The main difference between the salivary gland and the lymph node is that salivary gland is an exocrine gland that produces saliva whereas lymph node is a secondary lymphoid organ that filters foreign particles.
Generally, the salivary gland and lymph node are two small structures in the human body. Generally, the parotid gland, one of the salivary glands, is associated with lymph nodes.
Key Areas Covered
1. What is Salivary Gland
– Definition, Structure, Function
2. What is Lymph Node
– Definition, Structure, Function
3. Similarities Between Salivary Gland and Lymph Node
– Outline of Common Features
4. Difference Between Salivary Gland and Lymph Node
– Comparison of Key Differences
Key Terms
Lymph Node, Salivary Gland
What is Salivary Gland
The salivary gland is an exocrine gland that occurs in mammals. The main function of the salivary gland is to produce and secrete saliva into the oral cavity. Generally, humans have three paired salivary glands: parotid glands, submandibular, and sublingual glands. Apart from that, hundreds of minor salivary glands are in the oral cavity. Moreover, salivary glands are serous, mucous, or seromucous glands. In general, alpha-amylase is the main type of protein that occurs in serous secretions. Alpha-amylase is the enzyme responsible for the breakdown of starch into maltose and glucose inside the oral cavity.
Figure 1: Salivary Glands
Furthermore, the main protein in mucus secretion is mucin. It also acts as a lubricant. However, salivary glands produce 1200 to 11500 ml of saliva per day. In addition, parasympathetic secretion is responsible for the secretion of saliva into the oral cavity. Apart from that, the main function of salivary glands is to protect and lubricate the soft and hard tissues of the oral cavity.
What is Lymph Node
The lymph node is a type of secondary lymphoid organ of the lymphatic system. A number of lymph nodes occur along the lymphatic vessels. Generally, a lymph node is a kidney-shaped organ whose size can range from millimeters to 1-2 centimeters. Lymph nodes are more concentrated within the trunk of the body. The anatomical structure of a lymph node mainly consists of two main regions: the outer cortex and the inner medulla. The cortex consists of a capsule, which surrounds the medulla, except in the regions of the hilum. The branches of the capsule enter into the subcapsular sinus. From the superficial region, afferent lymphatic channels perforate the capsule.
Figure 2: Lymph Node
Moreover, the main function of a lymph node is to filter the lymph to capture pathogenic antigens. Since it is a secondary lymphoid organ, a lymph node hosts lymphocytes allowing them to capture antigens and develop an adaptive immune system.
Similarities Between Salivary Gland and Lymph Node
- The salivary gland and lymph nodes are two types of small structures in the human body.
- Generally, they have different functions in the body.
Difference Between Salivary Gland and Lymph Node
Definition
The salivary gland refers to exocrine glands that produce saliva through a system of ducts while the lymph node refers to small structures that filter foreign substances, such as cancer cells and infections.
Importance
The salivary gland is an exocrine gland while the lymph node is a secondary lymphoid organ.
Structure
Usually, salivary glands contain branched ducts that open into the oral cavity and glandular secretory end pieces, called acini while the lymph node is surrounded by a connective tissue capsule and divided into compartments called lymph nodules.
Occurrence
Parotid glands occur in front of and just below each ear, submandibular glands occur below the jaw, and sublingual glands occur under the tongue. Lymph nodes, on the other hand, occur in many parts of the body, including the neck, chest, abdomen (belly), armpit, and groin.
Function
Salivary glands lubricate the mouth and throat, aid in swallowing and digestion, and help shield teeth from cavity-causing bacteria while lymph node filters for foreign substances, such as cancer cells and infections.
Conclusion
In brief, salivary glands are branched ducts that open into the oral cavity. They also secrete saliva into the oral cavity. Generally, the three types of salivary glands are parotid glands, submandibular glands, and sublingual glands. The main function of the salivary gland is to lubricate the mouth and aid in digestion. Lymph nodes, on the other hand, are secondary lymphoid organs that occur in the lymphatic system. The main function of the lymph node is to filter foreign particles including bacteria and cancer cells. Therefore, the main difference between salivary gland and lymph node is their structure and function.
References:
- “Salivary Glands Anatomy.” Memorial Sloan Kettering Cancer Center, 1 Jan. 1970.
- “Lymph Nodes.” Healthdirect.
Image Courtesy:
- “Blausen 0780 SalivaryGlands” By BruceBlaus – Own work (Public Domain) via Commons Wikimedia
- “Schematic of lymph node showing lymph sinuses” By KC Panchal – Own Work (CC BY 3.0) via Commons Wikimedia Treehopper, adults, nymph
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