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Ch 8: Endocrine Physiology
Objectives
1.
2.
3.
4.
5.
6.
7.
8.
Become familiar w/endocrine glands of body.
Understand how hypothalamus controls endocrine system.
Learn pituitary hormones & effects on glands of body.
Understand some endocrine disorders.
Examine chemical classes of hormones.
Understand hormone solubility (polar vs nonpolar).
Understand types of hormone receptors.
Understand hormone polar receptors & 2nd messenger systems.
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1. Endocrine Glands of the Body
Endocrine System = system involving
regulation of body functions through use
secretory glands & chemical messengers
(hormones)
Endocrine glands of body:
 Pituitary = master endocrine gland
 Pineal gland = located in diencephalon
 Adrenal glands = located above kidneys
 Thyroid = located on anterior trachea
 Parathyroid glands = located on posterior trachea
 Gonads = ovaries & testes
 Pancreas
 GI tract
**All of these glands controlled
by hypothalamus!
Fig 8.1
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2. Hypothalamus controls endocrine system!
> Hypothalamus part of both nervous & endocrine systems
Controls endocrine system 3 ways:
1. Hypothalamic nuclei secrete neuro-hormones through
posterior pituitary.
Nuclei = ____________________________
____________________________
Neurohormones = ____________ & _________
Oxytocin
ADH
2. Hypothalamus secretes “______________________”,
which controls anterior pituitary.
3. Controls autonomic sympathetic secretion of
_____________________________ by the
_______________________
PP
AP
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Hypothalamus Directs Anterior Pituitary Secretions
Know hypothalamic hormone (acronym) and what it causes
anterior pituitary to secrete!
AP
NOT IN BOOK!
PP
CRH
GnRH
ACTH
FSH & LH
PIH
GHIH
TSH
TRH
GHRH
GH
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How hypothalamus &
neg. feedback regulates
anterior pituitary
NOT IN BOOK!
Stimulated by CRH & low glucocorticoids
ACTH
Inhibited by high blood glucocorticoids
Stimulated by TRH & low thyroid hormones
TSH
Inhibited by high blood thyroid hormones
GH
Stimulated by GHRH & low blood GH
Inhibited by GHIH & high blood GH
Stimulated by GnRH & low sex steroids
FSH
Inhibited by high blood sex steroids
(estrogen, progesterone, testosterone)
Stimulated by absence of hypothalamic PIH
PRL
Inhibited by PIH
LH
Stimulated b GnRH & low sex steroids y
Inhibited by high blood sex steroids
(estrogen, progesterone, testosterone)
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Anterior Pituitary
secretions & their
effects on target
organs or glands:
Effects:
Effects:
Stimulates
mammary
glands to
make milk
(lactation)
TSH
Prolactin
ACTH
Stimulates
body tissues
to grow!
GH
Fig 8.6
Produce T3 &
T4 to regulate
metabolism
Produce
- Sex steroids
- Aldosterone
- Cortisol
FSH
- Mature eggs
& sperm
LH
- Produce
testosterone
&
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estrogen
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How hypothalamus & neg. feedback
regulates anterior pituitary secretions:
QUES:
If the hypothalamus “senses” GH in blood is too high what does it do? __________________
What happens to anterior pituitary secretions of GH? ______________________
If GH in blood is too low, hypothalamus does what? ________________________
What does pituitary then do? ________________________
If hypothalamus “senses” high estrogen or testosterone in blood it _____________________
What does pituitary then do? ________________________
If hypothalamus “senses: low thyroid hormones in blood it ________________________
What does pituitary then do? ________________________
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Review
• Hypothalamic controls endocrine system
– Nuclei secrete ADH & oxytocin
– Releasing hormones (CRH, GnRH, TRH, GHRH, PIH, GHIH)
– Controls adrenal medulla secretion of norepineph./epineph.
