Q 01/05

Which body part, often wrongly called the body's strongest muscle, is really eight muscles woven together?

A) Jaw

B) Tongue

C) Heart

D) Thigh

Answer · why

B) Tongue

The tongue is eight muscles woven together with no bone inside, which is why it can bend and twist like an octopus arm or an elephant's trunk.

Q 02/05

Roughly how many skeletal muscles does an adult human body contain?

A) About 60

B) About 200

C) About 600

D) About 2,000

Answer · why

C) About 600

About 600 is the low end: counts run past 800, because a complex muscle such as the biceps can be tallied as one muscle or two.

Q 03/05

Which muscle shows up as a 'six-pack' on a lean, fit torso?

A) External oblique

B) Rectus abdominis

C) Serratus anterior

D) Pectoralis major

Answer · why

B) Rectus abdominis

Rectus abdominis is a single pair of long muscles, not six: fibrous bands cross each one, and the bulges between the bands make the 'six-pack'.

Q 04/05

Which muscle type can keep contracting on its own, with no signal from the nervous system?

A) Skeletal

B) Fast-twitch

C) Postural

D) Cardiac

Answer · why

D) Cardiac

Cardiac muscle starts every beat itself, in built-in pacemaker cells; nerves only speed the rhythm up or slow it down.

Q 05/05

Which muscle type is non-striated?

A) Cardiac

B) Skeletal

C) Pennate

D) Smooth

Answer · why

D) Smooth

Smooth muscle can lock its filaments together and hold a squeeze for long periods on very little energy, which is how artery walls and other organs ke...