Respuesta al daño celular Flashcards
Cuál es el mecanismo de acción de la inhalación de monóxido de carbono?
Previene el transporte de oxígeno
Mecanismo de daño de los accidentes traumáticos y térmicos
Disrupción y desnaturalización de proteínas –> trombosis vascular local –> isquemia –> muerte celular.
Mecanismo de daño del congelamiento
Los cristales de hielo perforan las membranas.
El mecanismo de acción de los virus es romper la membrana celular de las células que infectan. Que virus es una excepción de este mecanismo?
Hepatitis B, el daño tisular de la enfermedad es causado principalmente por la reacción inmune del huésped.
En qué vía metabólica interfiere el cianuro, y cómo lo hace?
En la respiración celular. El cianuro se une a los citocromo oxidasa –> interrumpe la utilización de oxígeno. Los miocitos son de los más vulnerables, ya que son células de alto requerimiento metabólico.
Células que son altamente dependientes de la glucosa para su funcionamiento
Neuronas
Agentes o medicamentos que afectan la síntesis de proteínas (a nivel de traducción)
Ricina y antibióticos como streptomicina, cloramfenicol y tetraciclina.
Physiopathology of ischemia and reperfusion injury
Impaired blood flow→ ceasing of mitochondrial ATP production→ anaerobic glycolysis→ accumulation of lactate → acidosis and calcium influx → disruption of mitochondria’s inner membrane (it exceeds its calcium storage capacity), activation of calcium-dependent proteases, leakage of endoplasmic reticulum’s calcium storage into the cytosol → necrosis
Physiopathology of free radicals
Damage to polyunsaturated fatty acids (essential components of cell membranes) and damage of lysosomal membranes → release of proteases (cathepsin) → damage of DNA → cell death .
Mechanisims of failure of membrane integrity (4)
Complement- mediated cytolysis, perforin - mediated cytolysis, specific blockage of ion channels and failure of membrane ion pumps and free radicals attack.
Result of ion pump failure
Cell swelling (oncosis or hydropic change) → may progress to cell death
The non-lethal DNA damage can be inherited by daughter cells, resulting in clone cells with abnormal growth characteristics → neoplastic transformation → tumors. (T or F)
True
Types of DNA damage (3)
Strand brakes, base alterations (nonsense/ missense) and cross-linking.
“Unreadable” mutation
Nonsense
“Read incorrectly” mutation
Missense
Type of DNA damage used by some radiotherapies
Cross-linking.
Cross-linking (physiopathology)
ROS cause linkage between complementary strands → inability to separate and to make new copies → DNA replication is blocked → “reproductive death”
Mutated ERCC6 gene → extreme skin sensitivity to sunlight → tumors (disease)
Xeroderma pigmentosum
Some people are more susceptible to ionizing radiation or ultraviolet light due to defective DNA repair mechanisms, such as enzymes. Name 2 diseases caused by this defect
Ataxia telangiectasia and xeroderma pigmentosum
Impair excision repair of double strand breaks due to a loss of function mutation of the ATM gene (disease)
Ataxia telangiectasia
Pattern of cellular injury in which the cytoplasm becomes pale and swollen due to accumulation of fluid. Generally caused by hypoxia or chemical poisoning.
Hydropic change (oncosis)
Pattern of cellular injury in which occurs vacuolation of cells due to accumulation of lipid droplets as a result of ribosomal dysfunction and uncoupling of lipids from protein metabolism. Liver is commonly affected this way by hypoxia, alcohol or diabetes
Fatty change
Cellular response to stress in which
cell components are isolated into intracellular vacuoles → these are processed through to lysosomes.
Autophagy
Main difference between apoptosis and necrosis
In apoptosis the cell membrane remains intact, there is NO inflammatory reaction and it follows a lower dose or shorter duration of damage.
Result of the failure of ATP production
Ineffective ion pumps → loss of homeostasis, influx of water, oncosis, lysis and cell death
Which cells are most affected by ischemia
Cortical neurons and cardiac myocytes will be most affected