Exam 4: Innate immunology Flashcards
Immunology
The study of the body’s natural defense against disease
Immunity
Ability of host to resist a particular disease or infection
Antigen
Foreign substance that induces an immune response in the body
Hematopoiesis
Development of white blood cells in bone marrow of mammals
Phagocytosis
the process of engulfing a solid particle
Pyrogen
a substance, typically produced by a bacterium, that produces fever when introduced or released into the blood
Lysozyme
an enzyme that catalyzes the destruction of the cell walls of certain bacteria
Lactoferrin
A secretion with bactericidal and iron-binding properties
Mast cells
Specialized tissue cells that trigger local inflammatory responses
Basophils
White blood cell that functions in inflammatory events and allergies
Eosinophils
White blood cells that are active in worm and fungal infections, allergy, and inflammation
Neutrophils
Blood phagocytes, very effective at chemotaxis, and engulfing and killing bacteria
Mast cells
Blood phagocytes that rapidly leave the circulation and mature into macrophages and dendritic cells
Macrophages
Large phagocyte that specializes in ingesting and killing foreign cells and critical to specific immune responses
Dendritic cells
Heterogeneous population of cells that reside throughout the tissues and are responsible for processing antigen and presenting it to lymphocytes
Describe the physical and mechanical barriers to infection
skin
mucous membranes
respiratory system
lacrimal apparatus
antimicrobial peptides
Gi tract
Genitourinary Tract
role of normal microbiota
Skin
-physical barrier to invasion
Two layers
-Epidermis: tightly packed layers of dead skin cells, shedding stop pathogens
Epidermal dendritic cells phagocytize pathogens
-Dermis: collagen fibers help skin resist abrasions that could allow entry of pathogens
~Skin Chemicals:
-Perspiration by sweat glands: salt inhibits growth, lysozyme destroys bacterial cell walls, other antimicrobial peptides
-Sebum: helps keep skin pliable and less easy to break, lowers pH to inhibitory level
Mucous Membranes
Line all body cavities open to the environment, creates protective covering, bathed in antimicrobial secretions
Two layers
-Epithelium: thin outer covering of living, tightly packed cells preventing entry of pathogens. Constant shedding carries away microorganisms
-Deeper layer that supports the epithelium
Respiratory System
Air flow deposits microbes onto mucosal surfaces
Mucociliary blanket: mucous secretions that trap microbes
Once trapped, microbes are transported away from lungs through coughing, sneezing, and washing into the stomach (mucociliary escalator)
Alveolar macrophages: phagocytic cells in alveoli of lungs
Lacrimal Apparatus
eyeball
Produces and drains tears
Blinking spreads tears, washing the surface of the eye.
Lysozyme in tears kills bacteria
Antimicrobial peptides
Present in skin, mucous membranes; act against a variety of microbes
GI tract
Gastric acid in stomach
Intestines contain pancreatic enzymes, bile, intestinal enzymes, GALT, peristalsis, shedding of columnar epithelial cells, secretory IgA, normal microbiota, paneth cells
Genitourinary Tract
Flushing with urine and mucous
Distance barrier of male urethra
Unfavorable environment (low pH of urine/vagina, toxicity of urine, hypertonic kidney medulla, normal microbiota)
Role of Normal Microbiota
Normal microbiota compete with potential pathogens for nutrients
Help stimulate the bodies second line of defense
Promote overall health by giving vitamins to host
List and describe protective chemicals in the body
Lysozyme: hydrolyzes bond connecting sugars in peptidoglycan
Lactoferrin: secreted by activated macrophages and PMNs- sequesters iron from plasma
Lactoperoxidase: produced superoxide radicals
perspiration: changes the salt concentration on the skin making it hard for microbes to survive
sebum (oil) that also resists tears by providing moisture and lowers the skin pH making life hard
tears: (tie into lysozymes)
gastric acid and other stomach enzymes
List the cells of the innate response and describe their specific roles
basophils: white blood cells that functions in inflammatory events and allergies
-non-phagocytic cells found in the blood (where they travel to inflamed tissues) where they regulate inflammation through the release of vasoactive mediators(such as histamine, prostaglandins, serotonin, and leukotrienes from granules)
-also play a role in allergic response and the development of allergies and hypersensitivities
eosinophils: are phagocytic (in a secondary way) cells that are found in the blood and rapidly traffic to inflamed tissue. MAY play a role in allergic reactions. they defend against protozoan and helminth parasites by…
-being eukaryotic receptors on antibodies
-recognizing Fc receptors on antibodies
-releasing cationic proteins and reactivating oxygen metabolites
neutrophils: circulate in blood tissues then migrate to sites of tissue damage. they are HIGHLY phagocytic and kill ingested microbes with lytic enzymes and reactive oxygen metabolites contained in primary and secondary granules
dendritic cells: are a heterogeneous group of cells with neuron-like appendages, they are present in small numbers in blood, skin, and mucus membranes of the noses/lungs/intestines. they also…
express pattern recognition receptors
contact phagocytose and process antigens
display foreign antigens on their surfaces (antigen presentation)
mast cells: are non-phagocytic, residential cells (meaning they are vascularized tissues throughout the body and prominently found in mucosal tissues that interface with the external environment) they regulate inflammation through the release of vasoactive mediators (such as histamine, prostaglandins, serotonins, and leukotriene from granules). they also aid allergic response by playing an important role in the development of allergies and hypersensitivities
macrophages: are highly phagocytic, larger than monocytes reside in specific tissues, and have a variety of surface receptors including pattern recognition receptors (which recognize pathogen-associated molecular patterns PAMPs)
Define phagocytosis and explain the process
Phagocytosis is the engulfing of a solid particle(usually bacteria)
6 stages:
1. Chemotaxis of phagocyte to microbe
2. Adherence to cell
3. Ingestion of microbes by phagocytes
4. maturation/ fusion of a series of vesicles, including lysosomes
5. Killing of microbes by enzymes/chemicals
6. Elimination from cell (exocytosis)
Discuss the complement system and its role in host defense
Complement: set of serum peptides designated numerically according to their discovery
-Complement activation results in lysis of the foreign cell
-Can be activated in 3 ways
1. Classical pathway- antibody-dependent
2. Alternate pathway- antibody-independent
3. Lectin pathway- lectin ligand
C1 becomes activated upon binding with the antibody-antigen complex. C1 enzyme creates a “complement cascade” of each C enzyme helping to form the next, finally creating the Membrane attack complex (MAC). the MAC drills a hole in of antigen cytoplasmic membrane, lysing the cell
Explain the process of inflammation and its importance. List the major signs.
-Nonspecific response to tissue damage from various causes
-Characteristics: redness, heat, swelling, pain and loss of function
Two types:
1. Acute:
Develops quickly and is short lives, typically beneficial, is important in the second line of defense
Dilation and increased permeability of thee blodd vessels
Migration of phagocytes
Tissue repair
2. Long-lasting (Chronic):
Develops slowly
Can cause damage to body
Can lead to disease
Discuss the importance of fever
-fever is over 37 degrees C
-Results when pyrogens trigger the hypothalamus to increase the body’s core temperature
-Pyrogens- include bacterial toxins, cytoplasmic contents of bacteria, antibody-antigen complexes
-Benefits
-inflammation
-Inhibits the growth of some
microorganisms
-Enhances phagocytosis
- Specific immunity
- Tissue repair
