Overview of the Endocrine System and Hormonal Functions

Hormones

Chemical messengers that are released into the bloodstream to act on an organ in another part of the body.

Target cells

Cells equipped with compatible receptors that are able to respond to hormones.

Blood sugar control

Regulated by insulin, a hormone that helps maintain glucose levels in the blood.

Testosterone

A hormone responsible for the differentiation, growth, and function of male reproductive organs.

Estradiol

A hormone involved in the differentiation, growth, and function of female reproductive organs.

Growth hormone

A hormone that plays a key role in body growth and energy production.

Thyroid hormone

Hormones produced by the thyroid gland that stimulate all cells in the body and control biological processes.

Hormone-receptor complex

The structure formed when a hormone binds to its receptor, which then carries out the hormone's instructions.

Estrogens

A group of hormones responsible for female sexual development, primarily produced by the ovaries.

Androgens

Hormones responsible for male sex characteristics, with testosterone being a primary example.

Thyroxine

One of the main hormones secreted by the thyroid gland that stimulates growth and metabolism.

Triiodothyronine

Another main hormone secreted by the thyroid gland that controls biological processes in the body.

Endocrine system

The system made up of all the body's hormones that regulates biological processes from conception through old age.

Ovaries

Female reproductive glands that produce estrogens and are part of the endocrine system.

Testes

Male reproductive glands that produce testosterone and are part of the endocrine system.

Pituitary gland

A major gland in the endocrine system that regulates various hormonal functions.

Thyroid gland

A gland that secretes hormones like thyroxine and triiodothyronine, controlling growth and metabolism.

Adrenal glands

Glands that produce hormones involved in stress response and metabolism, part of the endocrine system.

TRH

Thyrotropin-Releasing Hormone; stimulates the release of TSH (thyroid-stimulating hormone) and prolactin.

CRH

Corticotropin-Releasing Hormone; stimulates the release of ACTH (adrenocorticotropic hormone).

GnRH

Gonadotropin-Releasing Hormone; stimulates the release of FSH (follicle-stimulating hormone) and LH (luteinizing hormone).

GHRH

Growth Hormone-Releasing Hormone; stimulates the release of GH (growth hormone).

PRH

Prolactin-Releasing Hormone; regulates pituitary gland; links nervous and endocrine systems.

Growth Hormone (GH)

Stimulates other endocrine glands; growth; milk production; reproduction.

Thyroid-Stimulating Hormone (TSH)

Stimulates release of T3 (triiodothyronine) and T4 (thyroxine), which regulate metabolism.

Adrenocorticotropic Hormone (ACTH)

Stimulates release of cortisol, which helps in stress response, metabolism, and inflammation control.

Luteinizing Hormone (LH)

Triggers ovulation/testosterone production.

Follicle-Stimulating Hormone (FSH)

Promotes egg/sperm development.

Antidiuretic Hormone (ADH)

Regulates water balance.

Oxytocin

Involved in uterine contraction and milk ejection.

Thyroxine (T4)

Regulates metabolism.

Triiodothyronine (T3)

Regulates metabolism.

Calcitonin

Lowers blood calcium.

Parathyroid Hormone (PTH)

Increases blood calcium levels.

Cortisol

Involved in stress response.

Aldosterone

Regulates water/salt balance.

Epinephrine (Adrenaline)

Involved in fight-or-flight response.

Norepinephrine

Involved in fight-or-flight response.

Insulin

Lowers blood glucose.

Glucagon

Raises blood glucose.

Somatostatin

Regulates digestion.

Melatonin

Regulates sleep-wake cycle.

Estrogen

Female sexual development; menstrual cycle; pregnancy.

Progesterone

Female sexual development; menstrual cycle; pregnancy.

Thymosin

Maturation of T-cells (immune response).

Negative Feedback

Reverses original stimulus to maintain homeostasis.

Positive Feedback

Amplifies original stimulus to achieve a specific event quickly.