Chapter 48 Immune System Flashcards
(38 cards)
What are the two main types of immunity? How are they different?
Innate Immunity: Immunity that is present before exposure and effective from birth. Responds to a broad range of pathogens. Nonspecific
Adaptive Immunity: the ability to recognize and remember specific antigens and mount an attack on them
Describe the immune system of sponges/cnidarians:
Uses amoebocytes (phagocytic cells). Might be referred to as coelomocytes (in coelom) or hemocytes (in hemolymph). They engulf things that aren’t supposed to be there.
Even a sponge can recognize itself, as can most animals on some level.
Describe the annelid immune system:
basophilic amoebocytes (engulf things)
acidophilic granulocytes: cytoplasmic granulues (long term storage vesicles near the cellular membrane) are ready to be discharged.
They have antimicrobial properties and send a signal warning to other cells.
What are amoebocytes ? What are coelocytes? what are hemocytes?
Amoebocytes: phagocytic cells
Coelocytes: amoebocytes in coelom
Hemocytes: amoebocytes in hemolymph
Describe the anthropod immune system:
Barrier defense: chitinous exoskeleton is impervious to bacteria and other things trying to get into the body. However, insects can still get injured so also have internal mechanisms.
- Phagocytic cells
- Hemocytes (in hemolymph, engulf non-self cell)
- Antimicrobial compounds
Toll receptors: sensitive to particular compounds, and activate a signal transduction pathway that generates antimicrobial peptides and releases cytokines.
also have lysozyme
What are lysozymes?
an enzyme secreted from the digestive tract of insects, used to kill invaders
what are non-specific defenses?
bodily defenses that protect a person against all micro-organisms , regardless of prior exposure
What is the first line of defense for humans and most animals?
Epithelial Tissue: our first and biggest line of defense. Skin, lining of respiratory tract and digestive tract.
How does skin act as a barrier?
Antimicrobial compounds are made.
Physical and chemical barrier
Skin acidity (skin secretions).
Washing action secretions
Antimicrobial proteins
Lysozyme from skin secretions
Acidity of the stomach kills most things that you might digest.
Tight junction of epithelial cells prevents entry.
If this barrier is broken, we should be concerned about both water loss and infection.
what are neutrophils? how do they work?
60-70% white blood cells, most common ones, if there is infection they will multiply, engulf stuff that are not self, then die couple days after
what are basophils?
0.5% of leukocytes, largest, important in allergies, acute/chronic, degranulate and initiate inflammation
what are eosinophils?
2-5% of white cells, granulocytes, release toxins around lymphatic system and ovaries, for multicellular threats, don’t divide, mainly in tissue
what are monocytes?
5% of white cells, migrate into into tissue, develop into macrophage, kills microbes, engulfs them
what are macrophages?
amoeboid cells that roam connective tissue and engulf foreign particles and debris of dead cells, part of the innate immune system and adaptive immune system
how do macrophages work?
they have receptors that recognize certain molecular patterns that are unique to pathogens, such as bacterial cell walls or viral RNA. They engulf the pathogen, and destroy it by enzymes and toxic substances.
how does an inflammatory response work?
-damage occurs and cytokines are released
-bleeding occurs, platelets begin clotting process and attach to fibrinogens
-cells at the site release cytokines, macrophage engulf things
-most cells degranulate releasing histamines
neutrophils phagocytize foreign material (engulfing stuff in huge numbers)
-monocytes arrive and mature into macrophages, more cytokines, helps get rid of all invaders and tissue repair
what are NK cells?
natural killer cells, attract virus-infected cells. basically kills self/destruct, have the ability to recognize cells immediately, mature in bone marrow, large granular lymphocytes (LGL)
how do NK cells work?
release NO2 that react with death receptors and result in apoptosis.
how do inflammatory responses help fight an infection?
induces inflammation, release histamines that cause blood vessels to constrict and increase the blood flow into tissue.
what is a systematic inflammatory response?
severe infection or tissue damage, the number of leukocytes goes way up in a short time, vasodilation all over, not enough blood, can result in fever (resets the bodies natural thermostat), can result in sepsis.
how do B cells develop?
cells are manufactured in the bone marrow (mature in bursa) that create antibodies for isolating and destroying invading bacteria and viruses.
how do T cells develop?
cells created in the thymus that produce substances that attack infected cells in the body. Only have one antigen receptor (but lots of it) and are therefore very specific.
what is an antigen?
little pieces of proteins
how are B and T cells different?
B cells produce antibodies that specifically recognize and bind to antigens.T cells are involved in cell-mediated immunity which means they directly recognize and attack cells that are infected or abnormal. B cells recognize antigens on the surface through B-cell receptors while T cells recognize antigens that are presented on the surface of other cells in complex with MHC molecules.
