Understanding the Oral Mucous Membrane

Hi friends, welcome to Easy Dentistry. Friends, please subscribe to our channel and hit the bell icon to get the recent updates. Today's topic is oral mucus membrane. There were so many comments asking for this topic. This topic is quite lengthy and but it is very very important by exam point of view. So let's begin with today's topic, OMM. OMM in four parts in the first part we would be studying about the basics of OMM in the second part we would be studying about the non-keratinized epithelium in the third part we would be studying about the keratinized epithelium and in the final part will be studying about the gingival sulcus and the dento gingival junction. So let's begin with the first part which includes the basics of oral epithelium or the basics of oral mucus membrane. The oral mucus membrane is classified depending upon the function of the mucus membrane into three types. First is the masticatory mucosa, second is the lining mucosa and the third is the specialized mucosa. The Mastricatory Mucosa comprises of 60% of the oral mucous membrane and it includes the hard palate and the gingiva. The Lining Mucosa comprises 25% of the OMM and it includes the lip, cheek, vestibule, floor of mouth, alveolar mucosa and the soft palate. While the Specialized Mucosa comprises only 15% of the OMM and it includes the It includes the dorsum of tongue and the taste buds. Two different structures are also present in the oral mucous membrane which is slightly different. These are dentogen-trival junction and the vermilion border of lip. In the subsequent lectures, we would be studying each of these in detail. Now for descriptive purpose the oral mucous membrane is divided into two types the keratinized mucosa and the non-keratinized mucosa. The keratinized mucosa involves the masticatory mucosa and the vermilion border of lip while the non-keratinized mucosa involves the lining mucosa and the specialized mucosa. Now what is the function of the OMM? There are four functions of the OMM. These are defense, lubrication, sensory and protection. Now how does the oral mucus memory work? provides defense the oral mucous membrane prevents the entry of microorganisms and its toxins into the oral cavity and it is also impermeable to the toxins of the microorganisms. The second function is the lubrication. Saliva is secreted from the minor salivary gland present in the oral mucous membrane and this saliva keeps the mucous membrane moist. The moist mucous membrane help in proper speech, mastication, swallowing and also help in perception of taste of food. The third function is the sensory function. The oral mucous membrane is sensitive to touch, pressure, pain and temperature. There are numerous nerve endings present in the oral mucous membrane which help in sensory function of the mucous membrane. The last function is the protection. The oral mucous membrane, it protects the deeper tissues from mechanical trauma. Now let us study what the oral mucous membrane is in detail. So OMM consists of 4 layers. The topmost layer is the epithelium. Below the epithelium there is a connective tissue which is called as lymph. Lamina propria. Below the Lamina propria there is a layer of loose connective tissue which is called as submucosa. This submucosa connects the epithelium and Lamina propria complex to the underlying tissues which may be bone or muscle. Now let us study the one by one each of this structure. The first structure we will be studying is the epithelium. Now how is the epithelium of the oral mucosa? oral mucosa may be keratinized or non-keratinized. This keratinization may be orthokeratinization or parakeratinization. We will be studying about each of these in subsequent lectures. Now just remember the oral epithelium may be keratinized or non-keratinized. It may be orthokeratinized or parakeratinized. Below the epithelium there is the lamina propria. The lamina propria of the oral mucosa they contain the salivary gland. And below the lamina propria there is a layer of loose connective tissue which is called as the submucosa. This submucosal layer connects the epithelium and lamina propria complex to the underlying bone or muscle. Now let us study how is the skin. The skin comprises of an epithelium which is called as the epidermis and this epidermis is Always orthokeratinized. Non-keratinization or parakeratinization is never ever seen in the skin. It is always orthokeratinized. And below this epidermis is the dermis. And this dermis contains hair follicles, the sebaceous glands and the sweat glands. And there is no submucosal layer in the skin and there is a direct attachment of this epidermis and the dermis to the underlying bone or muscle. There is no submucosal layer present in the skin. Now let us see how is the intestinal mucosa The intestinal mucosa comprises of the epithelium, the lamina propria There is a characteristic layer present in the intestinal mucosa which is called as the muscularis mucosa It is called as muscularis mucosa because it contains all smooth muscles Let us see how is the intestinal mucosa This layer is characteristically present only and only in the intestinal epithelium and below this muscularis mucosa layer there is the submucosa and this submucosa it connects the upper structures to the underlying layer of bone or muscle. If we compare these three mucous membrane, we can see that the oral epithelium is made up of four layers. These are the epithelium, the connective tissue, the submucosa and the underlying layer of bone and muscle. While the skin is made up of only three layers. These are the epidermis, the dermis and the underlying layer of bone or muscle. While the gut mucosa is made up of epithelium, the lamina propria, the muscularis mucosa which is patent only in the gut epithelium. Then there is submucosa and the underlying layer of bone and muscle. Hope this is clear to all of you. Now let us see how is the interface between the epithelium and the lamina propria in the oral mucous membrane. This is the epithelium and this is the lamina propria. The epithelium and the lamina propria interface is corrugated this interface is not straight it is corrugated the epithelium it forms the projections which are called as the ridges remember the epithelium form the ridges And the connective tissue extensions are called as the papilla. The lamina propria extensions are called as the papilla. These ridges they fit well with the papilla of the connective tissue. and it forms a corrugated appearance. This is not straight, it is corrugated. This appearance of the interface may also be called as the serpentine appearance. Serpentine means like. a snake it appears like a snake so it is called as the serpentine