What do wounded cells release to help protect the skin?

• Defensins

• Cathelicidins

• Melanin

• Sebum

Which substances have limited penetration of the skin?

• Water-soluble substances

• Lipid-soluble substances and heavy metals

• Proteins and carbohydrates

• Vitamins and minerals

How does the skin contribute to preventing wrinkles?

• By synthesizing Vitamin D

• By activating hormones

• By making collagenase

• By absorbing calcium

Which of the following is NOT a cell type found in the epidermis?

• Keratinocytes

• Melanocytes

• Dendritic cells

• Fibroblasts

What is the primary function of keratinocytes in the epidermis?

• Produce pigment melanin

• Act as sensory receptors

• Produce fibrous keratin

• Activate the immune system

What is the role of dendritic (Langerhans) cells in the epidermis?

• Sense touch

• Produce keratin

• Activate the immune system

• Produce melanin

What is the outermost layer of the epidermis called?

• Stratum basale

• Stratum spinosum

• Stratum corneum

• Stratum granulosum

How do keratinocytes appear in the stratum spinosum layer?

• Flat

• Round

• Spikey

• Smooth

Which cells are abundant in the stratum spinosum?

• Red blood cells

• Melanosomes and dendritic cells

• Neurons

• Muscle cells

What happens to the cells in the Stratum granulosum?

• They become more rounded and active.

• They flatten, and nuclei and organelles disintegrate.

• They start producing sweat.

• They increase in size and multiply.