Frequently Asked Questions: Skeletal and Muscular Systems

Q. How many bones are there in the human skeleton?
A. About 206 bones

Q. What are the smallest bones in the human body?
A. The ear bones or ossicles

Q. Why is hitting your 'funny bone' on your elbow funny?
A. The part we call the 'funny bone' is at the lower end of the bone called the humerus (humorous, get it?).

Q. What are the differences in skeleton shapes between men and women?
A. In general, men have thicker skulls in some parts than women, particularly in the eyebrow area and above the neck. Men have a more tilted and smaller pelvis, whereas women have a flatter and wider pelvis to allow space for the growth of a baby.

Q. When a human skeleton is found, how do forensic scientists work out the age of the person?
A. The height gives the first indication of age. The long bones of the leg and the arm grow from a certain point at the end of each bone and there are obvious shapes to the bone ends when a person such as a teenager is still growing. Also the skull bones do not completely fuse or cement together until a person is about 25 years of age.

Q. Why can't babies control urination, yet adults can?
A. There is tube called the urethra that carries urine from the urinary bladder to the outside of the body when we go to the toilet. The end of the urethra is controlled by a small round muscle called a sphincter that older children and adults learn to control. Babies don't have the muscle strength to control this sphincter muscle.

Q. How many times its body length can a flea jump?
A. A flea can jump 100 times its body length.

Q. How many muscles does a person have in his/her body?
A. Humans have about 700 muscles.

Q. How fast can hummingbirds flap their wings?
A. 80 times per second

Q. Why do mosquitoes 'hum'?
A. It is a mating call. Male mosquitoes have a deeper hum by vibrating wings rapidly, and females have shriller hum.

Q. How high can flying fish fly?
A. 'Flying' fish can jump out of the water to a height of about 3 metres.

Q. How fast can a polar bear run?
A. The top speed of a polar bear is about 4 kilometres per hour. That is equal to the walking pace of a human. If a polar bear runs any faster, it would overheat!

Q. What happens when you 'crack' your knuckles?
A. The liquid between the ligaments in your joints changes pressure. An excess of knuckle-cracking would cause swollen ligaments.