https://www.khanacademy.org/science/hs-bio/x230b3ff252126bb6:from-cells-to-organisms/x230b3ff252126bb6:untitled-26/v/organization-of-multicellular-organisms 2024-05-06T19:22:43.24334365Z Organization of multicellular organisms Multicellular organisms have a hierarchical structural organization: cells make up tissues, tissues make up organs, and organs make up organ systems. Organ systems work together to carry out the many functions of the organism. Sal Khan video https://cdn.kastatic.org/ka_thumbnails_cache/bab7af19-6568-454a-8832-bd8ec95e106c_1280_720_base.png Organization of multicellular organisms Multicellular organisms have a hierarchical structural organization: cells make up tissues, tissues make up organs, and organs make up organ systems. Organ systems work together to carry out the many functions of the organism. https://cdn.kastatic.org/ka-youtube-converted/8pWMifyG5bU.mp4/8pWMifyG5bU.mp4 256 Organ systems at work https://www.khanacademy.org/science/health-and-medicine/human-anatomy-and-physiology/lymphatics/v/lymphatic-system-immunity 2020-07-23T09:05:55Z The lymphatic system's role in immunity Learn about how B and T cells reside in lymph nodes. Find out how that enables them to get a preview of what they need to be prepared to fight. By Patrick van Nieuwenhuizen. Patrick van Nieuwenhuizen video https://cdn.kastatic.org/googleusercontent/RqWgqLUyfOreZOXocm9EdSEm_7tAT20GnAGlOad513p8jsfRWmy6Uf74s4P6Hd-G58yIMn23dVtrUokjGJv0g3ssIA The lymphatic system's role in immunity Learn about how B and T cells reside in lymph nodes. Find out how that enables them to get a preview of what they need to be prepared to fight. By Patrick van Nieuwenhuizen. https://cdn.kastatic.org/ka-youtube-converted/kjLwVqxwaIM.mp4/kjLwVqxwaIM.mp4 583 Organ systems at work https://www.khanacademy.org/science/hs-bio/x230b3ff252126bb6:from-cells-to-organisms/x230b3ff252126bb6:untitled-26/a/tissues-organs-and-organ-systems 2026-03-25T13:00:37.369559121Z Tissues, organs, and organ systems Learn about the organization of multicellular organisms and about different types of tissues. article https://www.khanacademy.org/science/biology/principles-of-physiology/body-structure-and-homeostasis/a/tissues-organs-organ-systems 2025-05-28T19:29:35.242191944Z Tissues, organs, & organ systems Learn about the main tissue types and organ systems of the body and how they work together. article https://www.khanacademy.org/science/hs-bio/x230b3ff252126bb6:from-cells-to-organisms/x230b3ff252126bb6:human-body-systems/a/hs-the-musculoskeletal-system-review 2024-05-06T19:22:43.24334365Z The musculoskeletal system review Learn about the organs and functions of the musculoskeletal system. article https://www.khanacademy.org/science/hs-bio/x230b3ff252126bb6:from-cells-to-organisms/x230b3ff252126bb6:human-body-systems/a/hs-the-respiratory-system-review 2024-05-06T19:22:43.24334365Z The respiratory system review Learn about the organs and functions of the respiratory system. article https://www.khanacademy.org/science/hs-bio/x230b3ff252126bb6:from-cells-to-organisms/x230b3ff252126bb6:human-body-systems/a/hs-the-circulatory-system-review 2024-05-06T19:22:43.24334365Z The circulatory system review Learn about the organs and functions of the circulatory system. article https://www.khanacademy.org/science/hs-bio/x230b3ff252126bb6:from-cells-to-organisms/x230b3ff252126bb6:human-body-systems/a/hs-the-nervous-and-endocrine-systems-review 2025-01-13T20:24:18.651037414Z The nervous and endocrine systems review Learn about the organs and functions of the nervous and endocrine systems. article https://www.khanacademy.org/science/hs-bio/x230b3ff252126bb6:from-cells-to-organisms/x230b3ff252126bb6:human-body-systems/a/hs-the-immune-system-review 2024-09-19T19:08:55.413551339Z The immune system review Learn about the cells and functions of the immune system. article https://www.khanacademy.org/science/hs-bio/x230b3ff252126bb6:from-cells-to-organisms/x230b3ff252126bb6:human-body-systems/e/apply-organ-system-interactions 2026-03-25T13:00:37.369559121Z Apply: organ system interactions Apply your understanding of organ system interactions in this set of free, standards-aligned practice questions. Megan Cohn exercise https://www.khanacademy.org/science/shs-biology-2/x2ea931c66bba6acd:unit-1-name/x2ea931c66bba6acd:immune-system/e/hs-the-immune-system 2021-04-29T08:02:38Z The immune system Test your knowledge on the human immune system! Ashley exercise https://www.khanacademy.org/science/ka-biology-grade-12/x406cf103e0507862:in-in-human-health-and-disease/x406cf103e0507862:in-in-types-of-immunity-and-the-immune-system/e/vaccination-and-immunisation 2024-08-15T06:51:54.562347673Z Vaccination and immunisation Vaccination, memory B and T cells, passive immunisation, recombinant DNA technology exercise