The Endocrine System: Glands and Hormones

The Endocrine System

• The endocrine system produces and regulates hormones, which are chemical substances that regulate all biological processes in the body from conception to old age.

Glands and Hormones

• The primary endocrine glands are the pituitary (master gland), pineal, thyroid, parathyroid, adrenals, ovaries (in females), and testes (in males).
• Hormones are chemical transmitters that regulate growth and development, mood, tissue function, metabolism, and sexual function.
• Hormones act slower than nervous impulses but cause longer-lasting effects, and are used to stabilize the body’s internal environment (homeostasis).

Hormone Function

• Hormones are chemical messengers that transfer information and instructions from one set of cells to another.
• Hormones can stimulate or suppress various bodily functions, such as growth, metabolism, and sexual function.

Adrenal Gland and 'Fight or Flight' Response

• The adrenal gland releases adrenaline and norepinephrine in response to perceived danger or threat, triggering the "fight or flight" response.
• This response prepares the body to "fight" or "flee" from harm by constricting blood vessels, increasing breathing and heart rate, and tightening muscles.

Pancreas and Glucagon/Insulin

• The pancreas produces the hormone glucagon, which converts glycogen back to glucose in the liver.
• The pancreas also produces the hormone insulin, which controls the conversion of blood glucose to glycogen, stored in the liver.

Reproductive Organs and Homeostasis

• The endocrine system and nervous system work together to maintain homeostasis, with the hypothalamus as the primary link between the two systems.
• The hypothalamus produces chemicals that either stimulate or suppress hormone secretions of the pituitary gland.

Hormone Communication

• Hormones follow a complex path to reach their target, involving releasing hormones, stimulating hormones, and endocrine glands or organs.

Main Glands and Hormones

• Hypothalamus: produces releasing hormones that stimulate or suppress hormone secretions of the pituitary gland.
• Pituitary Gland: often referred to as the "master gland" due to its control over other endocrine glands.
• Pineal Gland: produces melatonin, which regulates sleep patterns.
• Thyroid: produces thyroxine, which regulates the rate of metabolism.
• Parathyroid Gland: produces parathyroid hormone, which helps maintain the right balance of calcium in the bloodstream.