A ductless gland that secretes hormones directly into the blood stream, the hormones are then carried throughout the body where they bind to a target organ cell with specific receptors triggering a reaction.
A chemical substance that is produced by the endocrine gland then secreted directly into the blood stream and carried throughout the body where they bind to a target organ cell.
Secretes its product via a duct onto laminal surface.
Cell having a specific receptor that reacts with a specific hormone, antigen, antibody, antibiotic, and sensitized T cell.
Any of several classes of intracellular signals acting at or situated within the plasma membrane and translating electrical or chemical messages from the environment into cellular responses.
Hormonal signaling in which a cell secretes a hormone, or chemical messenger, called the autocrine agent, that binds to autocrine receptors.
Type of hormone function in which hormone synthesized in and release from endocrine cells binds to its receptor in nearby cells and affects their function.
Signaling in which endocrine cells release hormones that act on distant target cells.
A chemical substance that is produced and secreted into the blood by an organ or tissue, and has a specific effect on target tissue.
Located inferior to the thalamus & just above the brain stem.
Receives input from other regions of the brain, internal organs and the visual system.
Body temperature, hunger, thirst, fatigue, anger, circadian cycles, and in tandem with the autonomic nervous system helps control sexual behavior and defensive reactions. Stress and Emotion can change it's activities.
A pea sized structure attached to the bottom of the hypothalamus. the pituitary is divided into two lobes: Anterior and posterior.
Pituitary Gland Function
Secretes hormones regulating homeostasis, including hormones that stimulate other endocrine glands.
Gonadotropin Releasing Hormone (GnRH)
Peptide hormone that stimulates the release of the follicle stimulating hormone (FSH) and leutinizing hormone (LH) from the anterior pituitary.
Thyrotropin Releasing Hormone (TRH)
Hormone that stimulates the release of thyroid-stimulating hormone (TSH) and prolactin from the anterior pituitary.
Corticotropin Releasing Hormone (CRH)
Hormone and neurotransmitter involved in the stress response. Stimulate the pituitary gland to secrete adrenocortictropin (ATCH).
Prolactin Inhibiting Hormone (PIH)
Hormone that inhibits prolactin production. Targets the anterior pituitary to inhibit milk production at the mammary gland.
Prolactin Releasing Hormone (PRH)
Stimulates prolactin production
Melanocyte Stimulating Hormone Inhibitin Factor (MIF)
Inhibits melanocytes stimulating hormone (MSH) production.
Melanocyte Stimulating Hormone Releasing Factor (MRF)
Influences melanocyte stimulating hormone (MSH) production. Melanin formation and deposition in the body and causing color changes in the skin.
Hypothalamic Hormones Function
Stimulate the anterior pituitary to synthesis and release its hormone.
Follicle Stimulating Hormones (FSH)
Hormone that regulates the development, growth, onset of puberty, and reproductive processes of the human body..
Leutinizing Hormones (LH))
Hormone that is essential for reproduction.
Hormone that is primarily associated with lactation.
Thyroid Stimulating Hormone (TSH)
Hormone which regulates the endocrine function of the thyroid gland.
Adrenocorticotropic Hormone (ACTH)
Hormone that stimulates the cortex of the adrenal gland and boosts the synthesis of corticosteroids and sex steroids.
Melanocytes Stimulating Hormone (MSH)
Hormone that stimulates the production and release of melanin in skin and hair. When released into the brain, has an effect on appetite and sexual arousal.
Human Growth Hormone (hGH)
A polypeptide secreted by the anterior pituitary. Promotes protein anabolism, lipid mobilization and catabolism, and indirectly inhibits glucose metabolism. Regulated by two hormones (GHRH, GHIH)
Growth Hormone Releasing Hormone (GHRH)
Increase the secretion of hGH. Stimulator - deep sleep, hypoglycemia, exercise, stress, high levels of insulin, and elevation of certain amino acids.
Growth Hormone Inhibiting Hormone (GHIH)
Decreases the secretion of hGH. Inhibitors - hyperglycemia, obesity, and increased glucocorticoids.
