Parasitology Exam 1 Flashcards
1
Q
Parasitology
A
The study of the most common mode of life on earth.
Centered on animal parasite of humans, domestic animals, and wildlife.
—-We do not talk about bacteria or virus.—-
2
Q
Parasite
A
Organism that lives in or on another organism (host) and either harms the host or lives at the expense of the host.
Ex. Feeding on the blood, nutrients mucous. Robbing nutrients
3
Q
Importance of Parasitology
A
- Parasite resistance (over time organisms evolve, we cannot use the same drugs anymore)
- Insecticide resistance (Some parasites use insects to develop) Exp. Malaria
- Increased mobility of people like vacation (popularity in tropics and subtropics)
- Migration of refugees from war-torn areas (some parasites are endemic to a specific area
- Military service personnel coming home from abroad
- Modifications of the environment
- Climate change (disease spread from tropics to more temperate regions)
- Immunosuppression becoming more widespread:
- AIDS; cancer chemotherapy and organ transplantation
- Indiscriminate release of toxic chemicals and carcinogens into the environment
4
Q
Parasitologist
A
Quaint person who seeks truth in strange places; a person who sits on one stool, staring at another
5
Q
Symbiosis
A
Interaction among organisms in which one organism lives with, in, or on the body of another.
6
Q
Symbionts
A
Organisms involved in symbiotic relationship with other organisms, the hosts.
–Smaller of the two organisms interacting–
7
Q
Neutralism
A
Lack of benefit or detriment experienced by either members of the pair of interacting organisms.
It describes interactions where the fitness of one species has absolutely no effect whatsoever on that of the other.
—- (0,0)—–
8
Q
Competition
A
Some degree of overlap in ecological niches of two populations in the same community, such that both depends on the same food resource, shelter, or other resources, and negatively affect each other.
—- (-,-)—–
not negative affected when one does not exist anymore, and it will not be competition after.
9
Q
Competition example
A
- Carnivorous animal compete for prey
- Plants compete for sunlight, water, nutrients, pollinators, and dispensers of fruit and seeds.
- The aquatic bladderwort plant (utricularia), a carnivorous plant, competes with tiny fishes for small arthropods ( crustaceans and insects)
10
Q
Phoresis
A
Form of symbiosis when the symbiont (phoront) is mechanically carried about by its host; neither is physiologically dependent on the other — means “to carry”
—-mechanical transfer of one organism for point A to point B.
11
Q
Phoresis example
A
- Bacteria on the legs of a fly. Bacteria lies the eggs on the feces, so the larvae can get the nutrients from the feces.
- Fungal spores on feet of a beetle.
- Aquatic snail eggs laid on birds feet
- Dermatobia hominis (Human botfly) Female deposits egg on surface of mosquito, the mosquito transport the eggs to out skin. Example as well of commensalism
12
Q
Protocooperation
A
A mutually beneficial symbiosis between organisms in which the interaction is not physiologically necessary to the survival of either
—- (+,+)—–
13
Q
Protocooperation Example
A
- Egyptian plover eats residuals from crocodile teeth. Removes residues from the teeth, allowing the gator to have strong teeth
- Cattle egret removes ectoparasites from the back of cow (bovine). Some situation it can change to parasitism, because they can be eating the skin or blood of the cow
- Hermit crab inside shell over which sea anemones live. They do it in order to camouflage, and the anemones gets a free ride.
- Ants and aphids with honeydew
14
Q
Mutualism
A
Type of symbiosis in which both host and symbiont benefit from association.
- –Usually obligatory
- –In most cases there is physiological dependence
- — (+,+)—–
15
Q
Mutualism example
A
- Termites and intestinal protozoan fauna. Release enzymes that help digest the wood into sugar.
- Blood-sucking leaches and intestinal bacteria. Feed on the blood, and need help to break down the hemoglobin in order to digest the blood.
- Wuchereria banchrofti and Onchorcerca volvulus infected with Wolbachia
- Cleaning symbiosis: cleaner wrasse ( Labroidus Dimidiatus). Fish helps to clean the ectoparasite.
