The document details the integument system, outlining the structure and functions of skin and its derivatives, including the epidermis and dermis. The epidermis serves as a protective layer, while the dermis contains connective tissue crucial for body heat regulation and defense against injury. It also discusses various epidermal structures such as scales and teeth, emphasizing their composition and origin.

1. -By zooomania

2. Integument
• There is nothing more conspicuous about an organism
than its skin.
• It is our primary means of identifying the organism,
and is what defines the boundary of its body.
• Skin is also the primary means through which an
organism interacts with its environment.

4. Function :
• support and protect soft tissues against abrasion, microbes
• reception and transduction of external stimuli - i.e. heat, chemical,
tactile
• transport of materials involved in excretion, secretion, resorption,
dehydration, rehydration
• heat regulation
• respiration
• nutrition/nutrient storage - i.e. storage of vitamins, synthesis of
Vitamin D
• locomotion
• coloration - cryptic or display

5. Basic structure of the integument:
• The integument consists primarily of the skin and its
derivatives.
• Skin is a functional unit composed layers of fairly distincy
epidermis (derived from ectoderm) and dermis (derived
from the dermatome of somites) that are separated by the
basement membrane.

6.  Epidermis
 It is relatively thin in most
animals
 The upper layer composed of
mostly dead, differentiated
cells (stratum corneum) with a
lot of keratin which helps the
skin maintain some protection
against water loss and
bacteria

7.  Dermis
 It is more of a
connective tissue than
protective
 Irregularly-shaped
connective tissue cells
that produce the
extracellular matrix,
including collagen and
elastic fibers.

8. THE INTEGUMENT AND ITS DERIVATIVES
Epidermis Dermis

9. EPIDERMIS FUNCTION
• The epidermis, derived from somatic ectoderm, is the
exterior-most covering of the chordate body.
• It provides protection against the invasion of
microorganisms, provides flexibility in motion, and seals in
moisture.
• As will be seen, it also gives rise to a variety of
differentiated structures such as feathers, hair, horns,
claws, nails and glands.

10. Epidermal Derivatives of the Integument
• The production of all of the following structures involves
keratinization.
• Epidermal Scales: a continuous layer of repetitious
thickenings of the stratum corneum.
• Claws and Talons: curved, laterally compressed
keratinized projections from the tips of digits.
• Hooves: enlarged keratinized plates found on the ends of
ungulate digits.
• Nails: keratinized epithelial cells.

11. Glands
Specialized to secrete specific products (oil, sweat,
milk, etc.), these structures are derived by an
infolding of the epidermis. In many cases they retain
a connection to the stratum corneum whereby their
secretions can be released at the skin surface.

12. THE DERMIS AND ITS DERIVATIVES
• The dermis is generally much thicker than the epidermis
and lies more deeply.
• It is made of a fibrous mass of connective tissue
(collagen) and is of mesodermal origin.
• It may directly produce dermal (membrane) bone.
• The dermis is important in defence against injury and in
the maintenance of body heat.
• Deeper regions of the dermis often contain fatty deposits,
smooth muscle, blood vessels and nerves.

13. • Dermal Bone
• Once present in some extinct fish.
• Now dermal bone is present in turtle dermal bone, antlers, and in
the dermal armour of armadillo.
• In most modern vertebrates, dermal bone (membrane bone) is
formed from embryonic mesenchyme by intramembranous
ossification, and contributes to the skull and skeleton, rather than
being manifested externally.
• An exception is teeth, which are partly derived from dermal bone..
•

14. Fish Scales
Fish scales are also called dermal scales since they are
derived mainly from the dermis.
• 1.Cosmoid Scales
• 2.Ganoid Scales.
• 3.Placoid Scales:
• 4) Teleost (bony fish) scales
4 a) Cycloid Scales
4 b) Ctenoid Scales:

15. scales

16. • TEETH
• Teeth are composed of three main parts.
• Enamel, the hardest substance in the body, covers the
tooth surface. It is epidermal in origin.
• Ganoin is a form of enamel.
• Dentin is similar to bone in structure but is harder. It is
located beneath the enamel and forms the walls of the
third component of teeth, the pulp cavity. These are of
dermal origin.
• Cosmine is a form of dentin. Dermal bone
called cementum is also present in mammalian teeth.

17. teeth

18. Thank you.