Chapter 13: Endocrine System

Vocabulary flashcards reviewing key terms, anatomical structures, mechanisms of action, and hormones from Chapter 13: Endocrine System.

Hormones

Chemical messengers secreted by glands and specialized cells into the bloodstream that influence almost every cell and organ in the body.

Endocrine Glands

Ductless glands that secrete hormones directly into the bloodstream to act within the body.

Exocrine Glands

Glands with ducts (exit routes) that secrete products onto external surfaces or into body cavities, such as sweat glands or digestive enzyme glands.

Target Cells

Cells possessing specific receptors for a particular hormone, making them capable of responding to that hormone.

Specificity

The principle that a hormone acts only on cells that have receptors specific to that hormone.

Steroid Hormones

Lipid-soluble hormones derived from cholesterol that pass easily through the cell membrane to bind with intracellular receptors in the nucleus.

Nonsteroid Hormones

Protein-based hormones synthesized from amino acids that bind to receptors on the cell surface rather than penetrating the cell membrane.

Second Messenger System

A cascade of intracellular processes triggered by the binding of a nonsteroid hormone to a surface receptor, resulting in enzyme activation and altered cellular response.

Cyclic Adenosine Monophosphate (cAMP)

The most prominent second messenger molecule used in nonsteroid hormone signaling pathways.

Pituitary Gland

A pea-sized gland sitting beneath the hypothalamus that consists of two distinct glands (anterior and posterior pituitary) and exerts major control over body processes.

Sella Turcica

A cavity within the sphenoid bone that cradles the pituitary gland.

Adenohypophysis

The anterior pituitary gland, composed of glandular tissue, which synthesizes and secretes tropic and other hormones under hypothalamic control.

Neurohypophysis

The posterior pituitary gland, which along with the adenohypophysis forms the pituitary gland.

Infundibulum

The stalk that connects the hypothalamus and the pituitary gland.

Hypophyseal Portal System

A system of blood vessels through which hypothalamic releasing and inhibiting hormones travel directly to target cells in the anterior pituitary.

Releasing Hormones

Hormones synthesized by hypothalamic neurons that stimulate the anterior pituitary to secrete its hormones.

Inhibiting Hormones

Hormones synthesized by hypothalamic neurons that suppress hormone secretion by the anterior pituitary.

Tropic Hormones

Anterior pituitary hormones (ending with the suffix -tropin or -tropic) that stimulate other endocrine cells to release their hormones.

Thyroid-Stimulating Hormone (TSH)

An anterior pituitary tropic hormone, also called thyrotropin, that stimulates the thyroid gland to secrete thyroid hormone.

Prolactin

An anterior pituitary hormone that stimulates milk production in female mammary glands and may increase testicular sensitivity to LH in males.

Growth Hormone (GH)

An anterior pituitary hormone, also called somatotropin, that acts on the entire body to promote protein synthesis, lipid and carbohydrate metabolism, and skeletal growth.

Adrenocorticotropic Hormone (ACTH)

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

Luteinizing Hormone (LH)

A gonadotropin secreted by the anterior pituitary that stimulates ovulation and estrogen/progesterone synthesis in females and testosterone secretion in males.

Follicle-Stimulating Hormone (FSH)

A gonadotropin secreted by the anterior pituitary that stimulates egg production in female ovaries and sperm production in male testes.

Gigantism

A condition resulting from the hypersecretion of growth hormone during a child's growth years, triggering rapid, excessive skeletal growth.

Acromegaly

A disorder caused by hypersecretion of growth hormone after epiphyseal plates have fused, causing enlargement of the hands, feet, face, and jaw.

Pituitary Dwarfism

A condition characterized by stunted body growth caused by a deficiency (hyposecretion) of growth hormone during childhood.

Somatostatin

A hypothalamic hormone that inhibits the secretion of growth hormone (GH) and thyroid-stimulating hormone (TSH) from the anterior pituitary.

Human Gut as an Endocrine Organ

The digestive tract's function in producing more than 30 hormone genes and numerous bioactive peptides.

Anatomy of Key Endocrine Organs

The layout of major endocrine glands, including the pineal, hypothalamus, pituitary, thyroid, parathyroids, thymus, adrenals, pancreas, ovaries, and testes.

Comparison of Endocrine and Nervous Pathways

An illustration showing endocrine cells releasing hormones into the bloodstream versus neurons releasing neurotransmitters across synapses.