ENDO-SYS

Endocrine System Overview

• The endocrine system is a network of glands that secrete hormones regulating various bodily functions.

  • Key functions include metabolism, growth and development, mood regulation, and reproduction.

• Hormones are organic substances released by glands directly into the bloodstream.

Major Glands of the Endocrine System

• Hypothalamus

• Pituitary Gland

• Pineal Gland

• Thyroid

• Parathyroid

• Thymus

• Pancreas

• Ovaries

• Adrenal Glands (in females)

• Kidney

• Uterus

• Testicles

Pituitary Gland

• The pituitary gland, located at the base of the brain, produces hormones that stimulate growth and regulate other glands.

• Function: Receives signals from the hypothalamus that either stimulate or suppress hormone production in the anterior pituitary.

  • Posterior Pituitary: Stores hormones from the hypothalamus and releases them as needed in the bloodstream.

Key Hormones Produced by the Pituitary

• Oxytocin

• Growth Hormone (GH)

• Prolactin (PRL)

• Luteinizing Hormone (LH)

• Follicle Stimulating Hormone (FSH)

• Adrenocorticotropic Hormone (ACTH)

• Antidiuretic Hormone (AH)

• Thyroid Stimulating Hormone (TSH)

Thyroid Gland

• Location: In front of the neck, below the voice box.

• Functions: Produces hormones that regulate metabolism and calcium storage.

Major Hormones of the Thyroid

• Thyroxine (T4)

• Triiodothyronine (T3)

  • Role in controlling metabolic rate and conversion of food to energy.

• Calcitonin: Regulates calcium levels in the blood, promoting storage in bones.

Parathyroid Gland

• Location: On the neck, next to the thyroid gland.

• Function: Regulates calcium levels in the body and normalizes bone growth.

Key Hormone Produced

• Parathyroid Hormone (PTH)

  • Increases calcium absorption in the intestines, releases calcium from bones, and reduces calcium excretion by kidneys.

Thymus Gland

• Location: In front of the heart.

• Functions: Produces hormones for T cell production, crucial for the immune response, primarily active before puberty.

Types of T Cells Produced

• Helper T Cells (CD4+ cells): Coordinate immune response by activating B cells and cytotoxic T cells.

• Cytotoxic T Cells (CD8+ cells): Directly attack infected or cancerous cells.

• Regulatory T Cells (Tregs): Suppress excessive immune responses to prevent autoimmune diseases.

• Memory T Cells: Remember past infections for quicker responses during reinfection.

Key Hormone Produced

• Thymosin: Promotes T cell development.

Adrenal Gland

• Location: On top of the kidneys.

• Function: Produces hormones that affect metabolism, the immune system, blood pressure, and stress response.

Major Hormones of the Adrenal Gland

• Cortisol: Regulates metabolism, reduces inflammation, assists stress response.

• Aldosterone: Manages sodium and potassium levels, controlling blood pressure.

• Adrenaline (Epinephrine) and Noradrenaline (Norepinephrine): Involved in the "fight-or-flight" response.

Pancreas

• Location: Behind the stomach.

• Function: Regulates blood sugar levels through its endocrine function.

Key Hormones Produced

• Insulin: Lowers blood sugar by facilitating glucose uptake into cells.

• Glucagon: Raises blood sugar by signaling the liver to release glucose.

Sexual Hormones

Testosterone

• Source: Leydig cells in the testes and small amounts from adrenal glands.

• Functions: Development of male secondary sexual characteristics, regulation of sperm production, maintenance of libido.

Estrogen

• Source: Ovaries (primarily), placenta during pregnancy, adrenal glands.

• Functions: Development of secondary sexual characteristics, regulation of the menstrual cycle, maintenance of vaginal and uterine health.

Progesterone

• Source: Ovaries (corpus luteum), placenta.

• Functions: Prepares uterine lining for implantation, maintains pregnancy, regulates menstrual cycles.

Pineal Gland

• Location: In the brain.

• Function: Regulates sleep-wake cycles by producing melatonin, synchronizing internal clocks with external light-dark cycles.

Key Hormone Produced

• Melatonin: Influences sleep patterns and may affect mood and reproductive hormones.