The average human brain is 93 mm high. The octopus brain has about 300 million neurons. The total surface area of the cerebral cortex is about 2200 sq. Unconsciousness will occur after 8-10 seconds after loss of blood supply to the brain. The weight of an adult human cerebellum is 150 g.
Cerebrospinal fluid is normally clear and colorless.
There are 12 pairs of cranial nerves. There are 31 pairs of spinal nerves. There are about 13,500,00 neurons in the human spinal cord. The human spinal cord is 45 cm long in men and 43 cm long in women. Humans can hear in the range of 20 Hz to 20,000 Hz.