Entamoeba histolytica Overview Quiz
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Questions and Answers

Where is Entamoeba histolytica commonly found?

  • Deserts (correct)
  • Arctic regions
  • Temperate climates
  • Tropical and subtropical regions

What is the primary mode of transmission for Entamoeba histolytica?

  • Sexually transmitted
  • Contaminated food or water (correct)
  • Contact with infected animals
  • Airborne particles

What feature characterizes the trophozoite of Entamoeba histolytica?

  • Single anteriorly directed pseudopod (correct)
  • Unicellular with a rigid cell wall
  • Highly differentiated ectoplasm and endoplasm
  • Active motility through multiple flagella

What initial site is commonly affected by Entamoeba histolytica upon colonization?

<p>Cecum (D)</p> Signup and view all the answers

What is a characteristic of the primary lesion caused by Entamoeba histolytica?

<p>Presents without complications (D)</p> Signup and view all the answers

Which region shows a higher prevalence of Entamoeba histolytica in humid climates?

<p>India (D)</p> Signup and view all the answers

What is a characteristic feature of Entamoeba histolytica?

<p>It is a unicellular parasite with a single pseudopod for movement. (A)</p> Signup and view all the answers

Does Entamoeba histolytica have an intermediate host in its life cycle?

<p>No, it does not have an intermediate host. (D)</p> Signup and view all the answers

What is a potential consequence of chronic primary lesions in the large intestine?

<p>Development of necrotic ulcers (C), Formation of amoebic liver abscesses (D)</p> Signup and view all the answers

How long can Entamoeba histolytica cysts survive in moist environments?

<p>Up to seven days (C)</p> Signup and view all the answers

What is the primary site for the origin of lesions caused by Entamoeba histolytica?

<p>Large intestine (A)</p> Signup and view all the answers

What could happen if amoebic lesions in the large intestine become chronic?

<p>They might rupture and cause internal bleeding (D)</p> Signup and view all the answers

What range of cysts can be excreted daily in severe cases of infection?

<p>30,000 to 45,000 (D)</p> Signup and view all the answers

How does the parasite Entamoeba histolytica typically enter the body?

<p>Through contaminated food or water (B)</p> Signup and view all the answers

What type of abscess can form in the liver due to amoebiasis?

<p>Amoebic liver abscess (C)</p> Signup and view all the answers

Which of the following is a significant factor in the transmission of amoebiasis?

<p>Direct contamination from infected feces (A)</p> Signup and view all the answers

In which regions is Entamoeba histolytica commonly found?

<p>Tropical and subtropical regions (A)</p> Signup and view all the answers

Why is proper waste disposal emphasized in the control of amoebiasis?

<p>To prevent the spread of cysts (A)</p> Signup and view all the answers

What is the predominant size of the Entamoeba histolytica trophozoite?

<p>25µm (D)</p> Signup and view all the answers

How does Entamoeba histolytica primarily transmit to humans?

<p>Fecal contamination of water and food (A)</p> Signup and view all the answers

What is the primary reason individuals infected with Entamoeba histolytica can spread the disease without showing symptoms?

<p>Asymptomatic carriers can excrete cysts (A)</p> Signup and view all the answers

What happens to the cysts of Entamoeba histolytica once ingested?

<p>They release amoebae into the intestinal lumen (A)</p> Signup and view all the answers

What is the first site of colonization for Entamoeba histolytica in the human body?

<p>Caecum (D)</p> Signup and view all the answers

What type of cellular structure does Entamoeba histolytica have?

<p>Partially differentiated protoplasm (C)</p> Signup and view all the answers

Which of the following describes the motility of Entamoeba histolytica?

<p>Highly active with pseudopodia (C)</p> Signup and view all the answers

What is the characteristic of primary lesions caused by Entamoeba histolytica?

<p>They show no inflammation or complication (B)</p> Signup and view all the answers

Which drug is known to be very effective against intestinal and extra-intestinal amoebiasis?

<p>Carbarsone (A)</p> Signup and view all the answers

What is the least effective drug against intestinal amoebiasis according to the information provided?

<p>Chloroquine phosphate (B)</p> Signup and view all the answers

During which stage does the amoeba reproduce through binary fission?

<p>Metacystic Trophozoites (D)</p> Signup and view all the answers

What action does Diodoquin specifically perform within the intestine?

<p>Kills trophozoites (C)</p> Signup and view all the answers

Which step marks the release of the amoeba from its cyst stage?

<p>Excystation (B)</p> Signup and view all the answers

What is the main function of the canal system in sponges?

