HESI A2
HESI A2 Anatomy and Physiology 2023
1. Which part of the eye is responsible for color vision?
- A. Cornea
- B. Iris
- C. Retina
- D. Lens
Correct answer: C
Rationale: The correct answer is option C: Retina. The retina contains photoreceptor cells, including cones that are responsible for color vision. Cones are sensitive to different wavelengths of light, allowing us to perceive and differentiate various colors. Choice A, Cornea, is the transparent outer layer of the eye that helps focus light. It does not play a direct role in color vision. Choice B, Iris, is the colored part of the eye that controls the size of the pupil and regulates the amount of light entering the eye. While it is essential for adjusting light levels, it is not directly involved in color vision. Choice D, Lens, is responsible for focusing light onto the retina. It helps to form clear images on the retina but does not play a role in color vision.
2. Which type of blood cell is primarily responsible for fighting infections?
- A. Red blood cells
- B. White blood cells
- C. Platelets
- D. Plasma
Correct answer: B
Rationale: White blood cells, also known as leukocytes, play a crucial role in the immune system by primarily combating infections. These cells can identify and destroy pathogens, such as bacteria and viruses, helping the body defend against illnesses and maintain overall health. Red blood cells are responsible for oxygen transport, platelets aid in blood clotting, and plasma carries various components throughout the circulatory system, but none of these functions involve fighting infections like white blood cells do.
3. Which type of joint allows for rotational movement?
- A. Hinge joint
- B. Pivot joint
- C. Ball and socket joint
- D. Saddle joint
Correct answer: B
Rationale: A pivot joint, such as the one found in the neck, allows for rotational movement, enabling the head to turn from side to side. This type of joint provides a specific axis of rotation, allowing for a turning motion around that axis. Choice A, the hinge joint, primarily allows movement in one plane, like the elbow joint's flexion and extension. Choice C, the ball and socket joint, allows for a wide range of motion in multiple directions, but it is not primarily known for rotational movement. Choice D, the saddle joint, allows for movements like bending, straightening, and limited rotation, but it is not primarily designed for rotational movement like the pivot joint.
4. What is the name of the structure that prevents food from entering the airway?
- A. trachea
- B. esophagus
- C. diaphragm
- D. epiglottis
Correct answer: D
Rationale: The epiglottis is the structure that prevents food from entering the airway. It acts as a lid over the trachea during swallowing, directing food to the esophagus instead of the windpipe (trachea). The trachea (Choice A) is the windpipe that allows air to pass into the lungs, the esophagus (Choice B) is the tube that carries food from the mouth to the stomach, and the diaphragm (Choice C) is a muscle involved in breathing and not in preventing food passage.
5. Which of the following is an organ of the respiratory system?
- A. Pancreas
- B. Brain
- C. Urethra
- D. Larynx
Correct answer: D
Rationale: The larynx is a vital organ of the respiratory system, responsible for producing sound and connecting the pharynx to the trachea. It plays a crucial role in breathing, swallowing, and vocalization. The brain, pancreas, and urethra are not part of the respiratory system; the brain is part of the nervous system, the pancreas is part of the digestive system, and the urethra is part of the urinary system. Therefore, the correct answer is the larynx.
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