ch38_lecture protection, support, movement

Chapter 38Biology, Seventh Edition
Solomon • Berg • Martin
Biology, Seventh Edition
Epithelial coverings for both vertebrates and invertebrates
Protect underlying tissues
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Outer epithelium secretions
Integumentary system of vertebrates
Fish scales
Mammal hair
Bird feathers
Mammalian skin
Human skin
Stratum corneum
Outer layer of the epidermis
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Stratum basale
Cells divide and are pushed upward toward the skin surface
Mature, flatten, produce keratin, and eventually die and slough off
Dermis
Composed of insulating fat
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Skeletal system
Transmits mechanical forces generated by muscles
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Hydrostatic skeleton
Soft-bodied invertebrates
Transmits forces generated by contractile cells or muscle
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Hydrostatic skeleton
Exoskeletons
Arthropods must molt periodically
Molting cicada
Endoskeletons
Consists of calcium-impregnated tissue
Vertebrate axial skeleton
Vertebrate appendicular skeleton
Human skeletal system
Long bone
Inner spongy bone
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Typical long bone
Endochondral bone formation
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Osteoblasts
Vertebrate joints
Ligaments are connective tissue
Bands that connect bones
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Immovable joints
Slightly movable joints
Joints between vertebrae
Freely movable joint
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Insect flight muscles
Large numbers of mitochondria
Vertebrate muscle
Types of muscle
Skeletal muscle is made up of hundreds of muscle fibers
Fibers consists of threadlike myofibrils
Myofibrils composed of smaller myofilaments
Striations reflect the overlapping of muscle filaments
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Muscle
structure
Sarcomere
Steps in muscle contraction
Acetylcholine released by a motor neuron combines with receptors on the surface of a muscle fiber
Calcium ions released from the sarcoplasmic reticulum
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CHAPTER 38 Protection, Support, and Movement
Calcium ions bind to troponin in the actin filaments causing the troponin to change shape
Troponin pushes tropomyosin away from the active sites on the actin filaments
ATP binds to myosin
ATP is split, putting the myosin head in a high-energy state
Energized myosin heads bind to the exposed active sites on the actin filaments
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Myosin head binds a new ATP
Myosin head detaches from the actin
Myosin reattaches to new active sites so that the filaments are pulled past one another
Muscle continues to shorten
Muscle
contraction
Providing energy for muscle contraction
ATP hydrolysis provides the energy to “cock” the myosin
Creatine phosphate is used for intermediate energy storage
Glycogen is the fuel stored in muscle fibers
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Antagonistic action of skeletal muscles
Agonist muscle contracts
Antagonist muscle relaxes
Groups of muscles work together
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Muscle action
Slow (red) fibers
Endurance activities

ch38_lecture protection, support, movement

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