Ch 14 Flashcards
Immune system
Collection of defenses (natural and adaptive) that protects the body from infection
Essence of immunology
Discrimination through recognition of self from non-self - keeps us from attacking ourselves
Genetic barriers
Allow us as a human race to be resistant to most plant and animal pathogens - the correct receptors for these pathogens are not present on human cells
Species resistance
Physiological processes of humans are not going compatible with those of the specific pathogen - conditions are incompatible with those needed for pathogen survival
First line of defense
Innate, nonspecific, blocks invasion, through portal of entry
- limits access to internal tissues
- physical barrier: skin, tears, coughing, sneezing
- Chemical barriers: low pH, lysozyme, digestive enzymes
- Genetic barriers: resistance inherent in genetic make up of host (pathogen can’t invade)
- skin (1.5-2 meters squared) lungs (70-140 meters squared) , gastrointestinal tract (40 meters squared)
* not a true immune response
Skin
- Composed of two major layers: epidermidis and dermis
- Contains chemicals that defend against pathogens: sweat and sebaceous glands
Epidermidis
- Multiple layers of tightly packed cells
- Few pathogens can penetrate these layers
- Shedding of dead skin cells removes microorganisms
Dermis
Collagen fibers helps skin resist, abrasions that could introduce microorganism’s
Perspiration secreted by sweat glands
- Salt, inhibits growth of pathogens
- antimicrobial peptides act against microorganisms
- Lysozyme destroy cell walls of bacteria
- Uses the flushing, the fact that helps remove micros
Sebaceous (oil) glands
- helps keep skin pliable, and less likely to break or tear
- Lower skin pH to a level inhibitory to many bacteria
Innate, natural defenses
Present at birth, and provide nonspecific resistance to infection
Adaptive immunities
Specific resistance, and must be acquired
Second line of defense
Innate - mostly nonspecific - consists of protective cells and fluids
- phagocytosis, inflammation, interferon, fever, and complement
* acts rapidly at both local and system levels
Phagocytosis
- cell uses its plasma membrane to engulf a large particle
Inflammation
Read, hot, swollen
Interferon
Interfere with viral replication
Complement
Uses antibodies to kill bacteria (compliments, antibacterial activity)
Third line of defense
Acquired, specific, occurs as a development of immuno logic memory
- Uses T lymphocytes, B lymphocytes, and antibodies
* provides long-term immunity 
Outer most layer of the skin
Stratum corneum
- Composed of epithelial cells that has become compacted, cemented together, and embedded with keratin (an insoluble protein) - this creates a thick, tough waterproof layer that is thickest in the soles of feet and palms of hand
- Physical barrier for first line of defense
Mucutaneous membranes
Found in digestive, urinary, respiratory tract’s, and of the eye
- moist and permeable
- Damaged cells are rapidly replaced
- Mucus coat impede the entry and attachment of some bacteria
- Rhinitis: inflammation of the nasal mucosa creates a copious flow of mucus and fluids that helps flush out nasal passages
Other physical barriers for the first line of defense are
- blinking and tear production: flushes the eye surface to get rid of irritants
- Flow of saliva: carries microbes in the harsh conditions of the stomach
- Vomiting and defecation: evacuate noxious substances, or microorganisms
- nasal hair: traps, larger particles found within the respiratory track
- Ciliary escalator: ciliated epithelium that is primarily in the trachea and bronchi that propels foreign particles trapped in mucus towards the pharynx to be removed
- Sneezing: expels a large volume of air at high velocity
- Coughing: the sensitivity of bronchi, trachea, and asked to foreign material triggers, this, which ejects irritants
- Genitourinary tract colon through the continuous trickle of urine, the bladder empties periodically and flushes the urethra
- Microbiota: presents can block the access of pathogens to epithelial services, and can compete with pathogens for limited resources, or alter the environment of the body, both of which can make it less welcoming for pathogens (some bacteria in the large intestine can secrete antibodies which can inhibit or kill other bacteria)
Chemical barriers first line of defense
Sebaceous, secretions, lysozyme, defensins, sweat, skin, stomach, intestines, semen, and vagina
Lysozyme: chemical first line
Enzyme that hydrolyzes the Pepto glycan in the cell wall of bacteria
Defenses: chemical first line
Peptides that are produced by various cells and tissues, that damage, cell membranes and lyse bacteria and fungi
- Skin cells: produce germicide in which eliminate bacteria
-Paneth cells: located in intestine and secrete defenses that can destroy or inhibit some types of infectious agents
Sweat in the context of chemical first line
Contains high concentrations of lactic acid in electrolytes that are inhibitory to many microbes
Skin in the context of chemical first line
Acidic pH in fatty acid content are inhibitory to many microbes
Intestines: chemical first line
Digestive juices and bile
Semen: chemical first line
Contains antimicrobial agent
Vagina: chemical first line
Protective acidic pH that has maintained by lactobacilli that are part of microbiota
Genetic resistance
- some pathogens have great specificity for one species that they are not capable of infecting other species
- ex: viruses can invade only by attaching to a specific host receptor
- Genetic differences in susceptibility can occur within one species - humans caring invitation for sickle cell disease are resistant to malaria and people with skin damage, blockages in tear ducks, salivary, glands, intestines, and urinary tract are at greater risk for infection
Immunology
Encompasses the study of all features of the bodies second and third line of defense
Function of a healthy immune system
- Surveillance of organs, tissues, and other compartments.
