Lecture 2 - Response To Cellular Stress Flashcards
What are labile cells?
Labile cells are cells that multiply constantly throughout life (e.g. epithelial cells)
What are stable cells?
Stable cells are cells that multiply only when needed (myocardial cells, liver, the proximal tubules of the kidney and endocrine glands
- Moves through cell cycle
What are quiescent cells?
Quiescent cell are cells in a reversible state which do not divide but retains the ability to re- enter cell proliferation (e.g satellite cells in muscle)
- Leaves cell cycle (G0)
What are causes of cellular stress? (7)
• Oxygen deprivation
• Physical trauma
• Chemical trauma
• Infectious agents
• Immunological agents
• Genetic derangements
• Nutritional imbalances
What is the most common cause of cell injury?
Hypoxia
What are causes of hypoxia?
Inadequate oxygenation
Loss of O2 carrying capacity
• Decreased Haemoglobin
• Decreased RBC production
What is ischaemia?
Restriction of blood supply - most devastating cause of hypoxia
What is the most common cause of general injury to the body?
Ischaemia
What happens during ischaemia?
Waste products cannot be removed. An accumulation of waste products results in pain.
What is hypoxic hypoxia?
Hypoxia insufficient O2 available to lungs which means the lungs are not able to deliver enough O2 to the blood passing through them
What are potential causes of hypoxic hypoxia?
– Drowning
– Blocked airway
– Reduced 02 in atmosphere e.g. high altitude
– Secondary to lung damage
What is anaemic hypoxia?
Hypoxia due to decreased concentration of functional haemoglobin or decreased number of RBCs
What can be the cause of decreased concentration
of functional haemoglobin?
Sickle cell anaemia
Thalassemia
What can be the cause of decreased number of RBCs?
Decreased or delayed production
Increased or early degeneration
What is ischaemic hypoxia?
Hypoxia due to an inadequate blood supply to the tissues
What are types of Ischaemic Hypoxia?
Generalised
Localised
Gradual
Acute
What is an example of generalised ischaemic hypoxia?
Heart Failure
What is an example of localised ischaemic hypoxia?
Vessel obstruction
What is an example of gradual ischaemic hypoxia?
Arteriosclerosis
What is an example of acute ischaemic hypoxia?
Embolus: infarction
What are the different types of physical trauma?
Mechanical
Thermal
• Hypothermia
• Hyperthermia
Electrical
Radiation
Damages DNA
Changes in atmospheric pressure
• Blast injury
• Decompression sickness
What are the different types of chemical trauma?
Hypertonicity
Poisons
Strong acids and alkalis
Environmental pollutants
Recreational drugs.
What are the effects of MDMA in cellular death?
Increase in serotonin which are involved in temperature
regulation.
Increased temperature
Increased water consumption
Cells swell -> burst and die
– Liver cells
– Lung cells
– Brain cells
• Respiration rate declines
• Heart rate increases
• Blood pressure decreases
What are the different types of infectious agents? (5)
• Fungi
• Viruses
• Parasites
• Protozoa
• Bacteria