Chapter 13 Medical Terminology and Body Structures Chapter 11 The Endocrine System.

Chapter 13 Medical Terminology and

Body Structures Chapter 11

The Endocrine System

Copyright © 2005 by Thomson Delmar Learning. ALL RIGHTS

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Function of the Endocrine systemis to produce hormones.


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Endocrine glands secrete chemicals (hormones) into the blood

Hormones perform general functions of communication and control but a slower, longer-lasting type of control than that provided by nerve impulses

Mechanisms of Hormone ActionMechanisms of Hormone Action


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Mechanisms of Hormone Action

Cells acted on by hormones are called target organ cells

Non-steroid hormones (first messenger) bind to receptors on the target cell membrane, triggering second messengers to affect the cell’s activities

Steroid hormones bind to receptors within the target cell nucleus and influence cell activity by acting on DNA


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Hormone secretion is controlled by homeostatic feedback

Negative feedback — mechanisms that reverse the direction of a change in a physiologic system

Positive feedback —(uncommon) mechanisms that amplify physiologic changes

Regulation of Hormone SecretionRegulation of Hormone Secretion


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Prostaglandins (tissue hormones)Prostaglandins (tissue hormones)

Prostaglandins (PGs) are powerful substances found in a wide variety of body tissues

PGs are often produced in a tissue and diffuse only a short distance to act on cells in that tissue


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ProstaglandinsProstaglandins

Several classes of PGs include prostaglandin A (PGA), prostaglandin E (PGE), and prostaglandin F (PGF)

PGs influence many body functions, including respiration, blood pressure, gastrointestinal secretions, and reproduction


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Medical Specialties & Pathology Related to the Endocrine System

Endocrinologist (Physician who specializes in diseases of the endocrine system)

Hypercrinism (Excessive secretion of any gland especially an endocrine gland)

Hypocrinism (Deficient secretion of any gland especially an endocrine gland)

Endocrinopathy (Disease to the disorder of the endocrine system)


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Diagnostic Procedures Related to the Endocrine System

Nuclear Medicine Imaging Techniques Hormone levels are measured in the blood

and/or urine


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Adrenal Glands (2)

Primary Functions Regulate electrolyte levels.

– Influence metabolism.– Respond to stress. – Located on top of each kidney– Consists of the adrenal cortex & adrenal medulla

Related Combining Form– adren/o


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Produce anti-immunity, anti-allergy effect; bring about a decrease in the number of lymphocytes and plasma cells and therefore a decrease in the amount of antibodies formed

Secretion of glucocorticoid quickly increases when the body is thrown into a condition of stress; high blood concentration of glucocorticoids, in turn, brings about many other stress responses

Adrenal GlandsAdrenal Glands


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Functions of Glucocorticoids

– Help maintain normal blood glucose concentration by increasing gluconeogenesis —the formation of “new” glucose from amino acids produced by the breakdown of proteins, mainly those in muscle tissue cells

– The conversion to glucose of fatty acids produced by the breakdown of fats stored in adipose tissue cells play an essential part in maintaining normal blood pressure—make it possible for epinephrine and norepinephrine to maintain a normal degree of vasoconstriction, a condition necessary for maintaining normal blood pressure

– Act with epinephrine and norepinephrine to produce an anti-inflammatory effect, to bring about normal recovery from inflammation of various kinds


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Functions of Glucocorticoids

Produce anti-immunity, anti-allergy effect; bring about a decrease in the number of lymphocytes and plasma cells and therefore a decrease in the amount of antibodies formed

Secretion of glucocorticoid quickly increases when the body is thrown into a condition of stress; high blood concentration of glucocorticoids, in turn, brings about many other stress responses


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Adrenal Cortex

Names of hormones (corticoids) Glucocorticoids (GCs)—chiefly

cortisol (hydrocortisone) Mineralocorticoids (MCs) —chiefly

aldosterone. Increase blood sodium and decrease body potassium concentrations by accelerating kidney tubule reabsorption of sodium and excretion of potassium

Sex hormones —small amounts of male hormones (androgens) secreted by adrenal cortex of both sexes

Three cell layers (zones)

– Outer layer, secretes mineralocorticoids

– Middle layer, secretes glucocorticoids

– Inner layer, secretes sex hormones


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Adrenal Medulla

– Names of hormones—epinephrine (adrenaline) and norepinephrine

– Functions of hormones—help the body resist stress by intensifying and prolonging the effects of sympathetic stimulation; increased epinephrine secretion is the first endocrine response to stress


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Secretions of the Adrenal Cortex & Adrenal Medulla

Mineralcorticoids (regulates mineral salts in the body)

Glucocrticoids (regulates the metabolism of carbohydrates, fats and proteins)

Gonadocorticoids (hormones that influence sex-related characteristics)

Adrenal medulla secretion

Epinephrine (adrenaline) Norepinephrine

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Pathology of the Adrenal Glands

Adrenalitis Addison’s Disease (insufficient hormone

production. Characterized by pain, fatigue, weight loss)

Aldosteronism (abnormal electrolyte balance caused by excessive aldosterone)

Primary hyperaldosteronism: Conn's syndrome is a disease of the adrenal glands involving excess production of a hormone, called aldosterone. Another name for the condition is primary hyperaldosteronism.

