To which system do the retinas belong?

Correct Answer: B

Rationale: The retinas belong to the nervous system. The retina is a layer of tissue at the back of the eye responsible for detecting light and sending visual information to the brain through the optic nerve. This process is essential for vision, which is controlled by the nervous system. Choices A, C, and D are incorrect because the retinas have no association with the skeletal, lymphatic, or circulatory systems.

Correct Answer: D

Rationale: The integumentary system, which includes the skin, hair, and nails, is primarily responsible for maintaining temperature control in the body. The skin helps regulate body temperature through processes like sweating to cool down and shivering to generate heat. Additionally, blood vessels in the skin can dilate or constrict to control the amount of heat lost or retained by the body. This system plays a crucial role in maintaining homeostasis and keeping the body at a stable temperature. The skeletal system (Choice A) provides structural support and protection to the body but is not directly involved in temperature regulation. The digestive system (Choice B) is responsible for breaking down food and absorbing nutrients, not for regulating body temperature. The nervous system (Choice C) controls body functions through electrical impulses but is not the primary system responsible for temperature control.

Correct Answer: B

Rationale: The correct answer is B: The pulmonary artery carries blood from the heart to the lungs. The first step in pulmonary circulation involves the right ventricle of the heart pumping deoxygenated blood into the pulmonary artery. The pulmonary artery then carries this deoxygenated blood from the heart to the lungs for oxygenation. This step is crucial for the exchange of carbon dioxide for oxygen to occur in the lungs, facilitating the oxygenation of blood. Choices A, C, and D are incorrect because they do not represent the initial step in pulmonary circulation. Option A refers to blood moving away from the heart, option C describes the gas exchange process that occurs in the lungs but not as the first step, and option D mentions oxygenated blood moving through the aorta, which happens after oxygenation in the lungs.

Correct Answer: A

Rationale: Thiamine is another name for Vitamin B1. It is an essential vitamin that plays a crucial role in energy metabolism and is important for the proper functioning of the nervous system. Vitamin B2 is riboflavin, not thiamine. Vitamin B6 is pyridoxine, not thiamine. Vitamin D is a different vitamin responsible for calcium absorption and bone health, not thiamine. Therefore, the correct answer is Vitamin B1.

Correct Answer: C

Rationale: The skeletal system collaborates with the nervous system by providing protection and support for critical nervous system components. The vertebrae of the spine play a crucial role in safeguarding the spinal cord, a key component of the nervous system responsible for transmitting messages between the brain and the body. Protecting the spinal cord is essential to prevent neurological complications. Choices A, B, and D are incorrect because while bones do play a role in body position and can sense pain, the primary focus of the skeletal system's interaction with the nervous system is to protect vital components like the spinal cord, rather than generating nerve cells.