Chapter 19 - Endocrine System Flashcards
pituitary gland
also known as the hypophysis. located on the underside of the brain in a depression at the base of the skull and is protected by the brain above it and the nasal cavities below it. it is a very complex gland that secretes many hormones that affect body functions. it is often referred to as the master gland. it contains two major parts, the anterior pituitary and the posterior pituitary lobes
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 the adams apple. the thyroid gland produces three hormones: thyroxian (helps maintain normal body metabolism), triiodthyronine (a chemically similar compound, helps regulate growth and development and control metabolism and body temperature), and calcitonin (regulates the level of calcium in the blood. it lowers the blood calcium level by inhibting the release of calcium from the bones by a negative feedback loop when blood calcium levels are high)
parathyrooid
the parathyroid glands are four small modules of tissue embedded in the back side of the thyroid glands. they secrete a hormone known as parathyroid hormone or parathormone (PTH), which increases blood calcium levels
adrenal
also called suprarenal galnds, the two adrenal glands sit one atop each kidney. each consists of two portions, the central region, or adrenal medula, and the outer region, or adrenal cortex. the adrenal cortex is the largest portion of the gland. it secretes three types of steroid hormones called corticosteriods. each has different functions (glucocorticoids, mineralocorticoids, gonadocorticoids) the adrenal medulla, the inner portion of the adrenal gland, secretes two nonsteroid hormones called catecholamines. the two hormones, adrenaline (epinephrine) and noradrenaline (norepinephrine), are the stress hormones that exert physiological changes during times of stress
pancreas
an elongated structure located behind the stomach in the left upper quadrant. the specialized cells that produce hormones are called the islets of Langerans. these cells produce two hormones, insulin and glucagon. both play a role in glucose levels in the body. the islets of langerhans carry on the endocrine functions of the pancreas; other cells within the organ carry on its exocrine functions
ovaries
two small glands located in the upper pelvic cavity, on either side of the uterine wall, near the fallopian tubes of the female. each of the pair is almond-shaped and held in place by ligaments. ovaries are the female sex glands, also known as female gonads. they produce mature ova as well as two hormones responsible for female sex characteristics and regulation of the menstrual cycle. the hormones are estrogen and progesterone
testes
male gonads, also known as testicles, are two small ovoid 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, they descend shortly before birth into the scrotum and remain there. testes are the primary organs of the male reproductive system. the testes produce male sperm cells and secret androgens, the male steroid hormone. they also produce 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 the skeletal muscles, deepening of the voice, and enlargement of the testicles, penis, and scrotum. testosterone is also responsible for sperm maturation
pineal
the pineal gland is a cone-shaped stucture attached by a stalk to the posterior wall of the cerebrum. its exact function is unclear, but it is thought to function as a light receptor and to play a part in regulation of the “biological clock” (patterns of sleeping, eating, and reproduction). it secretes melatonin, the hormone believed to induce sleep
thymus
a single gland located behind the sternum in the mediastinum. it resembles a lymph gland in structure, as it is part of the lymphatic system, but it is also 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 thymopitin, which stimulate the production of T cells, the specialized lymphocytes involved in the immune response
acromegaly
abnormal enlargement of the extremities of the skeleton, nose, jaws, fingers, and toes; caused by hypersecretion of the pituitary growth hormone after maturity
Addison’s disease
bronzelike pigmentation of the skin, severe prostration, progressive anemina, low blood pressure, diarrhea, and digestive disturbance, caused by adrenal hypofunction
adrenalectomy
surgical excision of the adrenal gland
adrenogenital syndrome
group of symptoms associated with alterations in sex characteristics due to abnormally increased production of androgens
adrenomegaly
enlargement of the adrenal gland
cretinism
arrested physical and mental development owing to congenital lack of thyroid secretion
Cushing’s disease
obesity, weakness, moon face, edema, and high blood pressure; caused by hyperfunction of the adrenals
diabetes insipidus
a condition caused by insufficient excretion of antidiuretic hormone (ADH) by the posterior pituitary gland. deifcient ADH causes the kidney tubules to fail to reabsorb needed water and salts. clinical symptoms include polyuria (increased urination) and polydipsia (increased thirst). the person will complain of excessive thirst and drink large volumes of water. the urine will be very dilute with a low specific gravity. synthetic preparations of ADH are administered as treatment for diabetes insipidus
diabetes mellitus
inability to metabolize sugar because of abnormal insulin function; high blood sugar, excessive urination, thirst, hunger, emaciation, and weakness are cardinal symptoms of the most severe type (type 1)
exophthalic goiter
toxic goiter; Graves’ disease; protrusion of the eyeballs, swollen neck, weight loss, shaking, and mental deterioration are symptoms
gestational diabetes
a condition in which pregnant woman sometimes show abnormal glucose levels during the course of pregnancy
goiter (simple)
enlargement of the thyroid gland; swelling in the front part of the neck, mostly caused by dietary deficiency of iodine
