Endocrine System Flashcards

Flashcards covering key vocabulary from the Endocrine System lecture notes.

Hormones

Mediator molecules that have effects on cells in the local area, or more distant part of the body.

Autocrine hormones

Secreted and bind to the same cell.

Paracrine hormones

Secreted into interstitial fluid and act on nearby cells.

Endocrine Hormones

Secreted into interstitial fluid and then absorbed into the bloodstream to be carried systemically to any cell that displays the appropriate type of receptor.

Lipid soluble hormones

Bind to receptors in the cytoplasm or nucleus of the cell.

Water soluble hormones

Bind to receptors on the surface of the cell.

Steroid hormones

Derived from cholesterol.

Thyroid hormones

Synthesized by attaching iodine to the amino acid tyrosine.

Nitric oxide (NO)

A gas that is both a hormone and a neurotransmitter; its synthesis is catalyzed by the enzyme nitric oxide synthase.

Eicosanoids

A group of local hormones derived from the arachidonic acid on our cell membranes.

Prostaglandins and Leukotrienes

Two major types of eicosanoids that both play a role in mediating the inflammatory response.

Cyclic AMP (cAMP)

A common second messenger produced inside the cell after a water-soluble hormone binds to its receptor.

Endocrine glands

Glands that secrete endocrine hormones into the bloodstream.

Negative feedback system

Hormone output reverses a particular stimulus.

Positive feedback system

Hormone output reinforces and encourages the stimulus.

Hypothalamus

The major link between the nervous and endocrine systems.

Pituitary gland (hypophysis)

Controlled mainly by the hypothalamus and consists of the anterior adenohypophysis and posterior neurohypophysis.

Adenohypophysis

The anterior pituitary, connected to the hypothalamus by the hypophyseal portal system.

Neurohypophysis

The posterior pituitary, releases hormones produced in neurosecretory hypothalamus cells.

Oxytocin

Causes uterine contractions and “milk letdown”.

ADH

Minimizes water loss in kidney and sweat glands, and constricts arterioles.

Thyroid gland

Inferior to the larynx and anterior to the trachea, composed of thyroid follicles that store a 100-day supply of its two hormones in TGB (for thyroglobulin).

TGB (thyroglobulin)

Made from the oxidation and iodination of the amino acid tyrosine and releases the hormones thyroxine (T4) and triiodothyronine (T3).

Thyroxine (T4)

Also known as tetraiodothyronine and is one of the two hormones released from TGB.

Triiodothyronine (T3)

One of the two hormones released from TGB.

Goiter

An enlargement of the thyroid gland associated with hyperthyroidism, hypothyroidism, or euthyroidism.

Tropic hormones

Secreted by the anterior pituitary, target other endocrine glands (all anterior pituitary hormones except hGH, Prolactin, and MSH, which directly target the end organs).