Life Cycle - Human Biology (2A)

  • Learning about hair.
  • Comparing the growth of hair.
  • curly
  • follicle
  • fur
  • hair 
  • skin
  • straight
  • wavy

Students look and compare different types of hair.



Human growth in body height usually stops at around 18-20 years.  However, there are other portions of a human body that will continue to grow like hair, fingernails, and fat cells.  Adult humans can get fatter, but rarely do they get taller.  This lab focuses on the hair and how it grows.

Hair is a threadlike structure that is used for insulation against the cold.  Mammal hairs are threadlike outgrowths of the skin.  Although the general structure of all human hair is similar,  there are some variations among ethnic groups.  In fact, differences can occur even among hair of people from the same regions.  Human hair is usually soft after birth and after a few months of infancy is  shed and replaced by the typical coarser hair which is longer and heavily pigmented.  Virtually the entire human skin is covered with hair, though much of it is too fine to be visible.  Hair  is very sensitive to the touch.  The part above the skin is the shaft, below the skin is the root.

  1. Draw the following picture of the hair follicle on the board and discuss the following parts with your students.   
  1. muscle can move the hair shaft
  2.  the papilla is the soft base of the shaft
  3. nerves help to interpret touch
  4.  sweat glands extract salts, water, and acids from the body
  5. oil glands keep skin soft, emit oil, prevent evaporation and heat loss.
  1. Students will look at different types of hair during lab.  Hair is a part of the skin, which is the largest organ of the human body.  If you haven't purchased the module you can make baggies of children's hair and save them.  You may want to ask children weeks before the lab that if they are getting a hair cut to save their hair in a baggy and bring it to school.
  2. Use the recommended book  as a reference.  The book shows the difference between the different hair follicles.  Straight hair has follicles that are round (in cross section); wavy hair has follicles that are oval (in cross section); tight, curly hair has follicles that are flat (in cross section).

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