HESI A2
Quizlet HESI A2 Anatomy and Physiology
1. Which gland produces melatonin?
- A. Pineal gland
- B. Thyroid gland
- C. Adrenal gland
- D. Pituitary gland
Correct answer: A
Rationale: The correct answer is the Pineal gland. This gland is responsible for producing melatonin, a hormone that helps regulate the sleep-wake cycle. Melatonin production is influenced by exposure to light, with levels typically rising in the evening to promote sleep and falling in the morning to aid wakefulness. The Thyroid gland (choice B) produces hormones that regulate metabolism, the Adrenal gland (choice C) produces hormones like adrenaline and cortisol, and the Pituitary gland (choice D) controls several other glands in the endocrine system.
2. Which muscle is responsible for breathing?
- A. Diaphragm
- B. Intercostal muscles
- C. Rectus abdominis
- D. Pectoralis major
Correct answer: A
Rationale: The diaphragm is the primary muscle responsible for breathing. It is a large, dome-shaped muscle located at the base of the chest cavity. When it contracts, it flattens, increasing the volume of the chest cavity and causing inhalation. When it relaxes, it returns to its dome shape, decreasing the volume of the chest cavity and causing exhalation. The intercostal muscles, located between the ribs, assist the diaphragm in breathing by expanding and contracting the chest cavity. The rectus abdominis and pectoralis major are not directly involved in the process of breathing.
3. What type of joint is found in the shoulder?
- A. Ball and socket joint
- B. Hinge joint
- C. Saddle joint
- D. Pivot joint
Correct answer: A
Rationale: The correct answer is a ball and socket joint. The shoulder joint is a ball and socket joint, allowing for a wide range of motion, including rotation. This joint provides excellent flexibility and mobility, making movements like circular motions and rotations possible. A hinge joint, like the elbow, allows movement in only one plane (flexion and extension). A saddle joint, found in the thumb, allows for a wide range of motion but not as much as a ball and socket joint. A pivot joint, such as the joint between the first and second vertebrae of the neck, allows rotation only.
4. The shoulder is _________ to the elbow.
- A. posterior
- B. proximal
- C. distal
- D. medial
Correct answer: B
Rationale: Proximal refers to a position closer to the point of attachment or origin. In this case, the shoulder is closer to the point of attachment to the body compared to the elbow, making it proximal to the elbow. 'Posterior' refers to the back side of the body, 'distal' means farther away from the point of attachment, and 'medial' refers to the middle of the body. These terms do not accurately describe the relationship between the shoulder and the elbow in this context.
5. Which parts of the heart are separated by the mitral valve?
- A. Left atrium and right atrium
- B. Right atrium and right ventricle
- C. Left ventricle and right ventricle
- D. Left atrium and left ventricle
Correct answer: D
Rationale: The mitral valve, also known as the bicuspid valve, separates the left atrium and the left ventricle of the heart. Its primary function is to prevent the backflow of blood from the left ventricle to the left atrium during the heart's contraction. Therefore, option D, 'Left atrium and left ventricle,' is the correct answer. Choices A, B, and C are incorrect because they do not represent the parts separated by the mitral valve.
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