Anatomy HESI A2 Practice Test

Correct Answer: B

Rationale: The correct answer is B: Hinge. The elbow joint is a hinge joint because it allows movement in only one plane, similar to a door hinge. It primarily enables flexion and extension movements. A: Ball and socket joints, like the hip joint, allow for a wider range of motion in multiple planes. C: Pivot joints, found in the neck, allow for rotational movements. D: Saddle joints, like the thumb joint, have a more complex shape that permits a variety of movements, but not present at the elbow.

Correct Answer: B

Rationale: White blood cells' main function is to fight infections. They are part of the immune system, detecting and destroying pathogens like bacteria and viruses. They do not carry oxygen (A), nutrients (C), or remove waste products (D). White blood cells play a crucial role in protecting the body from harmful invaders, making choice B the correct answer.

Correct Answer: A

Rationale: The correct answer is A: Vitamin A. Vitamin A is essential for vision as it plays a crucial role in the function of the retina and helps maintain a healthy cornea. It is also important for skin health by promoting skin cell growth and repair. Vitamin C (B) is important for immune function and collagen synthesis, not specifically for vision or skin health. Vitamin D (C) is crucial for bone health and immune function. Vitamin E (D) is an antioxidant that helps protect cells from damage, but it is not specifically essential for vision or skin health.

Correct Answer: B

Rationale: The correct answer is B: Cerebrum. The cerebrum, specifically the motor cortex located in the frontal lobe, controls voluntary movement. It sends signals to the muscles via the spinal cord. The cerebellum (A) is responsible for coordination and balance, not voluntary movement. The brainstem (C) controls basic life functions like breathing and heart rate, while the medulla oblongata (D) regulates vital functions such as blood pressure and breathing, not voluntary movement. Therefore, the cerebrum is the correct choice for controlling voluntary movement.

Correct Answer: C

Rationale: Platelets' primary function is to clot blood. When a blood vessel is damaged, platelets rush to the site and form a plug to stop bleeding. Platelets release chemicals that promote clotting. Platelets do not carry oxygen (A), fight infections (B), or transport nutrients (D). Oxygen is carried by red blood cells, immunity is the function of white blood cells, and nutrients are transported by plasma.