It belongs to the conducting zone of the respiratory system, It has an external part consisting of cartilage and skin, It has two internal parts called nasal cavities, It represents the normal entry way of air in the respiratory system

The oropharynx, situated posterior to the oral cavity, The oropharynx where the digestive and respiratory tracts meet, The laryngopharynx, situated posterior to the larynx, The nasopharynx, situated posterior to the nasal cavities

There are two kidneys, situated retroperitoneally, They lie laterally to the spinal column, Superiorly, they are in contact with the adrenal glands, They are supported by fatty and connective tissue

The afferent arteriole takes blood from the renal artery to the glomerulus, The afferent, microscopic, arterioles form the glomerular capillary network, The efferent arterioles form the peritubular capillary network, The peritubular capillaries drain into small veins which join together to form eventually the renal vein