- Recognition and differentiation of normal components of the body and foreign materials, such as pathogens
- Attack against and destroy foreign invaders
White blood cells
- leukocytes
- constantly move about the body, surveying the tissues for potential pathogens * motility and migration
- Have an innate capacity to recognize and differentiate any foreign material in the body
- Display special molecules on their membrane: pattern recognition receptors (PRR) ( sense, pathogens) - kinases, lectins, mannos type of molecules AND Toll-like receptors (reside in the membrane of early responders, like phagocytes) - these receptors can interact with molecules on the surface of many pathogens called pathogen associated molecular patterns (PAMPS)
PAMPS
Molecule shared by many micro organisms that are able to get the attention of white blood cells
- These molecules are peptidoglycan, Lipoteichoic acid, lipopolysaccharide bacterial cell walls, double-stranded RNA from certain viruses, zymosan from fungal cell walls, bacterial flagellin (all of these can alert PRR’s in TLRs)
The most extensive body compartments that participate in immune function
- Mono nuclear phagocyte system.
- The spaces surrounding tissue cells that contain extra cellular fluid.
- The blood stream.
- Lymphatic system.
* a reaction in one compartment will be communicated to others
Reticular system
Connective tissue fibers that originate in the cellular basal lamina that interconnect nearby cells in mesh with the mass of connective tissue Nettwerk surrounding all organs
Mononuclear phagocyte system
The massive connective tissue, Network, that surrounds all organs and thus provides a pathway within and between tissues and organs
Circulatory system
Includes heart, capillaries, arteries, and veins, which circulate blood
Lymphatic system
Includes lymphatic vessels, lymphatic organs (lymph nodes) that certainly lymph
Whole blood
Substance that courses through arteries, veins, and capillaries
- A liquid connective tissue consisting of blood cells suspended in plasma
- serum colon is a clear fluid in clotted blood that lacks clotting proteins that plasma contains - separates from clotted blood (clotting is basically just red and white blood cells clumping)
- Plasma: contains hundreds of different types of chemicals that are produced by the liver, white blood cells, endocrine, glands, and nervous system, and absorbed from the digestive tracks - 92% water and rest is proteins like albumin and globulin (including antibodies, other amino chemicals like fibrinogen, hormones, nutrients, ions, electrolytes, dissolved, gases, and waste products
Homopoiesis
Production of blood cells that begins early and embryonic development in the yolk sac and is later takes on by liver and lymphatic organs, and it is finally assumed entirely and permanently by red bone marrow - active marrow sites gradually receipt as they grow older 
Stem cells
The primary precursor of new blood cells that is a pool of undifferentiated cells that are maintained in bone marrow
- Immature and unspecialized cells develop the specialized form and function of mature cells - cells that arise from this process include red and white blood cells and platelets
Types of leukocytes
- Granulocyte: a mature leukocyte that contains noticeable granules in a write stain, lobed nucleus - neutrophils, eosinophils, basophils
- Agranulocyte: globular, non-lobed nuclei that lacks prominent cytoplasmic granules - rounded nucleus
Neutrophils
Fine, pale, lavender granules
- When they are newly released from bone marrow, the nucleus are horseshoe shaped, but they for multiple loaves as they age
- Polymorphonuclear neutrophils make up 55 to 90% of the circulating leukocytes
- contain cytoplasmic granules that carry digestive enzymes and other chemicals that degrade the phagocytic materials
- Life expectancy: two days
Eosinophils
Larger, orange/red granules, and bilobed nucleus
- More numerous and bone marrow and spleen, then in circulation
- 1% - 3% of total white blood cell count
- granules contain peroxidase, lysozyme, toxic proteins, inflammatory chemicals
- Attach industry, large eukaryotic pathogens
- Target larval forms of worm parasite that cause ascariasis, filariasis, and schistosomiasis
- earlier cells to accumulate near sights of inflammation in allergic reactions.
