Essentials of Medical Language: Chapter 12 - The Endocrine System

Vocabulary flashcards covering the organs, hormones, medical roots, pathologies, and clinical terminology of the endocrine system from Chapter 12.

Endocrine system

A network of ductless glands whose cells secrete hormones directly into the bloodstream to regulate body functions and maintain homeostasis.

Endocrinology

The medical specialty focused on the study of the endocrine system, its glands, and their hormonal secretions.

Hormone

A chemical messenger produced by an endocrine gland and secreted directly into the bloodstream to regulate the activity of target cells or organs.

Major endocrine glands of the brain

The hypothalamus, pituitary gland, and pineal gland, situated within the cranial cavity.

Major peripheral endocrine organs

The thyroid gland, parathyroid glands, thymus gland, adrenal glands, pancreas, and gonads (ovaries in females and testes in males).

Hypothalamus

An endocrine organ located in the brain that connects the nervous and endocrine systems, producing oxytocin and antidiuretic hormone ($\text{ADH}$).

Pineal gland

A small endocrine gland in the brain that secretes serotonin and melatonin.

Melatonin

A hormone produced by the pineal gland that helps modulate circadian rhythm and sleep-wake cycles.

Serotonin

A neurotransmitter and pineal hormone that plays a key role in mood regulation and serves as a chemical precursor to melatonin.

Oxytocin (OT)

A hormone synthesized by the hypothalamus and stored in the posterior pituitary that stimulates uterine contractions during labor and milk ejection during lactation.

Antidiuretic hormone (ADH)

A hormone produced by the hypothalamus and released by the posterior pituitary that stimulates the kidneys to conserve water and decrease urine output.

Follicle-stimulating hormone (FSH)

An anterior pituitary hormone that stimulates follicle maturation in the ovaries and spermatogenesis in the testes.

Luteinizing hormone (LH)

An anterior pituitary hormone that triggers ovulation in females and stimulates testosterone production in males.

Thyroid-stimulating hormone (TSH)

An anterior pituitary hormone that stimulates the thyroid gland to synthesize and secrete thyroid hormones.

Adrenocorticotropic hormone (ACTH)

An anterior pituitary hormone that stimulates the adrenal cortex to produce and secrete corticosteroids.

Prolactin (PRL)

An anterior pituitary hormone that stimulates milk production in the mammary glands.

Growth hormone (GH)

An anterior pituitary hormone that promotes tissue growth, cellular reproduction, and protein synthesis throughout the body.

Gigantism

A condition characterized by abnormal overgrowth of the body resulting from hypersecretion of growth hormone ($\text{GH}$) before epiphyseal fusion in childhood.

Acromegaly

A disorder caused by overproduction of growth hormone ($\text{GH}$) during adulthood, leading to thickening and enlargement of bones in the face, hands, and feet.

Pituitary dwarfism

A condition of abnormally short stature with normal body proportions resulting from hyposecretion of growth hormone ($\text{GH}$) during childhood.

Diabetes insipidus (DI)

A metabolic disorder caused by deficient production or decreased response to antidiuretic hormone ($\text{ADH}$), resulting in extreme thirst and large volumes of dilute urine.

Root: aden-

Medical word element referring to a gland (e.g., adenoma).

Root: bio-

Medical word element referring to life (e.g., biopsy).

Root: opt-

Medical word element referring to the eye or vision (e.g., optic).

Root: osmol-

Medical word element referring to osmotic concentration or osmolarity (e.g., osmolality).

Craniotomy

Surgical incision into the cranium with temporary removal of a bone flap to access intracranial structures.

Endoscopic transnasal transsphenoidal approach

A minimally invasive surgical procedure through the nasal passage and sphenoid sinus to reach and excise pituitary tumors.

Stereotactic

Pertaining to a precise three-dimensional localization method used in cranial surgery or targeted radiation therapy.

