Answer to Question 1
The pilomotor muscle attaches to the side of each hair follicle. When the skin is cooled or the individual has an emotional reaction, the skin often forms goose flesh as a result of contraction by these muscles.
Answer to Question 2
In the event of an injury, the inflammatory response is triggered. Fluids carrying phagocytic white blood cells go to the site of the injury. If bleeding occurs, clotting mechanisms are activated, and a clot or scab forms. The scab temporarily restores the skin's integrity. Cells of the deep epidermal layer begin to divide and migrate to the edges of the scab, and contraction occurs. Stem cells around the scab produce collagen fibers and ground substance. Blood vessels grow into the dermis, restoring circulation. Once the dermis has been regenerated, epithelial cells restore the epidermis. Major injuries result in formation of scar tissue because there are a large number of collagen fibers and few blood vessels.
Schematic representation of protein structure.
Structure of the proteasome
Structure of a complex of a type II DNA methylase with DNA
Ragged-red fibers in skeletal muscle cells
How skeletal muscle activity encourages blood flow through veins
Structure of a woody stem (comparison)