The document discusses the integumentary system, which includes the skin and its derivatives. It describes the three layers of skin - the epidermis, dermis and hypodermis. The epidermis is the outermost layer and contains keratinocytes that produce keratin to waterproof and strengthen the skin. The dermis lies beneath and contains connective tissue, blood vessels, glands and hair follicles. The innermost hypodermis contains fat cells, connective tissue and larger blood vessels. The skin performs many functions, including protection, moisture regulation, sensation, secretion, excretion and respiration.

1. Babasaheb Bhimrao Ambedkar University
Central University in Lucknow,
UTTAR PRADESH,INDIA
Integumentary system(Skin)
Course : M.Sc. Zoology
Subject : Comparative anatomy of vertebrate
Submitted to Submitted by
Dr. Suman Mishra Devanshu Kumar

2. Introduction
The word integument is derived from the Latin word
‘integumentum’ that means a covering.
Anatomy states that the largest organ of the body
of the vertebrates and humans is the integument.

3. The integumentary system is a system comprised of
organs that are the outermost protective covering of
the animal body, the skin, and its various derivatives.
IN humans the integumentary system includes
the skin .

4. Organs of the Integumentary System
SKIN
NAILS
HAIR
GLANDS
SCALES
FEATHERS

5. SKIN
Skin is the outermost covering of
the body.
It is the first organ of the body
that is visible when we encounter
an animal.
Skin is a complex organ that
performs many functions in the
body.
It is also called “The Jack of all
trades”.

6. Structure Of Skin
The structure of the skin is made
up of three layers of, namely:
• Epidermis: outermost layer
of the skin
• Dermis: beneath the epidermis
• Hypodermis: the innermost layer

7. Epidermis
 The cells in this layer are called keratinocytes.
 The keratinocytes are composed of a protein called
keratin.
 Keratin strengthens the skin and makes it
waterproof.
 The epidermis actually has 4 strata.
• Stratum corneum
• Stratum lucidum
• Stratum granulosum
• Stratum germinativum

8. Stratum corneum
Stratum lucidum
Stratum granulosum
Stratum germinativum

9. DERMIS
The dermis is beneath the epidermis and is composed of
connective tissue.
It contains the lymphatics, nerves, nerve endings, blood
vessels, sebaceous and sweat glands, elastic fibers, and
hair follicles.
It is divided into two layers:
• The papillary layer
• The reticular layer

11. Hypodermis
The hypodermis is the innermost layer.
 It is also known as the subcutaneous layer.
It contains the cells known as fibroblasts, adipose
tissue (fat cells), connective tissue, larger nerves and
blood vessels, and macrophages.
Its thickness is dependent on the region where they
appear and vary.
 It insulates the body from heat and cold.

12. Functions of skin
1. Protection
 The integument forms a covering of the body and is
protective.
 It protects the tissues against excessive loss of
moisture.
2. Food Storage
 The skin stores fat in its layers as reserve food material.
 In whales and seals the fat of the skin forms a thick layer.

13. 3. Secretion
 In mammals sebaceous glands secrete oil which
lubricates the skin and hairs.
 Mammary glands produce milk for nourishment of
the young.
 Lacrymal glands secretion wash the conjunctiva of
eyeball in mammals.
4. Excretion
 In mammals metabolic waste (salts, urea and water)
is removed from the blood by means of sweat.
 Chloride secreting cells are found in gills of marine
fishes.

14. 5. Sensation
Skin has various kinds of tactile cells and
corpuscles.
6. Respiration
Skin acts as an organ of respiration.
7. Locomotion
Derivatives of the integument bring about
locomotion in some animals.

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