Brain

About the Brain

The brain is the most complex organ, containing approximately 86 billion neurons and a roughly similar number of glial and other non neuronal cells, with an estimated 100 trillion synaptic connections. It weighs approximately 1.4 kg 3 pounds in adults and consumes 20 percent of total body oxygen and glucose despite being only 2 percent of body weight. Major divisions include the cerebrum with four lobes frontal executive function, motor cortex, Broca area speech, parietal sensory, temporal auditory, memory, Wernicke area comprehension, and occipital vision, cerebellum motor coordination and balance, brainstem vital functions breathing, heart rate, consciousness, and diencephalon thalamus relay station, hypothalamus homeostasis. The brain is protected by the skull meninges dura mater, arachnoid, pia mater and cerebrospinal fluid. Neurons communicate via action potentials electrical and neurotransmitters chemical including glutamate excitatory, GABA inhibitory, dopamine reward and motor, serotonin mood, acetylcholine memory, and norepinephrine arousal.