FIRST LINE OF DEFENSE
This is the largest organ of the human body, which is one major component of the First Line of Defense of the Innate Immune System
SKIN (epidermis)
HISTAMINE
Macrophages (MP) are part of the innate 2nd line of the body's defense, because they are non-specific "big eaters" that are part of a larger class of cells that eat/engulf invading pathogens. This larger class of cells is called THIS
PHAGOCYTES
TRUE OR FALSE: Natural Killer (NK) cells only are found in blood or lymph, not in body tissues
TRUE
The complement system, or simply complement, provides a major mechanism for destroying foreign substances in the body. NAME AT LEAST ONE WAY this system assists and/or enhances the rest of the body's innate AND adaptive immune system
(1) ENHANCES INFLAMMATION
(2) OPSONIZATION
(3) Forming of the MEMBRANE ATTACK COMPLEX (MAC) to LYSE target cells
Along with the skin, this component of the human body is the other major part of the First Line of Defense, found in all body cavities that open to the exterior: digestive, respiratory, urinary, and reproductive tracts
MUCUSAE /
MUCOUS MEMBRANES
Inflammation can be called the "hallmark" sign of the SECOND line of the body's INNATE line of defense, characterized by at least four "cardinal" signs.
NAME AT LEAST TWO
OF THESE KEY SIGNS OF INFLAMMATION
(1) REDNESS
(2) SWELLING (edema)
(3) HEAT
(4) PAIN
and sometimes (5) IMPAIRED FUNCTION
Most MPs (Macrophages) derive from a certain specific type of WBC that has left the blood stream and entered into the body's tissues. NAME THE CELL CIRCULATING IN THE BLOOD that can turn into a MP in the tissues after 8-12 hrs
MONOCYTE
Natural Killer cells, while sharing some things in common with lymphocytes of the adaptive/acquired/specific immune system, are nevertheless instead part of the body's innate immune system. BRIEFLY EXPLAIN WHY
Unlike lymphocytes of the adaptive immune system, which only recognize and react against SPECIFIC virus-infected or tumor cells (and must be educated and trained to recognize their specific targets), NK cells are NON-specific: THEY CAN ELIMINATE A WIDE VARIETY OF INFECTED OR CANCEROUS CELLS
The complement system, which circulates inactivated in the blood until signaled to activate, is made up of WHAT?
20+ types of plasma PROTEINS
Aside from providing physical barriers (e.g. keratin and the sloughing off of skin layers), LIST AT LEAST THREE WAYS that both skin and mucosal membranes provide first-line innate protection to the body
(1) ACID MANTLE
(2) Bacteria-destroying ENZYMES (e.g. in saliva, the stomach, or lacrimal fluid in the eyes)
(3) MUCIN that forms sticky MUCUS
(4) DEFENSINS (broad-spectrum anti-microbial peptides)
(5) OTHER TOXIC CHEMICALS IN SKIN (e.g. lipids in sebum; dermcidin in eccrine sweat)
Name at least TWO of the beneficial functions of inflammation in attempting to protect the body
(1) PREVENTING SPREAD of damaging agents (e.g. pathogens, toxic chemicals, etc.) to nearby tissues
(2) DISPOSAL OF PATHOGENS + CELL DEBRIS
(3) FACILITATES REPAIR PROCESS
MPs often "pick up where neutrophils (which respond more quickly) left off," continuing to attack invading pathogens (if any) and disposing of resulting debris (pathogens, dead neutrophils, degraded body tissues) as inflammation subsides. They do this "clean up" by engulfing and forming phagosomes which then fuse with THIS TYPE of vesicle full of toxic compounds and enzymes
LYSOSOME
TRUE OR FALSE: Natural Killer (NK) cells kill their targets through engulfing them (PHAGOCYTOSIS)
FALSE
Instead of phagocytosis, using the same method as cytotoxic T cells, NK cells secrete chemicals called PERFORINS that make a hole ("perforate") the membrane of the target cell and thus induce apoptosis. Despite the similar attack method, do not confuse NK cells with cytotoxic T Cells (which are part of specific/acquired immunity)
Define what is meant by OPSINIZATION