Hypersecretion of hGH
Gigantism - Abnormally rapid rate of skeletal growth in childhood.
Acromegaly - A condiction in which the cartilage in skeleton continues to form new bones during adulthood.
Hyposecretion of hGH
Pituitary dwarfism - may may be a caused
If diagnosed in infancy - Treated with recombinant hGH to normalize body growth.
An extension of the nerve tissue of the hypothalamus.
Posterior Pituitary Controls
Release of hormones is initially stimulated by nerve impulses coming from the hypothalamus. Maintained through a positive feedback mechanism, and once the stimulate is remove, the hormone is no longer released.
Peptide hormone that binds to the uterine smooth muscle which then stimulates concentration of the uterus. Rare example of positive feedback. Stimulates the release of milk.
A synthetic form of oxytocin, may be used to induce labor, prevent and control uterine bleeding after birth and to promote lactation.
Anti-Diuretic Hormone (ADH, Vasopressin)
Low doses - it reabsorption of water by the the distal tubules of the kidney and controls osmotic content of the blood.
High doses - Contraction of arterioles and capillaries, especially the coronary vessels.
Hyposecretion of ADH
Can lead to diabetes insipidus, Polyuria, and polydipsia.
Synthetic ADH can be administered to alleviate diabetes insipidus.
Has two glands, one on the superior of the kidney. Each gland has two distinct structure, adrenal cortex (outer) and adrenal medulla (inner).
Composed of three distinct layers or zones. Starting outward Zona Glomerulosa, Zona Fasciculata, Zona Reticularis.
Produced in the Zona glomerulosa - the main hormone in aldosterone.
Produced in the Zona fasciculata - the main hormone is cortisol.
Produced in the Zona reticularis - the main hormone are dehydroepiandrasterone (DHEA), androgens, estrogen, and testosterone.
Controls the kidney's ability to regulate sodium, chloride, potassium, and water. Increase levels of aldostreone causes the kidneys to excrete potassium in urine and reabsorb sodium and water back in the blood.
Promotes gluconeogenesis when blood levels are low, Lipid metabolism, maintain normal blood pressure, anti-immunity or anti-allergy effect.
Adrenal Cortex Disorder (Addison's Disease, Adrenocortical Hyperfuction Hypocortisolism)
Occurs when under active adrenal glands produce insufficient cortisol and occasionally aldosterone. Primary and Secondary Adrenal Insufficiency.
Adrenal Cortex Disorder Symptoms and Treatment
Symptoms: Fatigue, weakness, nausea, vomiting, muscle and joint pain, constipation, loss of appetite, weight loss, diarrhea, darkening of the skin and dizziness.
Treatment: Hydrocortisone and Prednisone.
Adrenocortical Hyperfunction (Cushing's Disease, Hypercortisolism)
Occurs when a person is exposed chronically to high levels of glucocorticoids. Over production of cortisol by the adrenal gland, high doses of corticosteroids, and tumors in the pituitary gland.
Adrenocortical Hyperfunction Symptoms and Treatment.
Symptoms: Weight gain, easy bruising, thinning of skin, round face, weak bones, high blood sugar, tiredness, weak muscles, mood swings, and depression
Treatment: High doses of corticosteroid treated with gradual doses, Hyperaldosteronism.
Inner core of the adrenal gland, source of the circulating catecholamines involved in the fight-or-flight reaction.
Epinephrine, norepinephrine, and dopamine.
Adrenal Medulla Disorder
Pheochromocytoma, hypersecretion of epinephrine, nonepinephrine and dopamine from a tumor of the adrenal medulla.
Is a bi-lobed butterfly shaped gland located in the front and sides of the trachea below the larynx. The two lobes are connected by the isthmus.
Thyroid Gland Hormones
Thyoxine(T4) and Triiodothyronine(T3) which control body's metabolic rate (BMR).
Calcitonin which regulates the calcium homeostasis along with the parathyroid hormone.
Thyroid Hormones Synthesis
Begins when ionized iodide (1) is absorbed from the diet, Follicular cells trap iodide with tyrosine where they covalently bond, Coupling of T1 and T2, Then made into T3 and T4 and stored in the thyroglobulin.
