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Lecture 15 - The Endocrine Organs
I. Endocrine Overview: Functions and Organs
A. General Functions
1. hormones
2. glands 3. hormones
metabolism of
- messengers transported via blood/lymph
structures that produce/release hormones
cause short to long lasting changes in
target cells with receptors for them
B. Endocrine Organs
1. pituitary, thyroid, parathyroid, adrenal, pineal,
thymus, pancreas, gonads (ovaries & testes)
2. hypothalamus - master regulator of endocrine glands
3. stomach, small intestine, kidneys, heart, placenta
II. Pituitary Gland (hypophysis)
A. Location, Structure and Hormones
1. sits on sella turcica of the sphenoid bone
2. infundibulum - connection to hypothalamus (superior)
3. posterior lobe - neurohypophysis (neural tissue)
a. oxytocin
b. antidiuretic hormone (ADH)
4. anterior lobe - adenohypophysis (glandular tissue)
a. thyroid stimulating hormone (TSH)
b. adrenocorticotropic hormone (ACTH)
c. follicle stimulating hormone (FSH)
d. luteinizing hormone (LH)
e. growth hormone (GH)
f. prolactin (PRL)
5. hypophyseal portal system - capillaries that carry
INHIBITORY and RELEASING hormones from hypothalamus
III. Thyroid Gland
A. Location, Structure and Hormones
1. anterior neck region, overlying the trachea
2. two lateral lobes connected by the isthmus
a. thyroid hormone (TH) - regulates rate of
metabolism; Iodine key part of hormone
b. calcitonin - lowers Ca++ in blood serum
IV. Adrenal Glands (suprarenal glands)
A. Location, Structure and Hormones
1. rests just over the kidneys cushioned in fat
2. adrenal medulla - part of sympathetic n. s.
a. epinephrine (adrenaline) - fight/flight
b. norepinephrine (noradren.) - fight/flight
3. adrenal cortex - surrounding the medulla
a. aldosterone - salt balance regulation
b. cortisol - response to stress (injury)
c. gonadocorticoids - sex hormones (small amount)
V. Pancreas
A. Location, Structure and Hormones
1. rests just behind superior border of stomach
2. alpha cells - glucagon: triggers glucose release
3. beta cells - insulin: triggers glucose uptake
VI. The Gonads (Ovaries and Testes) (more in Reproduction)
A. Hormones
1. ovaries - estrogen and progesterone
2. testes - testosterone
VII. Pineal Gland
A. Location and Hormones
1. nut-shaped structure; hangs from roof of Ventricle 3
a. melatonin - regulates circadian (daily) rhythms
VIII. Thymus Gland
A. Location and Function
1.
2.
3.
4.
deep to the sternum; difficult to dissect
diminishes in size from birth to adulthood
thymopoietin - regulates immune cell development
maturation site of T-cells of the immune system