Thyroid gland anatomy

A bi-lobed gland located inferior to the thyroid cartilage and anterior to the trachea, whose lobes are connected across the midline by an isthmus.

Thyroxine ($\text{T}_4$)

The principal hormone secreted by the thyroid gland, containing four iodine atoms, responsible for regulating basal metabolic rate.

Triiodothyronine ($\text{T}_3$)

The active thyroid hormone containing three iodine atoms that stimulates cellular metabolism throughout the body.

Calcitonin

A thyroid hormone secreted to lower blood calcium levels by inhibiting bone resorption.

Parathyroid hormone (PTH)

A hormone secreted by the parathyroid glands that increases blood calcium concentration, acting as an antagonist to calcitonin.

Thymus gland

A lymphoid and endocrine gland located in the thoracic mediastinum that secretes hormones promoting T lymphocyte maturation.

Goiter

Abnormal, visible enlargement of the thyroid gland.

Exophthalmos

Abnormal protrusion or forward displacement of the eyeballs, characteristic of Graves disease.

Graves disease

An autoimmune disorder characterized by excessive thyroid hormone secretion (hyperthyroidism), diffuse goiter, and exophthalmos.

Myxedema

A severe, advanced form of adult hypothyroidism characterized by non-pitting edema, lethargy, cold intolerance, and dry skin.

Hashimoto disease

An autoimmune disease causing chronic lymphocytic inflammation and destruction of the thyroid gland, frequently leading to hypothyroidism.

Cretinism

Severe congenital hypothyroidism leading to stunted physical growth and profound intellectual impairment if untreated.

Adrenal gland anatomy

A paired pyramid-shaped gland situated superior to each kidney, structurally differentiated into an outer cortex and an inner medulla.

Adrenal cortex

The outer portion of the adrenal gland that secretes steroid hormones including glucocorticoids, mineralocorticoids, and sex steroids.

Adrenal medulla

The inner core of the adrenal gland that produces and releases catecholamines (epinephrine and norepinephrine).

Addison disease

An endocrine disease resulting from adrenocortical hypofunction, presenting with fatigue, weight loss, hypotension, and cutaneous hyperpigmentation.

Cushing syndrome

A constellation of signs and symptoms produced by hypercortisolemia, characterized by central obesity, moon facies, and hypertension.

Pancreas and pancreatic islets

A retroperitoneal gland composed of a head, body, and tail adjacent to the duodenum, containing endocrine islets of Langerhans made up of alpha, beta, and delta cells.

Insulin

A hormone produced by beta cells in the pancreatic islets that lowers blood glucose by facilitating cellular uptake and storage of glucose.

Glucagon

A hormone synthesized by alpha cells in the pancreatic islets that elevates blood glucose by triggering glycogen breakdown.

Somatostatin

An inhibitory hormone produced by delta cells in the pancreatic islets that suppresses the release of both insulin and glucagon.

Gluconeogenesis

The metabolic synthesis of glucose from non-carbohydrate precursors such as amino acids, lactate, and glycerol.

Glycogenolysis

The biochemical breakdown of stored glycogen into free glucose monomers.

Type 1 diabetes

A form of diabetes mellitus resulting from autoimmune destruction of pancreatic beta cells, causing an absolute deficiency of insulin.

Type 2 diabetes

A form of diabetes mellitus characterized by peripheral insulin resistance paired with relative insulin deficiency.

Polydipsia

Excessive or abnormal thirst, commonly presenting as a primary symptom of diabetes.

Polyphagia

Excessive or voracious eating and hunger.

Polyuria

Excessive excretion of an abnormally large volume of urine.

Diabetic ketoacidosis (DKA)

An acute metabolic complication of diabetes marked by hyperglycemia, accumulation of ketone bodies, and severe metabolic acidosis.

Hb A1c

Glycated hemoglobin; a laboratory test indicating the average plasma glucose concentration over the preceding two to three months.