2: Hypoxia

Flashcards about Applied Bioscience for Health Instability lecture notes.

Adenosine triphosphate (ATP)

The major energy source of the cell.

Aerobic respiration

The production of ATP in the presence of oxygen, producing large amounts of ATP with water and carbon dioxide as by-products.

Anaerobic respiration

Produces ATP without oxygen by breaking down carbohydrate, with lactic acid as the by-product.

Apoptosis

An active process of cellular self-destruction, called programmed cell death.

Cellular injury

When normal cellular homeostasis is not maintained.

Hypoxia

Lack of cellular oxygen causing an increase in anaerobic respiration, leading to a lack of sodium and potassium transport across the cell membrane.

Irreversible cell injury

The point of no return passes and the cell dies, e.g., apoptosis and necrosis.

Ischaemia

A reduction in blood flow to the cells.

Necrosis

Cellular death leading to cellular dissolution (breaking up of cell).

Reversible cell injury

The cell can recover from cellular injury

Causes of Cellular Injury

Lack of oxygen (hypoxia), free radicals, toxic chemicals, infectious agents, inflammatory and immune responses, genetic factors, insufficient nutrients or physical trauma.

Initial Insult in Chemical Injury

Damage or destruction of the cell membrane.

Injurious Physical Agents

Temperature extremes, changes in atmospheric pressure, sunlight, and trauma.

Hypoxia

The single most common cause of cellular injury, resulting from problems with oxygen entering the blood or transporting oxygen around the body.

Conditions Causing Inadequate Oxygen Delivery to the Blood

Diseases of the respiratory system (e.g., Asthma) and blockage of the upper airways in the lungs (e.g., trauma).

Hypoxia Due to Insufficient Oxygen Transport

Decrease in haemoglobin (e.g., with blood loss), decreased production of red blood cells (e.g., anaemia), diseases of the cardiovascular system, where cardiac output is reduced and significant drops in blood pressure.

Ischaemia

Reduction in blood supply to the cells, the most common cause of hypoxia.

Ischaemia Causes

Gradual narrowing of arteries (e.g., arteriosclerosis) or complete blockage of arteries (e.g., thrombus).

Anoxia

Total lack of oxygen, can result from complete blockage of arteries.

Infarction

Cell death, can result from complete blockage of arteries.

Biochemical Changes Important to Cell Injury

ATP depletion, oxygen and oxygen-derived free radicals, and intracellular calcium and loss of calcium steady state.

Sequence of Events Leading to Cell Death

Decreased ATP production, failure of active transport mechanisms (the sodium–potassium pump), cellular swelling, other pathophysiological processes, lysis of the cell membrane, and death.

Initial Insult in Hypoxic Injury

Ischaemia (the cessation of blood flow into vessels that supply the cell with oxygen and nutrients).

Reversible Cell Injury

Cell injury from which the cell may recover.

Reversible Cell Injury Association

Cellular swelling and increases in intracellular lipid content.

Irreversible Cell Injury

Cell injury where the ‘point of no return’ is passed and the cell dies.

Types of Irreversible Cell Injury

Apoptosis and necrosis.

Apoptosis

A process of selective cellular self-destruction that occurs in normal and pathological tissue changes.

Necrosis

Cellular death manifested as cellular dissolution.

Structural Signs of Irreversible Injury and Progression to Necrosis

Dense clumping and disruption of genetic material, and disruption of the cell and organelle membranes.

Gangrenous Necrosis (Gangrene)

Tissue necrosis caused by hypoxia and the subsequent bacterial invasion.

Adenosine triphosphate (ATP)

The major energy source of the cell.

Aerobic respiration

The production of ATP in the presence of oxygen, producing large amounts of ATP with water and carbon dioxide as by-products.

Anaerobic respiration

Produces ATP without oxygen by breaking down carbohydrate, with lactic acid as the by-product.

Apoptosis

An active process of cellular self-destruction, called programmed cell death.

Cellular injury

When normal cellular homeostasis is not maintained.

Hypoxia

Lack of cellular oxygen causing an increase in anaerobic respiration, leading to a lack of sodium and potassium transport across the cell membrane.

Irreversible cell injury

The point of no return passes and the cell dies, e.g., apoptosis and necrosis.

Ischaemia

A reduction in blood flow to the cells.

Necrosis

Cellular death leading to cellular dissolution (breaking up of cell).

Reversible cell injury

The cell can recover from cellular injury

Causes of Cellular Injury

Lack of oxygen (hypoxia), free radicals, toxic chemicals, infectious agents, inflammatory and immune responses, genetic factors, insufficient nutrients or physical trauma.

Initial Insult in Chemical Injury

Damage or destruction of the cell membrane.

Injurious Physical Agents

Temperature extremes, changes in atmospheric pressure, sunlight, and trauma.

Hypoxia

The single most common cause of cellular injury, resulting from problems with oxygen entering the blood or transporting oxygen around the body.

Conditions Causing Inadequate Oxygen Delivery to the Blood

Diseases of the respiratory system (e.g., Asthma) and blockage of the upper airways in the lungs (e.g., trauma).

Hypoxia Due to Insufficient Oxygen Transport

Decrease in haemoglobin (e.g., with blood loss), decreased production of red blood cells (e.g., anaemia), diseases of the cardiovascular system, where cardiac output is reduced and significant drops in blood pressure.

Ischaemia

Reduction in blood supply to the cells, the most common cause of hypoxia.

Ischaemia Causes

Gradual narrowing of arteries (e.g., arteriosclerosis) or complete blockage of arteries (e.g., thrombus).

Anoxia

Total lack of oxygen, can result from complete blockage of arteries.

Infarction

Cell death, can result from complete blockage of arteries.

Biochemical Changes Important to Cell Injury

ATP depletion, oxygen and oxygen-derived free radicals, and intracellular calcium and loss of calcium steady state.

Sequence of Events Leading to Cell Death

Decreased ATP production, failure of active transport mechanisms (the sodium–potassium pump), cellular swelling, other pathophysiological processes, lysis of the cell membrane, and death.

Initial Insult in Hypoxic Injury

Ischaemia (the cessation of blood flow into vessels that supply the cell with oxygen and nutrients).

Reversible Cell Injury

Cell injury from which the cell may recover.

Reversible Cell Injury Association

Cellular swelling and increases in intracellular lipid content.

Irreversible Cell Injury

Cell injury where the ‘point of no return’ is passed and the cell dies.

Types of Irreversible Cell Injury

Apoptosis and necrosis.

Apoptosis

A process of selective cellular self-destruction that occurs in normal and pathological tissue changes.

Necrosis

Cellular death manifested as cellular dissolution.

Structural Signs of Irreversible Injury and Progression to Necrosis

Dense clumping and disruption of genetic material, and disruption of the cell and organelle membranes.

Gangrenous Necrosis (Gangrene)

Tissue necrosis caused by hypoxia and the subsequent bacterial invasion.