Exam 1 (Lecture 2) - Cell Injury Flashcards
What are cell membranes?
Fluidic phospholipid bilayers that enclose cells and their organelles.
What are the two major functions of cell membranes?
1) Serve as selective barriers
2) Form a structural base for the membrane-associated proteins (enzymes and receptors) that determine cell function
What does the term fluidic mean?
This means that the proteins and lipids in the membrane are not immoveable but can travel throughout the cell.
What is the importance of the plasma membrane?
The plasma membrane is the first contact with harmful substances such as toxins or infectious microbes.
What is the major function of mitochondria?
The generation of energy (ATP). (They HAVE to have O2)!!
What is the function of the rough ER?
Proteins are made there; they go into membranes or outside of cell.
What is the function of smooth ER?
Production of FAs and cholesterol.
What is contained in the nucleus?
Chromatin (DNA and proteins)
What is the function of the nucleolus?
The production of ribosomes/RNA.
What type of filament is actin?
Microfilament
What is the function of intermediate filaments?
Anchors the cell
What do microtubules do?
They’re the “highways” of the cell
What are the two broad causes of cell injury? Give examples of each.
1) Extrinsic: bacteria, viruses, toxins
2) Intrinsic: cell machinery not working correctly
Does the cell have an abundance of ways to respond to injury?
No; limited ways to respond to injury.
What are the fundamental mechanisms of cell injury?
1) ATP depletion
2) Permeabilization of cell membranes
3) Disruption of biochemical pathways
4) Damage to DNA: Can’t produce RNA = problems downstream (can’t make proteins)
What are the cellular responses to stress?
1) Adapt: (Increase in cell number, increase in cell size, alter structure)
2) Be reversibly injured: (Increased water, increased lipids)
3) Die: (Necrosis: not programmed; Apoptosis: programmed)
What are the causes of cell injury?
1) Oxygen deficiency
2) Physical agents
3) Infectious agents
4) Nutritional deficiency/imbalance
5) Genetic derangement
6) Workload imbalance
7) Chemicals/Drugs/Toxins
8) Immunologic dysfunction
9) Aging
What is an example of oxygen deficiency?
Hypoxia (cell won’t be able to produce enough ATP/energy)
What are examples of physical agents?
Heat, cold, radiation, toxins, trauma
What are examples of infectious agents?
Bacteria, viruses, parasites, prions
What are examples of nutritional deficiencies/imbalances?
Protein deficiency, vitamin/mineral deficiency
What are examples of genetic derangement?
Inherited, acquired
What is an example of a workload imbalance?
Too much, too little work
What are the causes of hypoxia?
1) Ischemia (decreased blood flow)
2) Anemia (decreased RBC, Hb)
3) Carbon monoxide (decreased O2)
4) Respiratory failure: asphyxia (decreased gas exchange)
5) Cardiac failure (decreased cardiac output)
6) Thrombus, trauma
What are the steps of acute cell swelling?
***In cell swelling, cytoplasm will appear pale due to increased water
Injury –> hypoxia –> ATP production decreases –> Na+ and water move into cell, K+ moves out –> osmotic pressure increases –> more water moves into cell –> cisternae of ER distend, rupture, and form vacuoles –> extensive vacuolation –> hydropic degeneration (acute cell swelling in liver/kidneys)
What is ballooning degeneration?
Acute cell swelling in epithelial cells (skin)
What is cytotoxic degeneration?
Acute cell swelling in neurons
Is cell swelling reversible?
To a point; until there is mitochondrial and/or cell membrane damage
What are the 3 forms of cell death?
1) Necrosis
2) Apoptosis
3) Post-mortem autolysis
How does cell swelling occur?
Hypoxia –> decreased ATP
Membrane injury –> loss of environmental control
