Endocrine System

Structures of the Endocrine System Composed of glands that secrete hormones. Hormones = chemical messengers that regulate the activity of other cells. Glands: Pituitary gland Thyroid Parathyroid Adrenal glands Pancreas Ovaries, testes

Functions Influences growth, development, metabolism. Helps maintain homeostasis.

Our defense against disease The Lymphatic System: Our defense against disease

Lymphatic System Structures: white blood cells, thymus, spleen, lymph nodes and vessels Function: Protect against disease.

Important Terms Immunity: Resistance to pathogens or their toxins. Pathogens: Agents that cause disease (Ex: Bacteria, Viruses, Fungi, Protozoans).

Sources of Immunity Skin/ mucus membranes keep foreign particles from entering the body. White blood cells Engulf and destroy foreign particles Produce antibodies (which attack specific pathogens) Vaccines: weakened form of a pathogen that causes immunity.

How the Body Fights Infection Fever: Bacteria and viruses cannot replicate as fast in higher temperatures. Inflammation: Infected area is walled off to prevent spread of infection. Some white blood cells phagocytize (eat) pathogens. T-cells kill infected cells and prevent pathogens from replicating. Also stimulate growth of B-cells. B-cells produce antibodies

Immune System Disorders Allergies: Overreaction of the immune system to something in the environment. Cells produce histamine, chemicals that cause the symptoms of allergies. Autoimmune disease: Immune system attacks the body’s own cells. Ex: Rheumatoid arthritis is caused by destruction of joints by immune system. AIDS: Caused by HIV, destroys T-cells

Did you know…More than 90% of people claim to wash their hands but only about 60% actually do and only about 16% do it correctly.

The Integumentary System

Organs Hair Skin Nails Sweat glands Oil glands

Skin Functions Protection barrier against infection, injury, UV radiation Maintain constant body temperature Sweat When hot, blood flow increases When cold, blood flow decreases

Hair Functions On head helps keep head cool/warm Protects from the sun On body sensation

Keep skin and hair soft, inhibits growth of bacteria/fungi Function of Oil Glands Keep skin and hair soft, inhibits growth of bacteria/fungi

Layers of the Skin Epidermis: top layer, made of dead cells. Has cells that make melanin (gives skin color) Dermis: thickest layer of skin. Contains glands, hair follicles, nerves, and blood vessels