UP

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.