1. Chapter 18
Objectives
Identify the endocrine glands and their hormones.
Gain an understanding of the functions of these hormones in the body.
Analyze medical terms related to the endocrine glands and their hormones.
Identify abnormal conditions resulting from excessive and deficient secretions of the endocrine glands.
Describe laboratory tests and clinical procedures related to endocrinology, and recognize relevant abbreviations.
Apply your new knowledge to understanding medical terms in their proper contexts, such as medical reports and records.

2. Endocrine System
Chapter 18
Pages 749 – 798

3. Page 750
Introduction
The endocrine system is an information signaling system.
Glands located in all over the body release hormones into the bloodstream that regulate many functions of the body.
Each hormone has its own receptor
Binding of a receptor by a hormone works like the interaction of a key and a lock.
The endocrine system is an information signaling system much like the nervous system.
However, the nervous system uses nerves to conduct information, whereas the endocrine system uses blood vessels as information channels. 
Glands located in many regions of the body release into the bloodstream specific chemical messengers called hormones that regulate the many and varied functions of an organism.
For example, one hormone stimulates the growth of bones, another causes the maturation of sex organs and reproductive cells, and another controls the metabolic rate (metabolism) within all the individual cells of the body.
In addition, one powerful endocrine gland below the brain secretes a wide variety of different hormones that travel through the bloodstream and regulate the activities of other endocrine glands.
Hormones produce their effects by binding to receptors, which are recognition sites in the various target tissues on which the hormones act.
The receptors initiate specific biologic effects when the hormones bind to them. Each hormone has its own receptor, and binding of a receptor by a hormone is much like the interaction of a key and a lock.

4. Endocrine vs Exocrine Page 750
ENDOCRINE glands – Secrete hormones directly into the bloodstream
EXOCRINE glands – Send chemical substances via ducts to the outside of the body
Endocrine glands, no matter which hormones they produce, secrete their hormones directly into the bloodstream. 
Exocrine glands send chemical substances (tears, sweat, milk, saliva) via ducts to the outside of the body.
Examples of exocrine glands are sweat, mammary, mucous, salivary, and lacrimal (tear) glands.

5. Endocrine Glands Page 750 Pineal gland Pituitary gland Thyroid
Ovaries (pair)
Parathyroid (four glands)
Testes (pair)
Adrenal glands (pair)
Pancreas (islets of Langerhans)
The ductless, internally secreting endocrine glands are listed as follows.
pineal gland
thyroid gland
parathyroid glands (four glands)
adrenal glands (one pair)
pancreas (islets of Langerhans)
pituitary gland
ovaries in female (one pair) and
testes in male (one pair)

6. Endocrine Tissue Table 18-1
Before we go deeper into the glands we need to talk about
Hormones that are secreted by endocrine tissue in other organs apart from the major endocrine glands.
Examples are erythropoietin (kidney), human chorionic gonadotropin (placenta), and cholecystokinin (gallbladder). 
Prostaglandins are hormone-like substances that affect the body in many ways.
First found in semen (produced by the prostate gland) but now recognized in cells throughout the body, prostaglandins have three functions: (1) stimulate the contraction of the uterus; (2) regulate body temperature, platelet aggregation, and acid secretion in the stomach; and (3) have the ability to lower blood pressure.

7. Page 750
Pineal Gland
Not much known about this gland; Ductless included as an endocrine gland
Located: central portion of the brain
Secretes: melatonin – increases with deprivation of light and is inhibited by sunlight
Linked to seasonal affective disorder (SAD), a mental condition in which the person suffers from depression in winter months.
The last gland on this list, the pineal gland, is included as an endocrine gland because it is ductless, although less is known about its endocrine function.
Located in the central portion of the brain, the pineal secretes melatonin. 
Melatonin functions to support the body's “biologic clock” and is thought to induce sleep.
The pineal gland has been linked to a mental condition, seasonal affective disorder (SAD), in which the person suffers from depression in winter months.
Melatonin secretion increases with deprivation of light and is inhibited by sunlight.
Calcification of the pineal gland can occur and can be an important radiologic landmark when x-rays of the brain are examined.

8. Page 752
Thyroid Gland
Location: composed of a right and left lobe on either side of the trachea, just below the thyroid cartilage (Adam's apple).
Isthmus = a narrow strip of glandular tissue that connects the two lobes.
Secretes: Thyroxine or tetraiodothyronine (T4), Triiodothyronine (T3), and Calcitonin
The thyroid gland is composed of a right and a left lobe on either side of the trachea, just below a large piece of cartilage called the thyroid cartilage.
The thyroid cartilage covers the larynx and produces the prominence on the neck known in men as the “Adam's apple.”
The isthmus of the thyroid gland is a narrow strip of glandular tissue that connects the two lobes on the ventral (anterior) surface of the trachea.

