Chapter 4 - Immune System Flashcards
Host
a person (or animal) that harbors an infectious organism
Vector
usually an insect, which transmits the disease causing organism between two individual hosts
- usually is not affected itself, but can pass the infectious organism to many hosts
Contagious
infectious diseases that can pass from person-to-person without vectors
Communicable diseases
can be passed from an animal to any other, and thus include vector-mediated disease
Immunodeficiency Disorder
occur when the body is unable to mount the appropriate immune responses to foreign microorganisms
Autoimmune Disorder
occur when the body mounts an immune response against itself
Allergic Reaction
occur when a normal immune response damages normal tissues
Thymus
- located in the chest between the sternum and the heart
- responsible for producing T cells
- active from infancy through adolescence, not much in adults
- functions to help T lymphocytes mature and become immunocompetent (able to recognize and bind to antigens)
Spleen
- size of a fist, located in the upper left quadrant just under the diaphragm
- functions to filter blood and lymph to remove abnormal red blood cells and platelets and to initiate an immune response against antigens through the actions of T and B cells
- macrophages work to remove cellular debris, bacteria, viruses, and toxins from the blood
Types of Infectious Organisms:
Bacteria
- structure: simple single-called organism
- mode of replication: replicate independent of host
- environmental factors: do no depend on host for survival
- immune response: macrophages stimulate T cells to stimulate neutrophils (general, cell-mediated) and some B cell and antibody action
Types of Infectious Organisms:
Viruses
- structure: non-cellular genetic strands
- mode of replication: use host’s cellular mechanisms to replicate
- environmental factors: cannot exist outside the biological environment of the hosts
- immune response: macrophages stimulate T cells to stimulate “killer” cells and cytotoxic T cells. Also, B cells and some humoral proteins that are effective against some viruses
Types of Infectious Organisms:
Parasites (protozoa)
- structure: complex single-called organism with multiple or undifferentiated cells
- mode of replication: replicate independent of host
- environmental factors: exist in the environment of the host
- immune response: macrophages stimulate T cells to stimulate eosinophils (general, cell-mediated). B cells particularly if toxins produced by parasite. Also, some humoral mechanisms
Types of Infectious Organisms:
Fungi (mycoses)
- structure: primitive single-called plants, commonly yeasts and molds
- mode of replication: replicate by spores
- environmental factors: dependent on host for growth (but not necessarily for reproduction)
- immune response: macrophages stimulate T cells to stimulate neutrophils (general, cell-mediated) and some B cell and antibody action
Lymphatic System:
Lymph
a clear fluid, rich in white blood cells, that circulates throughout the interstitial tissues
- collects plasma and debris from the interstitial tissues and is then reabsorbed into the lymphatic vessels
Lymphatic System:
Lymphatic Vessels
- located throughout the body alongside blood vessels
- walls are thin and contain one-way valves to help move the lymph unidirectionally toward the lymph nodes and then onto the lymphatic and thoracic ducts where it is dumped back into the circulatory system
Lymphatic System:
Lymphatic Ducts and Thoracic Ducts
Lymphatic - receives lymph drained from the right arm and the right side of the thorax, neck, and head
Thoracic - much larger and receives lymph from all remaining areas of the body
Lymphatic System:
Lymph Nodes
- located throughout the body in clusters
- functions to filter the lymph fluid as well as to monitor for antigens
- largest collections occurs in the axillary, neck, groin, (these three are easily palpated and are often found to be swollen and tender when someone is fighting an infection), popliteal, supraclavicular, abdominal, pelvic, and chest areas
Lymphatic System:
Bone Marrow
site for the production of red (mature) and white blood cells
White Blood Cells
enter the bloodstream and are transported to other sites for maturation
- granulocytes (neutrophils, eosinophils, and basophils)
- lymphocytes (T and B cells)
- monocytes (macrophages)
All collectively referred as leukocytes produced in the bone marrow from stem cells
Antibodies (Immunoglobulins, Igs)
proteins that bind to antigens to deactivate them, prevent them from moving through cell walls, or to mark them for the complement system to destroy
Antigen
any substance that triggers an immune response
- each antibody is capable of binding with a specific antigen
Complement System
made up of proteins, produces a cascade of chemical mediators that amplify the inflammatory or immune response
- process helps or “complements” the work of antibodies in destroying antigens
Components of Immune Response:
Humoral Response
involves activated proteins and Igs (B cell antibodies) that circulate in the bloodstream
- B cell antibodies work to neutralize microorganisms, toxins, and cancer cells or mark these antigens for destruction by the T cells
Components of Immune Response: Cell-mediated Response
involves the activation of specific immune system cells (T cells, phagocytes, neutrophils, and macrophages), which start a chemical cascade of events to eliminate the microorganism or other tissue debris
Innate Response System
provides the body’s first and second lines of defense against foreign invaders (microorganisms, bacteria, viruses)