- Nitrogen fixation, the bacteria Rhizobium spp.
- Lichen: microscopic green algae or cyanobacteria and filamentous fungi
16
Q
Commensalism
A
A kind of symbiosis in which the symbiont (a commensal) benefits, and the host (largest) is neither harmed nor helped by the association
- –Means eating at the same table
- — (+,0)—–
17
Q
Commensalism example
A
- Pilot fish and remoras (sucking disk) . Remoras on whale shark; transformed dorsal fin. Get some food when the shark eats.
- Entamoeba gingivalis
- Barnacle on a whale
- Epiphytes on a tree, able to get the light that they need
18
Q
Amensalism
A
Asymmetrical interactions in which one organism causes
a negative effect on another without being positively or negatively affected in return.
—- (0,-)—–
19
Q
Amensalism Example
A
- Bread mold Penecillium that produces penicillin, an antibiotic that kills bacteria
- Black walnut tree (Juglans nigra) produces juglone, an organic compound that is toxic or growth-stunting to many types of plants
20
Q
Predation
A
Animal interaction in which a predator kills its prey outright; it does not subsist on the prey while the prey is alive.
—- (+,-)—–
Ex lion and prey (impala)
21
Q
Parasitism
A
Symbiosis in which a symbiont benefits from the association, while it harms the host in some way or lives at the expense of the host.
—- (+,-)—–
22
Q
Both the parasite and predator live at the expense of the host or prey; interactions occurs only if there is an encounter
— Predator—
A
- kills its prey
- is large relative to the prey
- has numerous prey
- is not symbiotic
- no post-encounter interaction
23
Q
Both the parasite and predator live at the expense of the host or prey; interactions occurs only if there is an encounter
— Parasite—
A
- normally does not kill its host
- is small relative to the size of the host
- has only one host (or one host at each stage in its life cycle)
- is symbiotic
- post encounter interaction is where the real action begins!
24
Q
Macroparasites
A
Large parasite that does not multiply in the host of interest
- do not induce lasting immunity (some exceptions)
- have more stable populations, and cause endemic disease (in or within people, particular area).
Ex. Helminthes, arthropods, and other metazoans
- We can see with the naked eye
25
Microparasites
Small (or very small) parasite that multiplies within the host of interest
- Induce a lasting immunity
- have unstable populations, and cause epidemic diseases ( spread out to another area)
Ex. Funghi, protists, bacteria, and virus
- We need microscope to see it.
26
Ectoparasite
Parasite that lives on the outer surface of its host
| Ex: Lamprey, suck the blood of the fish
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Endoparasite
Parasite that lives inside its host
| Ex: Nematodes in the heart of a dog
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Obligate parasite
They cannot complete their life cycle without spending at least part of their time in a parasitic relationship. Need a host at some point.
Ex. Most parasites
29
Facultative parasites
Not normally parasitic but can become so when they are accidentally eaten or enter a wound or other body orifice. They do not need a host to live.
Ex. Naegleria fowleri (get inside thought the nasal cavity)
Ex. Micronema deletrix (get inside thought the foot)
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Accidental (incidental) parasite
A parasite found in other than its normal host
-Puts host and parasite into environmental conditions to which neither is well adapted
Ex. Toxocara canis in humans (visceral larval migrans)
31
Permanent parasite
Parasite that lives its entire adult life within or on a host
Ex. Trichinella spiralis never sees the light of day
32
Temporary (Intermittent) parasite or micropredators
Parasite that contacts its host to feed and then leaves
| Ex. Mosquito, bed bug, flea, etc.