9. Thyroid: Function Pages 752 – 753
Two of the hormones secreted by the thyroid gland are thyroxine or tetraiodothyronine (T4) and triiodothyronine (T3). 
These hormones are synthesized in the thyroid gland from iodine, which is picked up from the blood circulating through the gland, and an amino acid called tyrosine.
T4 (containing four atoms of iodine) is much more concentrated in the blood, whereas T3 (containing three atoms of iodine) is far more potent in affecting the metabolism of cells.
Most thyroid hormone is bound to protein molecules as it travels in the bloodstream.
T4 and T3 are necessary in the body to maintain a normal level of metabolism in all body cells.
Cells need oxygen to carry on metabolic processes, one aspect of which is burning food to release the energy stored within it.
Thyroid hormone aids cells in their uptake of oxygen and thus supports the metabolic rate in the body.
Injections of thyroid hormone raise the metabolic rate, whereas removal of the thyroid gland, diminishing thyroid hormone content in the body, results in a lower metabolic rate, heat loss, and poor physical and mental development.
A more recently discovered hormone produced by the thyroid gland is calcitonin. 
Calcitonin is secreted when calcium levels in the blood are high. It stimulates calcium to leave the blood and enter the bones, thereby lowering blood calcium back to normal.
Calcitonin contained in a nasal spray may be used for treatment of osteoporosis (loss of bone density).
By increasing calcium storage in bone, calcitonin strengthens weakened bone tissue and prevents spontaneous bone fractures. 
This Figure summarizes the hormones secreted by the thyroid gland.

10. Parathyroid Glands Page 753
Location: four small oval bodies located on the dorsal aspect of the thyroid gland.
Secretes: Parathyroid hormone (PTH) [parathormone]
The parathyroid glands are four small oval bodies located on the dorsal aspect of the thyroid gland.

11. Parathyroid: Function
Page 754
Parathyroid: Function
Parathyroid hormone (PTH) is secreted by the parathyroid glands.
This hormone (also known as parathormone) mobilizes calcium (a mineral substance) from bones into the bloodstream, where calcium is necessary for proper functioning of body tissues, especially muscles.
Normally, calcium in the food we eat is absorbed from the intestine and carried by the blood to the bones, where it is stored.
The adjustment of the level of calcium in the blood is a good example of the way hormones in general control the homeostasis (equilibrium or constancy in the internal environment) of the body.
If blood calcium decreases (as in pregnancy or with vitamin D deficiency), parathyroid hormone secretion increases, causing calcium to leave bones and enter the bloodstream.
In this way, blood calcium levels are brought back to normal.

12. Page 754
Adrenal Glands
Location: two small glands, one on top of each kidney. Each gland consists of two parts:
adrenal cortex = the outer portion
Secretes steroids or corticosteroids; chemicals derived from cholesterol
adrenal medulla = the inner portion
Secretes catecholamines; chemicals derived from amino acids
The adrenal glands are two small glands, one on top of each kidney.
Each gland consists of two parts: an outer portion, the adrenal cortex, and an inner portion, the adrenal medulla.
The adrenal cortex and the adrenal medulla are two glands in one, secreting different hormones.
The adrenal cortex secretes steroids or corticosteroids (complex chemicals derived from cholesterol); the adrenal medulla secretes catecholamines (chemicals derived from amino acids).

13. Pages 754 – 756
Adrenal Cortex
The adrenal cortex secretes three types of corticosteroids.
1. Glucocorticoids—These steroid hormones have an important influence on the metabolism of sugars, fats, and proteins within all body cells and have a powerful anti-inflammatory effect. Cortisol helps regulate glucose, fat, and protein metabolism. It raises blood glucose as part of a response to stress. 
Cortisone is a hormone very similar to cortisol and can be prepared synthetically. Cortisone is useful in treating inflammatory conditions such as rheumatoid arthritis.
2. Mineralocorticoids—The major mineralocorticoid is aldosterone. 
It regulates the concentration of mineral salts (electrolytes) in the body.
Aldosterone acts on the kidney to reabsorb sodium (an important electrolyte) and water and to excrete potassium (another major electrolyte).
Thus, it regulates blood volume and blood pressure and electrolyte concentration.
3. Sex hormones—Androgens (testosterone) and estrogens are secreted in small amounts and influence secondary sex characteristics, such as pubic and axillary hair in boys and girls. In females, the masculinizing effects of adrenal androgens (such as increased body hair) may appear when levels of ovarian estrogen decrease after menopause.
Think of the “three S's” to recall the main adrenal cortex hormones, which influence sugar (cortisol), salt (aldosterone), and sex (androgens and estrogens).

