1-There are approximately 400 feet of seminiferous tubules in the testes of a human male.c This is where sperm is stored.
2-The heart beats more than 2.5 billion times in an average lifetime.
3-An adult skeleton has 206 bones
4-The average human head has about 100,000 hairs
5-The appendix has no function in modern humans. It is believed to have been part of the digestive system in our primitive ancestors
6-As humans grow older, the lens in the eye grows thicker.
7-There are about 9,000 taste buds on the surface of the tongue
8-An adult human body contains approximately 100 trillion cells.
9-Humans produce about 10,000 gallons of saliva in a lifetime
10-The skin contains approximately 640,000 sense receptors, scattered unevenly over the body’s surface.
11-Hundreds of billions of neurons carry electrical signals that control the body from the brain and the spinal cord
12-There are more than 600 individual skeletal muscles in the human body.
13-At about five feet in length, the large intestine is shorter than the small intestine
14-Unlike other muscles, the heart muscle contracts without stimulus from the nervous system.
15-In a healthy adult, the small intestine can range between 18 and 23 feet long,
16-An estimated five million olfactory receptors are clustered in the membrane at the upper part of our nasal passages. These receptors help us distinguish among thousands of different odors
17-As a person ages, the diameter of each hair on the head shrinks
18-Cartilage is one of the few tissues that grows throughout life.
19-In the average adult, the skin covers 12-20 square feet and accounts for 12% of body weight
20-The body carries about 25 trillion red blood cells (erythrocytes), the most abundant cells in the body