33
Diversity of parasitism
| Fungal parasite
Many parasites are able to change the behavior of the host
Ex: Parasitic fungus Ophiocordyceps unilateralis with stalk protruding from ants head
Fruiting bodies release spores to infect ants and makes them Zombies ants
Yeast -> hyphae -> mycellium (release antimicrobial prevent other fungi to take nutrients from the host)
34
Diversity of parasitism
| mollusk parasite
Parasitic clams: Alter their mantle to make it look like a fish. Used as a decoy to attract bigger fish
Ex: Pocketbook mussel
Ex: Lampsilis fasciola
35
Diversity of parasitism
| crustacean parasite
Crustacean parasite: Tongue-eating isopod. Sucks the blood from the tongue. It replaces the organ and retains the same function of the organ
Ex: Cymothoa exigua (only parasite that is able to replace an organ)
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Diversity of parasitism
| Mammal parasite
Vampire bat: Only mammalian parasite. Take blood meals on mammals. Suck up so much blood that hey cannot fly afterwards. They has anticoagulants so we never notices that it happens
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Diversity of parasitism
| Plants parasite
Plant parasites: Use haustoria to insert into the host's vascular system.
Ex: Dodder vine
38
Diversity of parasitism
| Bird parasite
```
Bird parasites (avaian): Brood parasitism (reduce fecundity
Ex: Common cuckoo raised by Reed Warbler
```
39
Diversity of parasitism
| Fish parasite
Parasitic fish: Toothpick fish attracted to ammonia. Latch onto gills and suck blood.
Cases in the Amazon when people urinate swims up urethra and gets stuck.
40
Diversity of parasitism
| (Amphibian parasites)
Parasitic frogs (Amphibian parasite): The male of Rana lessonae mates with the female of Rana ridibunda and hybridization occurs. This is only beneficial to Rana ridibunda because only its chromosomes are passed on.
- Lessonae can only live in stagnant waters
- Ridibunda lives in waters constantly flowing
- Hybridized form can live in stagnant and also flast flowing water
- --- When hybridized gets ready to mate only chromosomes of ridibunda is passed on
- --AKA Genome parasite
41
The Example of brood parasitism described in lecture involved which of the following organisms?
a) Common Vampire Bat (Desmodus rotundus)
b) Candiru or toothpick fish (Vandellia cirrhosa)
c) Common cuckoo (Cuculus canorus)
d) Pocketbook mussel (lampsillis ovata)
e) Tongue eating isopod (Cymothoa exigua)
The Example of brood parasitism described in lecture involved which of the following organisms?
c) Common cuckoo (Cuculus canorus)
42
Which set of symbols below would best represent the organismal interaction between a lioness and crocodile preying upon the same water buffalo?
a) (+,+)
b) (-,-)
c) (+,-)
d) (0,0)
e) (+,0)
Which set of symbols below would best represent the organismal interaction between a lioness and crocodile preying upon the same water buffalo?
b) (-,-)
43
Parasitism example
Human infected with Guinea worm (Dracunculus medinensis) get infected by drinking contaminated water. They create a blister that burns which makes people put that part of the body in water, and provokes the parasite to get out of the body into the water. Start adapting into dogs and amphibians, which makes it harder to control
44
The organismal interaction between ants and aphids would best be described as ____.
a) Amensalism
b) Protocooperation
c) Mutualism
d) Parasitism
e) Competition
The organismal interaction between ants and aphids would best be described as ____.
b) Protocooperation
45
Parasitoid
Organism that is typical parasite early in its development but finally kills its host during or at the completion of its early development
- Often used in reference to many insect parasites of other insects
- Approximatly 10% of described insect species are parasitoids
Ex: Pseudacteon phorid
46
Hyperparasitism
Condition in which an organism is a parasite of another parasite
47
Coelozoic
A parasite living in the lumen of a hollow organ
| Ex. Intestine
48
Histozoic
A parasite living within the tissues of a host
| Ex. Liver
49
Vector
Any agent, such as water, wind, or insect (host), that transmits a disease organism
----Way that a parasite gets from one host to another, that does not need to be alive
Biotic: living things
Abiotic: nonliving things
50
Definitive host
host in which a parasite achieves sexual maturity; if there is no sexual reproduction in the life of the parasite, the host most important to humans is the definitive host
51
Intermediate host
host in which a parasite develops to some extent but not to sexual maturity
52
Paratenic (transport) host
host in which parasite survives without undergoing further development
53
Reservoir host
host that serve as a means of sustaining a parasite when it is not infecting humans, which is typically another suitable definitive host.
Serve as a source of infection an potential reinfection of humans.