Basophils
Pale stand, two loads nuclei that have prominent dark blue to Black granules
- Make up less than 0.5% of white blood cell count.
- Similar Marcels, which are nonmotile elements, bound to connective tissue around blood vessels, nerves, and epithelia
- Motel elements that migrate within in between compartments
- Like eosinophils, the granules with potent chemical mediators
Lymphocyte
Type of agranulocyte that are part of the third line of defense
- Second most common white blood cell composing 20% to 35%
- small, spherical with a uniformly, dark, rounded nucleus with a thin fringe of clear cytoplasm
- Consists of the B cells and T cells (both B and T cells are transported by bloodstream and length, and move freely between lymphoid organs and connective tissues - develop specifically for a single antigen
B cell
Produced in bone marrow
- Form specialized plasma, cells, which produce antibodies
T cells
Produce and bone marrow, but mature in the thymus gland
- Engage in a spectrum of immune function, called cell mediated immunity, which includes killing foreign cells directly and exerting control over immune function
Natural killer cells
- Active against cancerous and virally infected cells
- Never developed specifically for a single antigen and aren’t part of the third line of defense
- integrate the general features of virally infected cells in cancer cells, discriminate them from normal cells
- Integrate to specificity from antibodies to discriminants infected cells - similar to complement systems use of antibodies
- Both mechanisms of discrimination require direct cell to cell contact and result in natural killer cells, secreting per perforin/granzyme to destroy target sell
Monocytes
Largest white blood cell
- Is it matures, its nucleus becomes oval, or kidney shaped
- Discharge bone marrow into the bloodstream where they live as phagocytes for a few days and then they become macrophages
Macrophages
- Many types of specific and nonspecific, phagocyte and killing functions (they clean up the mess is from infection, and inflammation)
- Processing foreign molecules and presenting them to lymphocytes.
- Secrete, biologically, active compounds that assist, mediate, attract, and inhibit immune cells and reactions.
Dendritic Cells
A type of monocytes cell, long, thin, cell process, immature, dendritic cells move from the blood to the mono nuclear phagocyte system, and lymphatic tissues, where they trap pathogens - the ingestion of bacteria and viruses stimulates the cells to migrate to lymph nodes, and the spleen to participate in reactions with lymphocytes
Erythrocytes
Produced by stem cells - red blood cells involved in the transport of oxygen and carbon dioxide - can be the target of mean reactions
Platelets
Formed elements in circulating blood that aren’t whole cells through the disintegration of large, multi nucleic cells
- Function mainly in hemostasis (plugging broken blood vessels to stop bleeding) and then releasing chemicals that act in the blood clotting and inflammation
Lymphatic system
Part of the circulatory system - compartmentalized network of vessels, sells, and specialized accessory organs - begin as tiny capillaries that transport lymph through the lymph nodes
Function:
- provide an additional route for the return of extra cellular fluid circulatory spleen
- Help drain fluid that has accumulated due to its inflammatory response
- Render surveillance, recognition, protection against foreign materials, through a system of lymphocytes, phagocytes, and antibodies
Lymph
Plasma like liquid carried by lymphatic circulation
- Produced when blood components live blood vessels and diffuse into lymphatic capillaries
- Mostly water, dissolved salt, protein
- transports numerous white blood cells
- Red blood cells aren’t normally found in lymph
Lymphatic capillaries
Permeate all parts of the body, except the central nervous system and certain organ, such as bone, placenta, and thymus
- Send walls have a single layer of epithelial cells similar to blood, capillaries, with loose junctions that allow free entry of extra cellular fluid that collected from the circulatory system
* found in the high numbers in hands, feet, and breast
Differences between bloodstream and lymphatic system
Lymph only flows in one direction from the extremities toward the heart
