Endocrine System Overview

Endocrine System Overview

• The endocrine system is made up of different glands that release hormones into the bloodstream.
• These hormones control metabolism, growth, development, and reproduction, as well as mood.

Glands and Their Locations

• Pituitary gland: Located at the base of the brain.
  • Function: Produces hormones that stimulate growth and control other glands.
  • Example hormone: Growth hormone.
• Thyroid gland: Located in the front of the neck, below the voice box.
  • Function: Produces hormones that regulate metabolism and calcium storage in bones.
• Parathyroid glands: Located in the neck.
  • Function: Control calcium levels in the body and normalize bone growth.
• Thymus: Located in front of the heart.
  • Function: Produces hormones that enable the body to produce T cells before puberty.
• Adrenal glands: Located on top of the kidneys.
  • Function: Produces hormones affecting metabolism, immune system, blood pressure, and stress reaction.
• Pancreas: Located behind the stomach.
  • Function: Produces hormones that regulate blood sugar levels.
• Testes (Reproductive): Located in the scrotum.
  • Function: Produce hormones that control sperm maturation and the development of male secondary sexual characteristics.
• Ovaries (Reproductive): Located in the pelvic area.
  • Function: Produce hormones influencing the development of female secondary sexual characteristics, egg maturation, and ovulation.
• Pineal gland: Located in the brain.
  • Function: Produces a hormone that regulates the body's biological clock in some animals.

Hormones

• Hormones are organic substances released by endocrine glands into the bloodstream.
• They change the physiological and metabolic behaviors of target cells to maintain homeostasis.

Pituitary Hormones

• Growth hormone: Stimulates the growth of almost all cells and tissues in the body.
• Follicle-stimulating hormone (FSH): Plays a significant role in reproduction and development.
• Luteinizing hormone (LH): Influences reproduction and sexual development by affecting gonads and other organ systems.
• Prolactin: Promotes breast development and milk secretion.
• Oxytocin: Contracts the uterus during the birthing process.

Hormones Released by the Reproductive System (Testes)

• Androgen: Responsible for the development of secondary sexual characteristics in men.
• Testosterone: Stimulates growth of male sex organs and regulates sex drive (libido).

Hormones Released by the Reproductive System (Ovaries)

• Estrogen: Stimulates female sex organ development and various secondary sexual characteristics.
• Progesterone: Stimulates uterine milk secretion and helps develop the secretory apparatus of the breasts. It also helps prevent uterus muscle contractions that can detach eggs from the uterus.

Puberty

• Male Secondary Characteristics: Growth of facial, underarm, and chest hair; deepening of the voice; development of male musculature and genitals; increased secretion of oil and sweat; and increased muscular strength.
• Female Secondary Characteristics: Growth of underarm and pubic hair; breast development; wider hips and smaller waist; increased secretion of oil and sweat; and menstruation.

Male Reproductive Hormones

• The pituitary gland releases FSH and LH, which stimulate Sertoli cells to nourish sperm in the testes and interstitial cells (Leydig cells) to produce and release testosterone into the testes and the bloodstream.
• Testosterone production is regulated by the brain.

Female Reproductive Hormones

• The pituitary gland secretes FSH and LH, which travel to the ovaries.
• FSH produces estrogen, controlling egg growth and release.
• Progesterone works with estrogen to prepare the uterus for a fertilized egg.
• Production of estrogen and progesterone is regulated by the brain.