chapter 19: endocrine system

pheochromocytoma (hyperaldosteronism)

"pheochromo" means dusky color; tumor of the adrenal medulla and excessive production of aldosterone. Excessive aldosterone acts on the kidneys to retain sodium and water and to excrete too much potassium resulting in hypertension; symptoms include headache, rapid heart rate, and tremors

acidosis

A pathologic condition that results from the accumulation of acids in or loss of base from the body; symptom of uncontrolled diabetes mellitus

thymus

a single gland located behind the sternum in the mediastinum; it resembles a lymph gland in structure because it not only is apart of the lymphatic system, but it also is a hormone secreting endocrine gland. the thymus is large in children, but shrinks with age until there is only a trace of active tissue in older adults. the gland secretes thymosin and thymopoietin which stimulate the production of T cells, the specialized lymphocytes involved in the immune response

Congenital growth hormone deficiency

abnormalities in the development of the pituitary gland and surrounding structures, resulting in short stature in children unless treated with growth hormone (GH); puberty may be delayed or may not occur

primary hypogonadism

abnormality in the testicles resulting in lack of testosterone production; can begin during fetal development, before puberty, or during adulthood. Lack of testosterone during fetal development may cause impaired growth of the external sex organs. During puberty, hypogonadism may delay puberty or cause incomplete development

amenorrhea

absence of menstrual periods in women during reproductive age

ketoacidosis

accumulation of ketone bodies in the blood that results in metabolic acidosis; consequences of uncontrolled diabetes mellitus

cushing's syndrome

adrenal glands produce too much cortisol; often caused by high doses of corticosteroid medication treatment for autoimmune disease e.g. rheumatoid arthritis or asthma. untreated cushing's syndrome can lead to diabetes, high blood pressure, and osteoporosis

myxedema

advanced form of hypothyroidism in adults; a dry, waxy type of swelling with deposits of mucin in the skin, swollen lips, and thickened nose

pituitary gland

also known as hypophysis, the pituitary gland is about the size of a pea and is located on the underside of the brain in a depression at the base of the skull, protected by the brain above it and the nasal cavities below it. the pituitary is a very complex gland that is often referred to as the "master gland" because it produces hormones that affect body functions and because it travels throughout the body to stimulate other endocrine glands to secrete hormones. the pituitary gland secretes growth hormone (GH), prolactin (PRL), thyroid stimulating hormone (TSH), adenocorticotropin (ACTH), gonadotropins (FSH, LH), antidiuretic hormone (ADH), and oxytocin

pancreas

an elongated structure located behind the stomach in the left upper quadrant. the specialized cells that produce hormones are called the islets of langerhans; these cells produce two hormones, insulin and glucogon, and both play a role in maintaining normal glucose levels. the islets of langerhans carry on the endocrine functions of the pancreas; other cells within the organ carry on its exocrine functions e.g. the secretion of digestive enzymes Insulin, produced in the beta cells of the pancreas, is necessary for glucose to pass from the blood for storage (glycogenesis) in the liver. when blood sugar is high (hyperglycemia), the pancreas is stimulated to release insulin and convert excess glucose into glycogen Glucagon, produced in the alpha cells, increases blood levels of glucose by stimulating the breakdown of glycogen stored in the liver cells; glycogen is the storage form of carbohydrate in the body. this process, called glucogenolysis, helps maintain blood glucose levels between meals; glucagon also helps synthesize glucose from amino acids and glycerol derived from protein and triglycerides, respectively (gluconeogenesis) to elevate blood glucose levels

diabetes mellitus, type 1

autoimmune disease with destruction of insulin-producing cells in the pancreas. Most commonly diagnosed in children and young adults. Symptoms are high blood sugar, excessive urination (polyuria), thirst (polydipsia), hunger (polyphagia), emaciation, and weakness. Treatment requires daily insulin injections

Hypocalcemia

blood calcium below normal levels

hypercacemia

blood calcium levels above normal values

hyperglycemia

blood sugar (glucose) level above normal; sign of uncontrolled diabetes mellitus

hypoglycemia

blood sugar (glucose) level below normal

hashimoto's disease

chronic lymphocytic thyroiditis; most common cause of hypothyroidism in the United States. An autoimmune disease of the thyroid gland, with replacement of normal tissue with lymphoid tissue. The end result is a lack of production and secretion of thyroid hormone

