Chap013_-endocrine_system

Endocrine System

A system composed of cells and organs that synthesize and secrete hormones into the bloodstream to act at distant target cells.

Hypothalamus

The control center of the endocrine system, regulating hunger, thirst, sleep, wakefulness, and involuntary mechanisms.

Thyroid Glands

Glands that regulate energy and metabolism in the body.

Pancreas

aids in digestion and produces insulin to control blood sugar levels.

Ovaries

Female reproductive organs that influence blood circulation, mental vigor, and sex drive.

Pituitary Gland

The gland that controls all other endocrine glands and influences growth, metabolism, and regeneration.

Parathyroid

Glands that secrete hormones necessary for calcium absorption.

Thymus

An organ that helps build resistance to disease.

Adrenal Glands

Glands that secrete compounds like cortisol and adrenaline, regulating metabolic processes and reactions to emergencies.

Hormones

chemical messengers that affect target cells anatomically distant from the secreting cell.

G-Protein-Linked Receptors

Receptors utilized by most endocrine hormones to affect their targets through second messengers.

cAMP

A second messenger produced by G-Protein-Linked Receptors that activates protein kinase A.

Amplification of Hormone Activity

The process where small amounts of hormones lead to increasingly larger reactions.

Steroid Hormones

Hormones that diffuse easily through cell membranes and change gene expression by binding to intracellular receptors.

Downregulation

The process of decreasing the total number of receptor sites in cells, reducing responsiveness.

Upregulation

The gradual increase in the number of receptor sites in response to increased hormone levels.

Negative Feedback

A process that keeps hormone levels balanced by stopping more hormones from being released.

Triiodothyronine (T3)

A hormone produced by the thyroid that regulates metabolism and is involved in negative feedback systems.

Goiter

An abnormal enlargement of the thyroid gland that can be caused by various factors, including iodine deficiency.

Adrenocorticotropic Hormone (ACTH)

A hormone that stimulates the adrenal cortex to release steroid hormones

Cortisol

known as the stress hormone

Aldosterone

hormone that increases Na+ absorption and K+ excretion to regulate blood pressure.

Diabetes Insipidus

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

Insulin

lowers blood glucose levels by facilitating uptake into cells.

Glucagon

raises blood glucose levels by promoting glycogen breakdown in the liver.

Type 1 Diabetes Mellitus

An autoimmune disease characterized by absolute insulin deficiency, usually diagnosed in childhood.

Type 2 Diabetes Mellitus

A condition where insulin is present but cells are insensitive to it, often associated with obesity.

Hyperglycemia

Elevated blood glucose levels often associated with diabetes.

Metabolism

The sum of all chemical processes that occur within a living organism to maintain life.

Thyroid Hormone's Effects

Includes increased metabolic rate, calorogenic effect, growth, and responsiveness of the cardiovascular and nervous systems.

Melatonin

A hormone produced by the pineal gland that regulates circadian rhythms and sleep-wake cycles.