10 Questions
What is the primary factor that influences the ability of tissues to repair themselves?
The intrinsic proliferative capacity
Which cell type is capable of proliferating in response to injury or loss of tissue mass?
Quiescent cells
What is the characteristic of stable tissues?
Minimal replicative activity
Which of the following cells is an example of a stable cell?
Endothelial cell
What is the term for cells that are not actively dividing but can return to the cell cycle?
Quiescent cells
What is the exception to tissues that have a limited capacity to regenerate after injury?
Liver
Which of the following tissues is composed primarily of nondividing permanent cells?
Cardiac muscle
What is the importance of quiescent cells in wound healing?
They are responsible for tissue repair
What is the phase of the cell cycle that quiescent cells are in?
G0 phase
What are the three cell types found in most mature tissues?
Continuously dividing cells, quiescent cells, and nondividing cells
Study Notes
Stem Cells and Regenerative Medicine
- Regenerative medicine aims to regenerate and repopulate damaged organs using ES or adult stem cells, including stem cell therapy known as therapeutic cloning.
Cell Proliferation
- Cell proliferation is triggered by chemical mediators such as growth factors, hormones, and cytokines.
- Growth factors produced by leukocytes, parenchymal cells, or stromal cells can contribute to tissue repair.
- A vast array of growth factors is involved in tissue repair, with examples including:
- Platelet-derived growth factor (PDGF)
- Fibroblast growth factor (FGF)
- Epidermal growth factor (EGF)
- Transforming growth factor-beta (TGF-β)
Extracellular Matrix (ECM) and Cell-Matrix Interactions
- Tissue repair depends on interactions between cells and ECM components.
- The ECM is a dynamic, constantly remodeling macromolecular complex that surrounds cells.
- Cell-ECM interactions play a crucial role in repair processes, including cell proliferation and ECM repair.
Cell Proliferation and Repair
- Tissue repair involves the proliferation of various cells, including remnants of injured tissue, vascular endothelial cells, and fibroblasts.
- The normal size of cell populations is determined by a balance of cell proliferation, cell death by apoptosis, and the emergence of new differentiated cells from stem cells.
Cell Cycle and Proliferation
- The cell cycle has multiple controls, both positive and negative, and is critical in growth regulation.
- The key processes in cell proliferation are DNA replication and mitosis.
Tissue Proliferative Capacity
- The ability of tissues to repair themselves is critically influenced by their intrinsic proliferative capacity.
- Tissues are divided into three groups based on their proliferative capacity: labile, stable, and permanent tissues.
- Stable tissues, such as liver, kidney, and pancreas, have cells that are quiescent but can proliferate in response to injury or tissue loss.
Test your knowledge of stem cell biology, including differentiation capacity, cell proliferation, and regenerative medicine. Learn about the role of growth factors and therapeutic cloning in this field.
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