These are also known as "hair muscles". These are tiny muslces that are attached to the hair shaft. These muscles cause the hair to stand up or be erect. When the Arrector Pili muscles contract due to stress, fear or other nervous conditions, the hair becomes stiff and will actually "stand on end".
Daily Hair Tip
A perfect hair knot is one of the simplest ideas to jazz up the back of any hair. The most important part of having a hair knot is that it look immaculate and be pinned securely. If your hair is too short to form a hair knot you can clip on a fake ponytail and twist it into the knot of your choice.