Endocrinology...
The Study of Hormones
Today's Warm-up: Name one thing you think
hormones are responsible for doing in your body.
Let’s Start With Some Vocab…
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Hormone - substance produced by one
gland or organ of the body that then
travels through the bloodstream to
affect other tissues, organs, etc.
Gland – Specialized group of cells that
releases hormones into the bloodstream.
Organ - collection of tissues joined in structural
unit to serve a common function.
How Hormonal
Feedback Works
1) Based on feedback from the
body, the first endocrine gland
initiates release of a hormone.
Makes
Hormone #1
i.e. GHRH
Acts On
2) The first hormone travels through
the bloodstream to a second
(target) gland.
Acts On
Acts On
5) The hormone products from the
second gland and the target
organ travel through the
bloodstream to provide feedback
to the first and second endocrine
glands.
Hormone #2
i.e. GH
Hormone #3
i.e. IGF-I
4) The target organ has a specific
response to the hormone, and
performs some biological function.
Makes
Makes
3) The second gland releases a
second hormone, which travels
through the bloodstream to a
target organ.
Tissues
i.e. growth
of muscle
and bone.
Hormones Make All of Our Bodily
Functions Possible
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Growth Hormones
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Thyroid Hormones
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Sex Hormones
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Stress Hormones
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Pancreatic Hormones
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Pregnancy Hormones
Endocrine Glands
Make a Chart to Keep Track…
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In one column, put the “Hormone Name”
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In the 2nd column, put the “Hormone Source”
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In the 3rd column, put the “Hormone Target”
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In the 4th column, put the “Hormone Function”
Stress Hormones
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Key hormones:
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CRH (Corticotrophin Releasing Hormone)
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ACTH (Adrenocorticotropin)
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Source: Hypothalamus
Target: Anterior Pituitary Gland
Function: Causes the release of ACTH from the Anterior Pituitary
gland
Source: Anterior Pituitary gland
Target: Adrenal Gland
Function: Causes the release of Cortisol from the Adrenal gland
Cortisol
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Source: Adrenal Gland
Target: Systemic tissues
Function: “Fight-type” responses
Stress Hormone Cascade
Growth Hormones
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GHRH-Growth Hormone Releasing Hormone and SS Somatostatin
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Source: Hypothalamus
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Target: Anterior Pituitary Gland
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Function: Stimulate release of GH from Anterior Pituitary
GH – Growth Hormone
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Source: Anterior Pituitary gland
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Target: Liver
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Function: Stimulates release of IGF-I from the liver
IGF-I
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Source: Liver
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Target: Bone, muscle, connective tissues
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Function: Stimulates growth in tissues
Growth Hormone Axis
Male Sex Hormones
• GnRH – Gonadotropin-Releasing • Inhibin
Hormone
– Source: Testicles (Sertoli Cells)
– Source: Hypothalamus
– Target: Anterior Pituitary Gland
– Function: Stimulates the release of
LH and FSH from the Anterior
Pituitary
• LH – Luteinizing Hormone
– Source: Anterior Pituitary Gland
– Target: Leydig Cells of Testicle
– Function: Stimulates Testosterone
production
• FSH – Follicle-Stimulating
Hormone
– Source: Anterior Pituitary Gland
– Target: Sertoli Cells of Testicle
– Function: Stimulates sperm
production by the testis
– Target: Negative Feedback on FSH
production
– Function: Regulate spermatogenesis
• Testosterone
– Source: Testicles (Leydig Cells)
– Target: Hypothalamus, Anterior
Pituitary, Systemic Tissues
– Function: Negative feedback on LH
production, male sex characteristics
Male Sex Hormone Axis
Hormones and Spermatogenesis
The dreaded female hormones...
Female Sex Hormones
• GnRH – Gonadotropin-Releasing • Inhibin
Hormone
– Source: Ovary (Granulosa Cell)
– Source: Hypothalamus
– Target: Anterior Pituitary Gland
– Function: Stimulates the release of
LH and FSH from the Anterior
Pituitary
• LH – Luteinizing Hormone
– Source: Anterior Pituitary Gland
– Target: Ovary (Thecal Cells)
– Function: Stimulates Estrogen
production
• FSH – Follicle-Stimulating
Hormone
– Source: Anterior Pituitary Gland
– Target: Follicle (Granulosa cells) of
Ovary
– Function: Stimulates oogenesis
– Target: Negative Feedback on FSH
production
– Function: Regulate oogenesis
Progesterone
– Source: Granulosa Cell (CL)
– Target: Anterior Pituitary Gland,
Hypothalamus
– Function: Negative feedback on
hypothalamus and anterior pituitary
• Estrogen
– Source: Ovary (Theca and
Granulosa Cells)
– Target: Hypothaltmus, Anterior
Pituitary, Systemic Tissues
– Function: Negative feedback on
hypothalamus and anterior pituitary,
female sex characteristics
Feedback of
Female Sex
Hormones
Female Reproductive Hormones
Thyroid Hormones
• TRH – Thyroid Releasing
Hormone
– Source: Hypothalamus
– Target: Anterior Pituitary
– Function:Stimulates the release of
TSH from the Anterior Pituitary
gland
• TSH – Thyroid Stimulating
Hormone
– Source: Anterior Pituitary Gland
– Target: Thyroid Gland
– Function: Stimulates the release of
T3 and T4 from the Thyroid.
• T3 – Triiodothyronine (10%)
– Source: Thyroid Gland
– Target: Systemic Tissues
– Function: Metabolism, heart rate,
growth, brain development and
function
• T4 – Thyroxine Hormone (90%)
– Source: Thyroid Gland
– Target: Systemic Tissues
– Function: Metabolism, heart rate,
growth, brain development and
function
• Calcitonin
– Source: Thyroid Gland
– Target: Bone and kidneys
– Function: Bone regeneration, urine
production in the kidney
Thyroid Hormones
Neuroendocrine
feedback : the
Breastfeeding
Response
Pancreatic Hormones
Normal Pancreatic Hormones
Diabetes
Other Hormones of Note...
• Oxytocin
– Source: Posterior Pituitary
– Target: Uterus, breasts
– Function: Uterine contractions and
milk let-down
• Melatonin
• Renin
– Source: Kidney
– Target: Adrenal Gland
– Function: Regulates blood pressure
through regulation of aldosterone
secretion.
• Erythropoiten
– Source: Pineal Gland
– Source: Kidney
– Target: Bodily tissues
– Target: Bone Marrow
– Function: Sexual maturity and body
rhythms
– Function: Red blood cell production
• ANF (Atrial Naturietic Factor)
– Source: Heart
– Target: Kidney
– Function: Regulates blood pressure
• Aldosterone
– Source: Adrenal Gland
– Target: Kidney
– Function: Regulation of urine
volume and blood pressure
Other Hormones of Note...
• Parathyroid Hormone
– Source: Parathyroid
– Target: Plasma
– Function: Regulates plasma
calcium and phosphate
• Thymopoiten
– Source: Thymus
– Target: White blood cells
– Function: T-Lymphocyte
Function