- first line of defense provided by the physical barriers of the skin and the mucus membranes lining the mouth, nose, digestive tract, respiratory tract, urinate tract, and reproduction tract
- second line of defense provided by a combination of cellular and chemical defenders
- chemical mediators (histamine, complement, kinins, prostaglandins) are released which in turn attract phagocytes and natural killer cells to the area
- further enhanced by the work of antimicrobial proteins (interferon and complement)
- interferon proteins protect the uninfected cells in the area
- complement proteins kill invading microorganisms and enhance phagocytosis
- increases overall metabolism to mobilize energy sources and nutrients to meet the increased demands caused by the infection
Innate Response System:
Muscle Catabolism
which releases proteins into the blood to provide extra energy (through gluconeogenesis) and supplies amino acids for white blood cells to combat infections
- fast twitch muscle fibers followed by slow-twitch and ultimately cardiac muscle are affected
- inhibition of muscle energy through both the oxidative and glycolytic pathways impedes aerobic and strength performance
Innate Response System:
Fever phase
substances released from macrophages, monocytes, and T cells activate protein complement in the blood, which binds foreign particles as part of the humoral general response
Innate Response System:
Recovery Phase
- strength remains limited until the metabolized muscle protein is replaced (2-4 weeks)
- aerobic function is affected by decreases in blood volume (dehydration), hemoglobin, cardiac efficiency, and muscle mass (up to 3 months)
Adaptive Immune Response System
provides the body’s third line of defense and includes both cell-mediated and humoral components
Adaptive Immune Response System:
Cell-mediated response
involves activated T and B cells (lymphocytes)
- stimulated by antigens, which are proteins on the outer cell wall of the invading microbes
Adaptive Immune Response System:
Humoral specific response
B cells produce antibodies specific to the invading antigen
- antibodies cue phagocytes to recognize and destroy a foreign microbe
ex: vaccinations - B cells “remember” antigens and secrete the appropriate antibodies when stimulated by specific antigens
- T cells regulate B cell activity and stimulate the general immune response
Effect of Exercise on Immune Function
- decreases the circulating blood levels of lymphocytes, including T and B cells, return to normal (pre-exercise levels) within 24 hours
- prolonged, high intensity exercise can lead to sustained depression of the immune system
- prevalent when individuals fail to incorporate adequate recovery time between training sessions - bacterial infections do not worsen with exercise, but viral and parasitic infections nearly always increase
Signs and Symptoms:
Fever
most common sign of infection
- classified as low-grade (102F) and high-grade (102F and above)
- sustained body temperature over 104F kills brain cells and may cause irreversible cell necrosis in other organs
- normal body temperature = 37C (98.6F)
- varies based on oral condition and throughout the day (highest in evening, low in morning, and lowest while asleep)
- rectal and tympanic (external auditory canal) temperature = .5C to .9C (.9F to 1.4F) higher than oral temperatures
Signs and Symptoms:
Fatigue
chronic infection that continually stimulates the immune response
- metabolic rate increases with infection
- increased energy demand from the immune response causes catabolism of muscle and other tissues for fuel = progressive and persistent fatigue
Signs and Symptoms:
Lymphadenitis
swelling of the lymph nodes
- reaction to mediators from injured tissues and antigens cause the swelling
- located distal to the swollen lymph nodes
- swelling in the anterior neck nodes is associated with infections involving the mouth, throat, and ear
- axillary nodes drain the arm, lateral chest, and abdominal walls
- inguinal nodes filter the lower extremities, genitalia, lower abdomen, and buttocks
Signs and Symptoms:
Localized Pain, Redness, Heat, and Swelling
occur with inflammation caused by local infection and are easily observed when superficial tissues are affected
- distinctive red streaks or bands that run longitudinally may appear in limbs that have a distal infection, proximal to the infected site
Signs and Symptoms:
Unusual Muscle and Joint Pain
result by the inflammatory response to the invading organism
- does not change with movement and becomes progressively worse over time
- purulent (containing pus) drainage from wound or body part is signing local infection
- erythema and edema in joints and deep body tissue indicate presence of inflammatory response
Family History
reveal a family member experiencing or has experienced symptoms similar to those reported by a patient, suggesting an infection spreading within the family
Personal History
identify symptoms consistent with infection, like fever, fatigue, or myalgia
- course of symptoms important like origin, intensity, and duration of symptoms
Infectious Mononucleosis (Mono)
variant of herpes virus carried in saliva caused by the Epstein-Barr virus (EBV)
- most common among people age 15-25 years
- incubation period lasts over 1 month, then follows 3-5 day prodromal period in which the patient presents with headache, fatigue, loss of appetite, and myalgia
- maculopapular rash (flat red areas with small raised bumps) common
Diagnosis: Infectious Mononucleosis (Mono)
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