34.2 Glands of the Endocrine System Glands of the endocrine system Endocrine system disorders Control of the endocrine system Feedback inhibition
Functions of the Major Glands Pituitary • Located: Base of the brain • Function: The pituitary gland releases hormones that directly regulate bodily functions or control other glands • Hormones: GH Growth Hormone, stimulates protein synthesis and growth in cells
Hypothalamus • Hypothalamus • Location: above the pituitary gland in the brain. • Function: To act as the link between the nervous and endocrine systems. Controls the secretions of the pituitary gland. • Hormone: Releasing Hormones, ADH, and Oxytocin.
Adrenal Gland • Adrenal Gland • Location: on top of each kidney • Function: Helps the body prepare for and deal with stress • Hormones: Aldosterone: regulates blood volume and pressure ( a corticosteroid) • Epinephrine, released when the body goes into “fight or flight”
The Pancreas • Location: Above the small intestine • Function: An exocrine gland and an endocrine gland. • Hormones: Insulin, which stimulates cells ( in the liver, muscles, and fat cells) to pull glucose out of the bloodstream and store it. • Glucagon, stimulates liver and muscles to release glucose into the bloodstream
Thyroid and Parathyroid • Location: The Thyroid is at the base of the neck, the parathyroid is four small bodies on the side of the thyroid gland. • Function: These glands regulate the body’s metabolism • Hormones:Thyroxine, increases metabolism. Calcitonin, reduces calcium levels in the blood, parathyroid hormone is its opposite and increases calcium levels in the blood.
Reproductive Glands • Ovaries and Testes • Function: Produce gametes (eggs and sperm) and secrete sex hormones. • Hormones: Ovaries produce estrogen, while testes produce testosterone.
Malfunction of the Pituitary Gland • If the pituitary gland releases too much growth hormone (GH) then the body can grow too quickly during childhood resulting in gigantism. • If the pituitary gland releases too little GH, which then results in a condition called dwarfism.
Diabetes Mellitus • Diabetes comes in two types. • Type I diabetes occurs when the body’s immune system attacks the cells that make insulin in the pancreas (beta cells) so no insulin can be released. • Type II diabetes occurs later in life (40+) and occurs when either not enough insulin is produced or cells stop responding to insulin.
Feedback Inhibition • The levels of hormones in the body are controlled by feedback inhibition. This is one way our bodies maintain homeostasis. • Feedback inhibition is when a stimulus is opposed by a response. There are several examples: water level, glucose, and calcium levels just to name a few.