Nokea
Which of the following is produced by Natural Killer Cells to create pores for target cell rupture?
- A. Interferon
- B. Apoptosis
- C. Perforin
- D. Antibody
Correct Answer: C
Rationale: The correct answer is C, Perforin. Natural Killer cells release perforin, which forms pores in the membrane of target cells, leading to their lysis. Interferon (choice A) is a protein released by cells in response to viral infections, apoptosis (choice B) is programmed cell death, and antibodies (choice D) are produced by B cells to neutralize pathogens but are not directly involved in creating pores for cell rupture like perforin.
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What is the primary function of the cardiovascular system?
- A. To transport oxygen and nutrients
- B. To regulate blood pressure
- C. To digest food
- D. To filter waste products
Correct Answer: A
Rationale: The primary function of the cardiovascular system is indeed to transport oxygen and nutrients to various tissues in the body. Choice B, 'To regulate blood pressure,' is incorrect as blood pressure regulation is one of the functions of the cardiovascular system but not its primary function. Choice C, 'To digest food,' is incorrect as digestion is primarily a function of the digestive system, not the cardiovascular system. Choice D, 'To filter waste products,' is incorrect as waste product filtration is primarily carried out by the kidneys and liver, not the cardiovascular system.
Which of the following statements regarding the pericardium is not correct?
- A. It allows for the heart to work in a relatively friction-free environment
- B. It is a single-walled layer around the heart
- C. It prevents overfilling of the heart with blood
- D. It protects and anchors the heart
Correct Answer: B
Rationale: The correct statement about the pericardium is that it is double-walled, not single-walled. Choice A is correct because the pericardium does allow the heart to work in a relatively friction-free environment, reducing friction during heartbeats. Choice C is correct as the pericardium helps prevent the overfilling of the heart with blood. Choice D is also correct as the pericardium serves to protect and anchor the heart in place within the chest cavity.
Which of the following statements is true about an allergic reaction?
- A. An allergic reaction, such as hives or wheezing, results from overactive body systems such as the integumentary and respiratory systems.
- B. An allergic reaction is a result of overactive B-cells in the body that release various immunoglobulins.
- C. An allergic reaction is caused by overactive mast cells in the body, which are stimulated by Immunoglobulin E.
- D. An allergic reaction involves substances like histamine, keratin, and collagen.
Correct Answer: C
Rationale: The correct answer is C. Mast cells are responsible for releasing histamine and other chemicals during an allergic response. Choice A is incorrect because hives and wheezing are symptoms of an allergic reaction, not the causes. Choice B is incorrect as B-cells are not directly involved in allergic reactions. Choice D is incorrect as keratin and collagen are not typically involved in allergic reactions, and histamine is released by mast cells.
Which part of the brain is responsible for controlling involuntary functions like breathing and heart rate?
- A. Cerebrum
- B. Medulla oblongata
- C. Cerebellum
- D. Thalamus
Correct Answer: B
Rationale: The medulla oblongata is located at the base of the brainstem and is responsible for controlling vital involuntary functions such as breathing, heart rate, and blood pressure. The cerebrum, although the largest part of the brain, is primarily responsible for higher brain functions like thinking and voluntary muscle movements. The cerebellum is involved in coordination, balance, and muscle control. The thalamus acts as a relay station for sensory information but is not directly responsible for regulating involuntary functions like breathing and heart rate. Therefore, the correct answer is the medulla oblongata.
Which of the following is responsible for maintaining homeostasis in the body?
- A. Brainstem
- B. Hypothalamus
- C. Medulla oblongata
- D. Cerebrum
Correct Answer: B
Rationale: The correct answer is the Hypothalamus (choice B). The hypothalamus plays a crucial role in maintaining homeostasis by regulating various bodily functions such as hunger, thirst, body temperature, and sleep cycles. While the brainstem (choice A) is involved in basic life functions like breathing and heart rate, it is not primarily responsible for maintaining homeostasis. The medulla oblongata (choice C) is part of the brainstem and controls vital autonomic functions like breathing and heart rate, but it is not the main regulator of homeostasis. The cerebrum (choice D) is responsible for higher brain functions such as thinking, memory, and voluntary movement, but it is not directly involved in maintaining overall bodily balance or homeostasis.