Question
Which defence prevents pathogens from entering the body?
-
-
antibody production
-
mucus
-
phagocytosis
-
vaccination
Answer/ExplanationB
Mucus is the defense that prevents pathogens from entering the body.
Mucus is a sticky and viscous substance produced by the body’s mucous membranes, such as those in the respiratory and digestive tracts. It acts as a physical barrier that traps pathogens, dust, and other particles from entering the body. Mucus also contains various antimicrobial substances that help to neutralize and eliminate pathogens before they can reach and infect the underlying tissues.
-
Question
The body has different types of defences against pathogens.
1 antibodies
2 hairs in the nose
3 mucus
4 skin
Which defences help to prevent pathogens reaching the alveoli when breathing in?
A 1, 2, and 3 B 2, 3, and 4 C 2 and 3 only D 2 only
Answer/Explanation
C
The correct answer is C. 2 and 3 only (hairs in the nose and mucus).
The alveoli are the tiny air sacs in the lungs where the exchange of oxygen and carbon dioxide takes place. When breathing in, several defenses work together to prevent pathogens from reaching the alveoli:
Hairs in the nose: The hairs in the nose act as a physical barrier, helping to filter out large particles and pathogens from the inhaled air. They trap dust, pollen, and other particles, preventing them from reaching the alveoli.
Mucus: Mucus is produced by the respiratory system and serves as a protective layer in the airways. It traps pathogens and other particles, which are then either expelled by coughing or sneezing or moved upward by cilia (tiny hair-like structures) to be swallowed and destroyed by stomach acid. Mucus also helps humidify and warm the inhaled air.
Question
Antibiotics can be used to treat some infections.
Antibiotics can treat infections caused by
A all pathogens.
B bacteria and viruses only.
C bacteria only.
D viruses only.
Answer/Explanation
C bacteria only.
Antibiotics are effective in treating infections caused by bacteria, but they do not work against viruses. Viral infections are generally managed through antiviral medications, which specifically target viruses. It is important not to use antibiotics to treat viral infections as it can lead to antibiotic resistance and other potential side effects without effectively treating the viral infection.
Question
The diagram shows one way the body defends itself against pathogens.
▶️Answer/Explanation
C
Phagocytosis is a vital process performed by certain cells of the immune system to engulf and digest foreign particles, such as bacteria, viruses, dead cells, and other debris. It is an essential component of the body’s innate immune response, serving as a defense mechanism against potential threats. The primary cells responsible for phagocytosis are called phagocytes, which include various types of white blood cells, such as macrophages and neutrophils.
Phagocytosis is an essential process for maintaining the body’s defense against infections and plays a crucial role in both innate and adaptive immune responses.
Question
A pathogen is defined as
A a contaminated surface or food.
B a disease-causing organism.
C a transmissible disease.
D a virus.
▶️Answer/Explanation
B
B a disease-causing organism.
A pathogen is generally defined as any biological agent, such as a virus, bacterium, fungus, parasite, prion, or other microorganism, that causes disease or illness in its host organism. It is the causative agent responsible for the development of an infectious disease. Option B correctly represents this definition.