When C3b molecules COAT THE SURFACE of a microorganism, providing "handles" that receptors on Macrophages and Neutrophils can adhere to, allowing them to engulf the particle more rapidly (the term literally means: making the invaders more "TASTY" to phagocytes of the body's own immune system)
Explain the role that CILIA play in the body's first line of defense, and give an example of where in the body they play such a role
PROPEL DEBRIS-LADEN MUCUS AWAY FROM THE RESPIRATORY SYSTEM TOWARD THE DIGESTIVE SYSTEM (e.g. in the bronchi, in the nasal cavity)
In response to injury, sources such as injured cells, blood proteins, as well as select immune-system cells (phagocytes, lymphocytes, mast cells, basophils) all release histamines, kinins, prostaglandins, complement, and cytokines. Explain what these released chemicals/proteins do for the body's immune response
(1) ALL CAUSE NEARBY SMALL VESSELS to VASODILATE
(2) ALL INCREASE LOCAL CAPILLARY PERMIABILITY
(allowing passage of clotting factors + WBCs)
(3) Result in swelling which compresses nerve endings, causing PAIN
(4) SIGNAL immune-cells to come to that area (e.g. chemotaxis)
(5) COMPLEMENTS other defenses (e.g. complement system)
Give an example of AT LEAST ONE SPECIFIC TYPE OF MACROPHAGE (MP) that is a "fixed MP" having become a permanent resident of a particular tissue or organ
(1) MICROGLIA (resident in CNS)
(2) KUPFER/Stellate CELLS (resident in Liver)
(3) ALVEOLAR MP (resident in Lungs)
(4) INTESTINAL MP (resident in intestinal layers)
(5) DERMAL MP (resident in the dermis of the skin)
What might trigger a Natural Killer (NK) cell to attack another cell or pathogen it encounters?
NK cells detect general abnormalities on such cells, such as the lack of MHC-1 "self-declaring" surface proteins that healthy "native" body cells are expected to present (think of these like flying the body's own patriotic flag, signaling to other native body cells the message "Don't attack, I am one of you!")
Because "INNATELY, OUR OWN CELL PROTEINS INACTIVATE COMPLEMENT" which serves to protect our own cells from an "auto-immune" response
LIST AT LEAST THREE types of "penetrators," certain substances that are able to easily get past the body's first line of innate defenses
(1) LIPID-SOLUBLE / STEROIDAL SUBSTANCES (e.g. hydrocortisone cream)
(2) ORGANIC SOLVENTS (e.g. acetone)
(3) OLEORESINS (e.g. poison oak)
(4) HEAVY METAL SALTS (e.g. mercury, lead...)
(5) certain DRUG AGENTS (e.g. nicotine, fentanyl... - think of their use in drug "patches" placed on skin)
Inflammation is a very important LOCALIZED response to an invading pathogen, but NAME the SYSTEMIC heat-related response to the invasion of a microorganism that is more widespread, and EXPLAIN THE CHEMICALS that play a role in this defensive process
FEVER, an up-regulation of the body's natural "thermostat" that results when leukocytes and macrophages are exposed to foreign substances in the body and thus are caused to release chemicals called PYROGENS that act on the HYPOTHALAMUS
GIVE AN EXAMPLE OF A LYSOSOMAL-RESISTANT PATHOGEN (mentioned in both the textbook and your professor's notes) that can evade the body's immune system (as well as other antibiotics)
by "hiding out" in MPs
TUBERCULOSIS BACILLUS,
which "resists lysozomal enzymes" and may "proceed to colonize the phagolysosomes of many alveolar MPs," forming "granulomas surrounded by fibrous capsules" that may lay dormant/ asympomatic for years
MAJOR HISTOCOMPATIBILITY COMPLEX, made up of glycoproteins presented on a cell's surface
Like the clotting system, the activation of the complement system involves a type of "cascade" in which proteins are activated in a sequence. Name the number of the complement protein (C1, C2, C3, C4, C5, C6...?) which plays a central role in the process, representing where the classical, lectin, and alternative complement pathways all converge
C3