The integumentary system consists of the skin and its accessory structures. The skin is the largest organ of the body and is composed of three primary layers - the epidermis, dermis and hypodermis. The epidermis is the outer layer and contains multiple sublayers including the stratum corneum, stratum granulosum, and stratum basale. The dermis lies below the epidermis and contains collagen, elastic fibers, and structures like hair follicles and sweat glands. The deepest layer is the hypodermis, also known as subcutaneous tissue, which contains fat and connects the skin to underlying muscles and bones. The skin acts as a protective barrier and aids temperature regulation through processes like

1. Integumentary
system
9/3/20XX Presentation Title 1
By- Samruddhi S. Khonde
Asst. Prof
P. R. Patil Institute of Pharmacy

2. What is the
integumentary
system?
The integumentary system
consists of the skin and its
accessory structures, including
the hair, nails, sebaceous glands,
and sweat glands.
Presentation Title

3. The Skin….
• The skin is largest organ and the exterior
covering of the body.
• It is a protective covering for the skeletal
system and vital organs.
• For the adult human the average surface
area of the skin is between 1.5 – 2.0
square meters.
• The thickness of the skin varies over all
parts of the body and between men (1.3
mm) and women (1.26 mm).
• The skin is composed of three primary
layers, the epidermis, the dermis and the
hypodermis.
• The ph of the varies from 4.5 to 6.
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4. Structure of
Skin
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Fig: Structure of Skin

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Fig: Layers of
Skin

6. The Epidermis
• The epidermis is the outer or top layer and composed of stratified keratinised
squamous epithelium.
• It protects your body from harm, keeps your body hydrated, produces new skin cells
and contains melanin, which determines the colour of your skin.
• Its Thickness varies in different parts of the body. It is thickest on the palms of the
hands and soles of the feet.
• There are several layers (strata) of cells in the epidermis
A. Stratum Corneum
B. Stratum Lucidum
C. Stratum Granulosum
D. Stratum Mucosum
E. Stratum Germinativum
• There are no blood vessels or nerve endings in the epidermis, but its deeper layers are
bathed in interstitial fluid from the dermis, which provides oxygen and nutrients, and
drains away as lymph.
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Fig:- Layers (strata) of cells in the epidermis
8

