Pathology
LECTURE 1: Ch 2 - Cell injury, Cell death, and Adaptations
➢ Disease: a disfunction of an organ or a tissue because of damage to cells
➢ Aetiology: set of causes of a disease or condition.
➢ Pathogenesis: changes caused by bacterial, chemical, thermal, radiation etc.
➢ Radiation damages DNA → Missense mutation → change of one nucleotide causes
change of amino acid transcribed
➢ Cholera → caused by Vibrio cholerae (aetiology) → bacteria produces toxin
(pathogenesis) that influences the fluid balance in your body → diarrhoea
➢ Cell postulates by Schwan, Schleiden, and Virchow
➢ Dictyostelium discoideum (amoeba) → single celled but when unfavourable
conditions become multicellular → colonies
➢ Aggregate of cells working together → attracts more microorganisms → that’s why
immune system
➢ Aggregate of cells → division of tasks → that’s why proliferations of cells → but in
regulated manner otherwise → cancer
➢ Damage to cell can be reversible and lead to adaptation or death of cell
Cell Adaptation
➢ High bp → Workload increase on heart → heart muscle cell increases in size →
hypertrophy of cells → heart gets thicker wall becomes bigger → adaptation
➢ If cell injury in heart muscle cell → cell death → myocardial infarction
,➢ Pregnancy → uterus gets bigger → cells hypertrophy → adaptation
➢ Mechanical stretch of heart cells → increase in workload → more heart protein
production → hypertrophy of heart muscle cells
➢ Breast duct → lactating woman → makes more cells → hyperplasia: increase in no.
of cells
➢ After menopause in women → atrophy of uterus → decrease in cell size or number
➢ Brain of older people → Atrophy
Proteasomal degradation: destroys proteins to make cell smaller
➢ Atrophy Apoptosis: programmed cell death
Autophagy: cell gets rid of some organelles itself
,➢ Smokers → bronchi and trachea normally have columnar epithelium → smoking
damages it so replaced by squamous epithelium cause thicker → metaplasia of
tissue as it gets replaced
➢ Normal ciliated bronchial epithelium → clears mucus and dirt
Squamous bronchial epithelium → resistant to smoke but bad at clearing mucus
➢ Barrett’s metaplasia → due to leaking of gastric acids into oesophagus → intestinal
epithelium in oesophagus instead of squamous to make more resistant to acid →
but more tumours can arise in intestinal epithelium
➢ Cell Adaptation
• Hypertrophy: Increase in cell size.
Ex: heart increased workload, pregnant uterus
• Hyperplasia: Increase in number of cells.
Ex: lactating breast
• Atrophy: Decrease in cell size or number.
Ex: menopausal women uterus, elderly persons brain
• Metaplasia: Replacing one tissue by another to make it more resistant.
Ex: smokers bronchi, Barrett’s metaplasia
, Cell Death
➢ Kidney epithelium → sensitive to O2 depletion → shortage of O2 causes loss of
function in sodium potassium ATPase pump (pumps out Na and water and pumps in
K)→ pump stops working as O2 required for ATPase
➢ K+ moves out and Na+ moves into cell → kidney cells swell up with water → can be
reversed but needs to be done fast
Necrosis: death of a group of cells due to lack of blood flow
➢ Cell death
Apoptosis
Necrosis Apoptosis
Caused by injury Cellular fragmentation
Swelling of cell then breakdown Cell shrinks
Happens in groups of cells Isolated cells not groups
Cell contents released extracellularly Cell contents not released
Lighter staining Darker stainimg
Inflammatory response No inflammatory response
Pathological condition Normal condition, occurs continuously
LECTURE 1: Ch 2 - Cell injury, Cell death, and Adaptations
➢ Disease: a disfunction of an organ or a tissue because of damage to cells
➢ Aetiology: set of causes of a disease or condition.
➢ Pathogenesis: changes caused by bacterial, chemical, thermal, radiation etc.
➢ Radiation damages DNA → Missense mutation → change of one nucleotide causes
change of amino acid transcribed
➢ Cholera → caused by Vibrio cholerae (aetiology) → bacteria produces toxin
(pathogenesis) that influences the fluid balance in your body → diarrhoea
➢ Cell postulates by Schwan, Schleiden, and Virchow
➢ Dictyostelium discoideum (amoeba) → single celled but when unfavourable
conditions become multicellular → colonies
➢ Aggregate of cells working together → attracts more microorganisms → that’s why
immune system
➢ Aggregate of cells → division of tasks → that’s why proliferations of cells → but in
regulated manner otherwise → cancer
➢ Damage to cell can be reversible and lead to adaptation or death of cell
Cell Adaptation
➢ High bp → Workload increase on heart → heart muscle cell increases in size →
hypertrophy of cells → heart gets thicker wall becomes bigger → adaptation
➢ If cell injury in heart muscle cell → cell death → myocardial infarction
,➢ Pregnancy → uterus gets bigger → cells hypertrophy → adaptation
➢ Mechanical stretch of heart cells → increase in workload → more heart protein
production → hypertrophy of heart muscle cells
➢ Breast duct → lactating woman → makes more cells → hyperplasia: increase in no.
of cells
➢ After menopause in women → atrophy of uterus → decrease in cell size or number
➢ Brain of older people → Atrophy
Proteasomal degradation: destroys proteins to make cell smaller
➢ Atrophy Apoptosis: programmed cell death
Autophagy: cell gets rid of some organelles itself
,➢ Smokers → bronchi and trachea normally have columnar epithelium → smoking
damages it so replaced by squamous epithelium cause thicker → metaplasia of
tissue as it gets replaced
➢ Normal ciliated bronchial epithelium → clears mucus and dirt
Squamous bronchial epithelium → resistant to smoke but bad at clearing mucus
➢ Barrett’s metaplasia → due to leaking of gastric acids into oesophagus → intestinal
epithelium in oesophagus instead of squamous to make more resistant to acid →
but more tumours can arise in intestinal epithelium
➢ Cell Adaptation
• Hypertrophy: Increase in cell size.
Ex: heart increased workload, pregnant uterus
• Hyperplasia: Increase in number of cells.
Ex: lactating breast
• Atrophy: Decrease in cell size or number.
Ex: menopausal women uterus, elderly persons brain
• Metaplasia: Replacing one tissue by another to make it more resistant.
Ex: smokers bronchi, Barrett’s metaplasia
, Cell Death
➢ Kidney epithelium → sensitive to O2 depletion → shortage of O2 causes loss of
function in sodium potassium ATPase pump (pumps out Na and water and pumps in
K)→ pump stops working as O2 required for ATPase
➢ K+ moves out and Na+ moves into cell → kidney cells swell up with water → can be
reversed but needs to be done fast
Necrosis: death of a group of cells due to lack of blood flow
➢ Cell death
Apoptosis
Necrosis Apoptosis
Caused by injury Cellular fragmentation
Swelling of cell then breakdown Cell shrinks
Happens in groups of cells Isolated cells not groups
Cell contents released extracellularly Cell contents not released
Lighter staining Darker stainimg
Inflammatory response No inflammatory response
Pathological condition Normal condition, occurs continuously