Secondary aldosteronism is increased adrenal production of aldosterone in response to nonpituitary, extra-adrenal stimuli, including renal artery stenosis and hypovolemia. Symptoms are those of primary aldosteronism. Treatment involves correcting the cause.

Pheochromocytoma (benign tumor of the adrenal medulla)

Cushing’s Syndrome (hypercortisolism/hyperadre-nalism) Caused by prolonged exposure to high levels of cortisol. “Moon face”


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Adrenal Cancer

Overview Adrenal cancer is a rare disease that originates in the adrenal glands. The

adrenal glands are located on top of the kidneys and consist of two parts that function separately: the outer layer (cortex) and the inner area (medulla).

The cortex produces three major hormones: cortisol (a glucocorticoid), aldosterone (a mineralocorticoid), and dehydroepiandrosterone (DHEA; an androgen). The medulla produces epinephrine (adrenaline), norepinephrine, and dopamine.

Adrenal tumors can increase hormone production (called functioning tumors). Adrenal tumors that do not produce hormones are called nonfunctioning. Symptoms of adrenal cancer and treatment for the condition depend on whether the tumor is functioning or nonfunctioning, and on which hormone is being overproduced.

Types Most (99%) adrenal tumors are noncancerous (i.e., benign) adrenal cortical adenomas and do not require treatment. These tumors usually do not cause symptoms, are small, and are found incidentally during diagnostic imaging.

(metastasize) to the adrenal glands.


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The most common type of adrenal cancer develops in the adrenal cortex and is called adrenocortical carcinoma. Functioning adrenocortical carcinomas

may produce symptoms related to increased hormone production. Nonfunctioning tumors may cause pain from pressure on abdominal organs and a mass in the abdomen that is able to be felt with the fingers (palpable).

Cancers that develop in the adrenal medulla include neuroblastoma (originates in undeveloped nerve cells) and pheochromocytoma (originates

in cells that produce epinephrine and norephinephrine). Neuroblastoma usually occurs in infants and children and pheochromocytoma more

commonly occurs in people who are in their 30s and 40s. Other types of cancer (e.g., breast, lung) may spread


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Adrenal Cancer

Types Most (99%) adrenal tumors are noncancerous (i.e., benign) adrenal cortical adenomas and do not require treatment. These tumors usually do not cause symptoms, are small, and are found incidentally during diagnostic imaging.

The most common type of adrenal cancer develops in the adrenal cortex and is called adrenocortical carcinoma. Functioning adrenocortical carcinomas may produce symptoms related to increased hormone production.

Nonfunctioning tumors may cause pain from pressure on abdominal organs and a mass in the abdomen that is able to be felt with the fingers (palpable).


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Cancers that develop in the adrenal medulla include neuroblastoma (originates in undeveloped nerve cells) and pheochromocytoma (originates in cells that produce epinephrine and norephinephrine). Neuroblastoma usually occurs in infants and children and pheochromocytoma more commonly occurs in people who are in their 30s and 40s.

Other types of cancer (e.g., breast, lung) may spread (metastasize) to the adrenal glands.

Source: http://www.urologychannel.com/adrenalcancer

Adrenal Cancer


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Treatment Procedures of the Adrenal Glands

Laparoscopic adrenalectomy Hydrocortisone (immunosuppressant,

suppress inflammation) Epinephrine (vasoconstrictor causes the

blood vessels to contract)


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adrenalectomy

Laparoscopic adrenalectomy

Adrenal gland


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Hypothalamus

Actual production of ADH and oxytocin occurs in the hypothalamus

After production in the hypothalamus, hormones pass along axons into the pituitary gland

The secretion and release of posterior pituitary hormones are controlled by nervous stimulation

The hypothalamus controls many body functions related to homeostasis (temperature, appetite, and thirst)


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Pancreatic Islets

Primary Functions – Control blood sugar levels and glucose metabolism.

