Necrosis & apoptosis Flashcards by E Thomas

What is apoptosis?

Programmed cell death

How well did you know this?

Not at all

Perfectly

Describe the process of apoptosis (when the actual cell dies).

Nucleus condenses
Cell shrinks
Blebs form
Phagocyte digests

How well did you know this?

Not at all

Perfectly

What are blebs?!

When the cell’s cytoskeleton breaks up it causes the membrane to bulge outwards.

These bulges are called blebs

How well did you know this?

Not at all

Perfectly

What are apoptotic bodies?

When blebs detach from the cell taking some cytoplasm with them

How well did you know this?

Not at all

Perfectly

Why does apoptosis occur?

If cell is too old

If cell has DNA damage

How well did you know this?

Not at all

Perfectly

What regulates apoptosis? How does it do it?

p53 protein

It senses DNA damage in cells and triggers apoptosis

How well did you know this?

Not at all

Perfectly

In what instances can apoptosis be good?

In development: apoptosis is needed for healthy development, for example it separates the fingers

In parts of the body with high cell turnover: gut epithelia

Prevents many cancers + viral infections

How well did you know this?

Not at all

Perfectly

What happens when you have a lack of apoptosis?

Cancer

How well did you know this?

Not at all

Perfectly

In terms of apoptosis what is cancer?

A lack of apoptosis

How well did you know this?

Not at all

Perfectly

In terms of apoptosis what is HIV?

Too much apoptosis

HIV induces apoptosis of T helper cells, causing a weakened immune system

How well did you know this?

Not at all

Perfectly

What is necrosis?

Traumatic cell death. The cells are not expecting to die

How well did you know this?

Not at all

Perfectly

Causes of necrosis?

Infarction
Frostbite
Avascular necrosis of bone
Pancreatitis

How well did you know this?

Not at all

Perfectly

List the types of necrosis!

L G F F C C

Leadmill
Go + see
Fickle
Friends
Clean
Cut (kid)

Liquefactive
Gangrenous
Fat necrosis
Fibrinoid
Coagulative
Caseous

How well did you know this?

Not at all

Perfectly

What causes coagulative necrosis?

Blood loss

How well did you know this?

Not at all

Perfectly

Where can coagulative necrosis occur?

Any tissue except brain

How well did you know this?

Not at all

Perfectly

Macroscopic appearance of coagulative necrosis?

Tissue is firm

How well did you know this?

Not at all

Perfectly

Microscopic appearance of coagulative necrosis?

Cell outlines are preserved

Everything looks red

How well did you know this?

Not at all

Perfectly

What causes liquefactive necrosis?

Neutrophils releasing their toxic contents, liquefying the tissue

Also blood loss in the brain

How well did you know this?

Not at all

Perfectly

When is liquefactive necrosis seen?

In brain infarcts

In infections

Macroscopic appearance of liquefactive necrosis?

Tissue is liquidy, creamy yellow (pus)

Microscopic appearance of liquefactive necrosis?

Lots of neutrophils & cell debris

When is caseous necrosis seen?

Why?

In tuberculosis

Occurs because the body is trying to fight off and kill the infection with macrophages.

The lung itself gets damaged

Macroscopic appearance of caseous necrosis?

White, soft, cheesy looking

Microscopic appearance of caseous necrosis?

Fragmented cells and debris, surrounded by a collar of lymphocytes and macrophages
(a granuloma!)

What causes fat necrosis?

Damaged cells release lipases, which split triglyceride esters within fat cells

When is fat necrosis seen?

In acute pancreatitis

Macroscopic appearance of fat necrosis?

Chalky, white areas Caused by the combination of newly formed free fatty acids and calcium (saponification)

What is saponification? What does it look like?

When free fatty acids mix with calcium Looks chalky white

Microscopic appearance of fat necrosis?

Shadowy outlines of dead fat cells | Bluish cast from the calcium deposits, because they are basophilic

When is fibrinoid necrosis seen?

In immune reactions in vessels

What causes fibrinoid necrosis?

When antigen-antibody complexes combine with fibrin

Macroscopic appearance of fibrinoid necrosis?

None, the changes are too small

Microscopic appearance of fibrinoid necrosis?

Vessel walls are thickened and look pink-ish red

When is gangrenous necrosis seen?

When an entire limb loses blood supply and dies

Macroscopic appearance of gangrenous necrosis?

Skin looks black and dead | Underlying tissues are in varying stages of decomposition

Microscopic appearance of gangrenous necrosis?

Initially there is coagulative necrosis from the loss of blood supply - dry gangrene If bacterial infection is present you'll see liquefactive necrosis - wet gangrene

What is the difference between wet and dry gangrene?

Dry: coagulative necrosis due to loss of blood supply Wet: Liquefactive necrosis due to bacterial infection

What type of necrosis is this? A patient's finger feels firm to touch A sample is taken and when viewed under a microscope you see everything looks red with ghostly outlines of dead cells

Coagulative necrosis Caused by loss of blood supply

What type of necrosis is this? A patient has had a fatal stroke. In the autopsy you see the brain tissue looks liquidy and yellow.

Liquefactive necrosis

What type of necrosis is this? A patient's leg ulcer is seeping white/yellow fluid. A sample of skin viewed under a microscope shows many neutrophils and debris of dead cells.

Liquefactive necrosis Caused by infection

What type of necrosis is this? A patient presents with breathlessness and is coughing up blood. A lung biopsy shows the tissue is white and soft. When viewed under a microscope you see circular structures; surrounded by lymphocytes & macrophages, with fragmented dead cells in the centres.

Caseous necrosis Caused by TB The circular structures are granulomas

What type of necrosis is this? A patient dies of acute pancreatitis. The autopsy shows the tissue around the pancreas is chalky . Under the microscope you see a bluish tinge and outlines of dead cells.

Fat necrosis Chalky because of saponification Bluish because the calcium deposits are basophilic

What type of necrosis is this? A sample of tissue is viewed under the microscope looks pink-ish red and you can see that the vessel walls are thickened. The sample looks healthy to the naked eye

Fibrinoid necrosis Caused by immune reactions in vessels

What type of necrosis is this? A patient presents because their left leg has turned black with green tinges and they no longer have the use of it. Under the microscope you see everywhere looks red with outlines of dead cells

Gangrenous necrosis Dry gangrene: signs of coagulative necrosis This will have been caused by a lack of blood supply

What type of necrosis is this? A patient is in ITU with sepsis. You notice their fingers and toes begin looking black. A sample under a microscope shows many neutrophils mixed with cell debris

Gangrenous necrosis Wet gangrene: signs of liquefactive necrosis This will have been caused by infection