CAH

congenital adrenal hyperplasia

thyroid

consisting of a right and left lobe, the thyroid gland is a U or H shaped gland located in front of the neck just below the larynx; the lobes are connected by a narrow piece of thyroid cartilage that produces the prominence on the neck known as Adam's apple. thyroid hormones affect metabolism, brain development, breathing, heart, and nervous system functions, body temperature, muscle strength, skin dryness, menstrual cycles, weight, and cholesterol levels. the thyroid gland produces three hormones: 1)thyroxin (T4) helps maintain normal body metabolism 2) triiodothyronine (T3), a chemically similar compound, helps regulate growth and development and control metabolism and body temperature 3) calcitonin/thyrocalcitonin regulates the level of calcium in the blood. it lowers blood calcium by inhibiting the release of calcium from the bones by a negative feedback loop when blood calcium levels are too high

parathyroid

consists of four small nodules of tissue embedded in the back side of the thyroid glands. when blood calcium levels are low, the parathyroid glands secrete parathyroid hormone or parathormone (PTH), which increases blood calcium levels in three ways 1) calcium is released from the bones, 2) less calcium is excreted by the kidneys and 3) the kidney activates vitamin D which increases calcium absorption in the gastrointestinal tract

virilization

development of male physical characteristics (such as muscle bulk, body hair, and deep voice) in girls or precociously in a boy; caused by excess androgen production from either the adrenal glands or the gonads (testes in males and ovaries in females)

gestational diabetes

develops during pregnancy, most often in women with a family history of diabetes. typically, it disappears after deliver, although the condition is associated with an increased risk of developing type 2 diabetes later in life

hypoglycemic agent

drug for treating diabetes mellitus to normalize blood glucose

EMT

emergency medical technician

adrenomegaly

enlargement of the adrenal gland

goiter (simple)

enlargement of the thyroid gland causing swelling in front of the neck; caused by dietary deficiency of iodine, except in the United States where iodine is added to table salt. Can also be caused by over or under secretion of thyroid hormone

cushing's disease

excessive growth of the pituitary gland caused by a tumor of the pituitary gland; results in the release of too much ACTH, which then leads to over production of cortisol. symptoms of excess cortisol are obesity, weakness, moon face, edema and high blood pressure

polyphagia

excessive hunger; sign of uncontrolled diabetes mellitus

emaciation

excessive leanness, a wasted condition; sight of uncontrolled diabetes mellitus, hyperthyroidism, or diseases of the pituitary gland

hyperthyroidism

excessive secretion of thyroid hormone causing body functions to speed up e.g. rapid heartbeat and more frequent bowel movements or diarrhea. most common cause is grave's disease

polydipsia

excessive thirst; sign of uncontrolled diabetes mellitus or diabetes insipidus

polyuria

excessive urination; sign of uncontrolled diabetes mellitus or diabetes insipidus

hypophysectomy

excision of the pituitary gland

congenital

existing at birth, usually abnormal; nonhereditary

secondary hypogonadism

failure of pituitary gland to send chemical messages to the testicles to produce testosterone. Certain diseases and aging can also lower production of testosterone

ovaries

female gonads; two small glands located in the upper pelvic cavity, on either side of the uterine wall, near the fallopian tubes; each is almond shaped and held in place by ligaments. ovaries produce mature ova as well as two hormones (estrogen and progesterone) responsible for female sex characteristics and regulation of the menstrual cycle. estrogen promotes maturation of the ova in the ovary and prepares the uterine lining for implantation of a fertilized egg. it is also responsible for the development and maintenance of secondary female characteristics that occur in puberty, such as breast development, growth of pubic and axillary hair, widened pelvis, general growth spurt, and onset of menstruation. progesterone is responsible for preparation and maintenance of the uterus in pregnancy, and for the development of the placenta after implantation of a fertilized ovum

Simmonds' disease (panhypopituitarism)

generalized hypopituitarism owing to absence or damage of the pituitary gland; results in loss of function of thyroid and adrenal glands as well as gonads, testes, and ovaries; symptoms are exhaustion, emaciation, cachexia, and lack of secondary sex characteristics

insulin

genetically engineered preparation used in treatment of diabetes to restore the normal ability of the body to utilize glucose

