Hostology-Tissue Growth, Development, Repair, and Degeneration Flashcards
What are the modes of tissue growth?
-Hyperplasia: Increase in cell number.
-Hypertrophy: Increase in cell size.
-Metaplasia: Reversible transformation of one cell type to another.
-Neoplasia: Abnormal, uncontrolled growth of tissue (tumors).
What are adult stem cells and their developmental plasticity?
-Definition: Undifferentiated cells in tissues that can differentiate into specialized cell types.
-Plasticity: Limited; typically differentiate into cell types of their tissue of origin (multipotent or unipotent).
-Examples: Hematopoietic stem cells in bone marrow.
What are embryonic stem cells and their developmental plasticity?
Definition: Pluripotent cells from early embryos that can differentiate into almost any cell type.
-Plasticity: High; potential to become any cell type (pluripotent).
-Examples: Stem cells used in regenerative medicine research.
How can tissues change from one type to another?
-Differentiation: Specialized cells from less specialized cells.
-Metaplasia: Transformation of one cell type into another due to external stimuli.
-Transdifferentiation: Direct conversion of one differentiated cell type into another.
What are the modes and causes of tissue shrinkage?
-Atrophy: Decrease in tissue size due to reduced cell size or number (causes: disuse, aging, malnutrition).
-Apoptosis: Programmed cell death (normal or due to stress/damage).
-Necrosis: Pathological cell death leading to inflammation (causes: ischemia, toxins, trauma).
How does the body repair damaged tissues?
-Regeneration: Replacement with the same type of tissue (e.g., liver regeneration).
-Fibrosis: Replacement with fibrous connective tissue (scar tissue).
Repair Stages:
-Hemostasis: Blood clotting.
-Inflammation: Immune response and debris removal.
-Proliferation: New tissue formation (angiogenesis, fibroblast proliferation).
-Maturation/Remodeling: Tissue strengthening and maturation.
