The main difference between the papillary and reticular dermis is that the papillary dermis is a thin, superficial layer of loose connective tissue lying deep in the epidermis. In contrast, the reticular dermis is a thick layer of dense connective tissue beneath the epidermis.
The papillary and reticular dermis are the two dermis layers, a connective tissue layer located deep in the epidermis. The dermis functions include thermoregulation, sensation, and protecting the deep layers of the skin.
Key Areas Covered
1. What is Papillary Dermis
– Definition, Structure, Function
2. What is Reticular Dermis
– Definition, Structure, Function
3. Similarities Between Papillary and Reticular Dermis
– Outline of Common Features
4. Difference Between Papillary and Reticular Dermis
– Comparison of Key Differences
Key Terms
Papillary Dermis, Reticular Dermis
What is Papillary Dermis
The papillary dermis is the top layer of the dermis and is thinner than the reticular dermis, the other layer of the dermis. It comprises collagen fibers, fibroblast cells, fat cells, nerve fibers, blood vessels, touch receptors (Meissner corpuscles), and phagocytes. Also, it consists of oxytalanelastic fibers. Additionally, the papillary dermis contains more fibroblast than the reticular dermis. The type of connective tissue found in the papillary dermis is the loose areolar connective tissue.
Figure 1: Sections of the Skin
Moreover, the papillary dermis contains finger-like projections called dermal papillae. They extend towards the epidermis and include tactile Meissner’s corpuscles or a terminal network of blood capillaries. The dermal papillae are small, nipple-like extensions into the epidermis. They nourish all hair follicles in the epidermal layer. Also, they play a vital role in hair formation, growth, and cycling.
What is Reticular Dermis
The reticular dermis is the bottom layer of the dermis that occurs under the papillary dermis. The type of connective tissue occurring in the reticular dermis is dense irregular connective tissue. It composes of densely-packed collagen fibers. Additionally, the dermal elastic fibers occur in the reticular dermis. The key feature of the reticular dermis is its thickness. Therefore, it makes up 80% of the dermis. Also, in high concentrations, reticular connective tissue contains collagen, elastic, and reticular fibers. Importantly, these protein fibers give the dermis strength, elasticity, and extensibility.
Figure 2: Papillary and Reticular Dermis
Moreover, hair follicles, sweat glands, sebaceous glands, receptors, blood vessels, and nerves occur in the reticular region. Apart from that, Langer’s lines are the type of lines made up due to the orientation of collagen fibers in the reticular dermis.
Similarities Between Papillary and Reticular Dermis
- The papillary and reticular dermis are two layers of the dermis.
- They involve thermoregulation, sensation, and protecting deep layers of the skin.
- They are made up of connective tissue.
Difference Between Papillary and Reticular Dermis
Definition
The papillary dermis refers to the thin top layers of the dermis, while the reticular dermis refers to the thick bottom layer.
Thickness
The papillary dermis is thin, while the reticular dermis is thick.
Composition of the Dermis
The papillary dermis is 20% of the dermis, while the reticular dermis is 80%.
Type of Connective Tissue
The papillary dermis consists of areolar connective tissue, while the reticular dermis consists of dense irregular connective tissue.
Components
The papillary dermis comprises dermal papillae, capillaries, lymphatics, and sensory neurons, while the reticular dermis comprises elastic and collagen fibers.
Function
The papillary dermis nourishes the epidermis, while the reticular dermis provides strength and flexibility to the skin.
Conclusion
In brief, the papillary and reticular dermis are two layers of the skin’s dermis. Their function is to undergo thermoregulation, sensation, and protection. The papillary dermis is the top, thin layer, making up 20% of the dermis. Also, it consists of areolar connective tissue with dermal papillae, capillaries, lymphatics, and sensory neurons. The papillary dermis’s primary function is to nourish the epidermis. In comparison, the reticular dermis is the bottom, thick layer, making up 80% of the dermis. Additionally, it is made up of dense irregular connective tissue. It composes of elastic and collagen fibers. The primary function of the reticular connective tissue is to provide strength and flexibility to the skin. Therefore, the main difference between papillary and reticular connective tissue is its structure and function.
References:
- Brown TM, Krishnamurthy K. Histology, Dermis. [Updated 2022 Nov 14]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-.
Image Courtesy:
- “Epidermis, papillary dermis and reticular dermis” By Kilbad – Own work (CC0) via Commons Wikimedia
- “Blausen 0802 Skin DermalCirculation.” By BruceBlaus – Own Work (CC-BY 3.0) via Commons Wikimedia
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