Chpt 15 Flashcards
Ways in which the body
protects itself from pathogens
Host Defense Mechanisms
are general and serve to protect the body against many harmful substances
Nonspecific host defense mechanisms
First Line of Defense
Skin and Mucous Membranes as Physical Barriers
Second Line of Defense
Transferrin
Fever
Interferons
The Complement System
Acute-Phase Proteins
Cytokines
Levels of this glycoprotein
increase in response to
systemic bacterial infections
Transferrin
Stimulated by pyrogenic substances
Fever
Small antiviral proteins
produced by virus-infected cells; they prevent viruses from multiplying
Interferons
can cause nonspecific flu-like symptoms
Interferons
A group of about 30 different proteins found in normal blood plasma –
The Complement System
Complement components interact with each other in a stepwise manner known as
complement cascade
assists in the destruction of many different pathogens
The complement system
is a process by which phagocytosis is facilitated by the deposition of opsonins
Opsonization
Plasma proteins that increase rapidly in response to infection, inflammation, or tissue injury
Acute-Phase Proteins
Chemical mediators released from many different types of cells in the body; enable cells to communicate with each other – within the immune system and between the immune system and other systems of the body
Cytokines
they recruit phagocytes to sites where they are needed
chemoattractants
The body respondstoany local injury, irritation, microbial invasion, or bacterial toxin by a complex series of events referred to as
Inflammation
The 4 major signs and symptoms of inflammation are
redness, heat, swelling (edema), and pain
Plasma that escapes from the capillaries into the site causes the area to become
edematous (swollen)
Sequence of Events in Inflammation
- Tissue Injury
- Vasodilation
- Increased Permeability
- Emigration of Leukocytes
- Chemotaxis
- Phagocytosis
The accumulation of fluid, cells, and cellular debris at the inflammation site is known as an
inflammatory exudate.
is thick and greenish-yellow, containing many live and dead leukocytes, it is known as a
purulent exudate or pus.
pus- producing microorganisms
Pyogenic microorganisms
process by which they surround and engulf (ingest) foreign material is called
phagocytosis.
The 3 major categories of leukocytes
monocytes, lymphocytes, and granulocytes
types of granulocytes
eosinophils, basophils, and neutrophils.
most important groups of phagocytes in the human body
macrophages and neutrophils
the coating of microbes with complement components, such as C3b.
Opsonization
initially serve to protect the organism from phagocytosis (they serve an antiphagocytic function)
Capsules
Some bacteria produce an exoenzyme called which kills phagocytes.
leukocidin
an abnormally low number of circulating leukocytes
Leukopenia
