ATI RN

1. Which of the following bones is a component of the appendicular skeleton?

• A. Xiphoid process
• B. Symphysis pubis
• C. Sacrum
• D. Sternum

Correct Answer: Symphysis pubis

Rationale: The correct answer is B: Symphysis pubis. The symphysis pubis is a component of the appendicular skeleton, specifically part of the pelvic girdle. The xiphoid process (Choice A) is part of the axial skeleton, located at the lower end of the sternum. The sacrum (Choice C) is also part of the axial skeleton, forming the posterior part of the pelvis. The sternum (Choice D) is part of the axial skeleton, located in the center of the chest.

2. Testosterone production is regulated by which of the following glands?

• A. Pineal
• B. Thymus
• C. Parathyroid
• D. Pituitary

Correct Answer: D

Rationale: Testosterone production is regulated by the pituitary gland. The pituitary gland secretes luteinizing hormone (LH), which stimulates the Leydig cells in the testes to produce testosterone. This hormone is not regulated by the Pineal, Thymus, or Parathyroid glands. The Pineal gland is responsible for secreting melatonin, the Thymus gland is involved in immune function, and the Parathyroid glands regulate calcium levels in the blood.

3. Which of the following is the measurement of the percentage of red blood cells in whole blood?

• A. Hematocrit
• B. Hemoglobin
• C. Mean corpuscular volume
• D. Reticulocyte count

Correct Answer: Hematocrit

Rationale: The correct answer is 'Hematocrit.' Hematocrit is the measurement of the percentage of red blood cells in whole blood. It is used to diagnose conditions such as anemia and dehydration. Choice B, 'Hemoglobin,' measures the amount of hemoglobin in the blood, not the percentage of red blood cells. Choice C, 'Mean corpuscular volume,' measures the average volume of a red blood cell, not the percentage of red blood cells. Choice D, 'Reticulocyte count,' measures the percentage of young red blood cells in the blood, not the percentage of red blood cells.

4. Which of the following structures of the gastrointestinal system absorbs iron and bile salts?

• A. Ileum
• B. Jejunum
• C. Colon
• D. Duodenum

Correct Answer: Ileum

Rationale: The correct answer is the Ileum. The Ileum is the final section of the small intestine where the absorption of key nutrients such as iron and bile salts occurs. The Jejunum mainly absorbs nutrients like carbohydrates and proteins, while the Duodenum primarily facilitates the absorption of minerals and vitamins. The Colon's main function is to absorb water and electrolytes, not iron and bile salts. Therefore, choices B, C, and D are incorrect.

5. In a normally functioning cardiovascular system, where does the heartbeat originate?

• A. Atrioventricular nodes
• B. Bundle of His
• C. Purkinje fibers
• D. Sinoatrial node

Correct Answer: Sinoatrial node

Rationale: The correct answer is the Sinoatrial (SA) node. The SA node is known as the natural pacemaker of the heart as it initiates the electrical impulses responsible for the heartbeat. The other choices, such as the Atrioventricular (AV) nodes, Bundle of His, and Purkinje fibers, are involved in conducting the electrical signals generated by the SA node to coordinate the heart's contractions. Therefore, they do not serve as the primary origin of the heartbeat.