9. A. Stratum Corneum
• The Corneum layer is the top layer of your skin. This is the layer you can see.
• The cells on the surface are flat, thin, nonnucleated, dead cells, or squames, in which
the cytoplasm has been replaced by the fibrous protein keratin.
• These cells are constantly being rubbed off and replaced by cells that originated in the
germinative layer and have undergone gradual change as they progressed towards the
surface. Complete replacement of the epidermis takes about a month.
B. Stratum Lucidum
• Stratum Lucidum is a 2-3 layered thicker skin only found on the palms of your hands
and soles of your feet. This is the layer that thickens to fight mechanical attack.
• This cell contain cytoplasm.
C. Stratum Granulosum
• The Granulosum layer is where the cells are spindle shaped found with small granules
in them, thought to make the skin tough.
• Cells under this layer contain cytoplasm and are nucleated.
• Lips and skin under fingernails do not have this layer in them.
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10. D. Stratum Mucosum / Stratum Spinosum
• It contain polyhedral cells.
• The Mucosum layer is where tissue fluid is stored. This layer gives the epidermis its
strength.
E. Stratum Germinativum
• The Germinativum layer is the bottom layer and This layer connected to the
dermis.here the cells are constantly reproducing. As new cells are formed and mitosis
takes place, the old cells are pushed towards the surface of the skin
• This layer is composed of single layer of columnar epithelium or cuboidal cells.
• The melanocyte cells are also located in this layer.
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11. The Dermis
• The dermis is a connective tissue layer sandwiched between the epidermis and
subcutaneous tissue. sometimes called the true skin.
• The dermis is a fibrous structure composed of collagen, elastic tissue, and other
extracellular components that includes blood vessels, nerve endings, hair follicles,
and glands.
• The role of the dermis is to support and protect the skin and deeper layers, assist in
thermoregulation, and aid in sensation.
• Fibroblasts are the primary cells within the dermis, but histiocytes, mast cells, and
adipocytes also play important roles in maintaining the normal structure and function
of the dermis.
• This layer contains the blood vessels. These divide into a network of smaller vessels
called capillaries. The blood supplies essential materials for growth, nourishment and
repair of the skin.
• Nerves found in the dermis layer are sensitive to pressure, pain, heat touch and cold.
The nerves of the skin act as warning systems to the body and alert us to temperature
changes, degrees of pressure, whether something is hard or soft.
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12. The Dermis Layer
• The dermis is divided into two layers:
A. The papillary dermis
B. The reticular dermis.
A. Papillary Layer:
• The papillary dermis is the superficial layer, lying deep to the
epidermis.
• The papillary dermis is composed of loose connective tissue that
is highly vascular.
• In This Papillary Layer blood vessels called capillaries and nerve
endings are found. Melanocytes which produce pigment can be
found where the papillary layer joins the epidermis.
Reticular Layer:
• The reticular layer is the deep layer, forming a thick layer of
dense connective tissue that constitutes the bulk of the dermis.
• Reticular Layer helps by giving skin its elasticity. In this layer
there are Blood and Lymph vessels, nerve & sweat glands.
Collagen is found in this layer and is the most abundant protein
in the dermis.
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13. The Subcutaneous Tissue
• The hypodermis, also known as the subcutaneous layer, is the
layer of tissue beneath the skin that is mostly composed of
fat. This layer of fat provides insulation and cushioning for
the body and helps to protect the internal organs.
• The hypodermis also helps to regulate body temperature and
stores energy.
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A. Stratum Corneum
• This is the outermost layer of the epidermis and is therefore exposed to
the atmosphere outside of your body.
• There are usually 15 to 30 layers of cells in the stratum corneum, which
play an important protective role.
• The cells in this layer help to prevent bacteria, viruses, and fungi from
penetrating to deeper layers of skin, as well as provide protection
against abrasion and friction for the more delicate underlying layers.
This is the layer that makes the skin feel rough when it is dry.
• The “skin barrier” that prevents evaporation of water is also located
here.
• The entire stratum corneum layer is replaced with new cells in a process
known as desquamation. New cells travel up from the basale layer where
they are made and push out the old, lackluster cells on the surface.
• This process usually takes about four weeks.

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C. Stratum Granulosum
• This important layer has tiny granules full of components that are produced by skin
cells and packaged in the granules.
• Keratin, which is what gives strength, is packaged in little keratohyalin granules.
Epidermal skin cells are named “keratinocytes” because they produce keratin. The
keratinocytes in this layer also produce lipids and natural moisturizing factor (NMF)
that make skin waterproof and help it to hold onto moisture.
• The lipids, proteins, and natural moisturizing factors are produced in this layer inside
“keratohyaline granules.” These granules are produced by the keratinocytes in the
granular layer. It’s called the granular layer because of the presence of these
granules.
• In the upper layers of the epidermis (the stratum lucidum and stratum corneum), the
granules break open to release their contents into the space between the cells.
• This bathes the stratum lucidum and the stratum corneum with important lipids that
make up the skin barrier and many protective proteins.

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E. Stratum Germinativum
• The deepest layer of the epidermis is called the stratum basale, sometimes called
the stratum germinativum.
• The basal layer is where new skin cells known as “keratinocytes” are “born.”
• As they are produced, these new cells travel upward, pushing existing older cells
even higher in a process known as “keratinization”.
• Eventually, these skin cells reach the outer layer of your skin, where they push off
dead, flaky cells and replace them. This process can take 26-40 days and is
affected by age, genetics, hydration and cosmeceutical products.
• Two other types of cells are also found here: Merkel cells and melanocytes. Merkel
cells are receptors that send messages to your brain that get translated as your
sense of touch. You have lots of these cells on the palms of your hands and the
soles of your feet.
• Melanocytes produce melanin, which is the pigment that gives your skin and hair
their color.

17. Functions of skin…
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Specialised nerve endings in the
skin are able to detect, warmth,
coldness, touch and pain.
Sensation
Protection from Physical Attack.
Protection
The sweat glands in the skin
excrete sweat which is a waste
product of the body. Sweat helps
to control body temperature.
Excretion
The skin absorbs health - giving
vitamins through the action of
ultra-violet rays upon the skin.
Absorption
The skin helps regulate the
body temperature by means
of perspiration.
Regulation

18. Thank You
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