Chapter 12 Review Flashcards
Two major types of structures in lymphatic system
Lymphatic vessels (lymphatics) Lymphatic tissues/organs
What is lymph?
Excessive tissue fluid leaked out at capillaries, picked up by lymphatics, cleansed by lymph nodes, and transported back to heart via successively larger lymphatics
Function: lymph nodes
Cleanse lymph, preparing it for reentry to the blood
Function: tonsils
Trap and remove any bacteria or any foreign particles entering the throat
Function: thymus
Produce hormones (thymosin and others) that function in the programming of certain lymphocytes so that they can carry out their protective roles in the body
Function: Peyer’s patches
Their macrophages (very prevalent in small intestine) capture and destroy bacteria, thereby preventing them from penetrating the intestinal wall
Function(s): spleen
- Filters bacteria, viruses, and other debris from blood
- Destroys worn out RBCs and returns some of their breakdown products to the liver
- Stores platelets and acts as blood reservoir
First Line of Defense (Innate, nonspecific, defense mechanisms)
- Skin
- Mucous membranes
- Secretions of skin and mucous membranes
Second Line of Defense (Innate, nonspecific, defense mechanisms)
- Phagocytic cells
- Antimicrobial proteins
- The inflammatory response
- Natural Killer Cells
Third Line of Defense (Adaptive, specific, defense mechanisms)
- Lymphocytes
- Antibodies
- Macrophages
Protective function: Skin
- Keratinized epidermis provides barrier to most foreign microorganisms
- Acid mantle
- Everything from BIO 121
Protective function(s): Mucous membranes
- Line all body cavities exposed to exterior, trapping most particles that try to enter
- Mucous-covered hairs in nose also trap invading particles
- Mucous-covered cilia in respiratory tract sweeps substances AWAY from lungs
Protective function(s): Skin and mucous membrane secretions
- pH trammels bacterial growth; sebum has chemicals that are toxic to bacteria
- Stomach secretes hydrochloric acid and protein-digesting enzymes that work to kill pathogens
- Saliva and lacrimal fluid contain lysozyme (kills bacteria)
Function: Phagocytes
Engulfs foreign particle, enclosing it in a vacuole. It then fuses with enzymatic contents of lysosome, and the particle’s contents are broken or digested
Function(s): Natural Killer Cells
- Lyse and kill cancer cells and virus-infected body cells (recognizes sugars on cell’s membrane, and also lack of “self” cell surface molecules)
- Not phagocytic; releases PERFORINS through cell’s membrane, quickly causing the cell’s interior to disintegrate
Four signs of inflammation
- Heat
- Swelling
- Pain
- Redness
Inflammatory cells released at site of injured tissue/cells
- Histamine
- Kinins
Inflammation process: what causes redness and heat?
Dilation of blood vessels causes increased blood flow to area
Inflammation process: what causes swelling and pain?
Plasma leaks from blood into tissue space
Inflammation process (4)
1) Chemical “alarm” is sounded at injured site, releasing histamine and kinins
2) Prevents spreading of damaging agents to nearby tissues with diapedesis (neutrophils being squeezed through capillary walls) beginning
3) Disposes of cell debris and pathogens (with help of neutrophils and monocytes (eventually turning to insatiable macrophages))
4) Sets stage for repair: Clotting proteins (fibrin) begin to wall off area, initiating tissue repair. Heat helps speed up metabolic rate.
Function(s): Complement
- Group of plasma proteins that lyses microorganisms, enhances phagocytosis by opsonization, and intensifies inflammatory response
- MAC attacks
Function(s): Interferons
- Mobilize immune system
- Proteins released by virus-infected cells that prevent spread of virus
Function(s): Urine
- pH inhibits bacterial growth
- Cleanses lower urinary tract as it flushes from body
What is fever?
Systemic response triggered by pyrogens