Related Combining Form– pancreat/o


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Pancreatic Islets

Functions of hormones– Glucagon increases the

blood glucose level by accelerating liver glycogenolysis (conversion of glycogen to glucose)

– Insulin decreases the blood glucose by accelerating the movement of glucose out of the blood into cells, which increases glucose metabolism by cells

Names of hormones– Glucagon —secreted by

alpha cells– Insulin —secreted by beta

cells


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Pathology of the Pancreas

Hyperglycemia Polydipsia (excessive

thirst) Polyphagia (exccessive

hunger) Polyuria (excessive

urination) Hyperinsulinism

(excessive insulin secretion

Hypoglycemia Insulinoma (benign

tumor of the pancreas caused by hypoglycemia)

Pancreatalgia (pain in the pancreas)

Pancreatitis


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Diabetes

Diabetes mellitis (a group of metabolic disorders characterized by hyperglycemia)

Type 1 Diabetes (insulin-dependant diabetes or juvenile diabetes)

Type 2 Diabetes (non-insulin diabetes) Gestational Diabetes


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Diabetes Diagnostic Procedures/Emergencies/Complications

Diagnostic Procedures

Fasting Blood Sugar Oral Glucose Tolerance

Test Home blood glucose

monitoring Fructosamine test

(measures average glucose level over three weeks)

Hemoglobin

Emergencies Insulin Shock Diabetic Coma

Complications Heart Disease Kidney Disease Neuropathy Diabetes Retinopathy


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Pineal Gland (1)

Primary Function – Influences the sleep-wakefulness cycle.

Related Combining Form– pineal/o


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Pineal Gland

A small gland near the roof of the third ventricle of the brain

– Glandular tissue predominates in children and young adults

– Becomes fibrous and calcified with age

Called third eye because its influence on secretory activity is related to the amount of light entering the eyes

Secretes melatonin, which:– Inhibits ovarian activity– Regulates the body’s

internal clock


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Pathology & Treatment of the Pineal Gland

Pinealopathy Pinealectomy


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Pituitary Gland (hypophysis)

Primary Function – Secretes hormones that

control the activity of the other endocrine glands.

Related Combining Forms

– pituit/o, pituitar/o


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Pituitary Gland (Located at the base of the brain. Divided into lobes)Pituitary Gland (Located at the base of the brain. Divided into lobes)

Anterior pituitary gland (adenohypophysis)

Names of major hormones

– Thyroid-stimulating hormone (TSH)

– Adrenocorticotropic hormone (ACTH)

– Follicle-stimulating hormone (FSH)

– Luteinizing hormone (LH)– Growth hormone (GH)– Prolactin hormone (PH)


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TSH —stimulates growth of the thyroid gland; also stimulates it to secrete thyroid hormone (trophic hormone transmitter production)

ACTH —stimulates growth of the adrenal cortex and stimulates it to secrete glucocorticoids

FSH —initiates growth of ovarian follicles each month in the ovary and stimulates one or more follicles to develop to the stage of maturity and ovulation;

FSH also stimulates estrogen secretion by developing follicles; stimulates sperm production in the male

LH —acts with FSH to stimulate estrogen secretion and follicle growth to maturity; causes ovulation; causes luteinization of the ruptured follicle and stimulates progesterone secretion by corpus luteum; causes interstitial cells in the testes to secrete testosterone in the male

Pituitary Gland-Functions of major hormones


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GH —stimulates growth by accelerating protein anabolism; also accelerates fat

catabolism and slows glucose catabolism; by slowing glucose catabolism, tends to increase blood glucose to higher than

normal level (hyperglycemia) Prolactin or lactogenic hormone —stimulates breast development during

pregnancy and secretion of milk after the delivery of the baby


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Posterior Pituitary Gland

Posterior pituitary gland (neurohypophysis)

– Names of hormones Antidiuretic hormone

(ADH) (Vasopressin) Oxytocin

– Functions of hormones ADH —accelerates

water absorption from urine in the kidney tubules into the blood, thereby decreasing urine secretion

Oxytocin —stimulates the pregnant uterus to contract; may initiate labor; causes glandular cells of the breast to release milk into ducts


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Pathology of the Pituitary Gland

Acromegaly Gigantism Hyperpituitarism Hypopituitarism Puitarism Pituitary Adenoma Prolactin-producing

adenoma Diabetes Insipidus


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Treatment Procedures of the Pituitary Gland

Human Growth Hormone Therapy (recombinant GH)

Synthetic version of the growth hormone.

Administered to stimulate growth when the natural supply of the hormone is insufficient.


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Thyroid Gland (1)

Primary Functions – Stimulates metabolism,

growth, and the activity of the nervous system.

