sperm whale

The most powerful computer known is the brain. The human brain possesses about 100 billion neurons with roughly 1 quadrillion — 1 million billion — connections known as synapses wiring these cells together. Now scientists find dendrites may be more than passive wiring; in fact, they may actively process information.

about 1.5 kg

The average brain weight of the adult male was 1336 gr; for the adult female 1198 gr. With increasing age, brain weight decreases by 2.7 gr in males, and by 2.2 gr in females per year. Per centimeter body height brain weight increases independent of sex by an average of about 3.7 gr.

around 3 pounds

Brain size increased rapidly during human evolution due to the expansion of many brain regions, resulting in human brains being exceptionally larger than those of our closest relatives. Humans have much larger brains than other primates, but it is not clear exactly when and how this difference emerged during evolution.

In healthy volunteers, total brain volume weakly correlates with intelligence, with a correlation value between 0.3 and 0.4 out of a possible 1.0. Thus, on average, a bigger brain is associated with somewhat higher intelligence.

A human brain isn’t very much bigger – about the size of your two fists put together. It only weighs about 3 pounds, just 2% of the body’s total weight. But it’s the most complex thing in the known universe. Every second, your neurons are sending millions of electrical signals around this network inside your brain.

90% of Brain Growth Happens Before Kindergarten Incredibly, it doubles in size in the first year. It keeps growing to about 80% of adult size by age 3 and 90% – nearly full grown – by age 5. The brain is the command center of the human body.

Your heart sits in the middle of your chest, to the left. The heart is a muscle at the center of your circulatory system. The average adult heart is about the size of a fist: 5 inches long, 3.5 inches wide, and 2.5 inches deep.

Hold out your hand and make a fist. If you’re a kid, your heart is about the same size as your fist, and if you’re an adult, it’s about the same size as two fists. Your heart beats about 100,000 times in one day and about 35 million times in a year.