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Protection, Support & Movement Jeweled Joints In The News Movement in Humans • Primarily from muscle moving bones • Skin stretches to accommodate movement • Body uses chemical energy (ATP) to move muscle filaments Animal Skeletons & Movement • Hydroskeleton – Support system using fluid under pressure – Muscles attached to flexible body wall – Example: worms Animal Skeletons & Movement • Endoskeleton of hard plates – Found in echinoderms – Movement is by hydraulics Animal Skeletons & Movement • Exoskeleton • Found in arthropods • Muscles attach to external skeleton Animal Skeletons & Movement • Endoskeleton – Muscles attached to bones – Found in all vertebrates Bone • Type of connective tissue – Cells – Matrix of collagen & mineral salts in a semisolid gel Bone • Types of bone – Compact • Concentric ring structure • Cavity filled with yellow bone marrow – Spongy • Latticework of thin plates • Filled with red bone marrow Bone Structure Bone Function • Support the body • Protect internal structures • Store minerals • Produce blood cells • Aid in movement Human Skeleton • Axial skeleton & appendicular skeleton Axial Skeleton-80 bones • Skull – 8 cranial bones – 14 facial bones • Vertebral column – 26 vertebrae • Rib cage – 12 pair of ribs • Hyoid bone Appendicular Skeleton-126 bones • Appendages • Pectoral girdle • Pelvic girdle Ligaments • Dense connective tissue • Attaches bone to bone Tendons • Cords of dense connective tissue • Attach muscles to bones Joints • Articulation • Place where bones meet • Different joints allow different movements Synovial (freely movable) Joint Bone & Joint Health • Moderate exercise enhances health • Calcium helps maintain bone density Bone & Joint Conditions • Osteoporosis – Bones lose mineral density – Creates fragile bones • Osteoarthritis – Cartilage covers articulating ends of bones – Makes movement painful Muscles • Attach to bones by tendons • Move body parts by contracting Muscle Attachments • Origin - attachment to stationary bone • Insertion – attachment to moveable bone Muscle Structure • Orderly arrangement of filaments – Actin & Myosin Sarcomere • Contractile unit of muscles • As filaments move past each other, muscles shorten (contract) Muscle Movement • Forcefulness, speed, & degree of contraction depend on the number of contracting muscle fibers Integument • Outer covering • Protects underlying structures • Barrier to infection • Conserves water loss Types of Animal Integument • • • • • • Layer of epidermal cells Cuticle covering epidermal cells Shell Chitin cuticle Thin prickly epidermis Keratinized skin Animal Integuments Animal Integuments Animal Integuments Animal Integuments Animal Integuments Animal Integuments Layers of Human Skin • Epidermis, dermis, & hypodermis Functions of Human Skin • Protective barrier against microorganisms, water-loss, and damaging UV radiation (melanin) • Sensory surface for pressure, pain, heat, & cold • Compensates for body movement • Helps control body temperature- (vasoconstriction and and vasodilatation), sweat glands • Manufactures vitamin D in the presence of sunlight, this vitamin helps body retain calcium Integumentary System • Hair, nails, & skin Skin Development • Cells produced deep in skin rise to surface • Keratin is added to cells • Cells are dead by the time they reach the topmost layers • Dead cells are lost at the surface End chapter 34