Support and Protection (Test Two) Flashcards
What is integument?
The protective outer covering that includes skin, hair, scales, and feathers.
What are the 4 characteristics of integument?
- Tough and pliable to provide mechanical protection against abrasion and puncture
- Provides moisture proofing against water loss / gain
- Effective barrier against bacterial / viral infection
- Protects underlying layers from the damaging effects of UV light
Describe the invertebrate integument.
Most invertebrates have complex tissue coverings and some secrete a noncellular cuticle over the epidermis.
What is special about the integument of parasitic platyhelminths?
They have special tegument that is resistant to immune response of host and to digestive enzymes
What is special about the integument of molluscs?
They have a soft epidermis (mantle), which contains mucous glands that secrete their calcium carbonate shell
What is squid skin composed of?
- Yellow, red, and brown spots called chromatophores
- Underneath are bright iridescent cells called iridocytes
What are cephalopod chromatophores?
They are small sac-like cells with pigment granules surrounded by muscle cells that can stretch the cell into a pigmented sheet.
How do cephalopods change colors?
When the muscles contract the chromatophore expands and allows rapid color changes, and when the muscle relaxes the chromatophore shrinks quickly.
Explain the integument of arthropods.
- Arthropods have the most complex invertebrate integuments that provide protection and skeletal support
- A firm exoskeleton and jointed appendages allow for muscle attachment
Why was integument so important for the diversification of arthropods?
Because their unique integument allowed them to survive and become the largest and most varied of all animal groups
Why was integument so important for the diversification of arthropods?
Because their unique integument allowed them to survive and become the largest and most varied of all animal groups
What must happen in order for a arthropod to grow?
Since the arthropod cuticle is so tough, molting (shedding of cuticle) must occur
How does molting start?
Molting starts with epidermal cells dividing
From top down, what is the structure of arthropod integument?
- On top is the epicuticle
- Below the epicuticle is the pro cuticle
- Next is the epidermis
- Below the epidermis is the basement membrane
What happens to most of the pro cuticle of arthropods during molting?
Enzymes secreted by the epidermis digest most of the pro cuticle, which is then absorbed and reused.
How do arthropods get new cuticles?
- The space below the old cuticle grows a new epicuticle and pro cuticle
- After the old cuticle is shed, the new one is thickened and calcified
What is another term for calcified?
sclerotized
Explain vertebrate integument.
- Consists of thin outer epithelial layer called the epidermis, which is derived from the ectoderm
- Also consists of inner thicker layer called the dermis, which is derived from the mesoderm
What is the epidermis made of?
Several layers of epithelium
How does the epidermis renew cell layers?
The basal layer of epidermal cells undergo frequent mitosis so new cells are made and the old cells are displaced upward