Soma is the bulbous, non-process portion of neurons containing the cell nucleus. Soma can refer to neurons, astrocytes, oligodendrocytes, and microglia. Neuron sizes range from 5 micrometres to over 10 millimetres
The nervous system coordinates actions and sensory information in animals. It consists of the central nervous system (CNS) and peripheral nervous system (PNS). The CNS includes the brain and spinal cord, while the PNS consists of nerves. The PNS is divided into somatic and autonomic systems
Cerebral cortex is outer layer of neural tissue in cerebrum. Contains 14-16 billion neurons organized into horizontal layers. Divided into four major lobes: frontal, parietal, temporal, occipital. Cortex is folded into gyri (peaks) and sulci (grooves). Human cortex is 2-4 mm thick, making up 40% of brain mass
Nervous system generates, modulates and transmits information between body parts. Consists of two main divisions: CNS (brain and spinal cord) and PNS. PNS includes 12 cranial nerves and 31 spinal nerves
Action potential transmits electrical signals through neurons to muscles. Neurons fire in three steps: depolarization, overshoot, and repolarization. Resting potential of neuron is around -70 millivolts
Axons are thin fibers that enable communication between neurons. Every neuron has only one axon, ranging from millimeter to meter. Larger diameter axons transmit impulses faster