<p>Facilitating gas exchange and nutrient absorption (B)</p> Signup and view all the answers

Which cells form the openings (ostia) in the body wall of sponges?

<p>Porocytes (B)</p> Signup and view all the answers

What is the role of choanocytes in the canal system?

<p>They create a water current for feeding and gas exchange. (A)</p> Signup and view all the answers

How does the ascon type of canal system differ from more complex systems?

<p>It has a single cavity known as the spongocoel. (B)</p> Signup and view all the answers

What structure in asconoid sponges opens to the exterior through a narrow circular opening?

<p>Osculum (B)</p> Signup and view all the answers

What is a key characteristic of the leuconoid canal system in sponges?

<p>It arises from the folding of the body wall of the sycon type. (B)</p> Signup and view all the answers

How does the size of flagellated chambers in the leuconoid system compare to those in syconoid sponges?

<p>They are smaller. (D)</p> Signup and view all the answers

What happens to the spongocoel during the formation of the leuconoid canal system?

<p>It shrinks due to division and shrinkage. (B)</p> Signup and view all the answers

What types of cells line the flagellated chambers in the leuconoid canal system?

<p>Choanocytes and pinacocytes. (D)</p> Signup and view all the answers

What is lost due to the complexity of the leuconoid canal system?

<p>The radial symmetry. (C)</p> Signup and view all the answers

What is the primary function of the incurrent canals in the sycon type canal system?

<p>To facilitate the flow of water into the radial canals (B)</p> Signup and view all the answers

Which of the following statements about radial canals is correct?

<p>They end blindly in the body wall. (D)</p> Signup and view all the answers

What anatomical feature connects incurrent canals to adjacent radial canals in the sycon canal system?

<p>Prosopyles (C)</p> Signup and view all the answers

How are the incurrent canals of some syconoid sponges specialized compared to others?

<p>They have branched structures forming subdermal spaces. (C)</p> Signup and view all the answers

In syconoid sponges, what is the role of the osculum?

<p>To serve as the exit point for water (B)</p> Signup and view all the answers

Which type of cell lines the radial canals in a syconoid sponge?

<p>Choanocytes (B)</p> Signup and view all the answers

What initiates the complexity in the sycon canal system from the ascon type?

<p>The horizontal folding of its walls (D)</p> Signup and view all the answers

Which part of the sycon canal system allows for water flow towards the spongocoel?

<p>Apopyles (A)</p> Signup and view all the answers

Flashcards

Entamoeba histolytica distribution

Cosmopolitan parasite, common in tropical/subtropical regions. Higher epidemic rates reported in certain areas like India, China, etc.

Entamoeba histolytica transmission

Spread through contaminated water/food (vegetables) and poor hygiene.

Entamoeba histolytica life cycle

Direct transmission via tetranucleate cysts. No intermediate host needed.

Entamoeba histolytica location

Lives in the lower parts of human intestines.

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Entamoeba histolytica characteristics

One-celled parasite (trophozoite), 25µm size, with specific internal features (e.g., food vacuoles, peripheral granules).

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What is Entamoeba histolytica?

A single-celled parasite that lives in the intestines of humans and causes amoebiasis.

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Where is E. histolytica most common?

Found worldwide, but especially prevalent in tropical and subtropical regions, often causing outbreaks.

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How does E. histolytica spread?

Contaminated water, food, and poor hygiene are the main routes of transmission. Tetranucleate cysts are the infectious stage.

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What are the initial symptoms of E. histolytica infection?

Often asymptomatic, but can cause diarrhea, abdominal pain, and fever.

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What happens when E. histolytica invades the intestines?

It causes tissue damage, leading to ulcers and inflammation. This can result in amoebic dysentery.

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Amoebiasis

A disease caused by the parasite Entamoeba histolytica that infects the intestines and can spread to the liver.

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How is amoebiasis spread?

It is transmitted by contaminated food or water, direct contact with infected feces, and contaminated materials like moist soil.

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Amoebic Liver Abscess

A serious complication of amoebiasis where the infection spreads to the liver, forming pus-filled pockets.

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Preventing Amoebiasis

Proper waste disposal, clean water, thorough food hygiene, and avoiding contact with infected individuals are crucial for prevention.

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Carrier State

Some people infected with E. histolytica do not experience symptoms but can still carry and spread the parasite.

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Amoeba penetration

Amoeba can travel from the submucosa layer into the serosa, potentially causing perforation.

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Amoeba's target organs

Amoeba can infect organs other than the intestines, including the liver, lungs, brain, and skin.

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Amoebic lesion development

Amoebic lesions in the large intestine are secondary to other lesions, starting with primary bottle-neck lesions that might expel trophozoites in feces.

