Ch. 13 Flashcards
1
Q
innate immune system
A
- present at birth
- not antigen specific (exposure results in no immunologic memory)
- present at all times (immediate response to infection)
- does not improve with repeated exposure to an infectious agent
2
Q
adaptive immune system
A
- develops throughout life
- antigen specific (exposure results in immunologic memory: it “remembers” that it has encountered an invading organism and reacts more rapidly)
- lag time between infection and response (develops in response to infection)
- memory develops, which may provide lifelong immunity to reinfection to the same infectious agent
3
Q
function of immune system
A
- to defend the life of the host by identifying foreign substances and developing defense against them
- the body recognizes bacteria, viruses, fungi, and parasites as something foreign to itself and responds by sending certain types of cells to the infection site and producing biochemical substances to counteract the foreign invaders
- the way that an individual responds to an infection is known as the host response
4
Q
loss of immune function is…
A
- deadly to the body
- ex: HIV, disables specific group of immune cells responsible for coordinating immune response, these people die from opportunistic infections
5
Q
consequences of an overzealous immune response
A
- it begins to harm the body it is trying to protect
- ex: rheumatic heart disease, begins as infection of the skin or pharynx with streptococcal bacteria, these molecules are similar to heart tissue and immune responses against the bacteria also attack heart tissue
6
Q
polymorphonuclear leukocyte (PMN)
A
- (neutrophils)
- phagocytosis
- release of lysosomes
- release of powerful regulatory proteins (cytokines) that signal immune system to send additional phagocytic cells to the site of an infection
- play vital role in combating bacteria in plaque biofilms
- rapid responders, provide first line of defense
- are attracted to bacteria by a chemotaxis
- the cytoplasm contains granules (lysosomes) filled with strong bactericidal and digestive enzymes that kill and digest bacterial cells after phagocytosis.
- are short lived cells ( less than 1 day) that die when they become engorged with the bacteria they phagocytize. The pus formed contains many dead and dying PMNs.
7
Q
macrophage
A
- (leukocyte)
- are large phagocytes with one kidney-shaped nucleus and some granules
- are called monocytes when found in bloodstream and macrophages when they are located in the tissues
- phagocytosis
- are slower to arrive at the infection site than PMNs. the slower, long-lived macrophages are often the most numerous cells in chronic inflammation
- present antigen to T cells, together macrophages and T lymphocytes play important role in chronic inflammation
- release of lysosomes
- release of powerful regulatory proteins (cytokines) that signal the immune system to send additional phagocytic cells to the site of an infection
8
Q
B-lymphocyte/plasma cell
A
- production of immunoglobulins
- B lymphocytes can further differentiate into plasma B cells and memory B cells
- principal functions is to make antibodies
9
Q
t-lymphocytes
A
- further stimulate the immune response
- intensify response of other immune cells
- can produce cytokines (any protein that is secreted by cells and affects behavior of nearby cells) that further stimulate immune response
10
Q
immunoglobulins IgG, IgM, IgD, IgE
A
- neutralize bacteria or bacterial toxins
- coat bacteria to facilitate phagocytosis
- activate the complement system
11
Q
complement system
A
- complex series of proteins circulating in blood that work to facilitate phagocytosis or kill bacteria directly by puncturing bacterial cell membranes
- are activated by and work with (complement) the antibodies
- after activation, the complement proteins interact in a cascade to 1. destroy pathogens 2. opsonization of pathogens 3. recruitment of phagocytes 4. immune clearance
- lysis of cell membranes of certain bacteria
- phagocytosis
- recruitment of additional phagocytic cells to the infection site and clearance of immune complexes from circulation
12
Q
leukocytes
A
- white blood cells that act like independent single cell organisms able to move and capture microorganisms on their own
13
Q
neutropenia
A
- a PMN count of less than 1,000 cells/mL
- indicates an increased risk of infection
14
Q
lymphocytes
A
- small white blood cells that play important role in recognizing and controlling foreign invaders
- the two important ones are B cells and T cells
15
Q
antibodies
A
- Y-shaped proteins
- one end binds to the outside of the B cell, the other end binds to a microorganism and helps to kill it
- collectively known as immunoglobulins