Ex: Life cycle of Dioctophyme renale (giant kidney worm). Dog is the definite host where sexual reproduction occurs.
54
Urban (domestic) cycle
- normal to the human environments
- involves domesticated animals
ex: Dog-sheep, dog-goat, dog-pig)
55
Sylvatic cycle:
- existing normally in the wild
| - involves wildlife
56
Which of the following parasitological terms would not accurately represent this picture?
a) Macroparasite
b) Coelozoic
c) Obligate parasite
d) Histozoic
e) Endoparasite
Which of the following parasitological terms would not accurately represent this picture?
d) Histozoic
57
Population
Any group of individuals, usually of a single specie, occupying a given area at the same time
58
Mutation
a cell’s DNA and includes: change in nucleotide sequence, alternation of gene position, gene loss or duplication, and insertion of foreign sequence
59
Selective value (Adaptive value)
relative reproduction success (relative fitness) of an allele or genotype as compared to other alleles or genotypes
60
Preadaptation
The possession of a trait that coincidently predisposes an organism for survival in an environment different from those encountered in its evolutionary history; may occur because a natural population carries a huge quantity of genetic variability
- --Ex. Dinosaurs feathers initially used for insulation and display before using them for flying
- --Origin of larynx initially helped air breathing fish gulp air, before being connected with sound
- --Sweat glands in mammals being transformed into mammary glands
61
Adaptation
An evolutionary process whereby a population becomes better suited to its habitat over many generations
- Anatomical structure, a physiological process, or behavior trait that promotes the likelihood of an organism’s survival and reproduction in a particular environment
Ex: Adaptation of parasite to host internal environment
62
Selection
A composite of all the forces that cause differential survival and differential reproduction among genetic variants (artificial selection vs. natural selection); a key mechanism of evolution
A composite of all the forces that cause differential survival and differential reproduction among genetic variants (artificial selection vs. natural selection); a key mechanism of evolution
Parasite --> Host: We select for best bacteria; bacteria selects for best human
Predator --> Prey: Best cheetahs to get gazelles; most agile gazelles get away .
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Evolution
Genetic changes in populations of organisms through time that lead to differences among them.
- - evolution only occurs when there is a change in gene frequency within a population over time
- - these genetic differences are heritable and can be passed on to the next generation
64
It is in the best interest of the parasite to possess adaptations that allow it:
1. To encounter the host
- --parasites that possess a genetically determined behavioral trait that increases the probability of encountering the host will be positively selected for
2. To survive in the host if the encounter has occurred
- -- parasites whose genetically determined traits allow them to survive the host’s immune system will be positively selected for
65
It is in the best interest of the host to possess adaptation that allow it:
1. Avoid encountering the parasite
- --- hosts that behave in a genetically determined way that reduces its probability of encountering a parasite will be positively selected for
2. To get rid of a parasite if an encounter has taken place
- --hosts whose genetically determined traits allow them to eliminate the parasite will be positively selected for
66
Host-parasite Coevolution
Red Queen Hypothesis
Originally proposed by Leigh Van Valen (1973)
- Metaphor for Alice and the Red Queen from Lewis Carroll’s , Through the Looking Glass
- Species have to run (evolve) in order to stay in the same place (extant)
- Species have to run (evolve) in order to stay in the same place (extant)
Ex. Parasite-Host Coevolution
- - each time the parasite acquires a new weapon (Ex. New antigen), the host population is led to produce a new defense (new antibody, directed at this antigen)
- - Parasite and host populations are engaged in an endless arms race/ war
67
Adaptations for Parasite Transmission
A. Reproductive
produce more eggs and sperm then their free-living relative do
1. high reproductive potential
2. asexual reproduction
3. hermaphroditism
4. self-fertilization
68
Adaptations for Parasitic Transmission
B. Behavioral
1. adaptive advantage of parasite behavior
Ex. Schistosoma mansoni cercariae
2. parasite may alter host behavior
Ex. Dicrocoelium species
Cow to Snail to Ant to Cow
69
Adaptations for parasite Transmission
C. Morphological adaptations
1. size- many parasites are larger than their free-living relatives
2. attachment organs- suckers, hooks & spines, penetration organs, and cysts, etc
3. loss (regression) of anatomical structures- organs, locomotion, digestion, etc
70
Adaptations for parasite Transmission
D. Biochemical adaptations
1. Energy metabolism-catabolic pathway are usually reduced or modified in many parasites
2. Nutrient uptake- there is an elaboration of transport mechanisms
3. Synthetic reactions- synthetic capacities of parasites are reduced when compared with their free living relatives (they don't synthesize any nutrients, they get them from the host)
71
Adaptation for parasite Transmission
E. Immunological adaptations
1. Absorption of host antigen
Ex. Schistosoma spp.