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Ulcers and bleeding

Chronic amoebic lesions can be invaded by bacteria, leading to ulcers that release blood and mucus into the intestinal tract, visible in feces.

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Cyst survival

Entamoeba histolytica cysts can survive up to 7 days in moist environments but are vulnerable in dry or hot conditions.

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Entamoeba histolytica's Preferred Habitat

This parasite thrives in the lower parts of the human intestines, specifically in the small and large intestines.

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What does a tetranucleate cyst do?

This cyst stage of Entamoeba histolytica is how the parasite spreads. It can survive outside the host and is ingested through contaminated food or water.

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Entamoeba histolytica size

This parasitic amoeba is about 25µm in size, which is relatively large for a single-celled organism.

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How does Entamoeba histolytica move?

This amoeba uses pseudopodia, which are temporary extensions of its cytoplasm, to move around.

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Impact of Entamoeba histolytica on the Intestine

This parasite can cause significant damage to the intestinal lining, creating channels and destroying tissue.

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Entamoeba histolytica Initial Colonization

The caecum is often the first place Entamoeba histolytica sets up shop, but it can also colonize lower parts of the large intestine.

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Entamoeba histolytica Location and Prevalence

This parasite is found worldwide but is more common in tropical and subtropical areas, particularly in India, China, and South America.

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What is the canal system in sponges?

A network of channels and pores in sponges that facilitates water flow, essential for feeding, respiration, and excretion.

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What are porocytes?

Specialized cells in the outer layer of a sponge that form openings (ostia) allowing water to enter the canal system.

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What are choanocytes?

Collar cells lining the inner cavity of a sponge, with flagella that create water currents for feeding and respiration.

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What are the three types of canal systems?

Ascon, Sycon, and Leucon, each with increasing complexity and efficiency in water flow and filtration.

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What is the spongocoel?

The central cavity of a sponge where water flows through, lined with choanocytes.

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Amoebiasis Treatment

Treating amoebiasis involves using various drugs like Chiniofon, Diodoquin, and Carbarsone, each targeting different stages of the amoebic life cycle. The choice of drug depends on the type of infection (intestinal or extra-intestinal).

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Preventing Amoebic Infection

Thorough washing of vegetables before cooking is crucial to prevent cyst contamination and subsequent amoebic infection.

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Chiniofon

Chiniofon is an anti-amoebic drug that works by directly killing the amoeba and is typically administered orally as an aqueous solution. Its effectiveness is considered high.

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Amoeba Reproduction

Amoeba reproduce asexually by binary fission, where a single amoeba splits into two identical daughter amoebas.

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Amoeba Life Cycle

The amoeba's life cycle involves different stages: ingestion of RBCs, metacystic trophozoites (infective), binary fission for reproduction, excystation, and encystation.

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Leuconoid Canal System

A complex canal system found in sponges, characterized by smaller flagellated chambers and a reduced spongocoel compared to simpler systems. The system arises from folding of the sycon type, leading to loss of radial symmetry.

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Flagellated Chambers

Small chambers within the leuconoid canal system lined by choanocytes and pinacocytes. These chambers are responsible for filtering food particles from the water that flows through the sponge.

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Spongocoel in Leuconoid System

The central cavity of the sponge. In the leuconoid system, it is much smaller than in the syconoid or asconoid systems due to the folding and division of the cavity.

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Choanocytes

Collar cells lining the flagellated chambers in leuconoid sponges, responsible for creating water currents and capturing food particles.

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Pinacocytes

Flat cells covering the outer surface of the sponge and lining the canals.

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Sycon Canal System

A more complex canal system found in syconoid sponges, characterized by radial canals lined with choanocytes, incurrent canals, and a narrow spongocoel.

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Radial Canals

Parallel canals in the sycon canal system lined with choanocytes, responsible for water filtration and moving water towards the spongocoel.

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Incurrent Canals

Canals on the outer surface of the sycon sponge, leading to incurrent pores which allow water to enter the canal system.

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Prosopyles

Tiny openings connecting incurrent canals to the radial canals, allowing filtered water to move inward.

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Apopyles

Openings connecting the radial canals to the spongocoel, allowing filtered water to flow into the central chamber.

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Spongocoel

A narrow, non-flagellated central cavity in sycon sponges, lined by pinacocytes.

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Osculum

The single excurrent opening in sycon sponges, where filtered water exits the body.

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How is the sycon canal system derived?

It is derived by horizontally folding the walls of the ascon type canal system, a process that can be observed during the embryonic development of syconoid sponges.

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