Adeno-hypophysis
Growth hormone (GH)
–Causes the body to grow
Prolactin (PRL)
–Stimulates lactation (milk production) in females
–Stimulated lacrimation (desire to cry)
–Decreased in adolescent males so it decreases
desire to cry
Thyroid Stimulating Hormone (TSH)
–Causes the thyroid gland to release thyroid
hormone
Adeno-hypophysis
• Adrenocorticotropic hormone (ACTH)
– Acts on adrenal cortex to stimulate release of cortisol
– Helps to reduce when a person has stress
• Melanocyte-stimulating hormone (MSH)
– Darkens skin pigmentation
– Increases during pregnancy
– Also has effects on appetite and sexual arousal
• Follicle-stimulating hormone (FSH)
– Present in males and females, affects both
– Stimulates maturation of sex cells
• Luteinizing hormone (LH)
– Induces ovulation in females
– Induces testosterone in males
Neuro-hypophysis
• Oxytocin
– Childbirth contractions
• Anti-diuretic hormone (ADH)
– Signals kidneys to increase water reabsorption
• Di-Uresis : means more passage of urine.
• Anti- : means reduces urine production by
absorbing more water from the kidneys.
APPLIED ASPECT-PITUITARY DISORDERS
Hyper-secretion of GH in children
- Gigantism (overall growth)
Hyper-secretion of GH in adults
- Acromegaly- enlarged hands and feet
Hypo-secretion of GH
- Pituitary dwarfism
- Proportions are normal, overall size is small
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THYROID GLAND
Largest endocrine gland
in the body.
Weight about 20 – 25gm.
– Located along the
midline of the neck
– Secretes two
hormones.
• Thyroid hormone
• Calcitonin
Thyroid Hormones
• Thyroid hormone (TH)  T3,T4
– Acts on most cells of the body
– Increases metabolic rate
– Controlled by hormonal mechanism
– Iodine is needed to make TH
• Calcitonin
– Lowers blood calcium levels in children
– Slows osteoclasts to allow for bone deposition
– Regulates metabolism
• Increases protein synthesis
• Promotes glycolysis, gluconeogenesis, glucose uptake
• Calcitonin: calcium metabolism
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Thyroglobin
If a segment has two iodines, it is called T2.
If there are 3 iodines attached, it is called T3
(Tri-iodothyronine).
If it has 4 iodines, it is T4 (thyroxine).
The T3 and T4 are then released into
the bloodstream. Those thyroglobulin segments that
have only 1-2 iodines are recycled for parts and are
not released.
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• T4 is the most abundant form, but it is inert (inactive).
T3 has more activity on the cells. So, T3 gets used first
by the body cells. T4 takes longer to be ready; one iodine
has to drop off. As T3 is used up, T4 is being converted to
more T3.
• To make thyroid hormone, you need iodine in your body.
Iodized salt has enough to meet this need. Without enough
iodine in the diet, thyroid hormone cannot be made, no
matter how much TSH is present.
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ACTIONS OF THYROID HORMONE
• Increases GI motility
• Increases mental activity
• Increases endocrine activity
• Promotes growth and brain development in the
fetus and young children
• Stimulates fat metabolism
• Excites CNS
• Causes sleep difficulty
Thyroid Hormone Effects
• All cells respond to thyroid hormone, increasing their
metabolic rate (heart rate speeds up, beats with greater
force, more nutrients are used, etc).
• Too much thyroid hormone is hyperthyroidism; these
people are thin and active.
Graves’ Disease
• When levels of TH are too low, it is called
hypothyroidism; these people are overweight, move
slowly, have no energy.
Myxedema
Hypothalamus
TSH-RH
Hypothalamus makes TSH-RH
(Thyroid stimulating hormone
releasing hormone)
Pituitary
Pituitary makes TSH
(Thyroid stimulating hormone)
TSH
Thyroid
TH
Thyroid gland makes TH
(Thyroid hormone)
APPLIED ASPECT OF THYROID GLAND
GOITER
• Thyroid hormone is partly made of iodine. Iodine is
essential for the formation of thyroxine (T3). If a person
doesn’t eat enough iodine, they can’t make thyroid
hormone.
• The hypothalamus responds by putting out more TSH-RH
• The pituitary will respond by releasing TSH.
• But the thyroid can’t respond by releasing TH if it does
not have the iodine to make the hormone, so it the size of
the follicle grows  gland grows  GOITER.