• Anterior pituitary secretions & their target organs
– ACTH, TSH, GH, FSH, LH, PRL
• Endocrine glands of body
– Pituitary, adrenals, thyroid, parathyroids, gonads, pineal gland, pancreas, GI tract
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Growth Hormone (GH) Disorders: Clinical App Pg 203 & ONLINE
1. Insufficient GH = insufficient body growth
> Pituitary dwarfism
2. Excessive GH – excessive body growth
> Gigantism – when onset in childhood
> Acromagaly – when onset in adulthood
ACTH stim. Adrenal Cortex to
make:
1. Sex steroids
Ex. - estrogen, testosterone,
progesterone
Under sympathetic response hypothalamus stim. Adrenal
Medulla to make
- Epinephrine
2. Mineralcorticoids
Ex. - aldosterone
3. Glucocorticoids
Ex. - cortisol
Clinical App Pg 209 & ONLINE
Exogenous glucocorticoids and
negative feedback on adrenal cortex
Fig 8.9
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Adrenal Cortex Disorders:
A. Cushing’s Disease (“hypercortisolism”) – Excess Cortisol
Clinical View Pg 206 & ONLINE
Causes:
- Excess hypothalamic CRH or pituitary ACTH
- Adrenal gland tumor
Clinical Presentation:
- Hyperglycemia
(↑ blood glucose from glycogen breakdown)
- ↑ fats in blood (triglycerides and fatty acids)
- Fluid retention (hypervolemia)
(body swelling, especially in face --- “moon face”)
- Hypertension (from fluid retention)
Adrenal Cortex Disorders:
B. Addison’s Disease – Insufficient Aldosterone
Clinical View Pg 206
Causes:
- ↓hypothalamic CRH or pituitary ACTH.
- Adrenal cortex tumor or autoimmune disorder.
Clinical Presentation:
- ↓ Na+ reabsorption (hyponatremia)
Bronzing of skin
-  K+ reabsorption (hi blood K+ or Hyperkalemia)
- ↓ water retention (hypovolemia)
- Hypotension
- Weight loss
- Skin bronzing (overstimulation of melanocytes)
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Adrenal Medulla Disorders:
Pheochromocytoma = excessive norepinephrine/epinephrine
Clinical App ONLINE
Causes:
- adrenal medulla tumor
Clinical Presentation:
“fight or flight” symptoms
- ↑ heart (tachycardia)
- ↑ blood pressure (hypertension)
- ↑ respiratory rate
- Hyperglycemia (↑ blood glucose from glycogen breakdown)
- ↑ fats in blood (triglycerides and fatty acids)
- Nervousness, sweating
Thyroid Gland
Produces:
1. T3 (tri-iodothyronine)
Increase body
metabolism
2. T4 (thyroxine)
3. Calcitonin - ↓ blood Ca+2
Parathyroid Glands
Produce:
Parathyroid hormone - ↑blood Ca+2
Anterior
View
Posterior
View
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Thyroid gland disorders – Clinical App ONLINE
A. Hyperthyroidism = excessive thyroid hormones
Causes:
- thyroid tumor
- Graves disease = autoimmune attack,
over-stimulates thyroid receptors.
Clinical presentation:
- High metabolism & anxiety
- Intolerant to heat (sweating)
-  heart rate and blood pressure
tachycardia & hypertension
-↑ fluid behind eyes (“exopthalmos”)
B. Hypothyroidism = insufficient thyroid hormones
Causes: thyroid tumor, goiter, insufficient dietary iodine.
Clinical presentation:
- Low metabolism, depression
- Intolerance to cold, dry skin,
- Enlarged thyroid gland
- Ocurance in children called “cretanism”
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“Goiter” = thyroid can’t make thyroid hormones, it over-grows (swells)
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Gonads
Testes
Ovaries
Response to LH = make testosterone Response to LH = make estrogen and
progesterone, and it stimulates
Response to FSH = sperm production ovulation.
Response to FSH = mature eggs
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Pineal gland
- Makes melatonin at night
- helps regulate circadian rhythm
Pancreas
- Makes insulin and glucagon
Clinical App ONLINE
Diabetes mellitus &
Physiology in Health & Disease Pg 220
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GI Tract
1. Gastrin (stomach) = stimulates HCL production
(by parietal cells)
2. Secretin (sm. intestine) = stimulate water and bicarbonate secretion from
pancreas
3. Cholecystokinin (sm. intestine)
- stimulates gallbladder contraction
(get bile into duodenum)
- stimulates pancreatic enzyme secretion
4. Gastric inhibitory peptide (sm. intestine) =
- slows gastric motility (slow down)
- stimulates pancreatic insulin.
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Review
• Endocrine glands of body
– Pituitary, adrenals, thyroid, parathyroids, gonads, pineal gland, pancreas, GI tract
• Endocrine disorders
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