ZEB Chpt 3(1/2)Pg.65-80 And BIO 152 Chpt 24 Flashcards
- Helminths that affect humans belong to which two phyla a) Platyhelminthes and Annelida b) Platyhelminthes and Nematelminthes c) Nematelminthes and Cnidaria d) Cnidaria and Platyhelminthes
Answer b) Platyhelminthes and Nematelminthes Explanation These are the two major phyla that include helminths (worms) affecting humans Platyhelminthes (flatworms like trematodes and cestodes) and Nematelminthes (roundworms)
- What are the two subclasses of Trematoda a) Aspidogastrea and Cestoda b) Aspidogastrea and Digenea c) Digenea and Monogenea d) Cestoda and Monogenea
Answer b)monogenea and Digenea Explanation Trematoda is divided into monogenea (less parasitic) and Digenea (includes most parasitic flukes)
- What is the first host in the life cycle of almost all trematodes a) Fish b) Birds c) Molluscs d) Humans
Answer c) Molluscs Explanation Molluscs usually snails serve as the intermediate hosts for trematodes where larval development begins
- Which of the following is NOT a characteristic of Aspidogastrea a) They have no acetabulum b) They are commonly digenetic c) Reproduction in water is rare d) They primarily infect molluscs
Answer b) They are commonly digenetic Explanation Aspidogastrea are monogenetic requiring only one host unlike digenetic trematodes like Digenea
- What is the name of the larval form that exemplifies the remarkable life history of asexual reproduction in trematodes a) Miracidium b) Sporocyst c) Redia d) Cercaria
Answer a) Miracidium Explanation Miracidium is the first larval stage capable of asexual reproduction in its snail host
- What is the definitive host in the life cycle of Leucochloridium paradoxum a) Snail b) Bird c) Fish d) Mollusc
Answer b) Bird Explanation Birds are the definitive hosts where sexual reproduction occurs
- Which stage of the trematode life cycle is described as a transparent larvae a) Miracidia b) Sporocyst c) Redia d) Cercaria
Answer a) Miracidia Explanation The miracidium stage is free-swimming and transparent seeking its snail host
- Where in the snail’s body do redia move to mature into cercaria a) Digestive gland b) Brood sac c) Central body d) Foot
Answer b) Brood saExplanation Redia move to the brood sac for further development into cercaria
- Which genus of flukes has collars of spines behind the oral sucker a) Gastrodiscoides b) Echinostoma c) Paragonimus d) Clonorchis
Answer a) Gastrodiscoides Explanation These spines aid in attachment to the host
- In which host does the cercariae of the genus Paragonimus encyst a) Molluscs b) Crustaceans c) Insects d) Fish
Answer b) Crustaceans Explanation Cercariae encyst in crustaceans like crabs or crayfish
- Where are the testes located in flukes of the genus Opisthorchis a) Side by side behind the ovary b) In tandem behind the ovary c) In front of the ovary d) Within the ovary
Answer b) In tandem behind the ovary Explanation The testes of Opisthorchis are arranged in tandem (one behind the other) which is a distinguishing characteristic
- Which family of flukes is characterized as minute flukes a) Echinostomatidae b) Heterophyidae c) Opisthorchiidae d) Dicrocoeliidae
Answer b) Heterophyidae Explanation Heterophyidae flukes are small-sized intestinal parasites
- The excretory system of Heterophyes consists of what a) A single excretory pore b) Two intestinal caeca flame cells collecting tubules and an excretory pore c) Flame cells and an excretory pore d) Two intestinal caeca and an excretory pore
Answer b) Two intestinal caeca flame cells collecting tubules and an excretory pore Explanation This complex excretory system is typical of trematodes for osmoregulation and waste removal
- Intestinal and liver trematodes can be broadly divided into two groups What are they a) Those that reside in the bile ducts and those that inhabit the liver b) Those that reside in the liver and those that inhabit the intestines c) Those that reside in the intestines and those that inhabit the bile ducts d) Those that reside in the blood vessels and those that reside in the lungs
Answer c) Those that reside in the intestines and those that inhabit the bile ducts Explanation Trematodes are classified based on their habitat in the host’s body
- What is the intermediate host of Fasciola buski a) Fish b) Aquatic plants c) Snails d) Crabs
Answer c) snails Explanation Encysted metacercariae of snails are found on aquatic plants consumed by humans
- What is the morphology of adult trematodes worms a) Round b) Flat c) Cylindrical d) Spiral
Answer b) Flat Explanation Adult trematodes are dorsoventrally flattened earning them the name flatworms
- How can adult worms be readily differentiated a) By their size b) By their color c) By their shape and morphology d) By the host they infect
Answer c) By their shape and morphology Explanation The shape and structural details like spines and suckers help identify species
- Where are eggs in the life cycle pattern for intestinal flukes found a) Urine b) Feces c) Blood d) Sputum
Answer b) Feces Explanation Intestinal fluke eggs are expelled from the host in feces
- Where does the metacercariae encyst in the life cycle pattern for intestinal flukes a) Intestines of humans b) Vegetation or in fish crab or crayfish c) Lungs of humans d) Water
Answer b) Vegetation or in fish crab or crayfish Explanation Metacercariae encyst on vegetation or intermediate hosts before being ingested by humans
- How do cercariae emerge a) They are ingested b) They are inhaled c) They develop into progangani d) They are released from the snail into water
Answer d) They are released from the snail into water Explanation Cercariae actively leave the snail to seek their next host in water
- Why is the zinc sulphate floatation technique not recommended for concentrating trematode eggs? a) The eggs are too dense. b) The egg shell is very fragile and may break at the concentration of the salt. c) The eggs are too small. d) The eggs are not buoyant.
