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CHAPTER 17
ENDOCRINE SYSTEM
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Structure and Function
• Primary function of the endocrine system
– To produce hormones that monitor and coordinate
body activities
• Endocrine glands secrete hormones directly
into the bloodstream
• Three hormone categories
– Tropic hormones
– Sex hormones
– Anabolic hormones
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Figure 17-1 Endocrine
System
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Glands and Their Hormones
• Hypothalamus
– Structure located above the pituitary gland that
translates nervous system impulses into endocrine
system messages
• Pituitary gland
– Produces the hormones that regulate the secretion
of other glands
• Pineal body
– Produces the hormone melatonin
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Glands and Their Hormones
(continued)
• Thyroid
– Produces hormones that regulate body
metabolism
• Parathyroid
– Secretes parathyroid hormone, which affects the
amount of calcium in the blood
• Thymus
– Produces the hormone thymosin that stimulates
the lymphoid organs to produce T-lymphocytes or
antibodies in newborns and young children
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Glands and Their Hormones
(continued)
• Pancreas
– Produces the hormones insulin and glucagon.
Insulin regulates transportation of sugar, fatty
acids, and amino acids into the cells.
• Adrenal glands
– Produce about 30 hormones
• Gonads
– The primary sex glands
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Glands and Their Hormones
(continued)
• Prostaglandins
– Known to decrease blood pressure, cause fever,
increase hydrochloric acid secretion in the
stomach, increase uterine contraction during
pregnancy, and influence intestinal peristalsis
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Hormonal Changes of
Puberty
• Adrenal gland secretes the hormones that
begin the development of secondary sexual
characteristics
• In a man, the voice deepens and facial hair
begins to grow
• In a woman, the breasts enlarge and fatty
tissue is deposited around the hips
• In both men and women height and weight
increase
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Hormonal Changes of
Pregnancy
• The placenta, or interfacing organ between the fetal
and maternal circulation, produces a hormone called
human chorionic gonadotropin (hCG)
• Increased estrogen and progesterone from the
ovaries are maintained until the placenta begins to
produce these hormones
• Progesterone increases the mobility of the pelvic and
lower back bones to allow the birthing process
• The pituitary and thyroid glands increase in size,
resulting in a higher metabolic rate
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Hormonal Changes of
Menopause
• Menopause occurs following a decrease in
secretion of the gonadotropins folliclestimulating hormone (FSH) and luteinizing
hormone (LH)
• A decrease in the secretion of the hormone
estrogen by the ovaries occurs
• Hot flashes, periods of feeling extreme heat,
are the only universal symptom of
menopause
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Assessment Techniques
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•
•
•
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Basal metabolic rate (BMR)
Protein-bound iodine (PBI)
Immunoassay
Radioiodine uptake (RAIU) studies
Glucose tolerance testing (GTT)
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Disorders of the Endocrine
System
• Acromegaly
– An enlargement of the bones of the hands, feet,
and jaws
• Addison's disease
– Caused by hyposecretion of the hormones
produced by the cortex of the adrenal gland
• Cretinism
– Condition resulting from a congenital deficiency of
thyroid secretion or hypothyroidism
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Disorders of the Endocrine
System (continued)
• Cushing’s syndrome
– Disorder that causes hyperactivity of the adrenal
glands, which is triggered by the oversecretion of
the pituitary hormone ACTH
• Diabetes insipidus
– From an acquired or inherited decrease in the
antidiuretic hormone secreted by the pituitary
• Diabetes mellitus
– A disorder of carbohydrate, fat, and protein
metabolism resulting from insufficient insulin
production by the pancreas
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Disorders of the Endocrine
System (continued)
• Dwarfism
– Results from hyposecretion of the growth
hormone of the pituitary gland, which has been
caused by a tumor, infection, genetic factors, or
trauma
• Gigantism
– An excessive growth of the long bones caused by
hypersecretion of the somatotropic hormone
• Graves’ disease
– Caused by hyperthyroidism or thyrotoxicosis
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Disorders of the Endocrine
System (continued)
• Hyperparathyroidism
– Causes hypercalcemia, an increased calcium blood
level
• Hypoglycemia
– Results from increased insulin production by the
pancreas
• Hypoparathyroidism
– A decreased secretion of parathyroid hormone
that causes tetany
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Disorders of the Endocrine
System (continued)
• Hypothyroidism
– Also called Hashimoto's disease, results from an
insufficient production of thyroxine
• Syndrome of inappropriate antidiuretic
hormone (SIAD)
– Involves water intoxication and the dilution of
intracellular and extracellular body tissues, usually
resulting from lung cancer
• Virilism
– Results from increased secretion in the adrenal
glands
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Issues and Innovations
• Steroid abuse
– Causes problems for men such as stunted
growth, liver tumors, and decreased sperm
production
– Causes problems for women such as loss of
menstrual cycle and baldness
Copyright 2003 by Mosby, Inc. All
rights reserved.