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84 Cards in this Set
- Front
- Back
What are the 5 types of problems caused by arthropods? |
-annoyance -contamination -phobias -direct injury -disease transmission |
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What is Delusional Parasitosis? |
The mistaken belief of being infested. Can lead to self-mutilation. |
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Myiasis? |
The infestation/parasitism of fly larvae somewhere in the body. Ex: bot flies |
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Viruses transmitted by arthropods are known as what? |
Arboviruses |
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What's Biological Transmission? |
When the disease has an obligatory life cycle stage inside the vector species. |
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What is Mechanical Transmission? |
Incidental transfer of disease organism during contact between vector and host. Parasite does not reproduce/develop within the vector. Can be external or internal. ex: when cockroaches come into contact with food. |
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What are the 3 subphyla of phylum Arthropoda? |
1) Trilobitomorpha=trilobites 2) Chelicerata 3) Mandibulata |
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What kinds of species are in subphylum Chelicerata? |
mites, ticks, spiders, scorpions, horseshoe crabs |
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What kinds of species are in subphylum Mandibulata? |
Crustaceans, centipedes, insects |
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What is the name of the main body cavity (containing a circulatory fluid) found in arthropods? |
hemocoel |
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What is a tagmata? |
A body region type. For example, Arachnids have 2 tagmata: head and trunk. Insects have 3 tagmata: head, thorax and abdomen. |
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The epidermis of arthropods secretes a noncellular __________. |
cuticle |
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What are the 2 sections of the cuticle in arthropods? |
1) procuticle: proteins and chitin-hardened layer. 2) epicuticle: the varnish-like waterproof layer. |
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Developmental stages are separated by molts of the exoskeleton. What are the 2 possible kinds of developmental stages in insects? |
1) gradual development=found in primitive species (ex: cockroach); larvae look, move and feed like adults. 2) Complete development=found in advanced species (flies, fleas, etc.); larvae are very physically different than adults |
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What is the name of the opening tubes lining the body of arthropods that lead to the tracheal tubes on the inside of the body? |
spiracles |
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Which mosquito species vectors malaria? |
Anopheles gambiae |
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What is Morgellon's Disease? |
A fake disease characterized by unexplained infestation symptoms (crawling skin, etc) |
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What are the 3 sections of the digestive system in arthropods? |
1) foregut 2) midgut 3) hindgut |
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What is the structure of the foregut? What is its function? |
An infolding of the exoskeleton (so, it's lined with impermeable cuticle). Stores food. |
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What is the structure and funtion of the midgut? What is the peritrophic membrane? |
Not lined with cuticle; involved in nutrient absorption. The peritrophic membrane surrounds food to enhance digestion and isolate microbes in food. Infective microbes can invade hemocoel here by lysing the peritrophic membrane with enzymes. |
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What is the structure and function of the hindgut? |
An infolding of the exoskeleton; expels waste |
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What are the 6 main characteristics of arthropods? |
1) segmented body 2) exoskeleton 3) Jointed exoskeleton with paired appendages 4) hemocoel body cavity 5) Specialized respiratory system = trachea 6) Unique sensory structures: ocelli, setae; compound eyes |
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What is the difference between ocelli and ommatidia? |
ocelli=simple eyes/eyespots. Detect simple changes in light. Ommatidia=individual eye units that make up compound eyes. |
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What are setae? |
stiff, bristle/hair-like structures found on arthropods. Found on antennae |
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From outside to inside, what are the 3 layers of the insect exoskeleton? |
1) epicuticle (outside) 2) procuticle 3) epidermis (inside, living cells) |
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What is epidemiology? |
The study of maintenance, outbreak, ecology and prevention of diseases. |
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What are the 4 routes of infection in epidemiology? |
1) aerosols (inhalation of infectious particle) 2) physical contact (predation, sexual, etc) 3) Fomites= infection thru contact w/ infected object. 4) Vectors |
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What percentage of diseases are vector-borne? |
20% |
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What are the symptoms of Zika virus? How is it transmitted? |
Symptoms: fever, rash (2-7 days); can cause microcephaly in infants born to infected women. Transmitted by Aedes mosquitoes |
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From 1918 to 1919, how many people/what percentage of the population did the Spanish Flu kill?
