CSF is produced by choroid plexus, with 80% secretion rate. CSF circulates through ventricles, cisterns, and subarachnoid space. CSF absorption occurs through arachnoid villi into blood. CSF formation rate is 0.3-0.4 ml min-1 in humans
Sleep is a state of reduced mental and physical activity. Body alternates between REM and non-REM sleep cycles. Sleep occurs in repeating periods lasting 90 minutes. Dreams occur during certain sleep stages
Brain size can be measured by weight, volume via MRI or skull measurements. Human brain weighs about 1.5 kg, with volume around 1260 cm³ in men. Brain size varies between species and within individuals. Brain-to-body mass ratio follows power law with exponent of 0.75
Everyone dreams every night for about two hours. Most dreams last 5-20 minutes and are forgotten within minutes. People spend an average of six years dreaming during their lifetime
Left-brain theory suggests one side controls language and logic. Right-brain theory attributes creativity to the other side. Both sides of brain communicate through corpus callosum
Lotus represents resilience, rebirth, and spiritual enlightenment. Sacred in Buddhism and Hinduism, associated with seventh chakra. Symbolizes purity and rising above materialism. Represents transformation and endless rebirth through daily cycle