14. Adrenal Medulla Pages 754 – 756
The adrenal medulla secretes two types of catecholamine hormones:
1. Epinephrine (adrenaline)—Increases heart rate and blood pressure, dilates bronchial tubes, and releases glucose (sugars) from glycogen (storage substance) when the body needs it for more energy.
2. Norepinephrine (noradrenaline)—Constricts blood vessels to raise blood pressure.
Both epinephrine and norepinephrine are sympathomimetic agents because they mimic, or copy, the actions of the sympathetic nervous system.
They are released to help the body meet the challenges of stress in response to stimulation by the sympathetic nervous system.

15. Page 756
Pancreas
Located: near and partly behind the stomach at the level of the first and second lumbar vertebrae.
It is both an endocrine and exocrine gland:
Endocrine tissue = islets of Langerhans: secretes insulin and glucagon
Exocrine tissue = most of the tissue: secretes digestive enzymes.
The pancreas is located near and partly behind the stomach at the level of the first and second lumbar vertebrae.
The endocrine tissue of the pancreas consists of specialized hormone-producing cells called the islets of Langerhans or islet cells. 
More than 98% of the pancreas consists of exocrine cells (glands and ducts).
These cells secrete digestive enzymes into the gastrointestinal tract.

16. Pancreas Function Page 756
The islets of Langerhans produce insulin (produced by beta cells) and glucagon (produced by alpha cells).
Both play a role regulating blood glucose (sugar) levels. When blood glucose rises, insulin lowers blood sugar by helping it enter body cells.
Insulin also lowers blood sugar by causing conversion of glucose to glycogen (a starch storage form of sugar) in the liver.
If blood glucose levels fall too low, glucagon raises blood sugar by acting on liver cells to promote conversion of glycogen back to glucose.
Thus, the endocrine function of the pancreas is another example of homeostasis, the body's ability to regulate its inner environment to maintain stability.

17. Pituitary Gland (hypophysis)
Page 758
Pituitary Gland (hypophysis)
Location: Pea-sized gland in the sella turcica
Anterior lobe (adenohypophysis) composed of glandular epithelial tissue
Posterior lobe (neurohypophysis) composed of nervous tissue
The pituitary gland  (hypophysis) is a small pea-sized gland located at the base of the brain in a small pocket-like depression of the skull called the sella turcica. 
It is a well-protected gland, with the entire mass of the brain above it and the nasal cavity below.
The ancient Greeks incorrectly imagined that its function was to produce pituita, or nasal secretion.
The pituitary consists of two distinct parts: an anterior lobe or adenohypophysis, composed of glandular epithelial tissue, and a posterior lobe or neurohypophysis, composed of nervous tissue.

18. Hypothalamus and Pituitary Gland
Pages 757 – 758
Hypothalamus and Pituitary Gland
The hypothalamus is a region of the brain under the thalamus and above the pituitary gland.
Signals transmitted from the hypothalamus control secretions by the pituitary gland.
Special secretory neurons in the hypothalamus send releasing and inhibiting factors (hormones) via capillaries to the anterior pituitary gland.
These factors stimulate or inhibit secretion of hormones from the anterior lobe of the pituitary gland.
The hypothalamus also produces and secretes hormones directly to the posterior lobe of the pituitary gland, where the hormones are stored and then released.

