Page 651 - Fundamentals of anatomy physiology

638 Unit 3 Control and Regulation Pineal Gland
Melatonin
Figure 18–1 Organs and Tissues of the Endocrine System.
Parathyroid Glands
Hypothalamus (located on the posterior surface
Production of ADH, OXT, of the thyroid gland)
and regulatory hormones Parathyroid hormone (PTH)

Pituitary Gland Organs with Secondary
Anterior lobe Endocrine Functions
Heart
ACTH, TSH, GH, PRL, • Atrial natriuretic peptide (ANP)
FSH, LH, and MSH • Brain natriuretic peptide (BNP)
Posterior lobe
Release of oxytocin (OXT)
and antidiuretic hormone (ADH)

Thyroid Gland See
Chapter
21

TTrhiiyordooxtinheyr(oTn4i)ne (T3) Thymus (Undergoes atrophy during See
Calcitonin (CT) adulthood) Chapter
• Thymosins 22
18 Adrenal Glands Adipose Tissue See
Medulla • Leptin Chapter
Digestive Tract 25
Epinephrine (E) Secretes numerous hormones See
Norepinephrine (NE) involved in the coordination of Chapters
Cortex system functions, glucose 19 and 26
Cortisol, corticosterone, metabolism, and appetite
aldosterone, androgens Kidneys
• Erythropoietin (EPO)
Pancreatic Islets • Calcitriol
Insulin, glucagon

KEY TO PITUITARY HORMONES Gonads See
Testes (male) Chapters
ACTH Adrenocorticotropic hormone Testis 28 and 29
TSH Thyroid-stimulating hormone Ovary Androgens (especially testosterone),
GH Growth hormone inhibin
PRL Prolactin
FSH Follicle-stimulating hormone Ovaries (female)
LH Luteinizing hormone Estrogens, progesterone, inhibin
MSH Melanocyte-stimulating hormone

prostacyclins. Steroid hormones are lipids structurally similar Secretion and Distribution of Hormones
to cholesterol (Figure 2–17a, p. 75). The individual hormones
differ in the side chains attached to the basic ring structure. Hormones are typically released where capillaries are abun-
Over time, the liver gradually absorbs these steroids and con- dant, and the hormones quickly enter the bloodstream for
verts them to a soluble form that can be excreted in the bile or distribution throughout the body. Within the blood, hormones
urine (Spotlight Figure 18–2). may circulate freely or travel bound to special carrier proteins.
A freely circulating hormone remains functional for less than
In this chapter we focus on circulating hormones that one hour, and sometimes for as little as two minutes. It is inac-
function primarily to coordinate activities in many tissues tivated when (1) it diffuses out of the bloodstream and binds to
and organs. We consider eicosanoids in chapters that discuss receptors on target cells, (2) it is absorbed and broken down by
individual tissues and organs, including Chapters 19 (the cells of the liver or kidneys, or (3) it is broken down by enzymes
blood), 22 (the lymphatic system), and 28 (the reproductive in the blood or interstitial fluids.
system).