Nokea
Which valve prevents the return of blood into the right ventricle?
- A. Pulmonary semilunar valve
- B. Aortic semilunar valve
- C. Tricuspid valve
- D. Mitral valve
Correct Answer: A
Rationale: The correct answer is A: Pulmonary semilunar valve. The pulmonary semilunar valve is located between the right ventricle and the pulmonary artery. It opens to allow blood to be pumped into the pulmonary artery but closes to prevent blood from returning back into the right ventricle. The aortic semilunar valve is located between the left ventricle and the aorta. The tricuspid valve is located between the right atrium and right ventricle, and the mitral valve is located between the left atrium and left ventricle. Therefore, the pulmonary semilunar valve is the specific valve responsible for preventing the backflow of blood into the right ventricle during the cardiac cycle.
You may also like to solve these questions
Which of the following arteries are not branches of the facial artery in the cervical portion?
- A. Ascending palatine artery
- B. Glandular artery
- C. Superior labial artery
- D. Tonsillar artery
Correct Answer: C
Rationale: The correct answer is C, the Superior labial artery. It is a branch of the facial artery in the facial portion, not in the cervical portion. The ascending palatine artery, glandular artery, and tonsillar artery are branches of the facial artery in the cervical portion. The ascending palatine artery supplies the palate, the glandular artery provides blood to the salivary glands, and the tonsillar artery is responsible for supplying blood to the tonsils. These arteries play a crucial role in the vascular supply of the head and neck region, aiding in various physiological functions.
What are the two primary functions of the respiratory system?
- A. Delivering nutrients and removing CO2
- B. Delivering O2 and removing CO2, maintaining blood pH
- C. Maintaining blood pH and delivering nutrients
- D. Delivering O2 and nutrients to the cells
Correct Answer: B
Rationale: The correct answer is B. The respiratory system's primary functions include delivering oxygen (O2) to the body's cells for cellular respiration and removing carbon dioxide (CO2), thereby aiding in the maintenance of blood pH. These functions are crucial for gas exchange and the overall metabolic processes within the body. Choice A is incorrect as the respiratory system primarily delivers O2, not nutrients, and removes CO2, not delivering it. Choice C is incorrect as while the respiratory system helps maintain blood pH by removing CO2, it does not primarily deliver nutrients. Choice D is incorrect as it combines the functions of delivering O2 and nutrients, which are distinct roles of different systems in the body.
Which chamber of the heart is the largest?
- A. Right atrium
- B. Left atrium
- C. Right ventricle
- D. Left ventricle
Correct Answer: D
Rationale: The correct answer is D, the left ventricle. The left ventricle is the largest and strongest chamber of the heart. It is responsible for pumping oxygenated blood to the entire body through the aorta, playing a crucial role in the circulatory system. Choices A, B, and C are incorrect. The right atrium receives deoxygenated blood from the body, the left atrium receives oxygenated blood from the lungs, and the right ventricle pumps deoxygenated blood to the lungs for oxygenation. However, the left ventricle is the largest chamber and performs the vital function of pumping oxygen-rich blood to the body.
What is the main function of red blood cells?
- A. Transport oxygen
- B. Transport carbon dioxide
- C. Regulate blood pressure
- D. Regulate heart rate
Correct Answer: A
Rationale: The correct answer is A: Transport oxygen. Red blood cells are primarily responsible for carrying oxygen from the lungs to the tissues in the body. Hemoglobin, a protein found in red blood cells, binds to oxygen in the lungs and releases it to cells throughout the body. This oxygen transport is essential for cellular respiration and energy production in the body. Red blood cells do not regulate blood pressure or heart rate; their main role is oxygen transport. Choices B, C, and D are incorrect because red blood cells do not transport carbon dioxide, regulate blood pressure, or regulate heart rate. These functions are primarily carried out by other components of the circulatory and regulatory systems.
What is the purpose of sodium bicarbonate when released into the lumen of the small intestine?
- A. It works to chemically digest fats in the chyme.
- B. It decreases the pH of the chyme to prevent harm to the intestine.
- C. It works to chemically digest proteins in the chyme.
- D. It increases the pH of the chyme to prevent harm to the intestine.
Correct Answer: D
Rationale: Sodium bicarbonate, when released into the lumen of the small intestine, functions to increase the pH of the acidic chyme coming from the stomach. This increase in pH helps neutralize the acidity of the chyme, creating a more optimal environment for the digestive enzymes in the small intestine to function properly. Maintaining a slightly basic pH in the small intestine is crucial for overall digestion and absorption of nutrients. Choices A, B, and C are incorrect. Sodium bicarbonate does not chemically digest fats or proteins in the chyme, and it does not decrease the pH of the chyme as it actually increases the pH to prevent harm to the intestine.