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  2. Organ system - Wikipedia

    en.wikipedia.org/wiki/Organ_system

    An organ system is a biological system consisting of a group of organs that work together to perform one or more functions. [1] Each organ has a specialized role in a organism body, and is made up of distinct tissues .

  3. Plant cell - Wikipedia

    en.wikipedia.org/wiki/Plant_cell

    Structure of a plant cell. Plant cells are the cells present in green plants, photosynthetic eukaryotes of the kingdom Plantae.Their distinctive features include primary cell walls containing cellulose, hemicelluloses and pectin, the presence of plastids with the capability to perform photosynthesis and store starch, a large vacuole that regulates turgor pressure, the absence of flagella or ...

  4. Human body - Wikipedia

    en.wikipedia.org/wiki/Human_body

    The bladder is a hollow balloon shaped organ located in the pelvis. It stores urine until the brain signals it to relax the urinary sphincter and release the urine into the urethra starting urination. [54] A normal bladder can hold up to 16 ounces (half a liter) for 3–5 hours comfortably.

  5. Human digestive system - Wikipedia

    en.wikipedia.org/wiki/Human_digestive_system

    The pancreas is a major organ functioning as an accessory digestive gland in the digestive system. It is both an endocrine gland and an exocrine gland . [ 28 ] The endocrine part secretes insulin when the blood sugar becomes high; insulin moves glucose from the blood into the muscles and other tissues for use as energy.

  6. Biological system - Wikipedia

    en.wikipedia.org/wiki/Biological_system

    On the organ and tissue scale in mammals and other animals, examples include the circulatory system, the respiratory system, and the nervous system. On the micro to the nanoscopic scale, examples of biological systems are cells , organelles , macromolecular complexes and regulatory pathways.

  7. Integumentary system - Wikipedia

    en.wikipedia.org/wiki/Integumentary_system

    The skin (integument) is a composite organ, made up of at least two major layers of tissue: the epidermis and the dermis. [2] The epidermis is the outermost layer, providing the initial barrier to the external environment. It is separated from the dermis by the basement membrane (basal lamina and reticular lamina).

  8. Plant morphology - Wikipedia

    en.wikipedia.org/wiki/Plant_morphology

    The vegetative (somatic) structures of vascular plants include two major organ systems: (1) a shoot system, composed of stems and leaves, and (2) a root system. These two systems are common to nearly all vascular plants, and provide a unifying theme for the study of plant morphology.

  9. Photosynthesis - Wikipedia

    en.wikipedia.org/wiki/Photosynthesis

    Photosynthesis changes sunlight into chemical energy, splits water to liberate O 2, and fixes CO 2 into sugar.. Most photosynthetic organisms are photoautotrophs, which means that they are able to synthesize food directly from carbon dioxide and water using energy from light.