GH

growth hormone

glycosuria

high amount of glucose in the urine; symptom of uncontrolled diabetes mellitus

hyperprolactinemia

higher than normal amounts of prolactin in the blood and production of breast milk in women when not pregnant or nursing; caused by tumor of the pituitary gland, certain medications, and chronic liver or kidney disease

acromegaly

hyper secretion of the pituitary growth hormone (GH) after maturity; causes abnormal enlargement of the extremities of the skeleton, nose, jaws, fingers, and toes. most common cause is a noncancerous tumor of the pituitary gland

polycystic ovary syndrome (PCOS)

hyperandrogenism (abnormally elevated androgen levels); condition in women characterized by the absence of ovulation and menstrual periods, infertility, acne, excess body hair, and metabolic syndrome (obesity, prediabetes, hyperlipidemia)

addison's disease (adrenal insufficiency)

hypofunction of the adrenal gland; autoimmune disorder with inadequate amounts of hormones secreted by the adrenal gland (cortisol, aldosterone, and androgens); secondary cause is damage to the pituitary gland. Symptoms include a bronze-like pigmentation of the skin, dizziness, low blood pressure, low blood sugar, vomiting, and diarrhea

thyroiditis

inflammation of the thyroid gland

diabetes insipidus

insufficient excretion of antidiuretic hormone (ADH; vasopressin) by the posterior pituitary gland; most common cause is damage to the pituitary gland (or hypothalamus) from head injury, surgery, or tumors. lack of ADH causes the kidney tubules to fail to reabsorb water and salts. clinical symptoms include polyuria (increased urination) and polydipsia (increased thirst); excessive thirst results in drinking large volumes of water and a very dilute urine

diabetes mellitus, type 2

insulin resistance--insulin is produced, but the insulin doesn't function properly--or lack of insulin secretion. Most common form of diabetes; usually diagnosed in those over 40 years of age and in those who are obese

convulsions

involuntary muscular contraction; characteristic sign of disorders of calcium metabolism

Congenital Adrenal Hyperplasia (CAH)

lack of enzymes involved in the biosynthesis of cortisol and aldosterone. in many cases, CAH results in lack of cortisol and overproduction of androgen, causing development of male characteristics in girls and early sexual development in boys

hypothyroidism

lack of secretion of thyroid hormone causing body function to slow down, e.g. a slower heart rate and constipation. most common cause is hashimotos disease

congenital hypothyroidism (cretinism)

lack of thyroid secretion that affects infants from birth (congenital). The thyroid gland may be absent or severely reduced in size (hypoplastic) or abnormally located. If untreated, congenital hypothyroidism can lead to intellectual disability and slow physical growth. In the United States, infants are tested at birth and treated to allow for normal growth and development

anorexia

lack or loss of appetite for food; found in certain disease of the pituitary gland

testes

male gonads, also known as testicles, are two small egg shaped glands suspended from the inguinal region of the male by the spermatic cord and surrounded by the scrotal sac. after descending from high in the abdominal cavity during fetal growth, testes descend shortly before birth into the scrotum. testes are the primary organs of the male reproduction system. the testes produce male sperm cells and secrete testosterone, the male hormone necessary for secondary sex characteristics that appear in the male during puberty, such as growth of the beard and pubic hair, growth of skeletal muscles, deepening of the voice, and enlargement of the testicles, penis, and scrotum

cachexia

malnutrition, wasting, and emaciation; found in certain disease of the pituitary gland

cortisol

measured in the blood or saliva to evaluate for diseases of the adrenal gland

testosterone

measured in the blood to evaluate for diseases of the adrenal gland or testes (in males)

Triiodothyronine (T3)

measured in the blood to evaluate for diseases of the thyroid

thyroxine (T4)

measured in the blood to evaluate for diseases of the thyroid

ACTH (adrenocorticotropic hormone)

measured in the blood to evaluate for disorders of the pituitary and adrenal glands

estradiol

measured in the blood to evaluate for normal functioning of the ovaries (in females)

prolactin

measured in the blood when women (who are not pregnant or breastfeeding) secrete breast milk

serum calcium

measured to evaluate for diseases of the parathyroid glands

urine calcium

measured to evaluate for diseases of the parathyroid glands

serum potassium

measured to evaluate for tumors of the adrenal gland that cause excessive urinary excretion of potassium

