Final answer:
The submandibular salivary glands produce around 70% of the total saliva in the mouth, which is crucial for digestion. They secrete saliva that contains amylase for carbohydrate breakdown and is thickened with mucus.
Step-by-step explanation:
The submandibular salivary glands play a crucial role in the production of saliva, which is important for moistening food and initiating the digestion of carbohydrates. An average of 1 to 1.5 liters of saliva is secreted each day by various glands, which include the parotid, sublingual, and submandibular glands. The submandibular glands, located inferior to the floor of the oral cavity and medial to the body of the mandible, produce the majority of saliva. While the text provided doesn't specify the exact percentage the submandibular glands contribute to the total saliva production, it is commonly known that these glands produce around 70% of the saliva in the mouth.
The saliva produced by the submandibular glands contains amylase, which is an enzyme that helps break down carbohydrates, and this saliva is also thickened with mucus due to the presence of mucus-secreting cells. In contrast, the parotid glands secrete a watery saliva rich in amylase, and the sublingual glands secrete a thicker saliva with less amylase.