Question 5

The integumentary system uses keratin to protect the body from abrasion and microbes.

Keratin is a key structural protein found in the integumentary system, which includes the skin, hair, and nails. This system serves as the body’s first line of defense against physical damage and microbial invasion.

A) Integumentary

This option is correct because the integumentary system is specifically designed to provide protection against environmental hazards. Keratin, found in the outer layer of the skin, plays a crucial role in this protective function by making the skin resilient to abrasion and reducing the permeability to pathogens.

B) Lymphatic

The lymphatic system is primarily involved in the immune response and fluid balance, rather than providing a physical barrier. While it plays a critical role in defending the body against infections, it does not utilize keratin for protection, making this option incorrect.

C) Digestive

The digestive system is responsible for the breakdown and absorption of nutrients but is not designed to protect against abrasion or microbes through keratin. While the lining of the digestive tract does have protective features, they do not involve keratin, thus this option is also incorrect.

D) Respiratory

The respiratory system facilitates gas exchange and has mechanisms to filter and trap pathogens and particles in the air, but it does not rely on keratin for protection. The tissues involved do not have the same protective characteristics associated with keratin, making this option incorrect.

Conclusion

The integumentary system is definitively the correct answer as it directly employs keratin to protect against abrasion and microbes, while the other systems listed do not utilize keratin for such protective measures. This highlights the specialized function of the integumentary system in maintaining the body's integrity against external threats.