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197 Cards in this Set
- Front
- Back
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What make up the first line of defense
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skin
mucous membrane |
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What is a layer of tight cells that forms a mechanical barrier?
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epidermis (skin)
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What is the top layer of skin with dead cells that constantly shed?
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stratum corneum
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What are the 2 major layers of skin?
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epidermis
dermis |
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What does the epidermis contain?
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keratin
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What covers the epidermis?
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a layer of dead cells
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What does the dermis contain/
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collagen
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What is the only mos that can penetrate intact skin?
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dermatophytes because they have keratinase
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What is the waterproof part of skin
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keratin
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What is the epidermis
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multiple layers of tightly packed cells
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What happens to the dead cells on the epidermis?
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constantly shed from the surface of the skin
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What is a very effective mechanical barrier to mos
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intact skin
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What type of cells are in the skin
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dendritic cells (Langerhans cells) that are phagocytic and swallow and present mos to antigens
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What is the envt of the skin like?
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dry, salty, low pH (5) and has antimicrobial substances
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What are some antimicrobial substances on teh skin?
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antimicrobial peptides (sweat), Dermicidins (antimicrobial peptides secreted by sweat), lysozyme (digests bacteria peptidoglycan wall), and sebum (keeps skina nd hair moist and has antimicrobial property)
microbiota (like staphylococcus species) |
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What do antimicrobial peptides do
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cause cell lysis
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What are teh 2 layers of mucous membrane
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epithelium and connective tissue
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What is in the epithelium?
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a thin layer of cells that the surface is shed continuously and it has goblet cells which secrete mucus and some have cilia
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Whats the only epithelium with cilia
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trachea
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What is the point of goblet cells
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secrete mucus for mos to be trapped and to keep surface moist
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What does the Connective tissue of mucous membranes do?
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supports the epithelium
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What is a better barrier: epidermis or epithelium
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epidermis
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What are some defense mechanisms of the mucous membranes
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mucus, cilia, secretions to prevent colonization, antimicrobial chemicals, microbiota
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What do cilia do?
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in the trachea, they propel mucus and trapped particles upward
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Where are fatty acids?
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in sweat and earwax
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What is sebum
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unsaturated fatty acid secreted by sebaceous gland
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What is antimicrobial peptides
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dermicidins: in the sweat against G+ G- and fungi
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Where is lysozyme?
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in the tears and saliva
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What is in gastric juice?
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HCl and digestive enzyme
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What is mucin?
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a glycoprotein produced by the digestive system to coat mos and prevent attachment
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What is transferrin
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an iron binding protein on the surface of mucous membranes
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What is lactoferrin
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iron binding protein in milk
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What do normal microbiota do?
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microbial antagonism (compete with pathogens for space and nutrients and secrete antimicrobial substances), stimulate bodys defenses, some intestinal microbiota produce vitamins
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What is an example of a normal microbiota that secretes antimicrobial substances
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lactobacillus in vagina makes lactic acid
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What is blood part of?
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second line of defense
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What does plasma contain?
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water, electrolytes, gas, nutrients, plasma proteins, blood clotting proteins, iron binding proteins, complement proteins
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What help with clotting?
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platelets
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What are leukocytes?
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white blood cells
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What are teh 2 types of leukocytes?
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granulocytes and agranulocytes
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What is noted by the presence of granules in the cytoplasm
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granulocytes
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What are teh 3 granulocytes?
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neutrophils, basophils, eosinophils
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What are known as polymorphonuclearleukocytes?
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Neutrophil (PMN)
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What are neutrophils stainedby
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neutral dye
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What are neutrophils
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highly phagocytic; can leave blood vessels and enter infected tissue; first to arrive at infected area
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What is the abundance of neutrophils?
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60-70%
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What is the most abundant and most important WBC?
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neutrophils
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What arrive at the injured site first?
