week 4 Flashcards
Are fungi prokaryotic or eukaryotic?
Eukaryotic
Why are eukaryotic organisms difficult to treat?
it’s difficult to destroy the disease without harming our own cells
In what environments are fungi usually found?
Air, soil, animals, dry places
What are the nutritional requirements of fungi?
Heterotrophic - requires a source of carbon for growth.
What are the two types of fungi?
mold and yeast
What are molds?
multicellular fungi
What are yeasts?
unicellular fungi
What are hyphae?
threadlike filaments that make up mycelium
What protein do the fungi that grow on skin use for growth?
Keratin
What are the transmission routes that fungi can use?
spores, mycelial fragments, person to person, animal to person, contaminated floors, clothes, or hair brushes
What does it mean for a yeast to be dimorphic?
Switch from yeast form in the body, to filamentous form in the external environment
Where does candida albicans usually live?
on the skin and mucous membranes
When does candida albicans turn into an infection?
if the environment is altered in some way, inbalance in hormones or pH
What is the innate defense mechanism for candida albicans?
lactic acid production which maintains the vaginas pH
What is the treatment for Candida Albicans?
Antibiotics or antifungal medications that interfere with yeast production
What is chitin?
major constituent of fungal cell wall
What are dermatophytes?
fungi that require keratin
What are mycoses?
fungal infections
Why are protozoa classified as parasites?
because the host is adversely affected
What are the 4 groups of protozoa?
Sarcodena, Matigophora, Ciliophora, Sporozoa
What are sarcodena?
ameoba
What are Matigophora?
Flagella
What are ciliophora?
cilia
What are sporozoa?
non-motile
What are the ways that protozoal infections are commonly transmitted?
direct, indirect, giardiasis (arthopod vector), Malaria
What are the two forms Giardia exist in?
Trophozoites and Cysts
What are Trophozoite giardia
live in duodenum, multiply rapidly, have flagella and a sucker
What are Cyst Giardia?
formed by trophozoite and passed out in faeces. extremely resistant can survive for week sin a moist environment
What can be done to reduce the risk of picking up a giardia infection?
drinking water should be chloronitated to remove the cysts.
What protozoa causes malaria?
Plasmodium
After a mosquito bites a human, what is injected into the blood stream?
sporozites
where do sporozites travel to after being injected into the blood stream?
the liver where they undergo asexual reproduction.
What happens to malaria after it undergoes asexual reproduction?
It forms merozites. The liver cells rupture releasing the merozites into the bloodstream where they invade red blood cells.
How can malaria be prevented?
prophylactic chemotherapy before and after travelling, as well as wearing protective clothing.
What does prophylactive mean?
preventative
What are the three stages of a typical helminth life cycle.
Egg, Larva, adult worm
What part of the helminth life cycle is harboured by the definitive host?
Mature adult form of the parasite
List the 3 ways that helminth infections can be acquired?
Ingesting the larva stage, injection of the bit of an insect, penetration of the skin
What are the classifications of helminths?
Flat worms (flukes and tapeworms) and round worms
Where do tissue flukes reside in the body?
Liver or lungs
Where do blood flukes reside in the body?
Vascular System
What is the definitive host of flukes?
humans
What is the intermediate host of flukes?
snails
What is the life cycle of flukes?
eggs are passed by the human and reach an aquatic environment. the eggs hatch, releasing larvae which are eaten by the snails. Inside the snail, asexual reproduction occurs and then cercariae are produced which leave the snail and end up back in the aquatic environment.
What is the mode of infection for tissue flukes?
Cercariae penetrate into a second intermediate host where it becomes a cyst
What is the mode of infection for blood flukes?
the cercariae can infect the host directly where it can develop into an adult fluke
What does the term hermaphrodite mean?
has ovaries and testes so they can undergo self and cross fertilization
Where do tapeworms reside in the body and how do they stay there?
Intestine, and they absorb nutrients through pores
What is a proglottid?
a segment of a tapeworm (forms in the neck)
What disease does the worm echinococcis granulosis cause?
hyatid cysts
How are roundworms transmitted from one host to another?
eggs are shed into the intestine, eliminated with faeces, consumed in contaminated water, reproduction ccurs, females secrete itching substance into anus where it is picked up under finger nails and consumed again.
