Necesito ayuda para corregir un texto en inglés

Hola. Veréis, tengo una exposición de inglés y la profesora no corrige lo que vamos a exponer. Yo he releido ya el texto muchas veces pero no sé si está bien. Agradecería que me ayudaseis a mejorar la exposición. Gracias de antemano. Aquí dejo el texto, es sobre glándulas salivales:

Good morning everyone. Please, let me introduce myself. My name is Basilio and I am student of dentistry. The title of my oral presentation is salivary glands and pathologies because my goal is to explain you the role and types of salivary glands in the oral cavity and the pathologies caused by salivary glands alteration. The main points I want to show are salivary glands generalities, salivary glands types and salivary glands pathologies. For this reason, I have divided my presentation into two parts. In the first part I will explain types of salivary glands and in the next section I am going to show salivary glands associated pathologies. I have chosen to speak about this because it is an important subject in dentistry.

I am going to start, listen to me, please.

Well. Did you know human produce between one and two litres of saliva each day? The managers of producing this saliva are salivary glands. And not only that, but human can produce until thirty-four thousand litres throughout life also.

Salivary glands are a group of cells that secret saliva. Saliva, which is a colourless liquid, is spilled into the oral cavity. Saliva contains proteins, glicoproteins, carbohydrates, epithelial cells and leucocytes. Function of salivary glands is to produce saliva. Salivary glands are an important component of the oral cavity because it produces saliva for wetting food and for facilitating chewing and swallowing. In addition, saliva begins the digestion because it breaks down carbohydrates and lipids with enzymes.  That's not the only reason because saliva helps to keep oral health since it prevents the proliferation of microorganisms and bacterial plaque.  Salivary glands function can be affected by diseases.

Let us now move on to the second part.

In the first place, I have to say that salivary glands can be divided depending on cells types or size. Depending on cells types, we can find serous, mucous and mixed glands. Serous glands have serous cells only, mucous glands have mucous cells only and mixed glands have serous cells as much as mucous cells. Depending on size, we can find major or minor salivary glands. Did you know human have between 800 and 1000 minor salivary glands? These glands are located in the buccal, labial, and lingual mucosa, the soft palate, part of the hard palate and the floor of the mouth. Minor salivary glands produce 5-10% of saliva in the oral cavity. Major salivary glands are a pair of glands divided in parotid, submandibular and sublingual glands. Parotid gland is a serous gland because it has serous cells only and it is located near auricular canal, in both on the side of the face. Parotid gland is the largest salivary gland and it produces 20% of saliva in the oral cavity. Submandibular gland is a mixed gland because it has mucous and serous cells and it is located under the floor of the mouth. Submandibular gland produces 65-70% of saliva in the oral cavity approximately. Sublingual gland is located under the tongue and it has mainly mucous cells although it is considered as mixed gland. Sublingual gland makes 5% of saliva in the oral cavity approximately.

Now that we've seen types of salivary glands, let us explain to salivary glands pathologies.

Salivary glands can grow pathologies and these pathologies can change the secretion and composition of saliva. Basic pathological processes that affect salivary glands are reactive and obstructive lesions, infections, immunopathological disorders and neoplasms. In all these processes a glandular inflammation is made. Infectious and obstructive lesions usually are painful while immunological and neoplastic disorders often characterized for a painless inflammation. These pathologies affect men as much as women.  Reactive and obstructive lesions are not infectious because it is a response direct trauma or salivary discharge´s obstruction. Main reactive and obstructive lesions are: mucocele, which is a tissue inflammation caused by accumulated mucus in connective tissue; cyst, which is an inflammation caused by excretory canal obstruction of salivary gland; sialolithiasis, which refers to stone-related disease within the ductal systems of a gland and it is the most frequent pathology of major salivary glands; sialodenitis, which is a general inflammation of a salivary gland. Inmunopathological disorders are chronic and autoimmune diseases that they damage cells of salivary glands. Main inmunopathological disorder is Sjögren´s syndrome and it is most common in women. Sjögren´s syndrome is a chronic inflammation that affects salivary and lacrimal glands and it produces xerostomy. Neoplasms can be benign and malignant. Benign tumors are most common in major salivary glands and they affect women with largest frequency. Benign tumors are known as adenoma and malingnant tumors are known as carcinoma.

As I have already said earlier, salivary glands produce saliva and this saliva helps in digestion process and it prevents proliferation of microorganisms and bacterial plaque. For this reason, I’d like to stress the importance of salivary glands in oral health.

As we have seen today, most salivary glands diseases change salivary secretion and composition. For example, xerostomy complicates secretion of saliva. This reduction of secretion of saliva can increase the prevalence of caries because saliva decreases the proliferation of microorganism. Without saliva, the proliferation of microorganism grows and, therefore, caries increases also. For this reason, I think so salivary glands are an important component of oral cavity because they are essential in oral health.