which vitamin is important for vision

HESI A2

HESI A2 Practice Test Anatomy and Physiology

1. Which vitamin is important for vision?

A. Vitamin A
B. Vitamin C
C. Vitamin D
D. Vitamin K

Correct answer: A

Rationale: The correct answer is Vitamin A. Vitamin A is crucial for maintaining healthy vision, particularly in low-light conditions. It plays a key role in the health of the retina and is necessary for the proper functioning of the eye. Deficiency in Vitamin A can lead to night blindness and other vision problems. Vitamin C is important for the immune system and skin health, not specifically for vision. Vitamin D is essential for bone health and overall well-being, but it is not directly related to vision. Vitamin K is important for blood clotting, but it is not specifically linked to vision.

2. Which hormone is released by the posterior pituitary gland?

A. Oxytocin
B. Thyroxine
C. Insulin
D. ADH

Correct answer: A

Rationale: Oxytocin is the correct answer. It is released by the posterior pituitary gland and plays a vital role in childbirth and lactation. Oxytocin promotes uterine contractions during labor and milk ejection during breastfeeding. Choice B, Thyroxine, is incorrect as it is produced by the thyroid gland. Choice C, Insulin, is incorrect as it is produced by the pancreas. Choice D, ADH (Antidiuretic Hormone), is also released by the posterior pituitary gland, but it is not the hormone primarily associated with childbirth and lactation.

3. Which structure in the brain regulates sleep and wakefulness?

A. Hypothalamus
B. Thalamus
C. Pineal gland
D. Cerebellum

Correct answer: C

Rationale: The pineal gland, located in the brain, is responsible for regulating sleep and wakefulness by secreting the hormone melatonin. Melatonin plays a crucial role in controlling the sleep-wake cycle, with higher levels at night inducing sleepiness. The hypothalamus (Choice A) regulates various physiological processes but is not primarily responsible for sleep-wake cycles. The thalamus (Choice B) is involved in relaying sensory information but not specifically in regulating sleep. The cerebellum (Choice D) plays a role in coordination and motor control rather than sleep regulation.

4. Where are B-lymphocytes produced?

A. Thymus
B. Red bone marrow
C. Lymph nodes
D. Spleen

Correct answer: B

Rationale: B-lymphocytes are produced in the red bone marrow. The red bone marrow is the primary site for B-cell development, where they mature before entering the circulation. The thymus is responsible for T-lymphocyte maturation, not B-lymphocytes. Lymph nodes and spleen play roles in immune responses but are not the primary sites for B-lymphocyte production.

5. Which plane would you use to separate the abdominal cavity from the thoracic cavity?

A. Sagittal
B. Transverse
C. Frontal
D. Coronal

Correct answer: B

Rationale: The transverse plane, also known as the horizontal plane, runs horizontally from left to right, dividing the body into superior (upper) and inferior (lower) parts. This plane is ideal for separating the abdominal cavity (located below) from the thoracic cavity (located above). The sagittal plane (choice A) divides the body into left and right portions, the frontal plane (choice C) divides the body into front and back portions, and the coronal plane (choice D) is another term for the frontal plane. Therefore, when looking to separate the abdominal cavity from the thoracic cavity, the transverse plane is the most appropriate choice.