Nonspecific Host Defense Mechanisms Flashcards
True False: Skin is a physical barrier.
true
Keratin in cells makes them tough, fatty acid make acidic environment, and cells are frequently shed
Epidermis
Portal of entry for opportunistic pathogens
Broken skin
Cells make a moist sticky muscous to trap organisms
Mucous membranes
Tightly packed cells lining UG tract, blood vessels and certain other tissues to create barrier against invaders
Endothelia
Name 6 mechanical defenses
- Shedding skin
- Mucociliary elevator
- Peristalsis
- Urination
- Tears
- Eyelashes/lids
Resident microbiota of the skin, URT, GI tract, and GU tract
Microbiome
Compete with _____ for cellular binding sites and available ______.
Pathogens, nutrients
Provides oil barrier protecting hair follicle pores from pathogens
Sebum
From sebum and skin microbiota _________ lowers the pH to inhibit pathogens.
Oleic acid
Kills bacteria by attacking cell wall, located in secretions (tears)
Lysozyme
Located in the stomach, urine, and vagina _______ kills or inhibits bacteria
Acid
Located in the GI tract, _________ enzymes and ______ kill bacteria
Digestive, bile
Bind and sequester iron to inhibit bacterial growth
Lactoferrin and Transferrin
Located in the lungs, ________ kills bacteria
Surfactant
What does opsonization refer to?
The coating of a pathogen by a chemical substance (opsonin) that allows phagocytic cells to recognize, engulf, and destroy it more easily.
What are two additional important opsonins?
- Mannose-binding proteins
- Antibodies
What do anaphylatoxins activate?
Mast cells, causing degranulation and the release of inflammatory chemical signals.
What are the effects of the inflammatory chemical signals released by mast cells?
- Vasodilation
- Increased vascular permeability
What plasma protein mediator results in opsonization of pathogens to aid in phagocytosis?
Complements C3b and C4b
Includes C-reactive protein, serum amyloid A, ferritin, fibrinogen, transferrin, and mannose-binding lectin
Acute-phase proteins
Acute-phase proteins are a class of proteins whose plasma concentrations increase or decrease in response to inflammation.
What is one function of acute-phase proteins?
Inhibit the growth of bacteria and assist in the trapping and killing of bacteria
This function is crucial for the body’s immune response during infection.
Which complement proteins do acute-phase proteins complement?
C3b and C4b
These complements play a role in the immune response, particularly in opsonization.
What is opsonization?
Opsonization is the process by which pathogens are marked for ingestion and destruction by phagocytes.
Which complement protein is a chemoattractant for phagocytes?
Complement C5a
C5a helps recruit phagocytes to sites of infection or inflammation.
True or False: Complement C3a and C5a are proinflammatory anaphylatoxins.
True
Anaphylatoxins are small peptide fragments that promote inflammation.
Fill in the blank: Acute-phase proteins aid in the _______ of pathogens.
phagocytosis
Phagocytosis is the process by which cells engulf and digest pathogens.
What do interleukins do?
Stimulate and modulate most functions of the immune system
Interleukins are a group of cytokines that play a significant role in communication between cells in the immune system.
What is the role of chemokines?
Recruit WBCs to infected area
Chemokines are a subset of cytokines with functions related to the migration of white blood cells.
What do interferons alert cells to?
Viral infection
Interferons are proteins produced by cells in response to viral infections and are critical for the immune response.
What do interferons induce in virus-infected cells?
Apoptosis
Apoptosis is a form of programmed cell death that helps eliminate virus-infected cells.
What do interferons induce in nearby infected cells?
Antiviral defenses
This helps to protect neighboring cells from being infected by the virus.
What do interferons stimulate immune cells to do?
Attack virus-infected cells
This activation of immune cells is crucial for controlling viral infections.
Promotes vasodilation, bronchoconstriction, smooth muscle contraction, increased secretion and muscle production
Histamine
Promote inflammation, stronger and longer lasting than histamine
Leuktrienes
Promote inflammation and fever
Prostaglandins
Increases vasodilation and vascular permeability leading to edema
Bradykinin
Found in large numbers in the bloodstream and they primarily fight bacterial infections
Neutrophils
Target parasitic infections, involved in allergic reactions, and release histamine and other proinflammatory compounds from their granules
Eosinophils
Involved in allergic reactions, release histamine and other proinflammatory compounds from their granules
Basophils
Found in tissue outside the bloodstream, function similar to basophils
Mast cells
Large WBC, leave bloodstream and take up residence in tissue where they become tissue-specific macrophages and dendritic cells
monocytes
3 types: B cells, T cells, and NK cells
Lymphocytes
______ make antibodies that bind to pathogens to enable their destruction.
B cells
Cytotoxic ________ and ________ are able to kill cells of the body that are infected
T cells, NK cells
_______ curicial to immune response because they possess a unique “memory” system
T cells
Special form of endocytosis, engulf targets, performed by neutrophils, macrophages, and dendritic cells
Phagocytosis
5 observable signs of inflammation
- Erythema (redness)
- Edema (swelling)
- Heat
- Pain
- Altered function
Occurs when inflammatory response is unsuccessful, can result in formation of granulomas and scarring
Chronic inflammation
Vasodilation and increase blood vessel permeability
Vascular changes
Chemoattractant molecules stimulate WBC to exit blood vessel and migrate to injured tissue ______ undergo margination and diapedesis to exit blood vessels
Leukocyte recruitment
Fever is regulated and maintained by the _______ assisted by the chemical ________.
Hypothalamus, Pyrogens
Fever approacing _______ is life threating if not treated and ______ is fatal
105 F, 109 F
