Question

question 12

all cells in the epidermis arise from mitotic activity in stratum:

lucidum.
granulosum.
corneum.
basale.

question 13

what tissue composes the epidermis of the skin?

transitional epithelium
nonkeratinized simple squamous epithelium
keratinized stratified squamous epithelium
nonkeratinized stratified squamous epithelium

Explanation:

Analyze mitotic activity in epidermal layers

The first question asks: "All cells in the epidermis arise from mitotic activity in stratum:"
Using the Epidermal Layers knowledge point, we recall that the epidermis is a self-renewing epithelial tissue. Mitotic division (cell division) primarily occurs in the deepest layer of the epidermis, which is attached to the basement membrane. This layer is the stratum basale (also known as the stratum germinativum). The other layers (stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum) consist of cells that have migrated outward and are undergoing differentiation, keratinization, and eventually desquamation (shedding). Therefore, the correct option is "basale".

Identify the tissue composing the epidermis

The second question asks: "What tissue composes the epidermis of the skin?"
The epidermis is the outermost protective layer of the skin. It is composed of epithelial tissue. Specifically, because it must withstand friction and prevent water loss, it consists of multiple layers of flattened cells, making it a stratified squamous epithelium. Furthermore, the outer layers of the skin are filled with the tough, protective protein keratin to prevent dehydration and mechanical damage, making it keratinized. Therefore, the epidermis is composed of keratinized stratified squamous epithelium.

Answer:

Question 12

• lucidum.
• granulosum.
• corneum.
• basale. (Correct answer)

Question 13

• transitional epithelium
• nonkeratinized simple squamous epithelium
• keratinized stratified squamous epithelium (Correct answer)
• nonkeratinized stratified squamous epithelium