Chapter 2: Cell and tissue adaption & damage
Multicellular individuals: possibilities and problems:
- A lot of cells are attractive for pathogens, defence is required (immune system). Can
result in infectious disease
- Organisation and clear division of tasks in mandatory, with regards to proliferation.
Can result in cancer
Cell damage, stress and stressors:
- A disease is causes by damage to part of a cell, or to a group of cells (etiology)
- The initial damage can cause further damage (pathogenesis)
- The cell/organ reacts to minimize impact of damage (adaption)
- Damage can be reversible, adaptation or cell death
Adaptation versus cell death:
1. Adaption, hypertrophy: an increase of size of cells, not the number of cells. Example
is the uterus during pregnancy, or muscle growth in body builders.
Myocardial hypertrophy = mechanical stretch, agonist or/and growth factors could
lead to increase in size cells to decrease workload and increase mechanical
performance.
2. Adaption, hyperplasia: increase in number of cells (not the size of cells). Examples
are he breast ductal cells during breastfeeding.
3. Adaption, atrophy: decrease of tissue by number of cells or amount of cells. Example
is elderly people their brain.
There are 3 types of atrophy:
- Autophagy = self-eating of organelles in malnutrition
- Proteasomal degradation = degradation of proteins via a proteosome
- Apoptosis = cell death by releasing parts of cell and phagocytosis.
4. Adaption, metaplasia: replacement of one differentiated tissue by another tissue.
Most common is normal bronchial epithelium to squamous metaplastic epithelium,
happens often in smokers.
Cell death:
1. Cell damage by oxygen shortage, the cells swell: lack of ATP causes Na/K-ATPase
pump not to work, increase of water in the cells. Example is enlarged liver, when
acting quick, this is reversible.
2. Necrosis: after injury a cell tries to recover. When the cell cannot repair itself the
organelles break. Cell contents are released in the extracellularly. There is no
regulation since it is pathologic, it is pro-inflammatory. Involves often more than one
cell.
3. Apoptosis: Damage to cell. No induction of repair of or specific defence. Cell
contents are not released in surrounding, but this cellular suicide is under strict
regulation. Part of the normal physiology and happens often to only one cell.
Examples of necrosis:
Coagulation necrosis = example in liver, no nuclei. The initial preservation of necrotic
architecture.
Colliquative necrosis (liquefactive necrosis) = example in brain. Tissue turns into liquid,
result in a hole.
Caseous necrosis (TBC) = necrosis causes by tuberculosis infection. Very rare
Multicellular individuals: possibilities and problems:
- A lot of cells are attractive for pathogens, defence is required (immune system). Can
result in infectious disease
- Organisation and clear division of tasks in mandatory, with regards to proliferation.
Can result in cancer
Cell damage, stress and stressors:
- A disease is causes by damage to part of a cell, or to a group of cells (etiology)
- The initial damage can cause further damage (pathogenesis)
- The cell/organ reacts to minimize impact of damage (adaption)
- Damage can be reversible, adaptation or cell death
Adaptation versus cell death:
1. Adaption, hypertrophy: an increase of size of cells, not the number of cells. Example
is the uterus during pregnancy, or muscle growth in body builders.
Myocardial hypertrophy = mechanical stretch, agonist or/and growth factors could
lead to increase in size cells to decrease workload and increase mechanical
performance.
2. Adaption, hyperplasia: increase in number of cells (not the size of cells). Examples
are he breast ductal cells during breastfeeding.
3. Adaption, atrophy: decrease of tissue by number of cells or amount of cells. Example
is elderly people their brain.
There are 3 types of atrophy:
- Autophagy = self-eating of organelles in malnutrition
- Proteasomal degradation = degradation of proteins via a proteosome
- Apoptosis = cell death by releasing parts of cell and phagocytosis.
4. Adaption, metaplasia: replacement of one differentiated tissue by another tissue.
Most common is normal bronchial epithelium to squamous metaplastic epithelium,
happens often in smokers.
Cell death:
1. Cell damage by oxygen shortage, the cells swell: lack of ATP causes Na/K-ATPase
pump not to work, increase of water in the cells. Example is enlarged liver, when
acting quick, this is reversible.
2. Necrosis: after injury a cell tries to recover. When the cell cannot repair itself the
organelles break. Cell contents are released in the extracellularly. There is no
regulation since it is pathologic, it is pro-inflammatory. Involves often more than one
cell.
3. Apoptosis: Damage to cell. No induction of repair of or specific defence. Cell
contents are not released in surrounding, but this cellular suicide is under strict
regulation. Part of the normal physiology and happens often to only one cell.
Examples of necrosis:
Coagulation necrosis = example in liver, no nuclei. The initial preservation of necrotic
architecture.
Colliquative necrosis (liquefactive necrosis) = example in brain. Tissue turns into liquid,
result in a hole.
Caseous necrosis (TBC) = necrosis causes by tuberculosis infection. Very rare
