The Immune and Endocrine Systems Maintaining homeostasis

The Immune System The immune system protects the body against disease and infection. Something that causes a disease is called a pathogen. Pathogens can include bacteria, viruses, mold, fungi, protozoans, and other parasites.

Antigens = Bad Antigens are molecules that trigger an immune response. They can be pathogens, or they can be things like pollen, dust, or allergens.

Antibodies = Good Antibodies are proteins in our blood that recognize antigens, attach to them, and destroy them.

Innate Immunity We are all born with defenses to protect us from pathogens, which is called innate immunity. The skin and body secretions (mucus, oil, sweat, tears, saliva) are the first line of defense to help keep pathogens out.

Innate Immunity Inflammation is part of innate immunity. This is when your body produces redness, swelling, pain and heat due to increased blood flow to the affected area.

Innate Immunity Next, white blood cells are available to fight infections. White blood cells can kill pathogens (T cells) or eat pathogens (phagocytes) or make more antibodies (B cells) when they find them. Your body also makes special proteins, called interferons, that protect you from viruses.

Acquired Immunity As you get older and are exposed to different bacteria and virus, you build up your acquired immunity. Acquired immunity includes making antibodies to fight antigens, and making special white blood cells called T cells to destroy antigens.

Passive and active immunity Passive immunity happens when you get antibodies from someone else (your mother during nursing, or anti-venom). Active immunity occurs when you are exposed to antigens and make your own antibodies, such as when you are sick or when you get a vaccine.

The Endocrine System The endocrine system is a series of glands that release chemicals into the blood stream. The function of the endocrine system is to control the internal environment of your body.

Glands A gland is any organ that secretes a hormone. Hormones are chemicals that cause change in the body.

Glands you need to know Hypothalamus: the gland in the brain that connects the nervous and endocrine system. Pituitary: main gland of the endocrine system, controls other glands Thyroid: controls growth and metabolism Adrenal: controls our response to stress Ovary and Testes: controls reproductive system

Hormones The part of the body hormones cause to change are called target cells. Hormones bind to receptors, like a lock into a key, on the target cells. Some hormones are made of steroids or lipids, and can easily cross cell membranes. Some hormones are made of amino acids and have to bind to the outside of a cell membrane.

Feedback Your body has loops in place to control homeostasis. If you want to decrease, change, or stop something, a negative feedback loop starts (lower your blood pressure, or raise your body temperature) If you want to increase or continue something, a positive feedback loop is triggered (hormones during labor and delivery)

Diseases and Disorders HIV/AIDS: Human Immunodeficiency virus is the virus that causes acquired immune deficiency syndrome. It causes white blood cells to fall and the immune system to be unable to fight disease. Allergies: a normally harmless substance makes your immune system over-react.

Diseases and Disorders Autoimmune disease: any disease that causes the immune system to attack its own body. Hay fever: pollen, mold, or dander causes runny noses, watery eyes, and sneezing. Hives: an allergen (usually in food or plants) cause the skin to form itchy elevated and swollen patches.

Diseases and Disorders HTLV: human t-cell lymphotropic virus is a cancer of the immune system that is caused by a virus. Goiter: enlargement of the thyroid gland caused by not enough sodium Osteoporosis: bone disease caused by lack of calcium, caused by under functioning of the thyroid gland

Diseases and Disorders Cushing’s syndrome: kidneys secrete too much cortisol causing weight gain, blindness, organ failure Acromegaly: overproduction of growth hormone from the pituitary gland (gigantism)