interface now this epithelium and the connective tissue of the lamina propria are in intimate contact with each other and they at the junction of this epithelium and the lamina propria there is a structure which is called as the basement membrane And this basement membrane is very very very important structure. Let us now study this basement membrane in detail. Under light microscope, the structure is called as the basement membrane while in the electron microscope it is called as the basal lamina. Under light microscope this basement membrane appear 1 to 4 micrometer thick. It is a cell free zone. No cells are seen around the basement membrane and it is rich in mucopolysaccharide. rich in mucopolysaccharide which can be explained by its staining with pass stain. If we stain the basement membrane with periodic acid skiff this is a special stain and if we watch it under a microscope it it the basement membrane takes up this stain and we can see that it is not stained. It stains positively for pass or periodic acid skip. This is a very important question which is asked in Viva and MCQs. The basement membrane, it takes up the periodic acid skip and it is pass positive. This pass positivity indicates that the basement membrane is rich in mucopolysaccharide. Now let us see how it appears under the electron microscope. Under the electron microscope, it is called as the basal lamina. This basal lamina is if we see under the electron microscope this is the epithelium the red line is the epithelium and the basement membrane is made up of two zones the clear zone this is the clear zone and this is the dark zone the clear zone shown by empty white space and dark zone by the green broadband the clear zone is called as the lamina lucida and the dark zone is called as lamina densa The lamina lucida is adjacent to the epithelium while the lamina densa is always below it i.e. towards the connective tissue. This lamina lucida is 20 to 40 mm in thickness and it is a glycoprotein layer. This lamina lucida contains type 4 collagen. okay and it also contains laminin bullous pemphigoid antigen and other antigen the main this lamina lucida it forms the main part of the basement membrane or the basal lamina and it is made up of type 4 collagen so the when the question asked is asked in mcq or viva the basement membrane is made up of what type of collagen principally you should answer type 4 collagen. Remember the basement membrane. I will tell you an easy trick to remember this type of collagen. 4 is in floor. The basement membrane forms the floor of the epithelium. If this is the epithelium, the basement membrane forms the floor of the epithelium and it is made up of type 4 collagen. So, 4 is in the floor. I hope you will remember this now. Now we have seen the basal lamina is made up of lamina lucida and lamina densa. Now anchoring fibrils, if you can see these broad loops shown in blue lines, these are anchoring fibrils which are inserted into the lamina densa. These are made up of type 7 collagen. They form loops and are inserted into the lamina densa. And what you see in these pink lines, these are the type 1 and type 2 collagen fibers which run through these loops shown by the pink lines. These are type 1 and type 2 collagen fibers. Now let us see what is the lamina propria. The connective tissue below the epithelium is known as the lamina propria. The lamina propria is made up of two parts. First is the papillary part and the second part is the reticular part. The papillary zone is the zone of the epithelium. which is present just below the epithelium and which extends between the ridges of the epithelium this is the papillary zone and below it this is the reticular zone sometimes this papillary zone is absent when the epithelium as in gingiva or hard palate sorry in the gingiva or heart palate if the epithelium do not contain the epithelial ridges if it is straight then the papillary part of the lamina propria is absent. But the reticular part is always present. So the epithelium and connective tissue have tight interlocking arrangement. There is a tight interlocking arrangement between the epithelium and the connective tissue and this provides exercise. exchange of material between the epithelium and connective tissue. What does this ground substance of the lamina propria contain? The ground substance may contain many things. Mainly the collagen fiber present in the lamina propria is type 1 and type 3. Remember all these collagen fibers students they are frequently asked in multiple choice questions. And the other things which may be present in the ground substance are various glycoproteins and proteoglycans. And cells are present such as fibroblasts, mast cells, macrophages. Now let us see what is the submucosa. The connective tissue, it is a connective tissue layer of varying thickness. This is called as the submucosa. It is present below the lamina propria and the function of the submucosa is to connect the overlying structures to the underlying tissue which may be bone or muscle. This layer of connective tissue is very very loose. And And it may be also tight in some of the type of mucosa such as in hard palate and gingiva. In other lining mucosa it is loose. The submucosa contain glands, it contain the blood vessels, it contain the collagen fibers, it contain the adipose tissue and it may also contain the nerves. Now whenever we study any mucous membrane these are the points to be considered. First what is the type of epithelium? Either it is keratinized or non keratinized, whether it is para or ortho keratinized. We should also see what is the thickness of the epithelium. Then how is the lamina propria? The points to be noted in lamina propria. is the density, the thickness and presence or absence of elasticity of the lamina propria. Then we should also consider about the junction between the epithelium and the lamina propria. And finally, we should always comment about the submucosa. Now here we complete with the basic concept of oral mucus membrane. These are very very important to understand the upcoming lectures. So students please watch these lectures carefully. Now it is the quiz time. Students answer these questions in the comment box. The first question is the masticatory mucosa covers how much percent of the oral mucus membrane? The second question is the anchoring fibrils contain which type of collagen? And the final question is which layer is absent in the oral epithelium but present in the intestinal or the gut epithelium? All these questions are very very easy if you have watched this video carefully. Please provide your answers in the comment box. Students, please don't forget to subscribe to our channel. That's all for now. Happy studying!