2. Antigen variation
Ex. Trypanosoma brucei (VATs), Giardia
3. Occupation of immunological privileged sites
Ex. Leishmania spp. Trypanosoma cruzi, Plasmodium spp.
4. Disruption of the host’s immune response
Ex. Entamoeba histolytica
5. Molecular mimicry
Ex. Trypanosoma cruzi
6. Loss or masking of surface antigens
Ex. Trypanosoma brucei, Entamoeba histolytica, Ancylostomum caninum
72
Adaptation for Parasite Transmission
F. Life Cycle Adaptation
1. Reduction in the extent of the free-living phase of the life cycle (this avoids the variable external environment)
2. Behavioral responses to locate favorable environments
3. Responding to chemical stimuli from their host
4. Changing the behavior of the infected intermediate host to increase the chances of them being eaten by the final host
5. Infection of secondary and tertiary hosts. This has 4 advantages
A. Increased reproductive potential, since asexual reproduction can take place in the intermediate host.
Ex. Digeneans
B. Increases the range of the parasite in space and time
C. By infecting more than one host species the parasite can survive periods when one host is temporarily scarce
D. An intermediate host can channel the parasite towards its definitive host since the intermediate host is frequently part of the final host’s food chain
73
```
What is considered the raw material for evolution?
A. Selection
B. Mutation
C. Red Queen
D. Parasitism
E. Midichlorians
```
What is considered the raw material for evolution?
B. Mutation
74
Descriptive parasitology
Studies performed that are non-hypothesis driven; includes the discovery of : New parasites; Parasite morphology; Life cycle trends; Population survey of infected or non-infected hosts.
- -Proper identification of parasites and hosts is essential in trying to control diseases
- -It is naïve to try to control an infection without knowledge of how the parasite reproduces and gets from one host to another
75
Binomial nomenclature
System in which a species is given a compound name.
- - Carolus Linnaeus (1707-1778), father of modern taxonomy
- - 1st word is the genus in which the species is placed (first letter capitalized)
- - 2nd word is the species epithet (uncapitalized) used to create a species from other members of the same genus
- - names of genera and lower taxa are always italicized
76
Taxa
groups, ranging from species, to the increasingly inclusive genera, families, order, classes, phyla, kingdom, and domain
77
Taxonomy
Study of scientific classification; ordering & naming organisms
- basic subdiscipline of biology
- scientific name carries with it massive amounts of information
- includes (a) through (d)
a. describe organism in detail (utilize morphological and molecular characters)
b. provide scientific names for new species
c. preserve collections ( permanent slides and voucher specimens)
d. preserve collections ( permanent slides and voucher specimens)
78
Systematics
Study of classification & biological diversity, within an evolutionary context
- seek to understand the origin of diversity at all levels of classification
- includes (a) through (f)
a. describe organism in detail (utilize morphological and molecular characters)
b. provide scientific names for new species
c. preserve collections ( permanent slides and voucher specimens)
d. preserve collections ( permanent slides and voucher specimens)
e. Investigates their evolutionary history
f. Investigates their evolutionary history
79
Systematic
```
Investigating the evolutionary history of a taxon is not easy.
Unfortunately, history:
- is not something we can see
- only happened once
- only leaves behind clues
Systematics use clues to try to reconstruct evolutionary history; To research the pattern of events that have led to the distribution & diversity of life.
