Endocrine System Flashcards

Endocrine System

Overview

• The endocrine system coordinates cell and tissue activities by releasing hormones into the body.

• Endocrine glands differ from exocrine glands:

  • Endocrine glands: create and secrete hormones directly into the bloodstream.

  • Exocrine glands: secrete substances like sweat, saliva, and oil onto a surface (e.g., mouth or skin).

• Endocrine glands regulate body function and homeostasis.

Adrenal Glands

• Located atop the kidneys.

• Secrete epinephrine and norepinephrine.

• Hormones elevate blood pressure, heart rate, and blood sugar.

• Considered stress hormones; secreted during stress or in the sympathetic nervous response.

• Structure:

  • Medulla

  • Adrenal cortex:

    • Zona glomerulosa

    • Zona fasciculata

    • Zona reticularis

Pineal Gland

• Produces melatonin.

• Melatonin regulates the body's wake/sleep cycle, also known as the circadian rhythm.

Pituitary Gland

• Considered the "master gland".

• Secretes growth hormone: regulates growth.

• Secretes prolactin: stimulates milk production.

• Secretes follicle-stimulating hormone: influences production of female egg cells and male sperm cells.

Hypothalamus

• Produces dopamine.

• Dopamine increases blood pressure and heart rate.

• Considered the reward center hormone.

• Example: Release of dopamine during winning a game gives a sensation of excitement.

Ovaries

• Female gonads.

• Create estrogen and progesterone.

• These hormones contribute to female development and bone growth.

Pancreatic Islets

• Parts of the pancreas that create glucagon and insulin.

• Glucagon increases blood sugar levels.

• Insulin decreases blood sugar levels.

• Alpha cells create glucagon.

• Beta cells create insulin.

Testes

• Male gonads.

• Secrete testosterone.

• Testosterone is the primary male hormone, responsible for increasing bone and muscle mass.

Thyroid

• Gland in the neck

• Produces calcitonin, which decreases calcium levels in the bloodstream, preventing weakening of the bones and kidney stones.

Other Hormone-Producing Organs

• Placenta: produces estrogen and progesterone.

• Stomach: produces ghrelin, which stimulates appetite.