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neutrophils ecause they are distributed throughout the body
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What is basophil stained by
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basic dye
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What is a basophile
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NOT a phagocyte; release histamine to cause allergic reactions and inflammation
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What leukocyte is involved in allergic reactions
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basophils
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What is the abundance of basophils
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0.5-1%
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What are eosinophils stained by?
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acidic dye
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What are eosinophils?
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they can leave the blood vessels; they release toxic proteins to kill parasites and they are phagocytic to digest Ag-Ab complex
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What is a phagocyte but not a major one but has a special function
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eosinophil
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What is the abundance of eosinophils?
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2-4%
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What are known by a lack of granules in cytoplasmic membrane, with round nuclei?
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agranulocytes
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What are teh 2 agranulocytes?
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lymphocytes and monocytes
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What are lymphocytes
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NOT phagocytes, they're in the blood and lymphatic system and play a key role in immunity
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What are monocytes?
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NOT actively phagocytic, they leave the blood and mature in macrophages which are HIGHLY phagocytic
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What is the abundance of monocytes?
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3-8%
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What is the abundance of lymphocytes?
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20-25%
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What is the mature form of monocytes?
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macrophage
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What are lymph nodes
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filters for bacteria, viruses, etc. and returns lymph to blood
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What is the reticuloendothelial system?
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monocytes and all kinds of macrophages and relatives
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What do reticuloendothelial system cells do?
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attach to endothelial cells
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What are the 2 types of macrophages
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wandering and fixed
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What is a macrophage in teh liver?
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Kupffer cell
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What is a macrophage int eh lung?
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alveolar
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What is a macrophage in the nervous system
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microglial cells
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What is a macrophage in the lymph node?
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dendritic
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What activates macrophages?
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gamma interferon
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What is an activated/angry macrophage
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has a much stronger killing power (has better chance to kill TB)
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What does increased eosinophils mean?
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allergy or parasitic infection
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What does increased neutrophils mean?
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bacterial infection
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What does increased lymphocytes mean?
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viral infection
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What are lymphocytes part of
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cell mediated immunity
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What are the 5 steps of phagocytosis?
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chemotaxis
adherence ingestion digestion elimination |
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What is chemotaxis?
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phagocytes are attracted to the infection site by chemicals called chemotactic factors
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What released chemotactic factors?
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microbes, damaged tissue, WBC, Complement proteins, etc
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What do PMNs and macrophages migrated in response to?
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different chemicals
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What causes adherence for phagocytosis
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electrostatic force
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What can mos use to avoid adherence
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antiphagocytic capsule or M protein
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Who uses antiphagocytic capsule
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streptococcus penumoniae
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What uses M protein
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streptococcus pyogenes
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What can enhance adherence
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opsonins such as Ab and C3b
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What is coating a target mos with opsonins?
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opsonization
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What does opsonins do?
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first attach to mos and phagocytes have a special receptor for them and can swallow them
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What help the phagocyte attach
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opsonins
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What occurs in ingestion in phagocytosis
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The phagocyte extends pseudopodia to engulf the mos and the mos is enclosed in a phagosome (pouch/vaccum)
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What is used for phagocytosis?
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pseudopodia
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what is another name for digestion
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degranulation
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What occurs in digestion
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phagosome detached from cytoplasmic membrane and enters cytoplasm where it fuses with a lysosome and makes a phagolysosome and the mos is destroyed
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What are the contesnts of phagolysosome?
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low pH (3.5-4.0), enzymes (60 different including lysozyme), O2 metabolites (O2, H2O2, nitric acid NO, hydroxy radical OH, superoxide radical O2-, hypochlorite OCL-) generated by resp. burst
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What occurs in elimination
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debris are released
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What can survive phagocytes?
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mycobacterium tuberculosis
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Do PMN and macrophages make the same enzymes
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no
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Whats an example of extracellular killers?
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natural killer cells
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What recognize abnormal cells
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natural killer cells
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What do NK cells do?
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bind to cells, if it's normal, it releases it, if abnormal it kills it
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What is the receptor to protect self for NK
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MHC Class 1
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What is NK cell?