Explanation: Zinc sulphate floatation technique is not recommended because the egg shell of trematode eggs is fragile and the concentration of zinc sulphate may cause the eggs to break leading to inaccurate results.
- How can adult worms be detected in a patient undergoing treatment for a heavy infection? a) Urine sample b) Blood sample c) Sputum sample d) Feces
Explanation: Adult worms can be detected through fecal examination as the eggs or worms may be passed out in the feces during heavy infections.
- Which of the following is a characteristic of schistosomes that is different from other trematodes? a) They are hermaphrodites. b) They are not hermaphrodites. c) Their life cycle is the same as other trematodes. d) The infection occurs by ingestion.
Explanation: Schistosomes are dioecious (not hermaphroditic) unlike other trematodes that are typically hermaphrodites.
- How does the infection by the larval form the cercaria occur in schistosomes? a) Through skin penetration b) Through ingestion c) Through inhalation d) Through contact with contaminated water
Explanation: Schistosome infection occurs when cercariae penetrate the skin of the host.
- Where do adult worms of schistosomes live? a) Liver b) Intestines c) Lungs d) Blood vessels
Explanation: Adult schistosome worms reside in the blood vessels of the host particularly in the venules of the intestines or bladder.
- Which species of Schistosoma causes urinary schistosomiasis? a) Schistosoma mansoni b) Schistosoma japonicum c) Schistosoma haematobium d) Schistosoma mekongi
Explanation: Schistosoma haematobium is the species responsible for urinary schistosomiasis affecting the bladder and urinary tract.
- In what bodily fluid are eggs of schistosomes passed? a) Feces or urine b) Blood c) Sputum d) Saliva
Explanation: Schistosome eggs are passed in the feces or urine depending on the species.
- What is the name of the larval stage that penetrates snail host in the life cycle of schistosomes? a) Miracidium b) Cercariae c) Sporocyst d) Redia
Explanation: The miracidium are the free-swimming larval stage of schistosomes that penetrate the snail host.
- What characteristic of the cercariae helps them to penetrate human skin? a) They have a tail. b) They have a bifurcated tail. c) They are very small. d) They release enzymes.
Explanation: The enzyme activity of cercariae aids in and helps them penetrate human skin.
- Where in the human body do the cercariae of Schistosoma finally enter a blood vessel and mature into an adult? a) Heart b) Liver sinusoids c) Lungs d) Brain
Explanation: The cercariae enter the blood vessels through the liver sinusoids where they mature into adult worms.
- How do the adult worms of Schistosoma reside in the venules? a) Singly b) In groups c) In pairs d) It varies depending on the species.
Explanation: Adult schistosome worms are usually found in pairs in the venules with the female residing in the male’s gynecophoric canal.
- Where are the eggs of Schistosoma mansoni deposited? a) Veins of the bladder b) Intestine c) Liver d) Lungs
Explanation: Schistosoma mansoni eggs are deposited in the intestinal venules and later passed out in the feces.
- Where are the eggs of Schistosoma haematobium deposited? a) Veins of the bladder b) Intestine c) Liver d) Lungs
Explanation: Schistosoma haematobium eggs are deposited in the veins of the bladder and passed out through urine.
- What is the morphology of Schistosoma adult worms? a) Round b) Cylindrical c) Flat leaf-like d) Spiral
Explanation: Adult Schistosoma worms have a flat leaf-like morphology that allows them to fit within the venules.
- What is a distinctive feature of male Schistosoma worms? a) They have a gynecophoric canal. b) They have testes. c) They have a ventral sucker. d) Their body is folded to form a ventral gynaecophoric canal.
Explanation: Male Schistosoma worms have a folded body that forms a gynecophoric canal to house the female during mating.
