The portion of the hair follicle where cell divisions occur is the (a) shaft, (b) matrix, (c) root hair plexus, (d) cuticle.

Verified step by step guidance

1. Understand the structure of the hair follicle: The hair follicle is a complex structure that includes several parts such as the shaft, matrix, root hair plexus, and cuticle.
2. Identify the function of each part: The shaft is the visible part of the hair above the skin. The matrix is the region where cell division occurs, leading to hair growth. The root hair plexus is a network of sensory nerves around the base of the follicle. The cuticle is the outermost layer of the hair shaft.
3. Focus on the matrix: The matrix is located at the base of the hair follicle and is responsible for producing new hair cells through cell division.
4. Relate cell division to hair growth: Cell division in the matrix leads to the production of new cells, which push older cells upward, forming the hair shaft.
5. Conclude that the matrix is the correct answer: Since the matrix is where cell divisions occur, it is responsible for hair growth, making it the correct choice.

Key Concepts

Hair Follicle Structure

The hair follicle is a complex structure in the skin that produces hair. It consists of several parts, including the bulb, matrix, and shaft. Understanding the anatomy of the hair follicle is essential for identifying where specific functions, such as cell division, occur.

Matrix of the Hair Follicle

The matrix is the area at the base of the hair follicle where actively dividing cells are located. These cells are responsible for producing new hair cells, which push older cells upward, forming the hair shaft. Recognizing the role of the matrix is crucial for answering questions about hair growth and development.

Cell Division in Hair Growth

Cell division, particularly mitosis, is the process by which cells replicate to produce new cells. In the context of hair follicles, this process is vital for hair growth, as it allows for the continuous production of hair cells in the matrix. Understanding this biological process helps clarify how hair length and health are maintained.