Thyroxine Binding Globulin (TBG)
The main serum that transports protein where it binds with 90% T3 and T4 so that it can be transported throughout the blood.
T3 and T4 Metabolism
Thyroid gland secrete about 80% T4 and T3. However, T3 possesses about four times the hormone activity as T4. The majority of T4 transforms into T3 in the liver.
Thyroid Hormone Regulation
The hypothalamus secretes thyroid releasing hormone (TRH), which stimulates cells in the anterior pituitary to secrete thyroid stimulating hormone (TSH) in the blood.
Physiologic Effects of Thyroid Hormones
Regulates the BMR, Increases fat and carbohydrates metabolism, stimulates protein synthesis, increase heart and blood flow, key role in growth and development.
Term used to describe the signs and symptoms associated with the lack of sufficient thyroid hormones (slow metabolism)
Hypothyroidism Signs and Symptoms
Fatigue, weakness, cold intolerance, constipation, depression, weight gain, irritability, memory loss, coarse, dry hair, deceased libido, hair loss, and abnormal menstrual cycles.
The thyroid doesn't produce adequate amounts of T4. the thyroid has failed but the pituitary and hypothalamus are functioning properly. Hashimoto's thyroiditis, Cretinism, Myxedema, and Iodine deficiency.
An autoimmune disease in which the immune system fails to recognize the thyroid gland as part of the body's own tissue and attacks it as if it was a foreign body.
Congenital defect in newborns that lack a properly functioning thyroid gland.
This condition is characterized by a decreased metabolic rate which causes mental slowness, dry skin, hair loss, thickened edematous skin, enlarge tongue, and slow speech.
Due to the lack of iodine in the diet. Is required for the synthesis of T3 and T4. Limited iodine in the diet directly results in decreased in the production of these hormones.
The pituitary gland does not release sufficient thyroid-stimulating hormone (TSH) causing the thyroid to produce less thyroid hormones.
The term used to describe the signs and symptoms associated with an over production of thyroid hormones (Increased metabolism)
Hyperthyroidism Signs and Symptoms
Palpitations, insomia, muscle weakness, nervousness, fatigue, warm moist skin, fast heart rate, hair loss, breathlessness, staring gaze, weight lost, and heat intolerance.
Most common type of hyperthyroidism, This is an autoimmune disease in which antibodies are directed against the TSH receptor sites on the surface of the thyroid gland.
Treatment for Hyperthyroidism
Anti-thyroid drug therapy, radioactive iodine, and/or surgical removal of all of the thyroid.
Four to five parathyroid glands are embedded in the side of the thyroid gland. The primary hormone is the parathyroid hormone (PTH).
Effects of Parathyroid Hormone
Not regulated by the pituitary gland or the hypothalamus. Acts on the bones, kidneys, and the intestinal cells by increasing the release of calcium into the blood.
A protein produced by the parafollicular cells of the thyroid. These cells are located next to the thyroid secreting cell hormones in the thyroid gland.
Controls calcium, lower calcium levels in the bloodstream, recombinant calcitonin is used to treat osteoporosis.
Regulation is achieved through the combined interaction of PTH and calcitonin, low blood levels stimulate PTH and high blood levels inhibits PTH.
Physiological Calcium Homeostasis
Leads to normal neuromuscular excitiability, blood clotting, strong teeth and bones, cell membrane permeability.
Paired organs found within a sac called the Scrotum. Composed mainly of coils of sperm-producing seminiferous tebules.
Testosterone - responsible for the growth and maintenance of male sexual characteristics.
Inhibin - secreted by the Sertoli cells that inhibits secretion of FSH from the anterior pituitary gland.
Testicular, adrenal or pituitary tumors, Precocious puberty (early onset of puberty)
Hypogonadism, Klinefelter's syndrome, orchiectomy, delayed puberty, and elderly men.
An extra X chromosome is produced (XXY). Along with hypogonadism there may be also by gynecomastia.
Stimulate the building of and to increase mass and strength of skeletal muscle. Prolonged use, shuts down Gonadotropin Releasing Hormone.