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3% (about 50 million people worldwide) |
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The modern swine flu is a mutated version of what disease? |
the Spanish Flu |
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What's the difference between and Anthropozootic Disease and an Enzootic Disease? |
Anthropozootic Disease=parasite resides primarily in humans (ex: malaria) Enzootic disease=parasite primarily in animals, but can infect humans (ex: West Nile Virus) |
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What are the 2 kinds of disease transmission cycles? |
-Simple=disease vectored by mosquitoes among humans -complex=disease vectored by mosquitoes between humans and multiple different animals |
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What's the difference between an obligate and facultative parasite? |
obligate=only in host/vector facultative=in host/vector and in free living stages (ex: nematodes) |
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What is Vector competence and what is it affected by? |
Vector competence=the probability that a pathogen will be transmitted by a particular vector. The competence of a vector at spreading disease. Affected by -host selection (vector must feed on correct host) -vector susceptibility to pathogen -how often a vector feeds |
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What is the difference between horizontal transmission and vertical transmission? |
Horizontal transmission=from vector to host Vertical transmission=between vector generations |
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What are the 3 types of vertical transmission in vector species? |
1) Trans-stadial=within an organism's lifespan 2) Trans-ovarial=from mother to offspring 3) Venereal=from males to females |
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Regarding biological transmission, what is the difference between the extrinsic incubation time and intrinsic incubation time?
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extrinsic=the time a pathogen must develop/reproduce before the vector is infective. Competent vectors feed after the extrinsic period. intrinsic=the time for host to develop symptoms |
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Difference between endemics, epidemics and pandemics? |
Endemics=sustained, low levels of infection in an area. Epidemic=outbreak of disease Pandemic=epidemic across wide geographic area |
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What are sentinel animals? |
Animals that are often reservoirs for diseases and can be monitored to track disease prevalence. |
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What is the labrum in some insect species? |
the "upper lip"--the food tube |
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What are the maxillae and labium used for in some insects? |
to manipulate food (they're parts of the mouth) |
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What is the name for the "tongue" in some insect species? |
the hypopharynx |
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Having a flattened body is a necessary adaptation for some parasitic vector species. What are the 2 ways the body can be flattened? |
Dorsoventral=in ticks, lice, bedbugs Lateral compression=fleas |
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What are the 3 Classes (and their corresponding orders) of venomous arthropods? |
1) Insecta: order Hymenoptera 2) Arachnida: Order Scorpiones 3) Arachnida: Order Araneae (spiders) |
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Within the order Hymenoptera, what are the 3 families? |
1) Vespidae=wasps (predatory) 2) Formicidae= ants 3) Apoidea= bees (honey bees; pollinators) |
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How many of the 115,000 species of Hymenoptera are stingless? |
half |
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In hymenoptera, the thorax is joined by 2 segments via a flexible structure called ___________. |
Petiolate gaste (The "wasp waist") |
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In hymenoptera, what is the stinger made of? |
A Hollow stylet (sheath) plus 2 barbed, moveable lancets |
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What is the Schmidt scale? |
A scale of pain intensity of insect stings from 0-4 |
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What are the 2 different subspecies of honeybees? |
1) Apis m. mellifera=European honeybees 2) Apis m. scutellata=African honeybees (darker, less honey, more aggressive) |
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Hymenoptera venom has multiple components. What are they and what do they do? |
-histamines=increase capillary permeability, vasodilation, pain, itching. -mastoparans=induce release of histamines from target's own mast cells -hemolysins=rupture red blood cells -neurotoxins=cause pain, cardiac/respiratory arrest. -enzymes=phospholipidase, etc. Spread venom by degrading cell membranes |
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Bee venom contains ________, unique to honeybees. What does it do? |
Melittin (a peptide): enhances action of phospholipidases, pain, ruptures RBCs, vasodilation.
