Related by context. Frequent words. (Click for all words.) 63 nerve fibers 62 nerve cells 60 tendons 58 spinal cord 58 dermis 57 hair follicles 57 epidermis 57 glands 57 neurons 57 blood vessels 56 muscle tissue 56 muscles 56 internal organs 56 muscle fibers 56 soft tissues 55 cerebellum 55 cortex 55 connective tissue 54 synapses 54 spine 54 optic nerve 54 salivary glands 54 gland 53 receptors 53 capillaries 53 collagen 53 cochlea 53 axons 53 facial muscles 53 nerve 53 adrenal glands 53 synapse 53 brain 52 fatty tissue 52 electrical impulses 52 brainstem 51 hypothalamus 51 electrodes 51 neuron 51 tissues 51 gastrointestinal tract 50 axon 50 electrical pulses 50 scar tissue 50 tissue 50 ligaments 50 spinal column 50 diaphragm 50 GI tract 50 retina 50 intestines 49 cartilage 49 cell membrane 49 eardrum 49 retinas 49 thalamus 49 pancreas 49 motor neurons 49 soft tissue 49 nasal passages 49 joints 48 vasculature 48 cilia 48 neurotransmitters 48 clitoris 48 spines 48 digestive tract 48 bladder 47 ovaries 47 thyroid gland 47 pores 47 ion channels 47 neurotransmitter 47 ventricles 47 electrical stimulation 47 astrocytes 47 proteins 47 limbs 47 acetylcholine 47 intestinal tract 47 inner ear 47 dermal 47 sciatic nerve 46 mucous membranes 46 follicles 46 cerebral cortex 46 epithelial cells 46 frontal lobe 46 cortical 46 malignant cells 46 nerves 46 dopamine 46 lungs 46 secretions 46 urethra 46 pituitary gland 46 skeletal muscle 46 sinuses 46 vesicles 46 reproductive organs 46 glutamate