Lecture 1.2b - Cell injury and cell death 2

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Questions and Answers

What is the primary cause of metastatic calcification?

Increased secretion of parathyroid hormone

Destruction of bone tissue

Accumulation of damage to cellular constituents and DNA

Hypercalcaemia secondary to disturbances in calcium metabolism (correct)

What type of calcification occurs in normal tissues throughout the body due to hypercalcaemia?

Fibrocartilaginous calcification

Calcification of atherosclerotic plaques

Metastatic calcification (correct)

Dystrophic calcification

What is a possible consequence of ectopic secretion of parathyroid hormone-related protein by malignant tumours?

Osteosclerosis

Osteoporosis

Hypercalcaemia (correct)

Hypocalcaemia

Which of the following is NOT a cause of hypercalcaemia?

Virally-induced bone resorption Signup and view all the answers

What is the result of telomeres reaching a critical length in cellular ageing?

The cell can no longer divide Signup and view all the answers

Which of the following can lead to hypercalcaemia due to bone resorption?

All of the above Signup and view all the answers

What is the characteristic of haemosiderin deposition in hereditary haemochromatosis?

Deposition in the liver, pancreas, heart, and endocrine organs Signup and view all the answers

What is the primary function of conjugation of bilirubin with glucuronic acid in the liver?

To increase bilirubin's solubility in water Signup and view all the answers

What is the term used to describe the abnormal deposition of calcium salts within tissues?

Calcification of tissues Signup and view all the answers

What is the characteristic of dystrophic calcification?

Local change or disturbance that favours nucleation of hydroxyapatite crystals Signup and view all the answers

What is the primary mechanism of jaundice development?

Obstruction of bile flow Signup and view all the answers

In which of the following conditions is haemosiderin deposition commonly seen?

All of the above Signup and view all the answers

What is the primary function of albumin in bilirubin metabolism?

To transport bilirubin from tissues to the liver Signup and view all the answers

What is the term used to describe the generalized abnormal deposition of calcium salts within tissues?

Metastatic calcification Signup and view all the answers

What is the main reason for the accumulation of water and electrolytes in cells?

Cut off of energy supplies Signup and view all the answers

Which of the following is NOT a cause of lipid accumulation in cells?

Viral infection Signup and view all the answers

What is the term for the accumulation of abnormal substances in cells when metabolic processes become unbalanced?

Abnormal cellular accumulations Signup and view all the answers

Which type of imaging is used to recognize oedema in the brain?

CT imaging Signup and view all the answers

What is the term for the accumulation of triglycerides in liver cells?

Steatosis Signup and view all the answers

What can be a consequence of severe cellular distress?

Hydropic swelling Signup and view all the answers

Study Notes

Haemosiderosis and Hereditary Haemochromatosis

Haemosiderosis is a condition where haemosiderin is deposited in many organs due to systemic overload of iron.
Hereditary haemochromatosis is a genetically inherited disorder that results in increased intestinal absorption of dietary iron.
Iron is deposited in skin, liver, pancreas, heart, and endocrine organs, often associated with scarring in liver (cirrhosis) and pancreas.
Symptoms include liver damage, heart dysfunction, and multiple endocrine failures, especially of the pancreas.
Treatment is repeated bleeding.

Jaundice and Bilirubin Accumulation

Bilirubin is a breakdown product of heme, and its accumulation in the body causes jaundice.
Bilirubin is formed in all cells of the body, but must be eliminated in bile.
When bile flow is obstructed or overwhelmed, bilirubin in blood rises and jaundice results.
Bilirubin is deposited in tissues extracellularly or in macrophages.

Calcification of Tissues

Calcification is the abnormal deposition of calcium salts within tissues.
There are two types of calcification: dystrophic and metastatic.
Dystrophic calcification occurs in areas of dying tissue, atherosclerotic plaques, ageing or damaged heart valves, and some malignancies.
Metastatic calcification occurs due to hypercalcaemia secondary to disturbances in calcium metabolism.

Causes of Hypercalcaemia

Hypercalcaemia can be caused by increased secretion of parathyroid hormone (PTH) resulting in bone resorption.
Primary hyperparathyroidism is due to parathyroid hyperplasia or tumour.
Secondary hyperparathyroidism is due to renal failure and retention of phosphate.
Ectopic hyperparathyroidism is due to secretion of PTH-related protein by malignant tumours.
Destruction of bone tissue can also cause hypercalcaemia.

Cellular Ageing

Cellular ageing is caused by accumulation of damage to cellular constituents and DNA.
Cells reach replicative senescence after a certain number of divisions.
Telomeres, the ends of chromosomes, shorten with every replication, leading to cellular ageing.

Abnormal Cellular Accumulations

Abnormal cellular accumulations occur when metabolic processes become unbalanced.
They can be reversible, harmless, or toxic.
They can derive from the cell's own metabolism, the extracellular space, or the outer environment.

Types of Intracellular Accumulations

There are five main groups of intracellular accumulations: water and electrolytes, lipids, carbohydrates, proteins, and 'pigments'.

Fluid Accumulation in Cells

Fluid accumulation in cells, also known as hydropic swelling, occurs when energy supplies are cut off, e.g. hypoxia.
It indicates severe cellular distress and can be a particular problem in the brain (cerebral oedema).

Lipid Accumulation in Cells

Lipid accumulation in cells, also known as steatosis, often occurs in the liver.
It can be asymptomatic if mild, but can be caused by alcohol, diabetes mellitus, obesity, and toxins.

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Description

Learn about Haemosiderosis, a condition where excess iron is deposited in organs, and Hereditary Haemochromatosis, a genetic disorder causing increased iron absorption. Understand the effects on the liver, pancreas, heart, and endocrine organs.