Chapter 16: Innate Flashcards
The ability to ward off disease through body defenses
Immunity
Lack of immunity is called what
Susceptibility
First Line of Defense: Skin and Mucous Membranes
-the body’s first line of defense against infections is a physical barrier and the nonspecific chemicals of the skin and mucous membranes
First Line of Defense: Physical Factors
- the structure of intact skin and the waterproof protein keratin provide resistance to microbial invasion
- the lacrimal apparatus protects the eyes from irritating substances and microorganisms
- saliva washes microorganisms from teeth and gums
- mucus traps many microorganisms that enter the respiratory and gastrointestinal tracts, in the lower respiratory tract, the ciliary escalator moves mucus up and out
- the flow of urine moves microorganisms out of the urinary tract, and vaginal secretions move microorganisms out of the vagina
First Line of Defense: Chemical Factors
- fatty acids in sebum and earwax inhibit the growth of pathogenic bacteria
- perspiration washes microorganisms off the skin
- lysozyme is found in tears, saliva, nasal secretions, and perspiration
- the high acidity (pH 1.2-3.0) of gastric juice prevents microbial growth in the stomach
Normal Microbioata and Innate Immunity:
-normal microbiota change the environment, a process that can prevent the growth of pathogens
Second Line of Defense:
-a microbe’s penetration of the first line of defense encourages production of phagocytes, inflammation, and antimicrobial substances
Formed Elements in the Blood:
- blood consists of plasma (fluid) and formed elements (cells and platelets)
- leukocytes (white blood cells) are divided into granulocytes (neurotrophils, basophils, eosinophils) and agranulocytes
The Lymphatic System:
- the lymphatic system consists of lymph vessels, lymph nodes, and lymphoid tissue
- interstitial fluid is returned to the blood plasma via lymph vessels
Phagocytes:
- phagocytosis is the ingestion of microorganisms or particular matter by a cell
- phagocytosis is performed by phagocytes, certain types of white blood cells, or their derivatives
Actions of Phagocytes:
- enlarged monocytes become wandering macrophages and fixed macrophages
- fixed macrophages are located in selected tissues and are part of the mononuclear phagocytic system
- granulocytes, especially neutrophils, predominate during the early stages of infection, whereas monocytes predominante as the infection subsides
Mechanism of Phagocytosis:
- chemotaxis is the process by which phagocytes are attracted to microorganisms
- toll-like receptors on a phagocyte adhere to the microbial cells…adherence may be facilitated by opsonization=coating the microbe with serum proteins
- pseudopods of phagocytes engulf the microorganism and enclose it in a phagosome to complete ingestion
- many phagocytized microorganisms are killed by lysosomal enzymes and oxidizing agents
Mechanisms of Phagocytosis: Inflammation
- inflammation is a bodily response to cell damage; it is characterized by redness, pain, heat, swelling, and sometimes the loss of function
- TNF-a stimulates production of acute-phase proteins
Mechanisms of Phagocytosis: Inflammation: Vasodilation and Increased Permeability of Blood Vessels
- the release of histamine, kinins, and prostalglandins causes vasodialation and increased permeability of blood vessels
- blood clots form around an abscess to prevent dissemination of the infection
Mechanisms of Phagocytosis: Inflammation: Phagocyte Migration and Phagocytosis
-phagocytes have the ability to stick to the lining of the blood vessels (margination) and also have the ability to squeeze through blood vessels (diapedesis)
Mechanisms of Phagocytosis: Inflammation: Phagocyte Migration and Phagocytosis
- phagocytes have the ability to stick to the lining of the blood vessels (margination) and also have the ability to squeeze through blood vessels (diapedesis)
- pus is the accumulation of damaged tissue and dead microbes, granulocytes, and macrophages