19. Pituitary Functions Pages 757 – 758
Although no bigger than a pea, the pituitary gland is often called the “master gland” because it makes hormones that control several other endocrine glands.
The major hormones of the anterior pituitary gland are:
1. Growth hormone (GH), or somatotropin (STH)—Promotes protein synthesis that results in the growth of bones, muscles, and other tissues. GH also stimulates the liver to make insulin-like growth factor (also called IGF), which stimulates the growth of bones. It increases blood glucose levels and is secreted during exercise, sleep, and hypoglycemia.
2. Thyroid-stimulating hormone (TSH), or thyrotropin—Stimulates the growth of the thyroid gland and secretion of thyroxine (T4) and triiodothyronine (T3).
3. Adrenocorticotropic hormone (ACTH), or adrenocorticotropin—Stimulates the growth of the adrenal cortex and increases its secretion of steroid hormones (primarily cortisol).
4. Gonadotropic hormones—Several gonadotropic hormones influence the growth and hormone secretion of the ovaries in females and the testes in males. In the female, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) stimulate the growth of eggs in the ovaries, the production of hormones, and ovulation. In the male, FSH influences the production of sperm, and LH (an interstitial cell–stimulating hormone) stimulates the testes to produce testosterone.
5. Prolactin (PRL)—Stimulates breast development during pregnancy and sustains milk production after birth.
The posterior pituitary gland stores and releases two important hormones that are synthesized in the hypothalamus:
1. Antidiuretic hormone (ADH), also called vasopressin—Stimulates the reabsorption of water by the kidney tubules. In addition, ADH also increases blood pressure by constricting arterioles.
2. Oxytocin (OT)—Stimulates the uterus to contract during childbirth and maintains labor during childbirth. OT also is secreted during suckling and causes the production of milk from the mammary glands.

20. Page 759
Ovaries
Location: two small glands in the lower abdominal region of females.
Produce: the female gamete (ovum)
Secretes: estrogens and progesterone
LOCATION AND STRUCTURE
The ovaries are two small glands located in the lower abdominal region of the female.
The ovaries produce the female gamete, the ovum, as well as hormones that are responsible for female sex characteristics and regulation of the menstrual cycle.
FUNCTION
The ovarian hormones are estrogens (estradiol and estrone) and progesterone. 
Estrogens stimulate development of ova (eggs) and development of female secondary sex characteristics.
Progesterone is responsible for the preparation and maintenance of the uterus in pregnancy.

21. Page 760
Testes
Location: two small ovoid glands glands suspended by the spermatic cord and surrounded by the scrotal sac.
Produce: the male gametes (spermatozoa)
Secretes: testosterone
LOCATION AND STRUCTURE
The testes are two small ovoid glands suspended from the inguinal region of the male by the spermatic cord and surrounded by the scrotal sac.
The testes produce the male gametes, spermatozoa, as well as the male hormone called testosterone.
FUNCTION
Testosterone is an androgen (male steroid hormone) that stimulates development of sperm and secondary sex characteristics in the male (deepening of voice and development of beard and pubic hair).
Table 18-2 lists the major endocrine glands, their hormones, and the actions they produce.
Table 18-4 reviews the abnormal conditions associated with hypersecretions and hyposecretions of the endocrine glands.

22. Pathology: Thyroid Pages 768 – 769 Goiter Endemic goiter
Nodular goiter
Thyroid carcinoma
Slow-growing papillary carcinomas
Slow-growing follicular carcinomas
Rapidly growing anaplastic tumors
GOITER (GOY-tĕr) Enlargement of the thyroid gland
EXAMPLE:
ENDEMIC GOITER (ĕn-DĔM-ĭk GOY-tĕr) Enlargement of the thyroid gland due to lack of iodine in the diet
ETIOLOGY: low iodine levels lead to low T3 and T4 levels. This causes feedback to the hypothalamus and adenohypophysis, stimulating them to secrete releasing factors and TSH. TSH then promotes the thyroid gland to secrete T3 and T4, but because there is no iodine available, the only effect is to increase the size of the gland (goiter).
PREVENTION: increasing the supply of iodine (as iodized salt) in the diet.
NODULAR GOITER (NŎD-ū-lăr GOY-tĕr) Enlargement of the thyroid gland due to growth of nodules [adenomas] on the thyroid gland
SYMPTOM: Some patients develop hyperthyroidism with clinical signs and symptoms → rapid pulse, tremors, nervousness, and excessive sweating.
TREATMENT: thyroid-blocking drugs or radioactive iodine to suppress thyroid functioning.
NEOPLASMS
THYROID CARCINOMA (THĪ-royd kăr-sĭ-NŌ-mă) Malignant tumor of the thyroid gland
slow-growing papillary carcinomas → makes up more than one half of thyroid malignancies
slow-growing follicular carcinomas → makes up about one third of thyroid malignancies
rapidly growing anaplastic (widely metastatic) tumors
DIAGNOSIS: Radioactive iodine scans distinguish hyperfunctioning areas from hypofunctioning areas. “Hot” tumor areas (those collecting more radioactivity than surrounding tissues) usually indicate hyperthyroidism and benign growth; “cold,” nonfunctional nodules can be either benign or malignant. Ultimately, fine needle aspiration, surgical biopsy, or excision is required to make the diagnosis.
TREATMENT: Total or subtotal thyroidectomy with lymph node removal. Postsurgical treatment with radioactive iodine destroys remaining tissue, and high doses of exogenous thyroid hormone are given to suppress TSH, in an effort to cause regression of residual tumor dependent on TSH.

