What is the Difference Between Papillae and Follicles

The main difference between papillae and follicles is that papillae are raised areas of inflammation, whereas follicles are areas of accumulation.  

Papillae and follicles are two types of conjunctivitis or pink eye. They are categorized according to their macroscopic and microscopic appearance.  

Key Areas Covered

1. What is Papillae
– Definition, Facts, Characteristics
2. What are Follicles
– Definition, Facts, Characteristics
3. Similarities Between Papillae and Follicles
– Outline of Common Features
4. Difference Between Papillae and Follicles
– Comparison of Key Differences

Key Terms  

Follicles, Papillae

What are Papillae

Papillae are a type of pink eye with a cobblestone arrangement. They are flattened nodules that contain a central vascular core. Most commonly, they are associated with allergic immune responses. Therefore, they can occur due to foreign bodies such as contact lenses or ocular prostheses. Also, all papillae conjunctivitis are histologically identical. They are closely packed and have flat-topped projections. Additionally, they contain numerous eosinophils, plasma cells, lymphocytes, and mast cells surrounding a central vascular channel. Furthermore, papillae are raised areas of inflammation. They are red at the surface and paler at the base. They contain a central blood vessel.

Figure 2: Papillae

Also, papillae that occur in the tongue are lingual papillae. They are small structures that occur on the upper surface of the tongue. Significantly, they give a rough texture to the surface of the tongue. There are four types of papillae in the tongue. They are circumvallate (or vallate), fungiform, filiform, and foliate. The most numerous papillae in the tongue are lingual papillae. They are fine, small, cone-shaped papillae. The fungiform papillae are club-shaped projections that occur in red color. Further, the short vertical folds on each side of the tongue are foliate papillae. Also, circumvallate papillae are dome-shaped structures on the human tongue.      

What are Follicles

Follicles are another pink-eye condition due to inflammation caused by pathogens, including atypical bacteria, viruses, and toxins. Follicles are small, dome-shaped nodules with no prominent central vessel. Lymphoid follicle occurs in the subepithelial region histologically. It consists of a germinal center. Also, it contains an immature, proliferating lymphocytes. Additionally, mature lymphocytes and plasma cells occur surrounding the corona. Significantly, the follicle appears paler on the surface and redder at the base.

Figure 2: Viral

Moreover, follicles are the areas of accumulation of white blood cells. Importantly, they contain central blood vessels. 

Similarities Between Papillae and Follicles

• Papillae and follicles are two pink eye conditions.
• They are called conjunctivitis.
• They have characteristic macroscopic and microscopic conditions.

Difference Between Papillae and Follicles

Definition

Papillae refers to a small, rounded bump on a part or organ of the body. In contrast, follicles refer to a small secretory cavity, sac, or gland.

Significance

Papillae are raised areas of inflammation, while follicles are areas of accumulation of white blood cells.    

Structure

Papillae appear red at the surface and paler at the base, while follicles appear pale at the surface and redder at the base.

Central Vessel

Papillae contain a central blood vessel, while follicles contain a central blood vessel.

Occurrence

Papillae occur associated with allergic immune responses, while follicles cause inflammation due to pathogens. 

Type of Cells

Papillae contain numerous eosinophils, plasma cells, lymphocytes, and mast cells surrounding a central vascular channel, while follicles contain mature lymphocytes, plasma cells, and immature, proliferating lymphocytes.

Conclusion

In brief, papillae and follicles are anatomical features in conjunctivitis or pink eye. They have different macroscopic and microscopic conditions. Papillae are raised areas of inflammation with a central blood vessel. They appear red at the surface and paler at the base. Also, they are associated with allergic immune responses. Additionally, they contain numerous eosinophils, plasma cells, lymphocytes, and mast cells surrounding a central vascular channel. In comparison, follicles are the accumulation of white blood cells. They appear pale at the surface and redder at the base. Also, they contain a central blood vessel. Importantly, follicles cause inflammation due to pathogens. Therefore, the main difference between papillae and follicles is their structure. 

References:

1. Dexter, A. (2023, April 22). Optometry infographic: Papillae vs. Follicles. Optometry Infographic: Papillae vs. Follicles. 

Image Courtesy:

1. “Illu04 tongue2” By Microrao – Own Work (CC-BY SA 4.0) via Commons Wikimedia
2. “Viral conjunctivitis” By Lesion – Own Work (CC-BY SA 3.0) via Commons Wikimedia