This topic is quite lengthy and but it is very very important by exam point of view. So let's begin with today's topic, OMM. OMM in four parts in the first part we would be studying about the basics of OMM in the second part we would be studying about the non-keratinized epithelium in the third part we would be studying about the keratinized epithelium and in the final part will be studying about the gingival sulcus and the dento gingival junction. So let's begin with the first part which includes the basics of oral epithelium or the basics of oral mucus membrane. The oral mucus membrane is classified depending upon the function of the mucus membrane into three types.

First is the masticatory mucosa, second is the lining mucosa and the third is the specialized mucosa. The Mastricatory Mucosa comprises of 60% of the oral mucous membrane and it includes the hard palate and the gingiva. The Lining Mucosa comprises 25% of the OMM and it includes the lip, cheek, vestibule, floor of mouth, alveolar mucosa and the soft palate. While the Specialized Mucosa comprises only 15% of the OMM and it includes the It includes the dorsum of tongue and the taste buds.

Two different structures are also present in the oral mucous membrane which is slightly different. These are dentogen-trival junction and the vermilion border of lip. In the subsequent lectures, we would be studying each of these in detail.

Now for descriptive purpose the oral mucous membrane is divided into two types the keratinized mucosa and the non-keratinized mucosa. The keratinized mucosa involves the masticatory mucosa and the vermilion border of lip while the non-keratinized mucosa involves the lining mucosa and the specialized mucosa. Now what is the function of the OMM? There are four functions of the OMM. These are defense, lubrication, sensory and protection.

Now how does the oral mucus memory work? provides defense the oral mucous membrane prevents the entry of microorganisms and its toxins into the oral cavity and it is also impermeable to the toxins of the microorganisms. The second function is the lubrication.

Saliva is secreted from the minor salivary gland present in the oral mucous membrane and this saliva keeps the mucous membrane moist. The moist mucous membrane help in proper speech, mastication, swallowing and also help in perception of taste of food. The third function is the sensory function.

The oral mucous membrane is sensitive to touch, pressure, pain and temperature. There are numerous nerve endings present in the oral mucous membrane which help in sensory function of the mucous membrane. The last function is the protection. The oral mucous membrane, it protects the deeper tissues from mechanical trauma. Now let us study what the oral mucous membrane is in detail.