23. Pathology (cont’d) Pages 768 – 770 Hyperthyroidism Graves’ disease
Hypothyroidism
Myxedema
Cretinism
Hyperparathyroidism
Hypoparathyroidism
THYROID
HYPERSECRETION
HYPERTHYROIDISM (hī-pĕr-THĪ-royd-ĭsm) Increased secretion of thyroid hormones from the thyroid gland; Also known as thyrotoxicosis
EXAMPLE:
GRAVES DISEASE (GRĀVZ dĭ-ZĒZ) Hyperfunctioning of the thyroid gland; this is the most common type of hyperthyroidism
ETIOLOGY: autoimmune processes
SYMPTOM: increase in heart rate (with irregular beats), higher body temperature, hyperactivity, weight loss, and increased peristalsis [diarrhea], exophthalmos (ĕk-sŏf-THĂL-mōs) [protrusion of the eyeballs] occurs as a result of swelling of tissue behind the eyeball, pushing it forward.
TREATMENT: management with antithyroid drugs to reduce the amount of thyroid hormone produced by the gland and administration of radioactive iodine, which destroys the overactive glandular tissue. Exophthalmos usually persists despite treatment of Graves disease.
HYPOSECRETION
HYPOTHYROIDISM (hī-pō-THĪ-royd-ĭzm) Decreased secretion of thyroid hormones from the thyroid gland
ETIOLOGY: Any of several of the following: thyroidectomy, thyroiditis, endemic goiter, destruction of the gland by irradiation → all have similar physiologic effects.
SYMPTOM: fatigue, muscular and mental sluggishness, weight gain, fluid retention, slow heart rate, low body temperature, and constipation.
MYXEDEMA (mĭk-sĕ-DĒ-mă) Hypofunctioning of the thyroid gland in adults; Atrophy of the thyroid gland occurs, and practically no hormone is produced
SYMPTOM: skin becomes dry and puffy (edema) because of the collection of mucus-like material under the skin. Many patients also develop atherosclerosis because lack of thyroid hormone increases the quantity of blood lipids (fats).
TREATMENT: Recovery may be complete if thyroid hormone is given soon after symptoms appear. 
PICTURE – A, Myxedema. Note the dull, puffy, yellowed skin; coarse, sparse hair; prominent tongue.
CRETINISM (KRĒ-tĭn-ĭzm) Hypothyroidism during infancy and childhood leading to a lack of normal physical and mental growth.
Skeletal growth is more inhibited than soft tissue growth, so the affected person has the appearance of an obese, short, and stocky child.
TREATMENT: administration of thyroid hormone, which may be able to reverse some of the effects.
PARATHYROID
HYPERPARATHYROIDISM (hī-pĕr-pă-ră-THĪ-royd-ĭzm) Increased secretion of parathormone from the parathyroid glands
ETIOLOGY: parathyroid hyperplasia [parathyroid tumor]
SYMPTOM: HYPERCALCEMIA (hī-pĕr-kăl-SĒ-mē-ă) [High levels of calcium in the bloodstream], kidney and heart damage, osteoporosis [generalized loss of bone density and susceptible to fractures], formation of cysts, Kidney stones, and HYPERCALCIURIA (hī-pĕr-kăl-sē-ŪR-ē-ă) [High levels of calcium in urine].
TREATMENT: resection of the overactive tissue; Medical therapy is another option for the patient who is not a surgical candidate. Bisphosphonates, such as alendronate (Fosamax), decrease bone turnover and decrease hypercalcemia.
HYPOPARATHYROIDISM (hī-pō-pă-ră-THĪ-royd-ĭzm) Decreased secretion of parathormone from the parathyroid glands
SYMPTOM: HYPOCALCEMIA (hī-pō-kăl-SĒ-mē-ă) [Low levels of calcium in the blood], muscle and nerve weakness, spasms of muscles
COMPLICATION: tetany (TĔT-ă-nē) [constant muscle contraction]
TREATMENT: Administration of calcium plus large quantities of vitamin D (to promote absorption of calcium) can control the calcium level in the bloodstream.

