Hypothalamus & Pituitary Gland Functions

These flashcards cover essential vocabulary and concepts related to the hypothalamus and pituitary gland, their functions, hormones, mechanisms of action, and regulation in the endocrine system.

Hypothalamus

A brain region controlling the pituitary gland and maintaining homeostasis.

Pituitary gland

Known as the 'master gland,' it produces hormones that regulate various bodily functions.

Growth hormone (GH)

A hormone produced by the anterior pituitary that regulates growth and metabolism.

Gigantism

A condition causing excessive growth due to hypersecretion of GH in children.

Acromegaly

A condition resulting from excess GH in adults, leading to enlarged hands, feet, and face.

Pituitary dwarfism

A condition in children due to hyposecretion of GH, resulting in shorter stature.

Growth hormone-releasing hormone (GHRH)

A hypothalamic hormone that stimulates the release of GH.

Growth hormone-inhibiting hormone (GHIH)

A hypothalamic hormone that inhibits GH release.

Insulin-like growth factors (IGFs)

Hormones triggered by GH that stimulate cell division and bone matrix deposition.

Tropic hormones

Hormones that regulate the secretion of other hormones.

Non-tropic hormones

Hormones, like GH and PRL, that directly affect target organs.

Diabetes insipidus

A condition characterized by excessive thirst and urination due to ADH deficiency.

Antidiuretic hormone (ADH)

A hormone that promotes water reabsorption in the kidneys to reduce urine production.

Oxytocin

A hormone that stimulates uterine contractions and milk ejection during lactation.

Positive feedback mechanisms

Processes that enhance or amplify changes; oxytocin release during childbirth is an example.

Neurohypophysis

Another name for the posterior lobe of the pituitary gland.

Adenohypophysis

Another name for the anterior lobe of the pituitary gland.

Infundibulum

The stalk that connects the hypothalamus to the pituitary gland.

Cyclic AMP (cAMP) signaling

A second messenger system used by water-soluble hormones to activate target cells.

Vasopressin

Another name for ADH, as it can cause blood vessel constriction.

Hormonal stimuli

Hormones that trigger other endocrine glands to release their hormones.

Humoral stimuli

Changes in blood levels of ions and nutrients that stimulate hormone release.

Neural stimuli

Nerve fibers that stimulate hormone release from endocrine glands.

Half-life of hormones

The time required for the level of a hormone in the blood to decrease by half.

Water-soluble hormones

Hormones that cannot enter cells and act via membrane-bound receptors.

Lipid-soluble hormones

Hormones that can diffuse across the cell membrane to bind to internal receptors.

G protein pathways

Signaling pathways that are activated by hormones binding to G protein-coupled receptors.

Releasing hormones

Hormones secreted by the hypothalamus to control pituitary function.

Inhibiting hormones

Hormones secreted by the hypothalamus to stop the secretion of pituitary hormones.

Homeostasis

The physiological state of equilibrium or balance within the body.

Negative feedback system

A mechanism for maintaining hormone levels by decreasing secretion when effects are achieved.

Endocrine glands

Glands that secrete hormones directly into the bloodstream.

Anterior lobe hormones

Hormones produced in the anterior pituitary, including GH, TSH, ACTH, FSH, and LH.

Posterior lobe hormones

Hormones produced in the hypothalamus and secreted by the posterior pituitary, including ADH and oxytocin.

Neuroendocrine structure

A structure that integrates the nervous and endocrine systems.

Target organs of GH

Major targets include bone, cartilage, muscle, and liver.

Secretion

The process of producing and releasing hormones into the bloodstream.

Physiological effect

The response of target organs or cells to hormone signaling.

Amplification effect

An increase in signaling strength due to pathways like second messengers.

Amino acid-based hormones

Hormones made up of amino acids, such as insulin and adrenaline.

Steroid hormones

Hormones derived from cholesterol, including testosterone and cortisol.

Receptors

Proteins on or in cells that bind hormones and trigger responses.

Gene activation

The process by which hormones stimulate the synthesis of proteins by inducing gene expression.

Glycogenolysis

The breakdown of glycogen to glucose triggered by growth hormone.

Neurons

Cells in the nervous system that transmit signals and release neurohormones.

Portal system

A system of blood vessels that connect two capillary beds, as in the hypothalamic-hypophyseal portal system.

Plasma proteins

Proteins found in blood plasma that transport hormones.

Cellular uptake

The process by which cells absorb nutrients and hormones from the bloodstream.

Feedback inhibition

A process in which the product of a pathway inhibits an earlier step in the pathway.

Hormone secretion regulation

The mechanisms governing the release of hormones from glands.

Hydration status

The amount of water in the body, regulated by ADH.