Nursing Elites

1. Which of the following structures is responsible for preventing the backflow of blood from the left ventricle into the left atrium?

• A. Aortic valve
• B. Pulmonary valve
• C. Tricuspid valve
• D. Mitral valve

Correct answer: D

Rationale: The correct answer is D, the Mitral valve. The mitral valve, also known as the bicuspid valve, is situated between the left atrium and the left ventricle. Its primary function is to prevent the backflow of blood from the left ventricle into the left atrium during ventricular contraction. The other choices are incorrect because: A) The aortic valve prevents backflow from the aorta into the left ventricle. B) The pulmonary valve prevents backflow from the pulmonary artery into the right ventricle. C) The tricuspid valve prevents backflow from the right ventricle into the right atrium.

2. What is the role of the diaphragm in the respiratory system?

• A. To regulate blood pressure
• B. To contract and expand the lungs
• C. To produce red blood cells
• D. To absorb oxygen

Correct answer: B

Rationale: The correct answer is B: To contract and expand the lungs. The diaphragm plays a crucial role in the respiratory system by contracting and expanding the lungs. When it contracts, it flattens, increasing the volume of the thoracic cavity and causing air to be drawn into the lungs. Conversely, when it relaxes, it moves back up, decreasing the thoracic cavity volume and pushing air out of the lungs. This process is essential for breathing and the exchange of oxygen and carbon dioxide in the body. Choices A, C, and D are incorrect. The diaphragm is not involved in regulating blood pressure, producing red blood cells, or absorbing oxygen. Its primary function is to aid in respiration by facilitating breathing through its contraction and relaxation movements.

3. Which of the following is NOT one of the major types of bones in the human body?

• A. Dense bone
• B. Long bone
• C. Short bone
• D. Irregular bone

Correct answer: A

Rationale: The correct answer is A: 'Dense bone'. Dense bone is not a classification of bone types in the human body. The major types of bones include long, short, flat, and irregular bones. Long bones, like the femur, are characterized by being longer than they are wide. Short bones, such as those in the wrist (carpals) and ankle (tarsals), are generally cube-shaped. Flat bones, like the skull or scapula, are thin and provide protection. Irregular bones, such as the vertebrae, have complex shapes that do not fit into the other categories.

4. What is the name of the microscopic finger-like projections that increase the surface area for absorption in the small intestine?

• A. Goblet cells
• B. Paneth cells
• C. Villi
• D. Crypts of Lieberkühn

Correct answer: C

Rationale: A) Goblet cells: Goblet cells are specialized cells that secrete mucus to protect the lining of the digestive tract. While important for maintaining the health of the intestines, goblet cells do not increase the surface area for absorption in the small intestine. B) Paneth cells: Paneth cells are specialized cells found in the small intestine that secrete antimicrobial peptides. They play a role in protecting the intestinal stem cells and maintaining the gut microbiota balance, but they do not increase the surface area for absorption. C) Villi: Villi are microscopic finger-like projections found in the small intestine that increase the surface area available for absorption of nutrients. Each villus contains blood vessels and lacteals (lymphatic vessels) that help absorb nutrients from digested food. D) Crypts of Lieberkühn: Crypts of Lieberkühn are small pits located between the villi

5. Which hormone primarily triggers ovulation in the female menstrual cycle?

• A. Estrogen
• B. Progesterone
• C. Luteinizing hormone (LH)
• D. Follicle-stimulating hormone (FSH)

Correct answer: C

Rationale: Luteinizing hormone (LH) is the hormone primarily responsible for triggering ovulation in the female menstrual cycle. LH surge occurs around the middle of the menstrual cycle, causing the mature follicle to release an egg from the ovary. Estrogen and progesterone play crucial roles in regulating the menstrual cycle and preparing the endometrium for potential implantation of a fertilized egg, but they do not trigger ovulation directly. Follicle-stimulating hormone (FSH) is essential for the development of ovarian follicles but is not the primary hormone responsible for ovulation. Therefore, the correct answer is Luteinizing hormone (LH) as it directly initiates the release of the egg during ovulation.

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