the ENDOCRINE SYSTEM
A diverse collection of glands that make and release hormones into the circulatory system
ENDOCRINOLOGY
Endocrine System
Nervous System
Control other systems
But …
Nervous system is fast (msec)
“digital” (all or none)
effects end quickly
Endocrine system is slow
“analog”
has long‐lasting effects
AP
(lightening quick)
Neural
Event
Milliseconds
Endocrine
Event
Clean, discrete
integrated
System Messy, diverse
disarticulated
system GLANDS
dedicated
vs
dual function Q: What is the key anatomical difference between an endocrine gland and a sweat gland??
Q: Similarities??
Exocrine Endocrine
Protein
Receptor
Endocrine Cell with stored hormone
(‐)
Blood is a flowing mix of hormones … all “looking” for their target.
Target: vocal cords
TESTOSTERONE
TARGET CONCEPT
(as revealed by castrating boys)
the CASTRATI
Young boys with good voices: castration
Europe/Asia: church & opera (17th & 18th century)
Result? “ …the range of a soprano, but the greater development of the male lungs gave their singing remarkable power … their timbre is as clear and piercing as that of choirboys and much more powerful; they appear to sing an octave above the natural voice of women. Their voices…are brilliant, light, full of sparkle, very loud, and astound with a very wide range.”
Castrati?
HORMONE CHEMISTRY
Big Issue: Solubility
‐ water soluble hormones
‐ lipid soluble hormones
Water Soluble Hormones: small “protein” hormones
Lipid Soluble Hormones
STEROIDS
Produce Testosterone
Hormone MECHANISM OF ACTION
Hormone solubility constrains how they interact with target cells …
WHY??
Receptor Location
Lipid‐soluble Hormones easily enter cells
Simple
Diffusion
Steroid hormone crosses cell membrane by diffusion
Enters nucleus
Binds to receptor molecule
Turns a gene “on”
A new protein is made
Methandrostenolone (metandienone, methandienone, Averbol, Dianabol, Danabol, DBOL) is an orally‐effective anabolic steroid
‐ Ciba Pharmaceutical
‐ Suspicions about Soviet Block Olympic athletes
‐ Used by “Arnold” and many other body builders
‐ Given to U.S. weightlifters in the 1964(?) Olympics
‐ Now banned by the FDA
Jarmila Kratochvílová
800 m – 153:28
1983 Olympics (Munich)
Water Soluble Hormones
Peptides & Amines
Water Soluble Hormones: MECHANISM OF ACTION
PITUITARY GLAND
Posterior Pituitary
*
*
Posterior Pituitary
2 small protein hormones
‐ ADH
‐ Oxytocin
Oxytocin
A
D
H
ADH makes collecting duct permeable to water
Secrete either …
releasing hormone
inhibiting hormone
Anterior Pituitary
Anterior Pituitary
ALL PROTEINS
Growth Hormone can be over‐ and under‐produced
during childhood
ACROMEGALY … too much Growth Hormone
during adulthood
Pancreas …
a non‐pituitary endocrine gland
*
‐ Insulin
‐ Glucagon