1. Cell Death

2. You have approximately 30 trillion red blood cells.

3. Nearly 2 million die in the time that it takes to say this.
Why aren’t you anemic?
Bone marrow replaces them

4. Cells have a life span Different cells have different life spans
Ex. Esophagus maybe live hours, rbc may be 120 days

5. From a cell point of view, it’s not what caused the cell death, but what’s happening in the cell

6. Two Types of Cell Death:
Apoptosis: programmed cell death, “cell suicide”

7. Apoptosis

8. Necrosis: death caused by injury through trauma, virus, bacteria, toxins
We are looking at death caused by injurious agents

10. Cell Injury All injuries have an effect at the molecular level first
Cells are damaged long before injury is observed
Ex. Heart attacks account for a huge amount of cell death, but you can’t see any structural changes in a cardio cell for approximately 12 hours
We cannot tell the moment a cell dies

11. Cells that undergo traumatic death resulting from acute cellular injury demonstrate a characteristic series of changes including the following:

12. The cell and its organelles swell
Why?
Cannot control water and ion regulation
Cell contents leak out, leading to
Inflammation of surrounding tissue

13. Swelling
Endoplasmic Reticulum: folded membranes swell apart and eventually rupture
Ribosomes come off the rough ER
Cannot see under a compound microscope
Protein synthesis cannot occur even if cell is still alive
What happens?

14. Complete chaos
If one chemical pathway is interrupted, all others will be affected

15. Mitochondria: Swell and rupture
Cristae is lost
No ATP production
Cannot see this under a compound microscope

16. Nucleus: Nucleus takes on an irregular look (“clumping”)
Nuclear envelope begins to break apart
Normal nucleus looks smooth and homogenous
We can see this under the microscope

17. They do not kill the cell, they usually make dead cells go away
Lysosomes: rupture and release protein digesting enzymes that can destroy cells
They do not kill the cell, they usually make dead cells go away
Occurs often with infection, cuts

18. What would happen if you left dead cells/tissue in an area of your body?
Fertile ground for massive infection

19. Necrosis of the Heel

20. Necrosis can be divided into the following:
Necrosis: includes all of the above changes that can be observed following “accidental” cell death
Necrosis can be divided into the following:
Autolysis
Heterolysis

21. Autolysis Cellular degradation caused by the cell’s own enzymes
Occurs when a lysosome allows the digestive enzymes out of its membrane
Always occurs before heterolysis

22. Normal Liver Histology

23. Normal Liver

24. Autolysis (Image 2)

25. Autolysis (Image 3)

26. Autolysis (Image 4)

28. Characteristics of autolysis of liver cells
Disorganized intercellular material
Granular appearance of cytoplasm
Orange peel look
White spots within the cytoplasm
Fat accumulation
Clumping of nuclear material

29. Why do we see fat?

30. Cell has been damaged and is unable to adequately metabolize fat.
Small vacuoles of fat accumulate and become dispersed within cytoplasm.

31. Heterolysis
Digestive enzymes from other cells break down the dead cell
Usually leukocytes (white blood cells)