Exam 1- L1 Flashcards
(44 cards)
What functionally happens with reversible cell injury?
reduced oxidative phosphorylation resulting in the depletion of energy stores
What happens in cell injury when you deplete energy stores?
- NA/K ATPase– ATP dependent, so sodium flows into the cell and water follows, causing cell swelling
- Ca-ATPASE–> channel fails, increasing Ca influx, which causes amorphous densities in mitochondria
Describe/name reversible cell injury
- Dilation of ER
- Nuclear alterations
- Mitochondrial changes: swelling
- plasma membrane alterations (loss of microvilli, swelling of RER, blebbing, and blunting)
Describe irreversible cell injury
- cell death (apoptosis and necrosis)
- loss of membrane permeability
amorphous densities in mitochondria
myocardial ischemia
What is the difference between necrosis and apoptosis?
- Apoptosis: cell suicide ( no complete loss of cell membrane integrity and involves cell shrinkage…cells cleared by macrophages
- necrosis: result from damage to cell membranes and loss of homeostasis ; leakage if lysosomal enzymes, and leakage of cellular content—> cell swelling
Describe the electron micrograph of mitochondria with amorphous densities. Review: Why is it present?
Looks like a battleship smoke cloud within mitochondria
- present due to the failure of Ca-ATPase that was caused by the depletion of ATP (energy)..influx of calcium
Coronary artery disease can lead to ischemia due to a blockage.
Describe the course of action when blockage occurs.
1) fall in oxygen supply to area
2)loss of oxidative phosphorylation (ETC)..DECREASE of ATP
3) Failure of Na/K ATPase and Ca-ATPase
4) heart muscles cease to contract in 60sec of coronary occlusion
5)30-40 min later, it worsens….irreversible changes like amorphous densities in mito (calcium)
6) ca influx leads to necrosis and apoptosis–> degradation and leakage of cellular material
7) formation of myelin figures…eventually calcification
Describe what myocardial infarction looks like?(gross and histological)
gross image: pale/ white tissue
histo: cells without nuclei ( ghost outline of myocytes.. tombstones
- blue dots are inflamed cells due to leakage of cellular contents
What are the histological artifacts of cells undergoing apoptosis?
- shrunken cells
- retraction spaces that look like a clearing around the cell
What are causes of cell injury? (3) Give an example for each
1) hypoxia…. thrombi/occlusion
2) physical… radiation
3) chemical agents…. Tylenol
What are major causes of hypoxia? How so?
- cardiorespiratory failure
- anemia –>HB= heme + globin .. heme has Fe and porphyrin ring .. if you have low iron (lower heme) .. less oxygen is delivered to the tissues
-carbon monoxide–> carbon binds to Hb tightly… affinity switches to preferring carbon over oxygen when oxygen depletes or is at a lower level of saturation - after severe blood loss
What are examples of hypoxia? Describe how they lead to hypoxia
- anemia
- CO poisoning ( forms carboxyhemoglobin)
- methemoglobinemia
What is Methemoglobinemia?
when heme has Fe+3 (oxidized state) instead of Fe+2….. cannot deliver oxygen or bind oxygen
- indicated as it when RBC has more than 1% methemoglobin
What is the difference between congenital and acquired methemoglobinemia? Treatment?
Congenial: NADH reductase deficiency , which decreases the rate of reduction of iron (Fe+2) in Hb
- diffuse persistent slate-gray cyanosis; patients are typically asymptomatic
Acquired: due to ingestion of drugs or toxic substances.. like sulfa containing drugs or nitrites
Treatment: methylene blue (IV)
How is ischemia different from hypoxia?
- hypoxis: energy production continues in the form of glycolysis
- ischemia: no aerobic or anaerobic respiration
What does obstruction lead to?
Obstruction leads to a complete lack of oxygen and substrates
When looking at gross images, what is the difference of atherosclerosis and thrombotic occlusion?
- calcification is present within blood tissue of blood vessels.. narrows the lumen
- thrombi us within the lumen of a blood vessel…blocks the lumen
Name types of physical agents that can cause cell injury
- mechanical trauma
- extremes of temps ( burns and deep cold)
-sudden changes in ATM pressure
-radiation
-electric shock
What happens with acetaminophen poisoning? What disease does it cause?
- liver metabolizes and clears out all the comes in
- liver can be overwhelmed.. leading to P450 to produce intermediates ( reactive liver metabolites), which are free radicals
- body cannot clear out ROS, leading to cellular damage and function
- Acute Liver Failure
What are the mechanisms of cell injury?
What are chemical causes of cell injury?
drugs
chemicals
specific example: acetaminophen
In apoptosis, what does the leakage of cytochrome C cause?
leakage of cytochrome C causes the activation of executor caspases leading to apoptosis
Describe receptor induced apoptosis
- FAS and TNF binds to receptor
- causes initiator caspases to activate
-mitochondria leaks cytochrome C - leakage of cytochrome C causes the activation of executor caspases, inducing committing to apoptosis
Describe Acute Liver Failure caused by acetaminophen
- cause
-mechanism of action of cause
-symptom
-timing
- caused by massive hepatic necrosis
-parenchymal loss surrounding the islands of regenerating hepatocytes - changes take place within hours to days.. not enough time to regenerate or form scar
- symptoms: nausea, vomiting, and jaundice……..then life-threatening encephalopathy and coagulation defects
