1. What is the protective fluid that surrounds the brain and spinal cord?

A. Blood
B. Cerebrospinal fluid
C. Myelin sheath
D. Insulin

Correct answer: B

Rationale: The correct answer is B: Cerebrospinal fluid. This fluid acts as a cushion for the brain and spinal cord, providing protection from impacts. Blood is essential for transporting nutrients and oxygen, but it does not directly surround or protect these vital nervous system structures. Myelin sheath is a fatty substance that insulates nerve fibers, not the fluid surrounding the nervous system. Insulin is a hormone involved in regulating blood sugar levels and is not related to protecting the brain and spinal cord.

2. The Merkel cells, located in the epidermis, are specialized for:

A. Melanin production
B. Temperature sensation
C. Touch perception
D. Immune defense

Correct answer: C

Rationale: The correct answer is C: 'Touch perception.' Merkel cells, also known as Merkel discs, are found in the skin's epidermal layer and are responsible for sensing touch. These cells are located near nerve endings and help detect light touch and pressure on the skin. They play a crucial role in the perception of tactile sensations and are not involved in melanin production, temperature sensation, or immune defense. Therefore, the specialized function of Merkel cells is primarily related to touch perception, making option C the correct choice.

3. What is the outermost layer of the dermis, rich in collagen and elastin fibers that provide elasticity to the skin?

A. Papillary layer
B. Reticular layer
C. Stratum basale
D. Stratum corneum

Correct answer: A

Rationale: The correct answer is A: Papillary layer. The papillary layer is the outermost layer of the dermis and is rich in collagen and elastin fibers. These fibers provide elasticity to the skin, helping it maintain its structure and flexibility. The reticular layer, although deeper in the dermis, is not the outermost layer and is primarily responsible for providing strength and support to the skin. The stratum basale and stratum corneum are layers of the epidermis, not the dermis. The stratum basale is the deepest layer of the epidermis where new skin cells are formed, while the stratum corneum is the outermost layer of the epidermis composed of dead skin cells. Understanding the different layers of the skin is essential for comprehending its functions and properties.

4. Which type of cell is responsible for carrying oxygen throughout the body?

A. Nerve cell
B. Muscle cell
C. Skin cell
D. Red blood cell

Correct answer: D

Rationale: The correct answer is D: Red blood cell. Red blood cells, also known as erythrocytes, are responsible for carrying oxygen throughout the body. They contain hemoglobin, a protein that binds to oxygen in the lungs and transports it to tissues and organs. Nerve cells (option A) transmit electrical signals, muscle cells (option B) are involved in movement, and skin cells (option C) form the outer layer of the skin and provide protection.

5. Which blood vessels are responsible for carrying oxygenated blood away from the heart to the rest of the body?

A. Veins
B. Arteries
C. Capillaries
D. Venules

Correct answer: B

Rationale: The correct answer is B: Arteries. Arteries are blood vessels that carry oxygenated blood away from the heart to the rest of the body. They have thick and elastic walls to withstand the high pressure generated by the pumping action of the heart. Veins, on the other hand, carry deoxygenated blood back to the heart, while capillaries are tiny blood vessels where the exchange of oxygen and nutrients occurs. Venules are small veins that collect blood from capillaries and transport it to larger veins. Therefore, arteries are specifically designed to transport oxygenated blood away from the heart, making them the correct choice in this question.