Musculoskeletal Key

Key Points Apoptosis is a discrete form of cell death induced by multiple stimuli and mediated by a group of cysteine proteases known as caspases. This type of cell death…

Key Points Cells of the immune system sense environmental stimuli via receptors, which may be expressed on the cell surface or may be intra-cellular. Interaction of ligands with receptors initiates…

Key Points Platelets are small subcellular fragments that circulate in blood, where they promote hemostasis. Platelets express receptors and a multitude of mediators recognized as being active in inflammation. Inhibition…

Key Points Innate lymphoid cells (ILCs) and natural killer (NK) cells are components of the innate immune system that protect against invading pathogens. ILCs and NK cells contribute to immune…

Key Points Mast cells arise in the bone marrow, circulate as immature precursors, and develop into functional mast cells after entering peripheral tissues. The phenotype of mast cells is diverse,…

Key Points Fibroblasts are programmed epigenetically to determine the unique structure and function of different organs and tissues. These unique features might contribute to organ-specific disease. Tissue fibroblasts may be…

Key Points Immunoglobulins (Igs) are key to B cell function because they serve as both an antigen receptor and a major secreted product. The variable region binds antigen and is…

Key Points T cells develop primarily in the thymus. The importance of the thymus is underscored by the absence of T cells in patients in whom the thymus has failed…

Key Points Neutrophils are myeloid-lineage cells characterized by the presence of granules containing enzymes and other potentially toxic agents involved in host defense. Neutrophils are short-lived, terminally differentiated cells that…

Key Points At least two populations of tissue macrophages exist: tissue-resident cells that are embryonically derived and a monocyte-derived population. Their functions may be discrete. Macrophages are plastic and will…