Related by context. Frequent words. (Click for all words.) 78 nerve cells 75 axons 70 neurons 68 myelin 67 axon 64 motor neurons 63 nerve endings 63 neuron 62 blood vessels 61 cortex 59 astrocytes 59 fibroblasts 59 optic nerve 59 electrical impulses 59 capillaries 58 neuronal 58 cell membrane 57 visual cortex 57 synapses 57 muscle fibers 57 spinal cord 57 cochlea 56 synapse 56 hair follicles 56 cortical 56 cilia 56 microtubules 55 neurotransmitter 55 endothelial cells 54 proteins 54 cerebellum 54 filaments 54 glutamate 54 vesicles 54 hypothalamus 54 tumor cells 54 receptors 53 glands 53 neurotransmitters 53 acetylcholine 53 neural 53 cell membranes 53 epithelial cells 53 progenitor cells 53 connective tissue 53 muscle tissue 53 epidermis 52 immune cells 52 molecules 52 inhibitory 52 cells 52 ventricles 52 hippocampus 52 synaptic 51 brain 51 tissue 51 gastrointestinal tract 51 malignant cells 51 cerebral cortex 51 dendritic cells 51 signaling pathways 51 lymphocytes 51 brainstem 51 tissues 51 outer layer 50 membrane 50 frontal lobe 50 dopamine 50 molecule 50 macula 49 ion channels 49 small intestine 49 retina 49 secretion 49 mitochondria 49 cancerous cells 49 signaling pathway 49 membranes 49 urethra 49 actin 49 epithelial 49 autophagy 49 cytokines 49 GI tract 49 tendons 49 messenger RNA 48 electrodes 48 lipids 48 amyloid plaques 48 collagen 48 intracellular 48 fatty tissue 48 adipose tissue 48 extracellular matrix 48 macrophages 48 peptides 48 skeletal muscle 48 neurodegeneration 48 tumors 48 follicles 48 cytoskeleton