- Eventually it will return to the bloodstream through the thoracic duct near the base of the neck
- Blood is transported through the body by the heart, while lymph is moved through the contraction of skeletal muscles that surround the lymphatic ducts
Primary lymphoid organs
Thymus gland and bone marrow
- lymphocytes are formed and reside here
- Release lymphocytes to populate secondary sites
Secondary lymphatic organs and tissues
Lymph nodes and spleen
- Circulatory based locations where it encounters microbes anomie responses
Malt: mucosal associated lymphoid tissue
Galt: gut associated lymphoid tissue (Peyer’s patches)
Thymus
Butterfly shaped organ near the tip of the sternum that is the site of T cell maturation
- Size of thymus is greatest at birth, and continues to exhibit high rates of growth until puberty, after which it gradually shrinks through adulthood
Lymph nodes
Small, encapsulated, being shaped organ stations, along with Faldik channels in large blood vessels of the Racic and abdominal cavities - the location and structure helps nodes filter out materials that entered lymph and provided appropriate cells and niches for immune and reactions
Spleen
Lymphoid organ that filters blood instead of lymph - removes worn out blood cells from circulation, filters pathogens from the blood and their subsequent phagocytes by resident macrophages
MALT
embedded throughout systems lined with mucus membranes and discreet bundles of lymphocytes and other white blood cells
- Widespread system, which is able to provide local, rapid mechanism for responding to the constant influx of microbes entering through portals of entry
Pharynx
Houses MALT in the form of tonsils
GALT
Includes appendix, and Peyer’s patches - provides immune functions against intestinal pathogens, and is a significant site of some antibodies
PAMPS
Pathogen associated molecular patterns
- Molecule shared by micro organisms
-
PRR
Pathogen recognition receptors
- Receptors white blood cells use for PAMPS
Second line of defense process
Inflammation, fever, so I guess I ptosis, interferon, mediated antiviral response, complement system
Inflammation context used
- Tissue damage: information is the reaction to any traumatic events in the tissues that attempts to restore homeostasis
- Foreign molecules: information helps to clear away invading microbes in cellular debris left. I mean reactions.
Characteristics of inflammation
-redness: increase circulation and vasodilation in response to chemical mediators
- Warms: he given off by increase blood flow
- Swelling: increase fluid in the tissue is blood vessels dilate - edema; white blood cells, Microlab’s, debris, and fluid collect to form pus; prevent spread of infection
- Pain: stimulation of nerve endings
* inflammation can be localized to organs and tissues - can be systematic (anaphylaxis)
Primary functions of inflammation
- Bring immune cells to site of an injection /injury.
- Sequester, microbes to prevent further damage.
- Destroy microbes and remove debris.
- Initiate repair mechanisms.
Initiating event that response to chemical signals
Trauma, infections, foreign particle, cancer
Vasoactive actions
Affect the diameter of blood vessels
- Vasodilation: dilation of blood vessels
- Increase permeability of capillaries and small veins
- Stimulation of nerves, pain
- Vasoconstriction: constriction of Lascelles
- Edema: swelling caused by too much fluid, trapped in the tissues
Chemical mediators with vasoactive effects: histamine, prostaglandin
Chemo static actions
Migration of cells towards attractant, chemicals, or away from repellents
- Cells migrate to site of damage
- The neutrophils act as major phagocytes
- Platelets: release mediators
- macrophages colon major phagocytes and support for immune reactions
- Lymphocytes: respond specifically to a pathogen
Substances, with chemo static affects
Endotoxin, bacterial, peptides, tumor, necrosis factor
Mediators with both boys are active and hemostatic affects
Complement components, cytokines, like interferons and interleukin, platelet activators, some products of arachidonic acid
Major, inflammatory events
- Injury/immediate reactions: blood vessels, narrow, blood, clots, and most cells, release, chemokines, and cytokines into injured area
- Vascular reactions: nearby, blood vessels, dilate, increase blood flow, increase, vascular, permeability, increased leakage of fluid forms.