Related Combining Forms

– thyr/o, thyroid/o


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Thyroid Gland

Names of hormones (secretions)– Thyroid hormone —thyroxine (T4) and

triiodothyronine (T3)

– Calcitonin —decreases the blood calcium concentration by inhibiting breakdown of bone, which would release calcium into the blood


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Pathology of the Thyroid Gland

Hashimoto’s (the immune system attacks thyroid tissue)

Hypothroidism Cretinism (congenital

hypothyroidism) Myxedema (severe

form of adult hypothyroidism)

Hyperthyroidism Thyrotoxicosis

(excessive release of thyroid hormones)

Grave’s disease (autoimmune hyperthyroidism)

Goiter Exopthalmos


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Diagnostic & Treatment Procedures Related to the Thyroid Gland

Thyroid Scan (Nuclear Medicine)

Antithyroid Drug (slows the thyroid)

Lobectomy (removal of one of the four thyroid lobes)

Synthetic thyroid hormones (given for lost thyroid function)


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Thyroid Cancer

There are over 11,000 new cases of thyroid cancer each year in the United States. Females are more likely to have thyroid cancer at a ratio of three to one. Thyroid cancer can occur in any age group, although it is most common after age 30 and its aggressiveness increases significantly in older patients. The majority of patients present with a nodule on their thyroid which typically does not cause symptoms.

Occasionally, symptoms such as hoarseness, neck pain, and enlarged lymph nodes do occur. Although as much as 10 % of the population will have thyroid nodules, the vast majority are benign. Only approximately 5% of all thyroid nodules are malignant. A nodule which is cold on scan (shown in photo outlined in red and yellow) is more likely to be malignant, nevertheless, the majority of these are benign as well.


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Thyroid Cancer Type and Incidence

Papillary and mixed papillary/follicular ~ 78%

Follicular and Hurthle cell ~ 15% Medullary ~ 5% Anaplastic ~ 2%

Radioactive scanof the thyroid


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What's the Prognosis ??

Most thyroid cancers are very curable. In fact, the most common types of thyroid cancer (papillary and follicular) are the most curable. In younger patients, both papillary and follicular cancers can be expected to have better than 95% cure rate if treated appropriately. Both papillary and follicular cancers are typically treated with complete removal of the lobe of the thyroid which harbors the cancer, PLUS, removal of most or all of the other side. The bottom line, most thyroid cancers are papillary thyroid cancer, and this is one of the most curable cancers of ALL cancers that humans get.


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Medullary Cancer

Medullary cancer of the thyroid is significantly less common, but has a worse prognosis. Medullary cancers tend to spread to large numbers of lymph nodes very early on, and therefore requires a much more aggressive operation than does the more localized cancers such as papillary and follicular. This cancer requires complete thyroid removal PLUS a dissection to remove the lymph nodes of the front and sides of the neck.


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Anaplastic

The least common type of thyroid cancer is anaplastic which has a very poor prognosis...it tends to be found after it has spread and is not cured in most cases. Often an operation cannot remove all the tumor. These patients often require a tracheostomy during the treatment, and treatment is much more aggressive than for other types of thyroid cancer--because this cancer is much more aggressive.


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Thymus (1)

Primary Function – Plays a major role in the immune reaction.

Related Combining Form– thym/o


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Thymus

Name of hormone— thymosin

Function of hormone—plays an important role in the development and function of the body’s immune system


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Pathology & Treatment of the Thymus

Thymitis Thymoma Thymectomy


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Parathyroid Glands (4)

Primary Function – Regulate calcium levels

throughout the body.

Related Combining Form

– parathyroid/o


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Parathyroid Gland

Name of hormone —parathyroid hormone (PTH)

Function of hormone —increases blood calcium concentration by increasing the breakdown of bone with the release of calcium into the blood


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Pathology of the Parathyroid Glands

Hypoparathyroidism Hypocalcemia Tetany (painful muscle spasms)

Treatment of a diseased parathyroid gland(s) usually involves surgical treatment


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Gonads *

Primary Function – Regulate development and maintenance of

secondary sex characteristics.

Related Combining Form– gonad/o

*Males: testicles (2)

*Females: ovaries (2)


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Female Sex Glands

The ovaries contain two structures that secrete hormones—the ovarian follicles and the corpus luteum

Effects of estrogen (feminizing hormone)– Development and maturation of breasts and

external genitals– Development of adult female body contours– Initiation of menstrual cycle


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Pathology of the Gonads

Hypergonadism (excessive secretion of hormones)

Hypogonadism Gynecomastia


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Male Sex Glands

The interstitial cells of the testes secrete the male hormone testosterone

Effects of testosterone (masculinizing hormone)– Maturation of external genitals– Beard growth– Voice changes at puberty– Development of musculature and body contours

typical of the male


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Placenta

Name of hormones—chorionic gonadotropins, estrogens, and progesterone

Functions of hormones—maintain the corpus luteum during pregnancy


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Many organs (for example, the stomach, intestines, and kidneys) produce endocrine hormones

The atrial wall of the heart secretes atrial natriuretic hormone (ANH), which stimulates sodium loss from the kidneys

Fat-storing cells secrete leptin, which controls how full or hungry we feel

Other Endocrine StructuresOther Endocrine Structures


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The EndThe End

Chapter 13 Medical Terminology and Body Structures Chapter 11 The Endocrine System.

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endocrine system function

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