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What is an LD50? |
The amount of toxin per kg of body weight required to kill 50% of the population |
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The death-stalker scorpion's venom is comparable to what? Is the emperor scorpion as deadly? |
cobra venom; no, emperor scorpion is a popular pet. |
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What is the most dangerous species of scorpion in the US? |
the bark scorpion (Centruroides exilicauda) |
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In Scorpions, how many segments are found in the cephalothorax? |
6 segments: chelicera, pedipalps and 4 pairs of walking legs |
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In scorpions, how many segments are found in the abdomen? |
12 segments with 2 regions: front region and hind region |
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What are pectines?
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modified abdominal appendages unique to scorpions that look like combs. Found of the belly and can detect vibrations, moisture, taste, etc. |
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In scorpions, food is transferred from ________ to ____________. |
chelicera; gnathobases=region where pedipalps join body to grind prey; mouth is located here. |
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How do scorpions reproduce? |
Males signal females and wait for signal back to approach. Mating "dance"--> male drops spermatophore on ground and guides female over it. |
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How many species of spiders are there? How many in the US? |
40k species; 4k in US |
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How many segments are in the cephalothorax in spiders? |
6: chelicera, pedipalps, 4 pairs walking legs |
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Chelicera appear in what form in spiders? |
modified as venomous fangs |
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What species of spider can kill a person with a bite within 15 minutes? |
Australian Funnel-web spider |
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What are the 3 medically important spider species in the US? What kinds of venom do the 2 most dangerous possess? |
1) Black Widow (neurotoxin venom) 2) Brown Recluse (cytolytic venom) 3) Hobo spider |
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What subphyla, class and order are ticks found in? |
Subphyla Chelicerata --> Class Arachnida --->Order Acari |
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Ticks are found in the suborder Parasitiformes. What are the 2 families of ticks in this suborder? |
-Family Ixodidae (hard ticks) Family Argasidae (soft ticks) |
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How many species of ticks are there? |
1000 |
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What are the 2 differences in morphology between hard and soft ticks? |
1) hard ticks have a visible capitulum (mouth) 2) Hard ticks have a scutum |
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What are the 3 parts of the capitulum in ticks? |
1) chelicera: serrated for cutting 2) Pedipalps: for holding onto host 3) hypostome: a barbed, harpoon-like holdfast |
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There are 2 major regions on a tick: the "head" region and the idiosoma. What is the idiosoma made up of? |
posterior cephalothorax + abdomen |
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On the idiosoma of female ticks, where do you find the ventral gonopore? |
On the underside/belly |
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Where is the Haller's organ found on ticks and what does it do? |
Found on forelegs; detects taste, odors, touch. |
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How can you tell a female hard tick from a male hard tick? |
Female Ixodidae have smaller scutum on the idiosoma |
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What is "questing"? |
The practice of ambush ticks of sticking out forelegs and jumping/dropping/latching onto host as it passes by. |
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What is the stylostome? |
The feeding tube that forms on ticks during feeding by injecting saliva into the wound that then cements to the capitulum. |
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What is the difference of feeding between hard ticks and soft ticks? |
Hard ticks: add new cuticle; feed from 2 days-2 weeks. Soft ticks: stretch cuticle; take small meal; detach w/in hours. |
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What are the 2 strategies for getting onto a host for ticks? |
1) Hunting--tick runs up and seizes host 2) Ambush--tick waits and "quests" |
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Describe the mating and egg-laying process of ticks |
Female secretes hormones while feeding and males come up to her and attach to underside to insert spermatophore into the ventral gonopore. Female continues to feed until completely full then drops off. She lays eggs basically until she dies. |
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What is diapause? |
The state of dormancy a tick goes into between feeding. Reduces moisture/energy requirements. Induced by day length, humidity, temperature, etc. |
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How can ticks take in atmospheric moisture? |
By using a Hydrophilic Secretion: they secrete a salty substance around the mouth that that will attract atmospheric moisture if the humidity is greater than 40%.
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What are 4 important diseases vectored by ticks? |
1) Lyme disease 2) Rocky mountain spotted fever 3) Babesiosis 4) tick-borne encephalitis |
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Besides vectoring diseases, what other medically-important consequence can occur from a tick biting you? |
TIck paralysis--caused by toxic protein in saliva. Causes respiratory failure within 48 hours but recovery happens within days after removal. |