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type of lymphocytes
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What can NK cells kill?
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kill tumor cells and viral infected cells nonspecifically
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How do NK cells work
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recognize and bind to target cell and release lethal protein called perforin to lyse the target cell
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What does NK cells release
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perforin
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What can activate NK cells
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interferon
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What is important for controlling a tumor through surveillance
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natural killer cells
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What is a group of normal serum proteins
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complement
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how many complements are tehre
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20
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What is the only complement not in order
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C4
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What are the 3 outcomes of complement activation
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lysis of foreign cells, microbes, and enveloped viruses
opsonization (C3b is opsonin) inflammation |
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What are the 2 opsonins
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Ab and C3b
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What are the 2 ways to activate complement
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classic pathway and alternative pathway
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What plays a central role in both pathways
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C3
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What does cleavage of C3 into a and b initiate?
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process of forming C5-C9 membrane attack complex (MAC)
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Describe classic pathway
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initiated by Ag-Ab complex--> activates C1 -->activates C2 and C4 to split -->C2aC4b split C3 into-->C3a and C3b
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What initiates classic pathway
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Ag-Ab complex
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What initiates the alternative pathway
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certain substances such as LPA
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Describe alternative pathway
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LPS reacts with factor B, factor D, and properidin-->these combine and form an enzyme to cleave C3 into C3a and C3b
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What occurs with C3b?
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splits C5 into C5a and C5b--> C5b assembles C6, C7, C8, and 16 C9s sequentially on the surface of a target cell to form membrane attack complex
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What is the 1st outcome of MAC?
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lysis of target cell
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what makes up MAC?
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C5, C6, C7, C8, C9n
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What is C3b
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an opsonin to help adherence in phagocytosis
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What does C5a do?
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attracts phagocytes (2nd outcome)
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What do C3a, C4a, and C5a do?
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bind to basophils, mast cells, or platelets and cause these cells to release histamine causing vasodilation which starts inflammation (3rd outcome)
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What do C3a, c4a, and c5a cause?
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degranulation of mast cells, basophils, and platelets
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What is C5a
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a chemotactic factor
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What activates the C. Lectin pathway?
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lectin bound to mannose
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What is the C. lectin pathway?
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MBP binds to nonreduced mannose or fucose or glucosamine on bacterial cell wall or other cell surface and resembles C1q
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What is MBP
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lectin-mannose-binding protein (MBP) is a serum protein produced by the liver
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What does MBP on the bacterial cell wall do
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activate MBP associate serine protease with splits C4 and C2 and has C4b2a (C3 convertase)
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What is C4b2a
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C3 convertase
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How is C' inactivated?
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destroyed rapidly inside host to prevent damage to own cells
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What do regulatory proteins do?
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can present on certain host cell surface and the blood can destroy activated C'
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HOw do some mos evade the C'?
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some have sialic acid in capsule which causes rapid inactivation of C' and prevents MAC formation
some have long LPS to prevent MAC from adhering to cell surface |
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What are proteins released by host cells to prevent spreading of viral infection nonspecifically?
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interferons (IFN)
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What are interferons especially effective against
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RNA viruses
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What do interferons cause?
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malaise, muscle aches, chills, fever
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What are the 3 types of human IFN (interferon)
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Type 1: alpha and beta
Type 2: gamma |
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What IFN are produced after viral infection
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Type 1 (alpha and beta)
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What is alpha interferon
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produced by leukocyte
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What is beta interferon
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produced by a fibroblast
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What is a fibroblast
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undifferentiated cells in connective tissue
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What produced IFN gamma?
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sensitized T cell and NK: when T cell encounter antigen and activate
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What is AVP?
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antiviral proteins
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Can alpha or beta IFN kill virus?
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no
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What are the sources of IFNalpha
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epithelium, leukocytes
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What are the sources of IFN beta?
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fibroblast
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What are the functions of A and B IFN?
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stimulate other cells to make AVP
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Can A and B IFN kill viruses directly?
