1. adhering junction Junction where a mass of anchored proteins help adjoining cells adhere.
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2. adipose tissue A connective tissue having an abundance of fat-storing cells.
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3. blood Fluid connective tissue of water, solutes, and formed elements (blood cells, platelets). Transports substances to and from cells, helps maintain internal environment.
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4. bone tissue Of vertebrate skeleton, a tissue of osteoblast secretions hardened with minerals.
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5. cardiac muscle tissue A contractile tissue that is present only in the heart wall.
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6. cartilage Connective tissue with solid, pliable intercellular material that resists compression.
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7. dense, irregular connective tissue Animal tissue with fibroblasts, many asymmetrically positioned fibers in ground substance. In skin and some capsules around organs.
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8. dense, regular connective tissue Animal tissue with rows of fibroblasts between parallel bundles of fibers. In tendons, elastic ligaments.
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9. ectoderm The first-formed, outermost primary tissue layer of animal embryos; gives rise to nervous system tissues and integument's outer layer.
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10. endocrine gland Ductless gland that secretes hormones, which the bloodstream distributes.
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11. endoderm Inner primary tissue layer of animal embryos; source of inner gut lining and derived organs.
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12. epithelium Animal tissue that covers external surfaces and lines internal cavities and tubes. One surface is free and the other rests on a basement membrane.
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13. exocrine gland Glandular structure that secretes products, usually through ducts or tubes, to a free epithelial surface.
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14. gap junction Cylindrical arrays of proteins in the plasma membrane that pair up as open channels for signals between adjoining cells.
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15. gland cell A cell that secretes products unrelated to their own metabolism for use elsewhere.
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16. homeostasis State in which physical and chemical aspects of internal environment (blood, interstitial fluid) are being maintained within ranges suitable for cell activities.
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17. internal environment Blood + interstitial fluid.
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18. loose connective tissue Animal tissue with fibers, fibroblasts loosely arrayed in semifluid ground substance.
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19. mesoderm Primary tissue layer of all large, complex animals; gives rise to many internal organs and part of the integument.
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20. nervous tissue Connective tissue composed of neurons and often neuroglia.
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21. neuroglia Collectively, cells that structurally and metabolically support neurons. They make up about half the volume of nervous tissue in vertebrates.
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22. neuron Type of nerve cell; basic communication unit in most nervous systems.
23. organ Body structure with definite form and function that consists of more than one tissue.
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24. organ system Organs interacting chemically, physically, or both in a common task.
25. skeletal muscle tissue Striated contractile tissue that is the functional partner of bone.
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26. smooth muscle tissue Nonstriated contractile tissue found in soft internal organs.
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27. tight junction Cell junction where strands of fibrous proteins oriented in parallel with a tissue's free surface collectively block leaks between the adjoining cells.
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28. tissue Of multicelled organisms, a group of cells and intercellular substances that function together in one or more specialized tasks.
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