A1c/HbA1c (glycated hemoglobin)

measurement of the level of hemoglobin A1c determines average blood sugar concentrations for the preceding 2-3 months; normal levels below 5.7 percent indicate diabetes mellitus is well controlled

Secondary hyperparathyroidism

overactive parathyroid gland secondary to chronic kidney failure, the most common disease causing secondary hyperparathyroidism

Primary hyperparathyroidism (PHPT)

overactive parathyroid gland with excessive secretion of parathyroid hormone (PTH); most common cause is a benign tumor of the parathyroid gland. PTH increases serum calcium by releasing calcium from bone, reabsorption of calcium by the kidney, and increasing phosphorous excretion by the kidney

PTH

parathyroid hormone

hypopituitarism

pituitary insufficiency may be caused by a tumor or injury to the pituitary gland. Usually affects the anterior pituitary and releasing hormones necessary for normal functioning of other endocrine glands (thyroid, adrenal cortex, ovaries and testes)

PCOS

polycystic ovarian syndrome

PHPT

primary hyperparathyroidism

diaphoresis

profuse perspiration; often found in conditions of hypoglycemia in diabetes mellitus

PRL

prolactin

exophthalmic goiter

protrusion of the eyeballs; characteristic sign in Graves' disease

RAIU

radioactive iodine uptake

RH

releasing hormone

tetany

sharp flexion of the wrist and ankle joints, muscle twitching, cramps, and convulsion; caused by abnormal calcium metabolism

thyroid nodule

solid or fluid-filled lumps within the thyroid gland; most are benign (noncancerous), although in some cases, the nodules produce excessive amounts of thyroxine

thyrotomy

surgical division of thyroid cartilage

parathyroidectomy

surgical excision of the parathyroid glands

thyroidectomy

surgical excision of the thyroid gland

radioactive iodine uptake (RAIU)

test that measures the amount of radioactive iodine taken up by the thyroid gland; used to evaluate functioning of the thyroid gland

pineal

the pineal gland is a cone shaped structure attached by a stalk to the posterior wall of the cerebrum. this gland secretes melatonin, the hormone that responds to darkness in the external environment. darkness stimulates nerve impulses in the eyes to decrease and the secretion of melatonin to increase. the pineal gland functions as a "biological clock" to regulate patterns of sleep, eating, and reproduction

TSH

thyroid stimulating hormone

T4

thyroxin

grave's disease

toxic diffuse goiter; autoimmune disease and most common cause of hyperthyroidism in the US. symptoms are nervousness, difficulty sleeping, fatigue, weight loss, goiter, and protrusion of the eyeballs

thyrotherapy

treatment with thyroid preparations

T3

triiodo thyronine

adrenal

two adrenal glands sit atop each kidney; each consists of two portions: the central region or adrenal medulla and the outer region or adrenal cortex. the adrenal cortex is the largest portion of the gland, and it secrets three types of steroid hormones called corticosteroids. each has different functions: 1) glucocorticoids affect glucose metabolism and maintain blood glucose levels. 2)mineralocorticoids are involved in balance of electrolytes, sodium and potassium. the most important of these hormones is aldosterone, which acts on the kidney to regulate blood levels of sodium and potassium ions 3) gonadocorticoids are sex hormones released from the adrenal cortex instead of the gonads (testes and ovaries), but the small amounts secreted by the adrenal cortex contribute to the secondary sex characteristics, such as breast and beard development, and are necessary for reproduction the adrenal medulla, the inner portion of the adrenal gland, secretes two non steroidal hormones called catecholamines. the two hormones, adrenaline (epinephrine) and noradrenaline (nonrepinephrine), are the stress hormones that exert physiologic changes during times of stress (the fight or flight response)

MRI (magnetic resonance imaging)

use of radio waves and a computer to create pictures of areas inside the body; precise accuracy in detecting structural abnormalities of the body, including tumors

thyroid scan

use of radioactive iodine tracer to examine the structure and function of the thyroid gland; used to evaluate for thyroid nodules or goiter or an overactive thyroid gland