Along with the fallopian tubes and uterus are located in the pelvic cavity. Producing Estrogen and Progesterone.
Secreted by the follicle cells of the ovary. Stimulated by follicle stimulating hormone (FSH) from the anterior pituitary and promotes the maturation of the ovum and growth of blood vessels in the endometrium (lining) of the uterus and secondary sex characteristics.
Promotes storage of glycogen and the further growth of blood vessels in the endometrium, which thus becomes a potential placenta, also influences the secretory cells of the mammary glands.
Mensus (Menstrual Cycle)
Includes the activity of the ovaries and the anterior pituitary gland and the resultant changes in the ovaries and uterus. Average cycle is 28 days.
Menstrual Phase (Menstruation)
Loss of the functional layer of the endometrium, it may last 2-8 days. FSH is increasing.
Secretion of estrogen and LH. They promote the growth and maturation of the ovum. Estrogen further stimulates the growth of the blood vessels in the endometrium. This phase is the end of Ovulation.
When there is a sharp increase in LH causing a mature ovarian follicle to rupture into the fallopian tube.
Under the influence of LH, the ruptured follicle becomes the corpus luteum which secretes progesterone.
The absence of normal menstruation. Primary cause is pregnancy and menopause, cause hormonal imbalances, structural deformities, and weight loss.
Painful menstruation caused by the increased release of prostaglandins, cramp-like feelings to severe debilitating pelvic inflammation.
Premenstrual Syndrome (PMS)
Irritability, Fatigue, nervousness, depression and other problems. It may last for a few days to two weeks.
Coarse and pigmented hair on the face, back, chest and lower abdomen most apparent in women. Increase in androgen production, or masculinization in women, by menstrual dysfunction.
Oral contraceptives (birth control pills) Contain both synthetic estrogen and progesterone and is taken for 21 days.
Conception takes place in the fallopian tubes and occurs when a sperm enters an ovum. About 7-8 days after the egg implants on the uterine wall..
Composed of both maternal and fetal tissue. The umbilical cord connects the fetus to the placenta.
Site of exchanges between the maternal and fetal blood supply and secrete numerous hormones.
Secretion is from the pituitary gland and increases greatly in response to the high maternal estrogen levels. Stimulates lactogensis of the breast. Suppress reproductive function in the mother.
Maternal plasma levels peak in the first trimester and the decline. Decreases uterine muscle contractions, relaxes the mother's pelvis and softens the cervix by increasing collagenase activity.
Miscarriage (Spontaneous Abortion)
10-15% of all conceptions result, majority occurs within 14 days is unrecognized by the women.
Ectopic Pregnancy (Tubal Pregnancy)
The fertilized egg implants in the fallopian tubes as opposed to the uterine.
The exact mechanism for the initiation of the birth of the baby and their endocrine mediators is not clear.
Screening Test for Diagnosing Adrenal Cortex Disorder.
Plasma cortisol levels, Basel ACTH, Cortisol 24-hour urine and ACTH stimulation test.
Diagnosing Adrenal Medulla Disorders
Plasma Epinephrine, Norepinephrine and Dopamine levels. Urine 24-hour; Epinephrine, Norepinephrine, Dopamine, Metanephrine, and Vanillylmandelic Acid (VMA) levels.
Laboratory Testing for Thyroid Hormones
Thyroid Stimulating Hormones (TSH) is the single most sensitive test to detect primary hypothyroidism. Generally involves immunoassy methods.
Measures the concentration of Thyroxine in the serum. This measurement assays both protein bound T4 and free T4.
More active metabolically than T4, but its effect is shorter. T3 is the primary molecule that is important in the negative feedback loop.
FT3 (Free Triodothyronine)
This test can evaluate thyroid function and measures that fraction of circulating T3 that exists in the Free State in the blood.
TBG Thyroxine Binding Globulin Assays
Distingushes between hyperthyroidism causing elevated T4 and euthyroid patients with increased T4-binding by TBG.
Hereditary deficiencies of TBG.
hCG Laboratory Assays
All pregnancy tests are based on the detection of hCG in either serum or urine. hCG is composed of alpha and beta subunits.