- When are eggs of Schistosoma released immature? a) When first laid b) After a few days c) When they reach the liver d) When they reach the intestines
Explanation: Schistosoma eggs are released immature and only develop later in the environment.
- What is contained in the mature miracidium of Schistosoma? a) A tail b) A shell c) A fully developed embryo d) Eggs
Explanation: The mature miracidium contains a fully developed embryo that is capable of infecting the snail host.
- What helps in differentiating the eggs of Schistosoma? a) Size of the egg b) Shape of the egg c) Position of the spine d) All of the above
Explanation: Differentiating Schistosoma eggs relies on their size shape and position of the spine.
- What is contained within the Schistosoma egg when passed out in urine or feces? a) An immature embryo b) A fully developed miracidium c) A cercaria d) A sporocyst
The correct answer is a) An immature embryo.
Schistosoma eggs, when passed out in urine or feces, contain an immature embryo. These eggs are released by adult female Schistosoma worms and are passed out of the host’s body. Once they reach water, the eggs hatch, and the immature embryo inside develops into a miracidium, which is the next larval stage. The miracidium then swims in search of an intermediate host (usually a snail) to continue its life cycle.
Here’s the reasoning for each option:
a) An immature embryo: This is correct because Schistosoma eggs initially contain an immature embryo, which will later hatch into a miracidium.
b) A fully developed miracidium: Incorrect, as the miracidium is not fully developed inside the egg. It hatches and develops after the egg reaches water.
c) A cercaria: Incorrect, as the cercaria is a later stage in the life cycle that emerges from the snail after the miracidium has infected it.
d) A sporocyst: Incorrect, because the sporocyst is formed inside the snail, not within the egg.
Thus, Schistosoma eggs initially contain an immature embryo, which will hatch and continue the lifecycle in a freshwater environment.
- Which diagnostic method can be used to detect Schistosoma haematobium eggs that may not be seen in stool? a) Urine examination b) Rectal biopsy c) Blood test d) Sputum examination
Explanation: Rectal biopsy may be used to detect Schistosoma haematobium eggs in cases where they are not detected in stool samples.
- How is a viable miracidium indicated? a) By the presence of eggs b) By the presence of adult worms c) By the flickering of flame cells d) By the presence of granulomas
Explanation: The flickering of flame cells is an indication of a viable miracidium.
- How many phases can the clinical symptoms of schistosomiasis be divided into? a) Two b) Three c) Four d) Five
Explanation: The clinical symptoms of schistosomiasis are typically divided into three phases: acute subacute and chronic.
- When does Katayama fever occur in infections with Schistosoma mansoni and Schistosoma japonicum? a) Immediately after infection b) About a month after infection c) Several months after infection d) Years after infection
Explanation: Katayama fever occurs about a month after infection during the acute phase of schistosomiasis.
- What is the characteristic symptom of Schistosoma haematobium? a) Hepatosplenomegaly b) Diarrhea c) Hematuria d) Fever
Explanation: Hematuria (blood in urine) is a characteristic symptom of Schistosoma haematobium infection.
- What facilitates the passage of Schistosoma eggs on the lumen of the bladder or the intestine? a) Their size b) Their shape c) A number of enzymes d) Blood flow
Explanation: The passage of Schistosoma eggs is facilitated by a number of enzymes that help break down tissue barriers in the bladder or intestine.
- The concept of health can be understood differently depending on perspective. For a pathologist health primarily focuses on: a. Sound mind and normal function of the body b. Normal biochemical values c. Correct existence of genetic potential d. Normal cellular make-up
Explanation: The text explicitly states that “To a Pathologist it means normal cellular make-up.”
- Disease can be simply defined as: a. A state of complete physical mental and social well-being b. Absence of difficulty c. An abnormal condition a disorder of a structure or function that affects part or all of an organism d. Suffering and its study
Explanation: The text states that “Disease = absence of difficulty.” While the other options touch upon aspects of disease or health they don’t represent the simplified definition provided in the text.
- What is the core focus of the study of pathology? a. The causes of suffering b. The biological agent that causes a disease or illness c. The absence of difficulty d. The mechanisms by which an infection leads to disease
Explanation: Pathology is specifically defined as “the study of the cause of disease.”
- Which of the following is a defining characteristic of a pathogen? a. All pathogens are microorganisms b. They are capable of causing disease c. They always produce toxins d. They are solely responsible for virulence
Explanation: The text emphasizes that pathogens are “microbes that are capable of causing disease.” It’s important to note that not all microorganisms are pathogenic.
- Virulence factors contribute to a pathogen’s ability to: a. Reproduce within a host b. Evade the host’s immune system c. Cause disease in a host d. Be transmitted between hosts
Explanation: Virulence factors including toxins give reasonable contribution to cause the disease. They enhance the pathogen’s capacity to inflict harm on the host.