Chapter 39 & 46 Outline

Chapter 39 & 46 Outline - Protection, Support, and...

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Protection, Support, and Movement Chapter 39 KEY CONCEPTS Many structures and processes have evolved in animals for protection, support, and movement Learning Objective 1 Compare the functions of the external epithelium of invertebrates and vertebrates Epithelial Tissue In both invertebrates and vertebrates protects underlying tissues specialized to receive sensory signals, for gas exchange or respiratory functions Outer epithelium specialized to secrete Cuticle for protection lubricants or adhesives odorous or poisonous substances Integumentary System of Vertebrates Skin and structures that develop from it Fishes and reptiles have scales Amphibians with smooth skins and poison mucus Feathers of birds insulate, maintain temp. Colored for communication Mammalian skin includes hair, claws or nails, sweat glands, oil glands (sebum that empties into hair follicle and acts as an antibiotic), sensory receptors, mammary glands Learning Objective 2 Relate the structure of vertebrate skin to its functions Epidermis 1 Protects body from outer environment Stratum corneum most superficial layer consists of dead cells filled with keratin Diffusion barrier and most external layer Cells fake off and must be continuously replaced Keratin insoluble protein gives mechanical strength to skin reduces water loss
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Stratum basale cells divide, are pushed up to skin surface cells mature, flatten, produce keratin eventually die and slough off Contains melanocytes; cells that produce melanin Pigment acts as a UV protector Fair skinned people – more susceptible to malignant transformation to melanoma Dermis Underneath epidermis consists of: dense, fibrous connective tissue, collagen and blood vessels hair follicles and sweat glands Rests on layer of subcutaneous tissue composed largely of insulating fat (adipose tissue) Human Skin Fig 39-1 KEY CONCEPTS Epithelial coverings protect underlying tissues and may be specialized for sensory, respiratory, or other functions Learning Objective 3 Compare the structure and functions of different types of skeletal systems, including the hydrostatic skeleton, exoskeleton, and endoskeleton The Skeletal System Supports and protects the body Transmits mechanical forces generated by muscles Hydrostatic Skeleton Fluid in a closed body compartment transmits antagonistic forces generated by contractile cells or muscle Hydra (diploblastic cnidarian): Longitudinal epidermal layer contracts (shortens and thickens) while inner (circular) layer contracts (elongate and stretch) fluid movement causes lengthening Found in soft-bodied invertebrates Flatworms, annelids (triploblasts) More flexible than Hydra; isolated septa allow segment independence Hydrostatic Skeleton Fig 39-2 Exoskeletons Nonliving skeleton characteristic of mollusks and arthropods
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Chapter 39 & 46 Outline - Protection, Support, and...

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