Difference Between Epidermis and Dermis

Skin is the outermost layer of the body and serves as the first line of defense from invading foreign particles. It secrets acids and salt in liquid form. Epidermis is the outermost layer present on the body and the Dermis is the dense irregular connective tissue present beneath the epidermis. Dermis contains body fluids and vein that leads to blood circulation.

Epidermis:

The skin has three main layers Epidermis, Dermis, and Hypodermis. Epidermis is the upper layer of the skin. It protects the body from heat, Pathogens, and the outside world’s unwanted things of the body. It regulates body temperature and amount of the water to be released from the body.

Features of Epidermis:

• A most superficial and thin layer of skin.
• It contains cholesterol.
• Melanocytes are present in the epidermis and determine the color of the skin.
• Two types of pigments are secreted by the skin melanocytes.

1. Eumelanin: It provides pigmentation to skin, hair, and eyes.
2. Pheomelanin: It makes pink or red pigmentation.                                            

Layers of Epidermis:

Epidermis contains five layers including the stratum basal (Deepest Portion of the epidermis), Stratum spinosum, Stratum granulosum, Stratum lucidum, and stratum corneum (Superficial portion of the epidermis).

• Stratum Basal: It is the deepest layer of the epidermis. It separates the epidermis from the basal membrane and attaches the basal membrane by hemidesmosome. This layer contains melanocytes and also continuously produces keratinocytes. This layer consists of cuboidal to columnar active stem cells.
• Stratum Spinosum: It contains irregular cell structures sometimes also called prickled cells. It is always found in the 8-10 layer. It contacts neighboring cells by desmosomes. Dendritic cells can be found in this layer.
• Stratum Granulosum: It is of diamond-shaped cells. It contains lamellar granules. Keratohyalin granules found in this layer it is a keratine precursor that eventually aggregates, crosstalk, and forms bundles. Diamond shape cell usually contains 3-5 layers of cells.
• Stratum Lucidum: Here 2-3 layers of skin are found where ever thickness is needed in the skin of the body. It transforms the product of keratohyalin by eleidin.
• Stratum Corneum: It is the uppermost layer of skin. It is made of keratin and the dead layer of the horn scalp. Keratinocytes present in it that is our first immune defense. 

Functions of Epidermis:

The function of the epidermis includes touch, Sensation, and Protection against Pathogens. 

• It acts as the first line of defense.
• It produces fatty acids so that microbes can not survive on the skin.
• It contains melatonin that reaction gives skin color.
• It releases glycogen and a hydration reaction making skin moist and protecting the body.
• Contain always active stem cells that replace old cells with new cells.

Dermis:

Dermis is connected to the basal level of the epidermis. It consists of two layers of connective tissue, the papillary and the reticular dermis. The papillary layer is the upper layer of the dermis. It is thin and consists of loose connective tissues that connect the epidermis. The reticular layer is deeper, thicker, less cellular, and consists of bundles of collagen/dense connective tissue. It is the house of blood vessels, sensory neurons, and glands. 

Features of Dermis:

• This layer is present at the basal of the epidermis.
• Dermis is the thickets layer of skin.
• It is made up of fibrous and elastic tissue.
• It contains Glycoprotein, Mucopolysaccharides, and Chondroitin Sulfate which makes a gel-like constituency around the dermis. 
• This layer contains- Seat glands, Hair follicles, Muscles, Nerves, and Blood vessels.
• It consists of two layers of connective tissue that are the Reticular Dermis and the Papillary Dermis.

Reticular Dermis:

• The reticular layer presents the basal of the epidermis.
• It has a net-like structure supported by elastin and collagen fibers.
• Fibers help the skin in the movement of microtubules and stretches of the skin.

Papillary Dermis:

• Slightly thinner than the reticular dermis.
• It is the top layer of the dermis.
• It makes a strong bond that makes interlinking fingers between the dermis and the epidermis.
• It provides the basement support and strong attachment for the epidermis.

The Function of Dermis:

• It is a thick layer that contains glands, blood vessels, Hair follicles, lymphatic vessels, etc.
• It supports the epidermis.
• It is the main site of all chemical reactions in the skin.
• Produce vitamin D with the reaction of cholesterol and sunlight. 
• It participates in the body’s defense mechanism.
• It is the main site of Humoral Immunity. 

Difference Between Epidermis and Dermis:

Parameter of Comparison	Epidermis	Dermis
Cell Layers	It is the outermost layer of skin.	It presents beneath of epidermis.
Types	It contains three types of layers.	It contains two types of layers.
Glands/Cells	It has cuboidal and diamond shape cells that secret enzymes and glycolipids.	It does not have secretive cells.
Blood Vessels	Epidermis avoids blood vessels.	It contains blood vessels.
Nerve Cells	It does not contain nerve cells.	Dermis contains nerve cells.
Plants & Animal Difference	Epidermis is found in plants as well as animals.	It is only present in animals.
Nutrients	Essential nutrients and oxygen are obtained from the dermis.	Essential nutrients and oxygen are obtained from blood vessels.

Similarities Between Epidermis and Dermis:

• Epidermis and Dermis are the first lines of defense of the immune system.
• They are two layers to make the skin.
• Both can support mutually for their mutual benefit (chemical balance, nutritional exchange, etc.).

Conclusion: 

Epidermis and Dermis are the two basic layers that make skin cover the body. Together they protect the body in different mechanisms like Defence, Chemical reactions, Dehydration, and Internal organ damage. Melanin and dark pigments are that they protect from UV radiation. They have a role in the transport and generation of antibodies and body fluids. Prevents the body from mechanical damage.

FAQ:

Q1: Where does vitamin D synthesis take place in the body?

Answer:

Skin dermis layer where in presence of sunlight and cholesterol vit-D synthesizes.

Q2: What is the main component responsible for skin color?

Answer:

Here the main component is Melatonine. large amount of melatonine makes black skin colour, it synthesizes in the presence of sun light.

Q3: What is the major function of the dermis layer? 

Answer:

• It provides support to the epidermis.
• It’s major role in defence mechanism.
• All chemical reaction of skin occur in dermis layer.

Q4: How epidermis acts as the first line of defense?

Answer:

It produce salt and fatty acid that does not leads to survive pathogens and bacteria.