Chapter 32

Chapter 32 - Chapter 32 Defense Against Diseases: The...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 32 Defense Against Diseases: The Immune System Three lines of defense against microbial attack 1. External barriers (skin, mucous membranes) (to prevent and keep them out) a. Skin i. physical barrier to microbial entry ii. inhospitable environment for growth; dry, dead cells at surface. Sweat/sebaceous gland secreting acids and natural antibiotics like lactic acid b. Mucous membranes of respiratory and digestive tracts well-defined. Secretions have antibacterial enzymes. i. Dirt caught in mucus moved by cilia c. Stomach; if microbes swallowed, acids and protein-digesting enzymes destroy 2. Nonspecific internal defenses a. Phagocytic cells: white blood cells (WBC) in extracellular fluid, amoeboid shape, destroy microbes by phagocytosis. b. Natural killer cells: WBC that destroy body cells infected by viruses and cancerous cells by punching HOLES in them. c. Inflammatory response, caused by large-scale microbial invasion through wound i. Histamine released by damaged cells> increased blood flow “washes” out wound> inflammation (red, swollen, warm) ii. Other chemicals also attract WBCs> macrophages (WBS engulf bacteria, dirt, tissue debris) iii. Blood clotting “walls off” wounded area. Pus is just WBC dying iv. WBC exuded out of capillary walls d. Fever = response to microbes establishing major infection. Low-grade (100-1002 degrees F) fevers beneficial. i.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/18/2008 for the course BIOL 1002 taught by Professor Pomarico during the Spring '08 term at LSU.

Page1 / 5

Chapter 32 - Chapter 32 Defense Against Diseases: The...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online