-Fossil records
-Morphology
-DNA comparisons: sequencing genes
-Behavioral traits
```
80
Phylogenetic systematics (cladistics)
Methodology used by systematists to infer (hypothesize) a species’ evolutionary history (phylogeny)
- -Pioneered by Willi Hennig (1913-1976)
- -Used in the discovery of monophyletic groups ( evolutionary real entities)
- -This method exclusively relies on shared derived character states (homology)
81
There are 3 basic assumptions in cladistics:
1. Change in characteristics occur in lineages or groups over time
- Only when characteristics change are we able to recognize different lineages
2. Any group of organisms are related by descent from a common ancestor.
- Supported by many lines of evidence
Ex. Same genetic code (DNA), biochemical pathways (glycolysis), etc.
3. There is a bifurcating or branching pattern of cladistics
- When a lineage splits, it divides into two exact groups
82
Phylogeny
Evolutionary hypothesis of the origin and diversification of a taxon.
treelike diagram, relationships between taxa are shown in the branching patterns, characters among the taxa used to produce phylogenies include (anatomical, behavioral, physiological, or molecular attributes)
83
Clade
group of organism that includes an ancestor and all descendants of that ancestor
84
Ingroup
taxon of interest
85
Outgroup
related taxon chosen for the purpose of comparison
86
Node
internal branch point that represents the common ancestor of those descendants; a speciation event
87
Sistergroup
two descendants that split from the same node
88
Homologous character
character is similar (or present) in two taxa because their common ancestor had that character
89
Analogous character
a similar character that has the same function but different evolutionary origin
90
Homoplasy
is similarly NOT due to homology; resulting from convergance, parallelism or reversal
91
Plesiomorphic
Ancestral characters: present in both the ingroup and outgroup
- uninformative character
92
Autapomorphic
Derived character, evolutionary novelty; present only in one taxon of the ingroup
- uninformative character
93
Synapomorphies
Shared derived characters that set a taxon apart from related taxa and their most recent common ancestor
- informative character
94
Monophyletic
a group of taxa that includes a hypothetical ancestral taxon and all its descendants
- defined by a suite of shared-derived characters (synapomorphies)
Ex. Mammals
95
Paraphyletic
a group of taxa that includes a hypothetical ancestor but does not include all of the ancestor’s descendants
- defined by a suite of ancestral traits
(plesiomorphies) which have been modified or lost in the excluded species.
Ex. Class reptilia is paraphyletic by not including birds
96
Polyphyletic
a group of taxa that do not share a most recent common ancestor
- defined by convergent traits (homoplasies)
Ex. Wings of birds, bats, and butterflies
97
Immune System
a functional system whose components attack foreign substances or prevent their entry into the body
98
Immunity
state in which the host is more or less resistant to an infective agent
- used in reference to resistance arising from tissues that are capable or recognizing and protecting the animal against nonself invaders
99
Innate Immunity
a mechanism of defense that does not depend on prior exposure to the invader
100
Adaptive (acquired) immunity
mechanism of defense that is specific to the particular nonself material; requires time for development, and occurs more quickly and vigorously on secondary response
101
I. Nonspecific immunity (innate immunity)
| The first line of defense:
Skin and Mucous Membranes
102
Skin (integumentary system)
as an effective barrier against pathogens
A. oil & sweat glands give skin surface pH of 4-5.5
B. sweat contains lysozyme (digests bacterial cell wall)
C. normal flora include non-pathogenic bacteria & fungi
D. epidermis 10-30 cells thick, dermis 15-40 times thicker
103
Mucosal surfaces
| Digestive tract
as an effective barrier against pathogens
A. Digestive tract
1. Saliva contains lysozyme (also in tears)
2. acidic environment of stomach pH of 1.5-3.5 (concentrated HCl solution)
3. digestive enzyme in intestine
4. nonpathogenic normal flora
5. vomiting & diarrhea may expel pathogens
104
Mucosal surfaces
| Respiratory tract
B. Respiratory tract
1. pathogens trapped by mucus in bronchi and bronchioles
