Lymphatic System and Immunity Chapter 15- Part I

Maintaining physical health requires continuous combat against harmful agents

Disease producing microbes

Ability to ward off damage or disease

Lack of resistance

Innate (nonspecific) immunity Adaptive (specific) immunity

(nonspecific) immunity: defenses that are present from birth and are always available to protect us against disease. Does not involve specific recognition of a microbe Innate immunity does not have a memory component. Components are the first line of defense (skin and mucous membranes) and the second line of defense (natural killer cells and phagocytes, inflammation, fever, and antimicrobial substances).

(specific) immunity: defenses that involve specific recognition of a microbe. Is based on a specific response to a specific microbe; it adapts or adjusts to handle a single type of invader. Adaptive immunity is slower to respond but it does have a memory component. Adaptive immunity involves lymphocytes called T lymphocytes (T cells) and B lymphocytes (B cells).

Drains excess intersitial fluid and plasma proteinsTransports dietary liipids and vitamins from GI tract to bloodCarries out immune responses

Lymph Lymphatic vessels Structures and organs containing lymphocytes Red bone marrow

Lymphatic capillaries Lymphatic vessels Lymph nodes Lymph trunks and ducts

avascular tissues (such as cartilage, the epidermis, and the cornea of the eye), the central nervous system, portions of the spleen, and red bone marrow

Dietary lipids into lymphatic vessels and ultimately into the blood

The presence of these lipids causes the lymph draining from the small intestine to appear creamy white; such lymph

Lymphatic capillaries are slightly larger in diameter than blood capillaries A unique structure that permits interstitial fluid to flow into, but not out. The ends of endothelial cells that make up the wall of a lymphatic capillary overlap. When pressure is greater in the interstitial fluid than in lymph, the cells separate slightly, and interstitial fluid enters the lymphatic capillary.

Anchoring filaments, with elastic fibers