endocrine

• Endocrine system consists of cells, tissues, and organs collectively called endocrine glands that secrete hormones into the blood for transport to other tissues and organs
• Hormones are chemical messengers secreted by endocrine glands
• Endocrine glands are ductless glands whose secretions diffuse into the blood for distribution
• Negative feedback is a mechanism that returns a condition to its normal state, maintaining homeostasis
• Positive feedback is the amplification of a body's response to a stimulus
• Target cells are cells where functions are affected by a specific hormone
• All body cells are exposed to hormones, but each hormone only produces an action in a target cell
• Hormones are classified into two broad groups: steroids (derived from cholesterol) and non-steroids (derived from amino acids or proteins)
• Hormones work by binding to target cell receptors specific to that hormone
• Pituitary gland, also known as the Hypophysis, regulates many body functions and is controlled by neurons and chemicals from the Hypothalamus
• Anterior lobe of the Pituitary Gland is sometimes called "the master gland" and secretes six hormones
• Hormones of the Anterior Pituitary Gland include Growth Hormone (GH), Thyroid Stimulating Hormone (TSH), Adrenocorticotropic Hormone (ACTH), Gonadotropins (FSH and LH), and Prolactin (PRL)
• Posterior lobe of the Pituitary Gland produces Anti-diuretic hormone (ADH) and Oxytocin
• Thyroid Gland produces Thyroxine (T4), Triiodothyroxine (T3), and Calcitonin
• Parathyroid glands secrete Parathyroid hormone (PTH) which regulates blood calcium levels
• Adrenal Gland consists of the adrenal medulla and adrenal cortex, producing hormones like Epinephrine, Nor-epinephrine, Aldosterone, Cortisol, and Androgen
• Pancreas is both an endocrine and exocrine gland, producing Glucagon and Insulin
• Gonads are sex glands that produce hormones like Estrogen and Progesterone in females, and Testosterone in males
• Other glands include the Pineal Gland that secretes Melatonin and the Thymus Gland that produces Thymosins essential for immunity