24. Pathology: Adrenal Gland
Pages 770 – 771
Pathology: Adrenal Gland
Hypersecretion
Adrenal virilism
Cushing syndrome
Hyposecretion
Addison disease
Pheochromocytoma
ADRENAL CORTEX
HYPERSECRETION
ADRENAL VIRILISM (ă-DRĒ-năl VĬR-ĭ-lĭzm) Excessive secretion of adrenal androgens; noticeable in women – tends to make men infertile
ETIOLOGY: Adrenal hyperplasia or more commonly adrenal adenomas or carcinomas
SYMPTOM: amenorrhea, hirsutism (HĔR-soot-ĭzm) [excessive hair on the face and body], acne, and deepening of the voice.
TREATMENT: Drug therapy to suppress androgen production and adrenalectomy.
CUSHING SYNDROME (KŬSH-ĭng SĬN-drōm) Group of symptoms produced by excess cortisol from the adrenal cortex;
SYMPTOM: obesity, moon-like fullness of the face, excess deposition of fat in the thoracic region of the back (so-called buffalo hump), hyperglycemia, hypernatremia, hypokalemia, osteoporosis, virilization, and hypertension.
ETIOLOGY: excess ACTH secretion or tumor of the adrenal cortex. Most cases of Cushing syndrome result from chronic use of cortisone-like drugs, such as steroids.
Examples are the cases in young athletes seeking to improve their performance and in patients treated for autoimmune disorders, asthma, kidney, and skin conditions. Steroids (prednisone is an example) are never discontinued abruptly because the adrenal cortex and pituitary gland (ACTH producer) need time to “restart” after long periods of prescribed cortisol use (the adrenal gland stops producing cortisol when cortisol is given as therapy).
PICTURE
HYPOSECRETION
ADDISON DISEASE (ĂD-ĭ-sŏn dĭ-ZĒZ) Hypofunctioning of the adrenal cortex; decreased secretion of aldosterone and cortisol
The adrenal cortex is essential to life.
SYMPTOM: generalized malaise, weakness, muscle atrophy, and severe loss of fluids and electrolytes (with hypoglycemia, low blood pressure, and hyponatremia). An insufficient supply of cortisol signals the pituitary to secrete more ACTH, which increases pigmentation of scars, skin folds, and breast nipples (hyperpigmentation). ETIOLOGY: Primary insufficiency is believed to be due to autoimmune adrenalitis.
TREATMENT: daily cortisone administration and intake of salts or administration of a synthetic form of aldosterone.
PICTURE – supposed to have darker skin discoloration, epecially on the face
ADRENAL MEDULLA
PHEOCHROMOCYTOMA (fē-ō-krō-mō-sī-TŌ-mă) Benign tumor of the adrenal medulla; cells produce excess secretion of epinephrine and norepinephrine.
SYMPTOM: hypertension, tachycardia, palpitations, severe headaches, sweating, flushing of the face, and muscle spasms.
TREATMENT: Surgery to remove the tumor and administration of antihypertensive drugs

