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1QQ#8 10:30
Write A B C D E and circle the letter of each correct response.
A) Peptide hormones are stored in intracellular vesicles and
released as needed.
B) Renin is secreted from the adrenal cortex in response to a
drop in blood pressure.
C) Aldosterone acts to boost blood pressure by enhancing the
retention of sodium by the kidneys.
D) Oxytocin reaches the posterior pituitary gland by way of the
hypothalamo-hypophyseal portal system.
E) Trophic hormones stimulate the growth of their target cells.
1QQ#8 11:30
Write A B C D E and circle the letter of each correct response.
A) Catecholamine hormones are stored in vesicles and released
as needed.
B) Renin is secreted from the adrenal medulla in response to a
drop in blood pressure.
C) As blood pressure gets higher and higher, renin secretion
should decrease.
D) The neurohypophysis is connected to the hypothalamus by
the hypothalamo-hypophyseal portal system.
E) A hormone is said to be a tropic hormone if it stimulates the
growth of its target cells.
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Fig. 11.12b
Neurohypophysis
Adenohypophysis
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2
Tropic hormones control the function
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Trophic hormones promote survival and growth of targets
P P
P
P
A
P
Hypothalamo-hypophyseal portal system
P
P
S
P
P
P
A
Releasing Hormone
Release-inhibiting Hormone
P
S
Tropic hormones control the function
Trophic hormones promote survival and growth of targets
Short-loop Neg. Feed.
Long-loop negative feedback
Releasing Hormone
Release Inhibiting Hormone
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Thyroid Gland
• TH =T3 and T4
Biopsy of normal Thyroid Gland
Hematoxylin and Eosin Stain:
H stains nucleic acids dark blue.
E stains proteins and carbs pink.
Fenestrated Capillary
(typical of endocrine glands
and digestive tract)
Other classes of capillaries:
continuous (in CNS) and
discontinuous (in liver, bone marrow, spleen)
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Synthesis, Storage and Secretion of T3 and T4
Roles of TSH (Thyroid Stimulating Hormone)
Tropic: directs
controls, regulates
Trophic: growth
Transcription Factor
TH essential for normal
development, increases cell
metabolism & heat production
(Basal Metabolic Rate)
=Adrenergic Receptor
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Fig. 11.08
Permissive
effect
Thyroid hormone stimulates production of beta-adrenergic receptors,
which increases the target cell’s responsiveness to EPI.
Who
Cares?
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• Symptoms of
hypothyroidism
• Levels of TSH
and TH?
• Explain enlarged
thyroid gland
• Cause:
Inadequate
dietary intake of
iodine
• Treatment?
Endemic
Goiter
TRH
TSH
T3 & T4
Goiter
Elevates basal metabolic rate,
potentiates response to EPI
If hypothyroid during pregnancy…
cretinism = congenital hypothyroidism
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Synthesis, Storage and Secretion of T3 and T4
Roles of TSH (Thyroid Stimulating Hormone)
Follicles
swell with
thyroglobulin
Tropic: directs
controls, regulates
Trophic: growth
Who else
Cares?
Aunt Dot
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Symptoms: nervousness,
palpitations, hyperactivity,
increased sweating, heat
hypersensitivity, fatigue,
increased appetite, weight loss,
insomnia, weakness, and
frequent bowel movements
(occasionally diarrhea). Signs
may include warm, moist skin;
tremor; tachycardia; atrial
fibrillation; and palpitations.
Source: Merck Manual
Blood tests for
catecholamine levels are normal!
Many common symptoms of hyperthyroidism are similar to those of adrenergic excess.
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Aunt Dot’s Blood Test Results
• T3 and Total T3 very high
• TSH very low
Grave’s Disease = one form of Thyrotoxicosis
⇩
⇩
TRH from Hypothal.
TSH from Ant. Pit.
T3 and T4 from
Thyroid gland
⇧sensitivity to EPI
(up-regulation of adrenergic receptors)
Blood test:
TSH levels low
TH levels high
The cause: Abnormal
Immunoglobulins in patient
activate TSH receptors on
Thyroid cells
⇧Metabolic rate
⇧Temperature
⇧Heart rate and ⇧Blood Pressure
⇧Lipolysis and fuel mobilization
Weight loss
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Treating thyrotoxicosis with Radioactive Iodine
Accumulation of
radioactive iodine
Kills follicular
cells.
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Aunt Dot and Uncle Harold
Quiz #7
Choose two of the following false or misleading statements and make the
appropriate corrections:
1)
Steroid hormones are stored in secretory vesicles at the time of release from a
stimulated endocrine cell.
2)
All amine hormones are hydrophillic molecules that easily dissolve in water and
bind to receptors in the plasma membrane of the target cell.
3)
Thyroid hormone and epinephrine are synergistic because either can stimulate
the breakdown of fatty acids in adipocytes but together they enhance the
process.
4)
All hormones released from the pituitary are produced by cell bodies in the
hypothalamus.
Note: next Monday’s quiz will be based on material from this week’s lab.
Age 16, 33, 52
Another Endocrinological Disorder
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