So OMM consists of 4 layers. The topmost layer is the epithelium. Below the epithelium there is a connective tissue which is called as lymph.

Lamina propria. Below the Lamina propria there is a layer of loose connective tissue which is called as submucosa. This submucosa connects the epithelium and Lamina propria complex to the underlying tissues which may be bone or muscle. Now let us study the one by one each of this structure.

The first structure we will be studying is the epithelium. Now how is the epithelium of the oral mucosa? oral mucosa may be keratinized or non-keratinized.

This keratinization may be orthokeratinization or parakeratinization. We will be studying about each of these in subsequent lectures. Now just remember the oral epithelium may be keratinized or non-keratinized.

It may be orthokeratinized or parakeratinized. Below the epithelium there is the lamina propria. The lamina propria of the oral mucosa they contain the salivary gland. And below the lamina propria there is a layer of loose connective tissue which is called as the submucosa. This submucosal layer connects the epithelium and lamina propria complex to the underlying bone or muscle.

Now let us study how is the skin. The skin comprises of an epithelium which is called as the epidermis and this epidermis is Always orthokeratinized. Non-keratinization or parakeratinization is never ever seen in the skin.

It is always orthokeratinized. And below this epidermis is the dermis. And this dermis contains hair follicles, the sebaceous glands and the sweat glands. And there is no submucosal layer in the skin and there is a direct attachment of this epidermis and the dermis to the underlying bone or muscle. There is no submucosal layer present in the skin.

Now let us see how is the intestinal mucosa The intestinal mucosa comprises of the epithelium, the lamina propria There is a characteristic layer present in the intestinal mucosa which is called as the muscularis mucosa It is called as muscularis mucosa because it contains all smooth muscles Let us see how is the intestinal mucosa This layer is characteristically present only and only in the intestinal epithelium and below this muscularis mucosa layer there is the submucosa and this submucosa it connects the upper structures to the underlying layer of bone or muscle. If we compare these three mucous membrane, we can see that the oral epithelium is made up of four layers. These are the epithelium, the connective tissue, the submucosa and the underlying layer of bone and muscle.

While the skin is made up of only three layers. These are the epidermis, the dermis and the underlying layer of bone or muscle. While the gut mucosa is made up of epithelium, the lamina propria, the muscularis mucosa which is patent only in the gut epithelium.

Then there is submucosa and the underlying layer of bone and muscle. Hope this is clear to all of you. Now let us see how is the interface between the epithelium and the lamina propria in the oral mucous membrane. This is the epithelium and this is the lamina propria. The epithelium and the lamina propria interface is corrugated this interface is not straight it is corrugated the epithelium it forms the projections which are called as the ridges remember the epithelium form the ridges And the connective tissue extensions are called as the papilla.

The lamina propria extensions are called as the papilla. These ridges they fit well with the papilla of the connective tissue. and it forms a corrugated appearance.

This is not straight, it is corrugated. This appearance of the interface may also be called as the serpentine appearance. Serpentine means like. a snake it appears like a snake so it is called as the serpentine interface now this epithelium and the connective tissue of the lamina propria are in intimate contact with each other and they at the junction of this epithelium and the lamina propria there is a structure which is called as the basement membrane And this basement membrane is very very very important structure. Let us now study this basement membrane in detail.

Under light microscope, the structure is called as the basement membrane while in the electron microscope it is called as the basal lamina. Under light microscope this basement membrane appear 1 to 4 micrometer thick. It is a cell free zone.

No cells are seen around the basement membrane and it is rich in mucopolysaccharide. rich in mucopolysaccharide which can be explained by its staining with pass stain. If we stain the basement membrane with periodic acid skiff this is a special stain and if we watch it under a microscope it it the basement membrane takes up this stain and we can see that it is not stained.

It stains positively for pass or periodic acid skip. This is a very important question which is asked in Viva and MCQs. The basement membrane, it takes up the periodic acid skip and it is pass positive.

This pass positivity indicates that the basement membrane is rich in mucopolysaccharide. Now let us see how it appears under the electron microscope. Under the electron microscope, it is called as the basal lamina.

