Cell death

What is nuclear fading due to chromatin dissolution during cell death called?

• Karyolysis

• Pyknosis

• Karyorrhexis

• Pyrexia

Answer explanation

Nuclear fading and chromatin dissolution is referred to as karyolysis.

Pyrexia is a fever (high temperature).

What is nuclear shrinkage during cell death called?

• Karyolysis

• Pyknosis

• Karyorrhexis

• Karyotype

Answer explanation

Nuclear shrinkage is called pyknosis.

Karyotype is the general appearance of the complete set of metaphase chromosomes, mainly used to describe their sizes, numbers, and shapes.

What is nuclear fragmentation during cell death called?

• Karyolysis

• Pyknosis

• Karyorrhexis

• Karyokinesis

Answer explanation

Nuclear fragmentation is called karyorrhexis. This happens when the membrane of a pyknotic nucleus ruptures.

Karyokinesis is the division of the nucleus of a cell during cell division.

Note karyo- is the root that means nucleus.

Sometimes, a bacterial infection can cause the release of hydrolytic enzymes in brain or lung tissue, leaving behind a soft lesion of pus and fluid remains. This is called:

• Liquefactive necrosis

• Caseous necrosis

• Coagulative necrosis

• Fatty necrosis

Answer explanation

This is liquefactive necrosis.

Hydrolytic enzymes, or hydrolases, are simply those that use water to break apart larger molecules.

What is the effect of reduced ATP production, due to ischaemia, on intracellular ion concentrations?

• Increase in K⁺

• Increase in Na⁺

• Decrease in Ca⁺

• There is no change

Answer explanation

The correct answer is an increase in Na⁺.

The decreased ATP availability means ionic pumps do not work properly, in particular the Na⁺/K⁺ ATPase pump. This leads to an increase in Na⁺ and a decrease in K⁺ with the cell.

Since "water follows sodium", this leads to cellular oedema.

Lack of ATP is also associated with an increase in intracellular Ca²⁺.

What is the name of the folds in the cell membrane that occur either due to oedema in necrosis, or due to initiation of apoptosis?

• Blobs

• Bleebs

• Blebs

• Blabs

Answer explanation

These are membrane blebs.

Sometimes, cells in solid organs experience ischaemia, leading to necrosis leaving behind a "ghostly" loss of definition on a pathology slide (as around the yellow star in the image). This is called:

• Liquefactive necrosis

• Caseous necrosis

• Coagulative necrosis

• Fatty necrosis

Answer explanation

This is coagulative necrosis.

This occurs in solid organs due to ischaemia.

In the image of a slice of kidney tissue, green is healthy cells. Blue is a Bowman's capsule. The area around the yellow star has been infarcted, leading to the characteristic "ghostly" appearance of the necrotic cells.

After death of a whole organism, or after tissue removal from an organism, death of cells occurs due to digestive enzyme release from within cells. This is called:

• Endolysis

• Paralysis

• Self-destruction

• Autolysis

Answer explanation

The correct answer is autolysis.

It can also be known as self-digestion.

Decreased blood flow to or from an organ is known as

• Anaemia

• Ischemia

• Poisoning

• Necrosis

Answer explanation

Ischaemia is defined as a lack of blood flow to a tissue.

By the fact that blood carries oxygen, ischaemia implies hypoxia.

Single cell death within clusters of other cells is known as

• Necrosis

• Autolysis

• Apoptosis

• Heterolysis

Answer explanation

This is most likely to be apoptosis, as autolysis or necrosis would affect a large number of cells around the single cell that is dying here.