2. ciliated epithelial cells sweep mucus towards the glottis
3. coughing and sneezing expels pathogens
105
Mucosal surfaces
| Urogenital tract
C. Urogenital tract
1. vaginal secretions viscous and acidic
2. secretions promote growth of normal flora
3. acidic urine of both sexes may wash out pathogens
106
II. Nonspecific Immunity (Innate Immunity)
| The Second line of defense
Phagocytes, inflammation, complement & interferon, cytokines & chemical signals, and antimicrobial proteins
- Recognize a wide spectrum of pathogens without a need for prior exposure
- Key players include, neutrophils, monocytes and macrophages
- These cells phagocytose pathogens and trigger then cytokine and chemokine network
- Can lead to inflammation and specific immune responses
107
Macrophages
Agranulocytes (mononuclear leukocytes)
1. Monocytes mature into active macrophages at site of infection
2. intracellular killing and digest pathogens via phagocytosis
3. phagosome fuses with lysosome, (oxygen-containing and nitrogen containing free radicals)
4. roam continuously in the extracellular fluid bathing tissue
5. antigen-presenting cell (APC) for helper T cells (TH)
6. respiratory burst for additional cell-killing ability (liberates deluge of free radicals)
7. express Fc receptor molecules for igG to trap antigen-antibody complexes
Ex. –Kupffer cells of liver
- Dendritic cells in blood
- Microglial cells in CNS,
108
Neutrophils
Granulocytes (polymorphonuclear leukocytes)
1. Most abundant circulating leukocytes (50-70% of peripheral blood leukocytes)
2. First cell on site of tissue damage or infection
3. Intracellular killing via phagocytosis, greater range of reactive oxygen radicals
4. Large numbers in blood until attracted to tissues during inflammation
5. Roam in the extracellular fluid bathing tissues
6. Express Fc receptor molecules for lgE
109
Eosinophils
Granulocytes (polymorphonuclear leukocytes)
1. 2%-5% of the total leukocytes in blood
2. important in the elimination of parasites
3. degranulation, next to parasite, releases extremely potent mediators (enzymes & toxins)
4. high blood count is often associated with parasitic infection & allergic diseases
5. express Fc receptor molecules for lgE
110
Basophilis
Granulocytes (polymorphonuclear leukocytes)
1. circulating cells, least numerous at about 0.5%
2. not important as phagocytes
3. release mediators such as histamine to promote inflammation
4. express Fc receptor molecules for lgE
111
Lymphocytes
Natural Killer (NK) Cells
1. Do not kill pathogen directly, but induce apoptosis of infected cells(cancer and viral)
2. Release perforins, insert in membrane and make pores, granzymes enter infected cell and activate caspase enzymes that induce apoptosis
3. Big player in immune surveillance and the bodies defense against cancer
4. Do not have T-cell receptors, but do express Fc receptor molecules for lgE
112
Mast Cells
1. Primarily located under mucosal surfaces
2. Release chemical mediator such as histamine to promote inflammation
3. Triggered during allergic responses express Fc receptor molecules for lgE
4. Important component of the inflammatory response
113
Acute inflammation
occurs over seconds, minutes, hours, and days.
chemical signals are released by infected or injured during initial response to tissue damage (acute phase.)
Ex. (histamine, prostaglandins, & bradykinins)
1. dilation of local blood vessels increases blood flow at site (red & warm)
2. increased permeability of capillaries causing edema (tissue swelling)
3. tissue swelling puts pressure on nerve endings (pain & potential loss of function)
4. macrophages and neutrophils release cytokines interleukin-1 (IL-1) and tumor necrosis factor (TNF) which acts on hypothalamus to raise body temp. (fever)
A. fever is one of the most common symptoms of infection
B. fever stimulates phagocytosis and causes liver and spleen to store iron and zinc needed by bacteria
C. fever may destabilize certain viruses and bacteria
5. cell death (necrosis) always occurs to some degree during inflammation
114
Which set of symbols below would best represent the organismal interaction between an elephant and organisms beneath its feet?
a. (+,+)
b. (0,-)
c. (0,0)
d. (+,-)
e. (+,0)
Which set of symbols below would best represent the organismal interaction between an elephant and organisms beneath its feet?
b. (0,-)