This basal lamina is if we see under the electron microscope this is the epithelium the red line is the epithelium and the basement membrane is made up of two zones the clear zone this is the clear zone and this is the dark zone the clear zone shown by empty white space and dark zone by the green broadband the clear zone is called as the lamina lucida and the dark zone is called as lamina densa The lamina lucida is adjacent to the epithelium while the lamina densa is always below it i.e. towards the connective tissue. This lamina lucida is 20 to 40 mm in thickness and it is a glycoprotein layer. This lamina lucida contains type 4 collagen.

okay and it also contains laminin bullous pemphigoid antigen and other antigen the main this lamina lucida it forms the main part of the basement membrane or the basal lamina and it is made up of type 4 collagen so the when the question asked is asked in mcq or viva the basement membrane is made up of what type of collagen principally you should answer type 4 collagen. Remember the basement membrane. I will tell you an easy trick to remember this type of collagen.

4 is in floor. The basement membrane forms the floor of the epithelium. If this is the epithelium, the basement membrane forms the floor of the epithelium and it is made up of type 4 collagen.

So, 4 is in the floor. I hope you will remember this now. Now we have seen the basal lamina is made up of lamina lucida and lamina densa.

Now anchoring fibrils, if you can see these broad loops shown in blue lines, these are anchoring fibrils which are inserted into the lamina densa. These are made up of type 7 collagen. They form loops and are inserted into the lamina densa.

And what you see in these pink lines, these are the type 1 and type 2 collagen fibers which run through these loops shown by the pink lines. These are type 1 and type 2 collagen fibers. Now let us see what is the lamina propria. The connective tissue below the epithelium is known as the lamina propria.

The lamina propria is made up of two parts. First is the papillary part and the second part is the reticular part. The papillary zone is the zone of the epithelium.

which is present just below the epithelium and which extends between the ridges of the epithelium this is the papillary zone and below it this is the reticular zone sometimes this papillary zone is absent when the epithelium as in gingiva or hard palate sorry in the gingiva or heart palate if the epithelium do not contain the epithelial ridges if it is straight then the papillary part of the lamina propria is absent. But the reticular part is always present. So the epithelium and connective tissue have tight interlocking arrangement. There is a tight interlocking arrangement between the epithelium and the connective tissue and this provides exercise. exchange of material between the epithelium and connective tissue.

What does this ground substance of the lamina propria contain? The ground substance may contain many things. Mainly the collagen fiber present in the lamina propria is type 1 and type 3. Remember all these collagen fibers students they are frequently asked in multiple choice questions.

And the other things which may be present in the ground substance are various glycoproteins and proteoglycans. And cells are present such as fibroblasts, mast cells, macrophages. Now let us see what is the submucosa.

The connective tissue, it is a connective tissue layer of varying thickness. This is called as the submucosa. It is present below the lamina propria and the function of the submucosa is to connect the overlying structures to the underlying tissue which may be bone or muscle. This layer of connective tissue is very very loose.

And And it may be also tight in some of the type of mucosa such as in hard palate and gingiva. In other lining mucosa it is loose. The submucosa contain glands, it contain the blood vessels, it contain the collagen fibers, it contain the adipose tissue and it may also contain the nerves.

Now whenever we study any mucous membrane these are the points to be considered. First what is the type of epithelium? Either it is keratinized or non keratinized, whether it is para or ortho keratinized.

We should also see what is the thickness of the epithelium. Then how is the lamina propria? The points to be noted in lamina propria.

is the density, the thickness and presence or absence of elasticity of the lamina propria. Then we should also consider about the junction between the epithelium and the lamina propria. And finally, we should always comment about the submucosa.

Now here we complete with the basic concept of oral mucus membrane. These are very very important to understand the upcoming lectures. So students please watch these lectures carefully.

Now it is the quiz time. Students answer these questions in the comment box. The first question is the masticatory mucosa covers how much percent of the oral mucus membrane? The second question is the anchoring fibrils contain which type of collagen?

And the final question is which layer is absent in the oral epithelium but present in the intestinal or the gut epithelium? All these questions are very very easy if you have watched this video carefully. Please provide your answers in the comment box.

Students, please don't forget to subscribe to our channel. That's all for now. Happy studying!

Transcript for:Understanding the Oral Mucous Membrane

Transcript for:
Understanding the Oral Mucous Membrane