CBSE Questions for Class 12 Medical Biology Human Health And Disease Quiz 10 - MCQExams.com

• Nematodes commonly parasitic on humans include ascarids (Ascaris), filariasis, hookworms, pinworms (Enterobius), and whipworms (Trichuris trichiura).
• Helminths include members of the following taxa: monogeneans, cestodes (tapeworms), nematodes (roundworms), trematodes (flukes), and acanthocephalans (thorny-headed worms).
• Filariasis is a parasitic disease caused by an infection with roundworms of the Filarioidea type.

• Filariasis is a parasitic disease caused by an infection with roundworms(For example,wuchereria bancrofti) of the Filarioidea type. Common symptoms include swollen lymph nodes.
• In India, filariasis is transmitted by Culex fatigens mosquito. It is a  medium-sized mosquito found in tropical and subtropical regions of the world.
  
• Hence In India, filariasis is transmitted by Culex fatigens.
• So, the correct answer is 'Culex fatigens'.

• The pseudocoelom is a fluid-filled body cavity lying inside the external body wall of the nematode that bathes the internal organs, including the alimentary system and the reproductive system.

• The rhabditid nematode (roundworm) Strongyloides stercoralis is the major causative agent of strongyloidiasis in humans and also a free-living autoinfective parasite.
• The life cycle of this parasite alters between two different types: a free-living cycle and a parasitic cycle. That means it can survive as both free-living and parasitic worm.
  
• Its parasitic life cycle begins once it is inside the host, then filariform larvae travel to the lungs through the circulatory system.
• Here they penetrate and enter the alveolar cavities, are carried up through the bronchi, the trachea, and into the pharynx (essentially the host coughs up the larvae), where they are swallowed by the host and eventually reach the small intestine. 
• In the small intestine, the larvae develop into an adult female worm that produces eggs by parthenogenesis, these eggs then hatch to release rhabditiform larvae.
• These rhabditiform larvae now enter the autoinfection cycle.
• In autoinfection, the newly hatched rhabditiform larvae molt to become infective filariform larvae and later again penetrates the intestinal mucosa to enter circulation, and the same cycle is repeated.

• Filariasis is a parasitic disease caused by an infection with roundworms of the Filarioidea type. These are spread by blood-feeding Diptera as black flies and mosquitoes.
• Leishmaniasis is a disease caused by parasites of the Leishmania type. It is spread by the bite of certain types of sandflies.
  
• Malaria is a life-threatening disease caused by parasites that are transmitted to people through the bites of infected female Anopheles mosquitoes.
• Ascariasis occurs when a type of roundworm known as Ascaris lumbricoides infects the small intestine.

• A macrophage is a type of white blood cell (WBC) present within the immune system of the body.
• It engulfs and digests cell debris, foreign substances, microbes, cancer cells etc and this process is known as phagocytosis.
• They are also known as phagocytes and are present in all the tissues where they keep a check for the pathogens.
• They show amoeboid movement. 

• The anterior V-spot in Wuchereria represents the rudimentary excretory system.
  
• It is rudimentary as it functioned during the larval stage called the microfilaria.

• Third stage larva of Wuchereria bancrofti called microfilarie develops on 10-11th day of development. 
  
• It is almost five times to that of second stage. The spiky tail degenerates, while various organs; such as digestive and genital organs; and the body cavity are well developed. 
• The third stage larva is infective to man. On about 14th day, it migrates to the proboscis of the mosquito.
  

• Ascaris is a roundworm (phylum Nematoda) and has a segmented body.
• 
  
• Platyhelminthes have flat and segmented bodies.

Increase in size of the cells is called Auxetic growth. It occurs in both plants and animals. In plants, auxetic growth is concerned in increasing in cell size. In animals, it occurs in certain tissues, such as muscles, of the higher animals as well as in some organisms like nematodes, tunicates, and rotifers.

Increase in size of the cells is called Auxetic growth. It occurs in both plants and animals. In plants, auxetic growth is concerned in increasing in cell size. In animals, it occurs in certain tissues, such as muscles, of the higher animals as well as in some organisms like nematodes, tunicates, and rotifers.

A. Auxetic growth – Growth takes place only by an increase in the volume of cells.

B. Multiplicative growth – Growth takes place only by an increase in the number of cells.

C. Accretionary growth - It involves a cell secretion to increase the volume of the extracellular spaces. Many adult tissues will only divide when induced by injury or other stimuli. It occurs in cartilage and bone.

D. Differential growth – Growth involves the formation of different types of cells.

• Marijuana is extracted from the leaves and flowers of Cannabis sativa. It is considered as one of the abused drugs. 
• It can be used for smoking. It is usually green, brown, or gray in color. It is a mixture of dried-out leaves, stems, flowers, and seeds of the hemp plant. It is popularly known as cannabis. 
• Dizziness, vomiting, and hallucinations are some common symptoms.

Ascaris lumbricoides is the large roundworm infecting human beings. It is the most common roundworm infecting humans. It is responsible for ascariasis disease. An estimated one-sixth of the human population is infected by Ascaris lumbricoides. The mode of transmission of disease in humans is via the faecal-oral route. Eggs released by adult females are shed in faeces. So, the correct answer is 'Ascaris lumbricoides'.