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no
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What appears later during infection
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Type 2 IFN (gamma)
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What does type 2 IFN do?
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stimulates NK and macrophages to increase killing power
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What is a weak antiviral activity
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Type 2 IFN gamma
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What are host specific
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IFN
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Are IFN viral specific
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no
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Are IFN host specific
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yes
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What are IFN synthesized by?
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recomibinant DNA methods to treat cancer
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What are side effects of interferon?
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nausea, vomiting, fever, etc
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What are iron binding proteins found in blood, milk, saliva, tears?
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transferrin
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What do transferrins do?
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keep iron concentration low in body fluid which makes it unfavorable for microbial growth
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What do antimicrobial peptides do?
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bind to microbial plasma membrane and cause cell lysis
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What produces antimicrobial peptides?
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mucous membranes and phagocytes
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What triggers inflammation?
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tissue damage
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What are the 4 fundamental signs/symptoms of inflammation?
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redness, swelling, heat, pain
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What are teh 3 functions of inflammation
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destroy or remove injurious agent
limit its effect (confine or wall off the injurious agents) repair or replace the damaged tissue |
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What do damaged cells release?
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histamine, leukotrienes, and prostaglandins
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What release histamine after degranulation?
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basophils, mast cells, and platelets
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What do vasodilating chemicals do?
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increase size of blood vessels to increase blood
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What do chemotactic factors do?
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attract phagocytes
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What is vasodilation?
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increased diameter of blood vessels in the area which increased blood flow to injured area and this causes redness and heat
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What are the 4 parts of inflammation
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inflammatory chemicals, response of blood vessels, phagocytic response, tissue repair
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What occurs with blood vessels in inflammation
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increased permeability and vasodilation
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What does increased permeability of blood vessels do?
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allow defense substances (fluid and blood cells move from blood vessels to injured area), results in swelling and pain
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What do prostaglandins and leukotrienes do?
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make vessels more permeable
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What do histamines do?
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causes vasodilation, increasing blood flow to site
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What do macrophages and neutrophils do?
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squeeze through the walls of blood vessels (diapedesis)
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What occurs in phagocyte response?
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phagocytes aggregate at the area of infection
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What do phagocytes do in inflammation response
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move from capillary to tissue (margination and diapedesis) and engulf and destroy microbes and damaged tissue
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What do macrophages release?
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Tumor necrosis factor (TNF) alpha and cause vasodilation and edema
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What does blood clotting do?
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prevent spread of microbes
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What is pus
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consists of dead cells (mos and tissue) abscess
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What occurs in tissue repair of inflammation?
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some tissues (with undifferentiated stem cells) such as skin and mucous membrane repair rapidly
some tissues will repair with scars that may influence normal function (when fibroblasts are involved) Some cannot be repaired |
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In what tissue is damage permanent?
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cardiac muscle and parts of brain
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When is scar impair functioning
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when fibroblasts are involved
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What causes chronic inflammation?
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inflammatory agent persists and causes tissue damage continuously
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What is an example of chronic inflammation?
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arthritis
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What is normal body temp
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37C
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What controls body temp
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hypothalamus
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What occurs with fever
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bacterial endotoxin (lipid A in LPS of G-) can increase macrophages to produced endogenous pyrogen (interleukin-1/ IL-1) and this resets the hypothalamus to a higher temp and increases metabolism which increases temperature
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What does interleukin 1 do?
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reset hypothalamus to a higher temp to increase metabolism and increase temperature
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What is something that causes fever
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pyrogen
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What is from outside
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exogenous
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What is from inside
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produced by self; endogenous
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What causes hypothalsmus to increase body temp
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prostaglandin
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What is high fever
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harmful to host
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What is 43 C
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death
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What is mild fever
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beneficial
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How is mild fever beneficial?
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increases metabolism and increases inflammation and interferon actions and repair; inhibits certain mos (decreases growth rate and inactivates some enzymes and toxins)
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