25. Pathology: Pancreas Pages 772 – 774 Hypersecretion Hyperinsulinism
Hyposecretion
Diabetes mellitus
Type 1: childhood onset
Type 2: adult onset
Gestational diabetes
HYPERSECRETION
HYPERINSULINISM (hī-pĕr-ĬN-sū-lĭn-ĭzm) Increased secretion of insulin from the beta islet cells of the pancreas leads to an overdose of insulin.
SYMPTOM: Hypoglycemia, Fainting spells, convulsions, and loss of consciousness are common because a minimal level of blood sugar is necessary for proper mental functioning.
HYPOSECRETION
DIABETES MELLITUS (dī-ă-BĒ-tēz MĔL-ĭ-tŭs) Lack of insulin secretion [Type 1] or improper utilization of insulin by cells [Type 2] leading to a chronic disorder of carbohydrate, fat, and protein metabolism in cells
EXAMPLE:
Type 1 diabetes – Onset is usually in early childhood but can occur in adulthood
ETIOLOGY: autoimmune disease that involves destruction of the beta islet cells, producing complete deficiency of insulin in the body.
SYMPTOM: Patients usually are thin and require frequent injections of insulin to maintain a normal level of glucose in the blood.  
TREATMENT: requires patients to monitor their blood glucose levels several times a day using a glucometer. [At a minimum, patients test before each meal and at bedtime, but many test up to 12 times a day.], continually balance insulin levels with food and exercise, injecting insulin into the body (buttocks, thighs, abdomen and arms), or use a portable pump, which infuses the drug continuously through a indwelling needle under the skin. 
Type 2 diabetes – Patients often are older
RISK FACTOR: Obesity, family history of type 2 diabetes
ETIOLOGY: The islet cells are not initially destroyed, and there is a relative deficiency of insulin secretion with a resistance by target tissues to insulin. 
Insulin resistance usually develops 5 to 10 years before type 2 diabetes is diagnosed, and is associated with an increased risk of cardiovascular disease.
Often, high blood pressure, high cholesterol, and central abdominal obesity are seen in people who have insulin resistance.
TREATMENT: diet, weight reduction, exercise, and, if necessary, insulin or oral hypoglycemic agents. Oral hypoglycemic agents stimulate the release of insulin from the pancreas and improve the body's sensitivity to insulin.
COMPLICATIONS: Both type 1 and type 2 diabetes are associated with primary and secondary complications.
PRIMARY COMPLICATION:
hyperglycemia [often seen in type 1; seldom see in type 2] which can lead to
KETOACIDOSIS (kē-tō-ă-sĭ-DŌ-sĭs) High levels of acids [ketones] in the blood; occurrs when cells burn high levels of fats [producing ketones] because sugar is not available as fuel
SYMPTOM: upset stomach and vomiting
Hypoglycemia [too much insulin is taken] which can lead to
Insulin shock [severe hypoglycemia caused by an overdose of insulin, decreased intake of food, or excessive exercise]
SYMPTOM: sweating, hunger, confusion, trembling, nervousness, and numbness.
TREATMENT: severe hypoglycemia is with either a shot of glucagon or intravenous glucose to restore normal blood glucose levels. If treatment is not given → Convulsions, coma, and loss of consciousness and death. 
SECONDARY COMPLICATION [long-term]: may appear many years after the patient develops diabetes.
DIABETIC retinopathy [destruction of retinal blood vessels → visual loss and blindness], DIABETIC nephropathy [destruction of the kidneys → renal insufficiency and often requiring hemodialysis or renal transplantation], atherosclerosis [destruction of blood vessels → stroke, heart disease, and peripherovascular ischemia (gangrene, infection, and loss of limbs)], DIABETIC neuropathy [destruction of nerves involving pain or loss of sensation, most commonly in the extremities] and GASTROPARESIS (găs-trō-păr-Ē-sĭs) [Loss of motility of the stomach muscles]
PICTURE - Complications can be avoided or minimized with optimal glycemic control.
GESTATIONAL DIABETES (jĕ-stā-SHŏn-ăl dī-ă-BĒ-tēz) diabetes during the second or third trimester of pregnancy.
ETIOLOGY: hormonal changes during pregnancy and a predisposition to diabetes
After delivery, blood glucose usually returns to normal. Type 2 diabetes may develop in these women later in life.

26. Pathology: Pituitary (Anterior Lobe)
Pages 775 – 776
Pathology: Pituitary (Anterior Lobe)
Hypersecretion
Acromegaly
Gigantism
Hyposecretion
Dwarfism
Panhypopituitarism
HYPERSECRETION
ACROMEGALY (ăk-rō-MĔG-ă-lē) Enlargement of extremities due to increased secretion of growth hormone from the anterior pituitary gland
ETIOLOGY: adenomas of the pituitary gland that occur during adulthood.
This excess GH stimulates the liver to secrete a hormone (somatomedin C, or insulin-like growth factor [IGF]) that causes the clinical manifestations of acromegaly (acr/o in this term means extremities).
SYMPTOM: Bones in the hands, feet, face, and jaw grow abnormally large, producing a characteristic “coarsened” facial appearance.
TREATMENT: pituitary adenoma can be irradiated or surgically removed.
Measurement of blood levels of somatomedin C as GH fluctuates is a test for acromegaly.
PICTURE - 
A, The patient at the age of 9 years; 
B, at age 16, with possible early features of acromegaly; 
C, at age 33, with well-established acromegaly; 
D, at age 52, with end-stage acromegaly.
GIGANTISM (JĪ-găn-tĭzm) Hypersecretion of growth hormone from the anterior pituitary gland before puberty, leading to abnormal overgrowth of body tissues
ETIOLOGY: Benign adenomas of the pituitary gland that occur before a child reaches puberty produce an excess of growth hormone.
TREATMENT: can be corrected by early diagnosis in childhood
PICTURE –
A 22-year-old man with gigantism due to excess growth hormone is standing next to his identical twin. Their height and features began to diverge at the age of approximately 13 years.
HYPOSECRETION
DWARFISM (DWĂRF-ĭzm) Congenital hyposecretion of growth hormone from the anterior pituitary gland. Children who are affected are normal mentally, but their bones remain small.
TREATMENT: administration of growth hormone
Achondroplastic dwarfs differ from hypopituitary dwarfs in that they have a genetic defect in cartilage formation that limits the growth of long bones.
PANHYPOPITUITARISM (păn-hī-pō-pĭ-TŪ-ĭ-tăr-ĭzm) Deficiency of all pituitary gland hormones that stimulate major glands in the body
ETIOLOGY: Tumors of the sella turcica as well as arterial aneurysms

