THE INTEGUMENTARY SYSTEM
Integument- external covering of an animal
Functions:
• Protection
• First line of defense against
microorganisms and toxic substances
• Regulation of body temperature
• Reception of environmental stimuli
(pain, temp, pressure)
• Excretion of waste materials
• Movement of gases (for some
animals)
• Locomotion (for some animals)
• Some possess (specialization)
Variations in Invertebrates a) cuticle- waxy substance in
epidermis of rotifers, crustaceans,
A. Single-celled Protozoa arachnids, insects, nematodes and
- Plasma membrane as external annelids
covering b) shell- CaCO3 in cnidarians (e.g.,
- E.g., Paramecium, Euglena corals) and Echinoderms (starfish,
sea urchins)
Pellicle- thick protein coat
c) Tegument- in parasitic flatworms
- For nutrient absorption and
B. Multicellular Invertebrates protection against digestion by host
enzymes
I. Epidermis- In most multicellular
invertebrate, outer layer
- Single layer of columnar epithelial
cells
Hydra- Few cell layers thick
Nematodes and Annelids- one-cell thick
which secretes multilayered cuticle
, d) Cilia- in echinoderms, ciliated epidermis
and dermis containing CaCO3
Ciliated Epidermis of Echinoderms
Arthropods- most complex of invertebrates
because Integument is a specialized VARIATIONS IN VERTEBRATES
exoskeleton (chitinous)
• Jawless Fishes (Lampreys and
Hagfishes)
- Thick skin due to multilayered
epidermis with glandular cells and
fat storage cells in the hypodermis
• Cartilaginous Fishes (Shark)
- Multilayered and contains bone in
the form of denticles (teeth)
• Bony Fishes (Teleost)
- Contains scales
Chitinous Exoskeletons of Arthropods • Amphibians
- Stratified and contains mucous and
several glands (mucous and poison
VERTEBRATES INTEGUMENT: SKIN glands) plus pigmentation
- Sensory nerves in epidermis
SKIN- Largest organ (with respect to
- Warts in toads are special sensory
surface area)
structures (w/ sensory cells)
2 Main Layers: • Reptiles
- thick epidermis and keratinized
I. Epidermis-
scales
• Outermost layer of epithelial tissue - absence of integumentary glands
(squamous) (dry skin)
• one to several cells thick • Birds
- Soft and thin epidermis with no
II. Dermis-
epidermal glands
• Thicker layer of connective tissue - Contains feathers
beneath the epidermis • Mammals
- Consists of several layers
Integument- external covering of an animal
Functions:
• Protection
• First line of defense against
microorganisms and toxic substances
• Regulation of body temperature
• Reception of environmental stimuli
(pain, temp, pressure)
• Excretion of waste materials
• Movement of gases (for some
animals)
• Locomotion (for some animals)
• Some possess (specialization)
Variations in Invertebrates a) cuticle- waxy substance in
epidermis of rotifers, crustaceans,
A. Single-celled Protozoa arachnids, insects, nematodes and
- Plasma membrane as external annelids
covering b) shell- CaCO3 in cnidarians (e.g.,
- E.g., Paramecium, Euglena corals) and Echinoderms (starfish,
sea urchins)
Pellicle- thick protein coat
c) Tegument- in parasitic flatworms
- For nutrient absorption and
B. Multicellular Invertebrates protection against digestion by host
enzymes
I. Epidermis- In most multicellular
invertebrate, outer layer
- Single layer of columnar epithelial
cells
Hydra- Few cell layers thick
Nematodes and Annelids- one-cell thick
which secretes multilayered cuticle
, d) Cilia- in echinoderms, ciliated epidermis
and dermis containing CaCO3
Ciliated Epidermis of Echinoderms
Arthropods- most complex of invertebrates
because Integument is a specialized VARIATIONS IN VERTEBRATES
exoskeleton (chitinous)
• Jawless Fishes (Lampreys and
Hagfishes)
- Thick skin due to multilayered
epidermis with glandular cells and
fat storage cells in the hypodermis
• Cartilaginous Fishes (Shark)
- Multilayered and contains bone in
the form of denticles (teeth)
• Bony Fishes (Teleost)
- Contains scales
Chitinous Exoskeletons of Arthropods • Amphibians
- Stratified and contains mucous and
several glands (mucous and poison
VERTEBRATES INTEGUMENT: SKIN glands) plus pigmentation
- Sensory nerves in epidermis
SKIN- Largest organ (with respect to
- Warts in toads are special sensory
surface area)
structures (w/ sensory cells)
2 Main Layers: • Reptiles
- thick epidermis and keratinized
I. Epidermis-
scales
• Outermost layer of epithelial tissue - absence of integumentary glands
(squamous) (dry skin)
• one to several cells thick • Birds
- Soft and thin epidermis with no
II. Dermis-
epidermal glands
• Thicker layer of connective tissue - Contains feathers
beneath the epidermis • Mammals
- Consists of several layers
