Chap 1: Cellular Injury Flashcards
when does cellular injury occur
stress exceeds the cell’s ability to adapt
compare neurons and skeletal muscles when it comes to comparing types of cellular injury
neurons susceptible to ischemic injury, skeletal muscle is more resistant
slowly developing ischemia results in ____; whereas, acute ischemia results in ____
atrophy
injury
what is an example of a slowly developing ischemia
renal artery atherosclerosis
what is an example of acute ischemia
renal artery embolus
define hypoxia
low oxygen delivery to tissue
what is the role of oxygen in the electron transport chain of oxidative phosphorlyation
final electron acceptor
decreased oxygen results in
decreased ATP
what are three causes of hypoxia
ischemia
hypoxemia
decreased O2-carrying capacity of blood
define ischemia
decreased blood flow through an organ
what are 3 causes of ischemia
- decreased arterial perfusion
- decreased venous drainage
- Shock
what is a pathological reason for decreased arterial perfusion
atherosclerosis
what is syndrome that can cause decreased venous drainage
Budd-Chiari syndrome
what are the most common cause of Budd-Chirari syndrome
- Polycythemia vera: increased RBC, increase viscosity and thickness of blood
- patient with lupus anticoagulants
what is Budd-Chiari syndrome
occlusion of the hepatic veins that drain the liver
what is shock
generalized hypotension resulting in poor tissue perfusion
define hypoxemia
low partial pressure of oxygen in blood
what are 4 causes of hypoxemia
- high altitude
- hypoventilation
- diffusion defect
- V/Q mismatch
name a disease what will not allow PAO2 to push as much O2 into blood due to thicker diffusion barrier
interstitial pulmonary fibrosis
what happens in V/Q mistmatch
- blood bypasses oxygenated lung
2. oxygenated air cannot reach blood
what conditions does blood bypass oxygenated blood
circulation problem
right-to-left shunt
what problems can cause oxygenated air to not reach blood
ventilation problem
atelectasis
atelectasis
Complete or partial collapse of a lung or a section (lobe) of a lung
decreased O2 carrying capacity arises in hemoglobin from what 3 causes
- anemia
- carbon monoxide
- methemoglobinemia
define anema
decreased in RBC mass
what are PaO2 and SaO2 values for anemia
both normal
what are PaO2 and SaO2 values for carbon monoxide poisoning
PaO2 normal
SaO2 decreased
what are common exposures that can cause carbon monoxide poisoning
- smoke from fires
- exhaust from cars
- exhaust from gas heaters
what is the classic clinical findings for carbon monoxide poisoining
cherry-red appearance of skin
what is an early sign of carbon monoxide poisoning
headache
-significant exposure leads to coma/death
what form of iron binds oxygen
Fe2+
what happens in methemoglobinemia
iron in heme is oxidized to Fe3+ , which cannot bind oxygen
what are PaO2 and SaO2 values for methemoglobinemia
PaO2 normal
SaO2 decreased
what are classic clinical findings for methemoglobinemia
cyanosis with chocolate-colored blood
what is the treatment for methemoglobinemia
methylene blue : helps reduce Fe3+ back to Fe2+
what can cause methemoglobinemia
oxidant stress: sulfa and nitrate drugs
newborns
A low ATP disrupts what key cellular functions
- Na-K pump
- Ca pump
- switches to anaerobic glycolysis
what happens when the Na-K pump stops working
sodium and water builds up
what happens when the Ca pump stops working
Ca buildup in cytosol
Ca is an enzyme activator
switching to anaerobic glycolysis results in waht
lactic acid build up –> low pH –> denature protein and precipitates DNA
what is the hallmark of reversible cell injury
cellular swelling
cytosol swelling results in
loss of microvilli
membrane blebbing
Swelling of rough endoplasmic reticulum results in
dissociation of ribosomes and decreased protein synthesis
what is the hallmark of irreversible injury
membrane damage
what are 3 membrane damage that can occur in irreversible cell injury
plasma
mitochondrial
lysosome
plasma membrane damage results in
- cytosolic enzymes leaking into the serum
2. additional calcium entering the cell
mitochondrial membrane damage results in
- loss of electron transport chain
2. cytochome c leaking into cytosol
where does electron transport chain occur in mitochondira
inner mitochondrial membraine
cytochrome c activates what
apoptosis
lysosome membrane damage results in
hydrolytic enzymes leaking into cytosol
- these enzymes get activated by Ca
what is the end result of irreversible injury
cell death
