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level: STEP 4 C. CONTINUATION

Questions and Answers List

level questions: STEP 4 C. CONTINUATION

Question	Answer
C. TISSUE REPAIR (Proliferation: Regeneration of Tissue) a) Replacement of Lost Cells by Mitosis 1 Soon after injury, cells adjacent to the damaged area enter the __ 2 __ residing in G0 enter G1 and progress to mitosis (M). 3 occur in the cells that are DESTINED TO DIVIDE. 4 Early after injury, __, and expression of numerous genes is __	. 1 cell division cycle. 2 Quiescent cells 3 Sequential changes 4 intracellular signaling turns on, increased.
C. TISSUE REPAIR (Proliferation: Regeneration of Tissue) a) Replacement of Lost Cells by Mitosis 1 These genes become temporarily OVEREXPRESSED 2 initiated by the RELEASE OF CHEMICAL MEDIATORS FROM DAMAGED CELLS. 3 DICTATED BY GROWTH FACTORS & CYTOKINES OPERATIVE in tissue repair elsewhere and also by specific peptides with the mucous layer of the GI tract that become overexpressed at SITES OF MUCOSAL INJURY.	. 1 Genes for the cell cycle accelerator proteins & genes whose products decelerate the cell cycle 2 regenerative process 3 Mucosal repair
C. TISSUE REPAIR (Proliferation: Regeneration of Tissue) b) Replacement of the Extracellular Matrix 1 ACTIVATION of resting STELLATE CELLS is mediated chiefly by two growth factors, __ 2 __ induced by the potent mitogen PDGF 3 __ ACTS ON THE STELLATE CELLS to STIMULATE THE SYNTHESIS OF EXTRACELLULAR MATRIX components, including collagens, fibronectin, tenascin, and proteoglycans.	. 1 Platelet-derived growth factor (PDGF) and Transforming growth factorβ (TGFβ). 2 Proliferation of stellate cells 3 Transforming growth factorβ (TGFβ)
C. TISSUE REPAIR (Side Reactions to Tissue Injury) 1 PRODUCE INFLAMMATION, altered production of ACUTE PHASE PROTEIN, and generalized reactions such as FEVER.	. 1 Resident macrophages and Endothelial cells activated by cell injury
C. TISSUE REPAIR (Side Reactions to Tissue Injury) a) Inflammation 1 Alteration of the microcirculation and accumulation of inflammatory cells are largely initiated by resident MACROPHAGES SECRETING CYTOKINES such as __ in response to tissue damage. 2 These cytokines, in turn, stimulate neighboring stromal cells, such as the endothelial cells and fibroblasts, to release mediators that induce dilation of the local microvasculature and cause __	. 1 (Tumor Necrosis Factor) TNFα and IL1 2 permeabilization of capillaries.
C. TISSUE REPAIR (Side Reactions to Tissue Injury) a) Inflammation 1 Macrophages as well as leukocytes recruited to a site of injury undergo a __, producing free radicals and activated enzymes	. 1 Respiratory burst
C. TISSUE REPAIR (Side Reactions to Tissue Injury) b) Altered Protein Synthesis: Acute- Phase Proteins 1 Cytokines released from macrophages and endothelial cells of injured tissues, __, act on cell surface receptors to INCREASE OR DECREASE TRANSCRIPTIONAL ACTIVITY of genes encoding certain proteins called POSITIVE & NEGATIVE ACUTE PHASE PROTEINS. 2 __ may play roles in minimizing tissue injury and facilitating repair. For example, many of them INHIBIT LYSOSOMAL PROTEASES released from the injured cells and recruited leukocytes.	. 1) IL6, IL1, and TNF 2 Positive acute phase proteins
C. TISSUE REPAIR (Side Reactions to Tissue Injury) b) Altered Protein Synthesis: Acute- Phase Proteins 1 Cytokines released from activated macrophages and endothelial cells at the site of injury also may evoke __. Thus, IL1, IL6 & TNF alter the temperature set point of the hypothalamus, triggering fever. 2 act on the pituitary to induce the RELEASE OF (Adrenocorticotropic hormone) ACTH, which in turn stimulates the SECRETION OF CORTISOL from the adrenals	1 neurohormonal responses 2) IL1 and IL6 - This represents a NEGATIVE FEEDBACK LOOP because corticosteroids inhibit cytokine gene expression