Cellular Injury Flashcards
What is important to understand about cellular injury?
- occurs in many ways (eg. due to pathogens (harmful microbes) or trauma (infection, burns, lesions, stress)
- Injury leads to l/o fx (may not always be visible or obvious)
What does the extent of injury depend on?
- Agent (eg. bacterial meningitis vs. viral meningitis)
- Intensity (eg. 1st, 2nd, 3rd degree burns)
- Duration - how long agent is active
- Cell type - where in the body is affected
- Loss of perfusion
- Cell recovery or death
What are the 3 major mechanisms of injury?
- Hypoxia
- Ca+ Imbalance
- Free radicals
What occurs to the cell if there is a Ca+ imbalance (mechanism of injury)?
Upon injury, intracellular Ca+ concentration is increased. Ca+ moves into the cell and organelles release Ca+ into cytoplasm. This increased concentration of Ca+ in the cell causes an inappropriate activation of enzymes leading to cell damage.
Name some roles of the functions of Ca+ in the body.
- Generates ATP (Ca+ gates open @ threshold)
- Muscle contraction (Ca+ binds to troponin)
- Coagulation (used in the intrinsic and extrinsic pathway)
Name some examples of enzymes and what can occur if their is an inappropriate activation of these enzymes.
- Proteases (break down protein)
- ATPase (can lead to a deficiency of energy because it breaks down ATP so you lose energy)
What are free radicals?
Fragments of chemicals formed from chemical reactions (toxic chemical fragments)
What occurs to the cell if there is free radical production (mechanism of injury)?
Free radicals are reactive, unstable, toxic chemicals derived from cell injury. The oxidization process causes cellular injury because it causes chemical interference which disrupts DNA, cell proteins, and membranes.
Oxidizing?
“stealing” an electron from the closest molecule and causing that molecule to become a free radical.
List an example of the oxidization process causing cellular injuring affecting DNA, cell proteins and membranes.
If a free radical attaches to the phospholipid it changes the property of the membrane and disrupts its functions.
Hypoxia?
Deficiency of oxygen in tissues
How is hypoxia a mechanism of injury?
Oxygen is required for ATP production because it is needed in aerobic cellular respiration. W/O adequate ATP supply, regular cellular functions don’t occur.
(decrease oxygen in tissues -> decrease ATP production -> affects cell function)
ATP?
energy for cells
What does the suffix -ase tell you?
It is an enzyme
Hypoxemia?
Deficiency of oxygen in arterial blood
