Related by context. Frequent words. (Click for all words.) 62 gastrointestinal tract 61 digestive tract 59 intestines 59 capillaries 57 abdominal cavity 56 metabolized 56 intestinal tract 55 cell membrane 55 excreted 55 nasal passages 55 small intestine 55 blood vessels 55 cell membranes 54 immune cells 54 lymphatic system 54 lungs 53 pancreas 53 intestine 53 clot 52 cerebrospinal fluid 52 toxins 52 metabolize 51 spinal fluid 51 secretions 51 neutrophils 51 toxin 51 tumor cells 51 esophagus 51 respiratory tract 50 placenta 50 mucus 50 muscle tissue 50 clots 49 hair follicles 48 cancerous cells 48 lung tissue 48 tissues 48 clotting 48 pores 48 macrophages 48 epithelial cells 48 lymph 48 liver 48 uterus 47 molecules 47 saliva 47 excrete 47 cells 47 bacteria 47 malignant cells 47 aorta 47 particles 46 glucose 46 neurotoxin 46 lipids 46 ingested 46 lymphocytes 46 stress hormones 46 intravenously 46 inhaled 45 soluble 45 circulatory 45 molecule 45 excretion 45 platelets 45 nerve cells 45 neurotransmitter 45 arteries 45 intracellular 44 nitric oxide 44 secretion 44 water soluble 44 spores 44 epidermis 44 digestive 44 trachea 44 cytokines 44 nanoparticles 44 stomach acid 44 left ventricle 43 mitochondria 43 nutrients 43 glutamate 43 gland 43 fluids 43 sugars 43 neurotransmitters 43 oxygen 43 lactic acid 43 antibodies 43 urethra 43 ions 43 amniotic fluid 43 metabolism 42 uric acid 42 tiny particles 42 fibroblasts 42 thyroid gland 42 proteins 42 hemoglobin 42 occurs naturally