissue
• Increases metabolism
• Increases body temperature
• Increases normal growth and
development
Fig. 10.18-2
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Abdominal aorta
Adrenal gland
Fat
Renal artery
Adrenal
glands
Renal vein
Kidney
Ureter
(a)
Cortex
Medulla
(b)
Adrenal
gland
Anterior view
Fig. 10.21
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
ACTH-releasing hormone
Stimulatory
1
Hypothalamus
Inhibitory
Hypothalamic-pituitary
portal system
1
In response to stress or low blood glucose,
ACTH-releasing hormone passes from the
hypothalamus through the hypothalamicpituitary portal system to the anterior
pituitary. The releasing hormone binds to
and stimulates cells that secrete ACTH
into the general circulation.
Anterior
pituitary
ACTH
4
Cortisol
2 ACTH acts on the adrenal cortex and
stimulates the secretion of cortisol into
the general circulation.
3 Cortisol acts on its target tissues
to increase protein breakdown
and blood glucose.
4 Cortisol acts on the hypothalamus
and anterior pituitary to decrease
ACTH secretion.
2
Adrenal cortex
3
Target tissue
• Increases fat and protein
breakdown
• Increases blood glucose
levels
• Has anti-inflammatory
effects
Fig. 10.7
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Water-soluble hormone
(glucagon, prolactin)
Lipid-soluble hormone
(thyroid or steroid)
Membrane-bound receptor
G protein
complex
Cellular
responses
ATP
cAMP
Protein
kinase
Nucleus
Hormone
DNA
(a)
Nuclear
receptor
Cellular responses
(b)
Adenylate
cyclase
Fig. 10.8-5
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
1 Lipid-soluble hormones diffuse through
the plasma membrane.
2 Lipid-soluble hormones bind to
cytoplasmic receptors and travel to the
nucleus or bind to nuclear receptors.
Some lipid-soluble hormones bind
receptors in the cytoplasm and then
move into the nucleus.
Lipid-soluble
hormone
Plasma
membrane
1
Nuclear
membrane
3 The hormone–receptor complex binds
to a hormone response element on the
DNA, acting as a transcription factor.
Ribosome
2
4 The binding of the hormone–receptor
complex to DNA stimulates the
synthesis of messenger RNA (mRNA),
which codes for specific proteins.
5 The mRNA leaves the nucleus, passes
into the cytoplasm of the cell, and
binds to ribosomes, where it directs the
synthesis of specific proteins.
3
Nuclear receptor
Hormone–receptor complex
mRNA
DNA
5
Hormone
response
element
mRNA synthesis
4
Proteins produced
mRNA
Nuclear pore
Fig. 10.7
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Water-soluble hormone
(glucagon, prolactin)
Lipid-soluble hormone
(thyroid or steroid)
Membrane-bound receptor
G protein
complex
Cellular
responses
ATP
cAMP
Protein
kinase
Nucleus
Hormone
DNA
(a)
Nuclear
receptor
Cellular responses
(b)
Adenylate
cyclase
Fig. 10.11
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Receptor
Hormone
Activated
G proteins
Activated
adenylate
cyclase
cAMP
Activated protein
kinase enzymes
Table 10.1
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
TABLE 10.1 Classes of Chemical Messengers
Chemical Messengers
Autocrine
Paracrine
Description
Example
Secreted by cells in a local
area; influences the activity
of the same cell from which
it was secreted
Eicosanoids (prostaglandins,
thromboxanes, prostacyclins,
leukotrienes)
Produced by a wide variety
of tissues and secreted into
extracellular fluid; has a
localized effect on other tissues
Somatostatin, histamine,
eicosanoids
Chemical messenger
Autocrine
Chemical messenger
Paracrine
Neurotransmitter
Produced by neurons;
Acetylcholine, epinephrine
secreted into a synaptic cleft
by presynaptic nerve terminals;
travels short distances; influences
postsynaptic cells
Neuron
Endocrine
Secreted into the blood by
specialized cells; travels some
distance to target tissues;
results in coordinated
regulation of cell function
Thyroid hormones,
growth hormone, insulin,
epinephrine, estrogen,
progesterone, testosterone,
prostaglandins
Neurotransmitter
Hormone
Endocrine