regions brain forebrain midbrain hindbrain hemispheres thalami hypothalamus animation kidney function contrast nephron glomerulus filtration arteriole renal tubule vasoconstrict RBC clot formation breakdown Amicar platelet fibrinolysis clotting dissolving factors medicine 3d yoga diaphragm respiration anatomy physiology breathing breath view pranayama health physical science visual arts athletics movement diaphrammatic humanities muscles human mechanics Retina capillaries retinal pigmented epithelial cells cornea aqueous humor pupil lens vitreous retina lycocytes mononuclear granulocytes macrophage lymphocyte dendritic cell neurotrophil eosinophil basophil myofibril sarcomere transverse band myosin actin contractile protein neurotransmitter presynaptic postsynaptic axon neuron synaptic cleft G-protein GPCR receptor transmembrane ion channel glutamate GABA synapse action potential vesicle terminal soma dendrite nucleus body nerve sodium potassium membrane depolarization repolarization pain CNS perception transmission transduction modulation afferent nociceptor hemostasis blood vasoconstriction monocyte fibrin coagulation renin angiotensin aldosterone adrenal pressure digestive system small intestine gastrointestinal abdomen