basics of skin, review of skin, Integumentary system, the structure of the skin, Functions of skin, skin appendages, Hair, sweat glands, sebaceous glands, Nails, dermis, epidermis, subcutaneous tissue. anatomy and physiology

1. • Ms. S. Jasmine Debora, Professor ,
• Dept of Medical surgical Nursing,
• Mr. B. John victor,3 yr B.sc Nursing
• NRI College of Nursing
• Guntur,
• Andhrapradesh

2. Introduction
• The skin is also known as cutaneous membrane or in
tegument, covers the external surface of the body
• It is a sensory organ which is an largest organ of
• the body in both surface area and weight
• Integumentary system is composed of skin, hair, nai
ls, glands pH - 4 to 5.6
•

4. STRUCTURE
OF THE SKIN
Three layers of skin :
Epidermis;
- Superficial layer of the skin
- composed of epithelial tissue
Dermis;
- The deeper layer of the skin
- primarily composed of connective tissue
Subcutaneous tissue
Deep to the dermis is the subcutaneous layer
or hypodermis
- It consists of areolar and adipose tissue

5. Epidermis
 Stratum corneum = many layers of flat, dead, scale like cells full
of keratin
 Stratum lucidum = one or two layers of dying cells
 Stratum Granulosum = Three or four layers of skin; actively
 synthesizing protein keratin
 Stratum spinosum = three or four layers of cells with some
cell division
 Stratum Basale = Single row of dividing cells (columnar cells)

6. Primary cell type in epidermis =
Keratin cutes which produce a large amou
nt of protein keratin
Other cell types ;
Melanocytes produce pigment
melanin & transfer it to
keratinocytes
Langerhans cells(immune cells) protect ag
ainst pathogens and toxins

7. DERMIS
Dense irregular connective tissue
Separated from epidermis (stratified
squamous epithelium) by basement mem
brane
Highly vascular
Highly innervated
Two layers ;
Papillary layer just below epidermis
Reticular layer forms deep 80 %

8. Dermis
• Contains many types of sensory receptors for touch ,
pressure, vibration, pain , temperature etc ..
• Papillary layer is folded into ridges which extend into
upper epidermal layer. The exposed ridges form conge
nital patterns called finger prints and foot prints
• Reticular layer contains collagen Elastic and reticular
fibers

9. Subcutaneous tissue
• Lies below the dermis and is not part of skin. It att
aches the skin to underlying tissue such as muscle a
nd bone. The subcutaneous tissue contains loose fat
cells, that provide insulation.
• The anatomic distribution of subcutaneous tissue v
aries according to gender, hereditary, age, nutrition
al status. Thus layer also stores lipids, regulates te
mperature, and provides shock absorption.

10. Appendages of skin
• Hair follicle and Hair
• Sweat and sebaceous glands
• Nails on fingers and toes

11. Hair follicle and Hair
 Hair is composed primarily of keratin. The dead keratinocytes fuse
together to form the hair. At the base of the follicle is the bulb,
which contains cells that give rise to the keratinocytes that make up
the hair, as well as blood vessels that nourish the growing hair.
 Lengthening fibers of keratin-filled dead cells, grouped around the
semi hollow medulla, make up the cortex. A living structure called
the bulb (visible as a white lump at the end of a plucked hair)
surrounds and feeds the root, which lies in a pocket of the epidermis
called the follicle.
 Each hair follicle also contains the arrector pili, a muscle that
contracts in response to cold, fright, and other emotions. When the
muscle contracts, it pulls the hair in the follicle into a vertical
position.

12.  This response may help some mammals keep warm or look bigger
to frighten or intimidate their enemies.
 But in humans, because of our sparse coat of body hair, it merely
produces “goose bumps.”
 The color of hair is due to melanin. Dark hair contains true
melanin like that found in the skin.
 Blond and red hair result from types of melanin that contain
sulfur and iron.
 Hair goes gray when melanocytes age and lose the enzyme
necessary to produce melanin.
 White hair occurs when air bubbles become incorporated into
the growing hair.

13. Sweat and Sebaceous Gland
 An adult human has between 1.6 to 4 million sudoriferous
glands, or sweat glands. Most are of a type known as
eccrine sweat glands, which are found almost all over the
surface of the body and are most numerous on the palms
and soles. Eccrine sweat glands begin deep in the dermis
and connect to the surface of the skin by a coiled duct.
 In addition, nerve fibers that encircle the sweat glands
stimulate the glands in response to fear, excitement, or
anxiety.

14. Nails on fingers and toes
 Nails on the fingers and toes are made of hard, keratin-
filled epidermal cells. They protect the ends of the digits
from injury, help us grasp small objects, and enable us to
scratch.
 The part of the nail that is visible is called the nail body or
nail plate, and the portion of the nail body that extends
past the end of the digit is called the free edge. The nail
groove is the fold on the side and the eponychium is the
skin that holds the nail root.

15.  Most of the nail body appears pink because of blood
flowing in the tissue underneath. The pale,
semicircular area called the lunula appears white due
to an underlying thick layer of epidermis that does not
contain blood vessels.
 The part of the nail that is buried under the skin is
called the root. Nails grow as epidermal cells below
the nail root and transform into hard nail cells that
accumulate at the base of the nail, pushing the rest of
the nail forward.

16.  Other sweat glands, known as apocrine sweat glands, are much less
numerous than eccrine sweat glands. They are also anchored deep in
the dermis, but open into hair follicles rather than onto the surface
of the skin.
 Apocrine sweat glands are located mainly in the armpit, genital
area, and around the nipples of the breasts.
 Oil, or sebaceous, glands are found all over the body except on
the palms, the soles, and the top of the feet. They are most
numerous on the face and scalp. Most sebaceous glands open into
hair follicles, but the glands also occur in some hairless areas,
such as the lips and inside the mouth.

17.  Glands of this type produce an oily substance called
sebum, which keeps the skin and hair from drying out
and inhibits the growth of certain harmful bacteria.
 Wax, or ceruminous, glands are located in the ear
canal. They secrete a waxy substance that helps
prevent foreign particles from entering the ear.
Ceruminous glands are modified sweat glands.

18. Functions of skin
• Skin controls heat regulation by responding to changes in t
emperature with vasoconstriction and vasodilatation
• Helps to maintain homeostasis through fluid and electrolyt
e balance
• Sebum and Sweat are secreted by skin and lubricate skin s
urface
• Endogenous synthesis of vit-D, which is critical to calcium
and potassium balance, occurs in epidermis

19. Skin physiology

20. • Vit -D synthesized by action of UV lights in vit -D precu
rsor in epidermal cells
• The esthetic function of skin include the expression of
various emotions such as anger or embarrassment, as wel
l as displaying the individual identity of a person
• Skin with its nerve endings and special receptor provide
s sensory perception for environmental stimuli. These hig
hly specialized nerve endings supply information to brain
related to pain, heat and cold, touch, pressure, vibration.
.

21. Bibliography
• Gerard j Tortora; Bryan Derrick son; John Wil
ey sons; Principles of anatomy and Physiology,H
oboken ,Newjersey, John Wiley & Sons, Inc., [
2017]