Diapedesis - type of vascular reaction that is unique to leukocytes.
Migration of cells out of blood vessels into the tissues
Chemotaxis - type of vascular reaction that is unique to leukocytes
Migration in response to specific chemicals at the site of injury or infection
Edema and pus formation
Collection of fluids, Adema/swelling, infiltration by neutrophils information of pus
Resolution/scar formation
Macrophages, lymphocytes, and fibroblasts migrate in, initiate immune response and repair for injury, scar and loss of normal tissue
Fever
Initiated by circulating pyrogens, which reset the hypothalamus to increase body temperatures, signals muscles to increase heat, production, and vasoconstriction
- benefits: inhibits, multiplication of temperature, sensitive, micro organisms, impedes nutrition of bacteria by reducing the available iron, increases metabolism, and stimulates onion reactions, and protective physiological processes
- Downside: acute fever difficult to control, young infants, Exogenesis pyrogens
Exogenous pyronsv
Products of infectious agents, endotoxin
Endogenous pyrons
Liberated by monocytes, neutrophils, and macrophages, during phagocytosis, interleukins –1
(IL - 1) and tumor necrosis factor(TNF)
Phagocytes
- To survey tissue, compartments, and discover microbes, particulate matter, and dead, or injured cells.
- To adjust and eliminate these materials.
- To extract immunogenic information from foreign matter.
Categories of phagocytes
- Neutrophils: react early to bacteria and other foreign materials and damaged tissue
- eosinophils: attracted to sites of parasitic infections and antigen antibody reactions
- monocyte/macrophage lineage: derives from monocytes, scavenge and process foreign substances to prepare them for reactions with B and T lymphocytes- wandering or fixed in tissue - include macrophages, and dendritic cells
Opsonization
Cells are chemically modified to have stronger interactions with all surface receptors on phagocytes and antibodies
Phagocytosis process
 Respond to chemotactic factors
- Once they get there, they must be able to recognize and attach to either one of the PAMPS or they need to recognize that some thing has been tagged for destruction by using one of the opsonins
- Once it is able to attach, then it must ingest by bringing it in as a phagosome. (Encompassed in a membrane bound compartment of the cell)
- Destroy: through the fusion of another vesicle called a lysosome, which contain digestive enzymes - when they fused it, exposes the bacteria/debris with lots of digestive enzymes, and turns it into a phaglysosome
- Release of material now that the debris/bacteria is killed or destroyed
Interferon - antiviral response (AVR)
Small proteins, produced by certain white blood cells and tissue cells in response to viruses, RNA, immune products, and antigens - severe flu like symptoms
- Chemical signal that elicits a response
- Diversity of functions that focused on eliminating virally infected cells
- All these types bind to Sal services and induce expression of anti-viral proteins and inhibit expression of cancer genes
- Interferons, alpha and beta stimulate phagocytosis
- interferon gamma is a new regulator of macrophages and T and B cells
Types of interferons
Localized
1. Interferon alpha: products of lymphocytes and macrophages
2. Interferon beta: product a fibroblasts and epithelial cells.
Specialized
1. Interferon gamma: product of T cells
Complement system
Often compliments other parts of the immune system that are innate and adaptive
- nonspecific and not a back up system
- Less than 20 proteins involved in the system
- 10% of all plasma proteins complement related
- Circulating blood/lymph
Purpose of complement system
- Increase phagocytosis.- opsonization of bacteria
- Lyse Cells: using the membrane attract complex
- Regulates inflammation
Complement proteins
Are activated by cleavage, - Cascade reactions pathways
Cascade reaction pathways
- Classical: activated by the presence of antibody, bound to microorganism
- Lectin pathway: nonspecific reaction of a host serum protein that binds Manon.
- Alternative: begins when complement proteins, bind to normal cell walls and surface component of microorganisms.
Activating the complement cascade
- All pathways activate the same major complement proteins
- complement proteins, discriminate and break down to do something different and can even come together to form other enzymes
- Classical pathway activation: antibody that recognizes a specific antigen allows complement proteins, 12 and four to binds to it, and it changes shape, allowing it to start chopping things
Classical pathway – more in depth 