27. Pathology: Pituitary (Posterior Lobe)
Page 777
Pathology: Pituitary (Posterior Lobe)
Hypersecretion
Syndrome of inappropriate ADH (SIADH)
Hyposecretion
Diabetes insipidus
HYPERSECRETION
SYNDROME OF INAPPROPRIATE ADH (SĬN-drōm ŏf ĭn-ă-PRŌ-prē-ĭt A-D-H) [SIADH] Excessive secretion of antidiuretic hormone [ADH, or vasopressin] leading to water retention
TREATMENT: dietary water restriction
ETIOLOGY: Tumor, drug reactions, and head injury
HYPOSECRETION
DIABETES INSIPIDUS (dī-ă-BĒ-tēz ĭn-SĬP-ĭ-dŭs) Insufficient secretion of antidiuretic hormone [vasopressin] which causes the kidney tubules to fail to hold back (reabsorb) needed water and salts.
SYMPTOM: polyuria and polydipsia
TREATMENT: Synthetic ADH is administered through nasal sprays or intramuscularly
 Insipidus means tasteless, reflecting the condition of dilute urine, as opposed to mellitus, meaning sweet or like honey, reflecting the sugar content of urine in diabetes mellitus.

28. Laboratory Tests Page 778 Fasting plasma glucose (FPG)
Glucose tolerance test
glycosylated hemoglobin test (HbA1C or A1C)
Serum and urine tests
Urinary microalbumin assay
Thyroid function tests
FASTING PLASMA GLUCOSE (FĂS-tĭng PLĂS-măh GLŪ-kōs) Measures circulating glucose level in a patient who has fasted at least 8 hours; this test can diagnose diabetes mellitusand prediabetes [blood glucose is higher than normal but not high enough for diagnosis of diabetes]; Also known as fasting blood sugar test NORMAL: 99 mg/dL or belower.
PREDIABETES: 100 to 125 mg/Dl
DIABETES: 126 mg/dL and above.
A casual non-fasting plasma glucose level of 200 mg/dL plus the presence of signs and symptoms such as increased urination, increased thirst, and unexplained weight loss also can diagnose diabetes.
GLUCOSE TOLERANCE TEST (GLOO-kōs TŎL-ĕr-ăns tĕst) Measures the glucose levels in a blood sample taken at various intervals from a patient who has previously ingested glucose; used to diagnose prediabetes and gestational diabetes.
glycosylated hemoglobin test (HbA1C or A1C), performed by measuring the percentage of red blood cells with glucose attached, monitors long-term glucose control.
A high level indicates poor glucose control in diabetic patients.
serum and urine tests – Measurement of hormones, electrolytes, glucose, and other substances in serum (blood) and urine as indicators of endocrine function. Serum studies include assays for growth hormone, somatomedin C (insulin-like growth factor), prolactin level, gonadotropin levels, parathyroid hormone, calcium, and cortisol.
urinary microalbumin assay may detect small quantities of albumin in urine as a marker or harbinger of diabetic nephropathy.
THYROID FUNCTION TESTS (THĪ-royd FŬNK-shŭn tĕsts) Measurement of thyroxine [T4], triiodothyronine [T3], and thyroid-stimulating hormone [TSH] in the bloodstream

29. Clinical Procedures Page 778 Exophthalmometry
Computed tomography (CT) scan
Magnetic resonance imaging (MRI)
Thyroid scan
Ultrasound examination
EXOPHTHALMOMETRY (ĕk-sŏf-thăl-MŎM-ĕ-trē) Measurement of eyeball protrusion [Graves disease] with an exophthalmometer.
computed tomography (CT) scan – X-ray imaging of endocrine glands in cross section and other views, to assess size and infiltration by tumor.
magnetic resonance imaging (MRI) – Magnetic waves produce images of the hypothalamus and pituitary gland to locate abnormalities.
THYROID SCAN (THĪ-royd skăn) Administration of a radioactive compound and visualization of the thyroid gland with a scanning device; Thyroid function is assessed; nodules and tumors can be evaluated
ultrasound examination – Sound waves show images of endocrine organs. Thyroid ultrasound is the best method to evaluate thyroid structures and abnormalities (nodules).