Pathological Processes: Overall Flashcards
What can severe changes in the environment of a cell lead to?
Cell adaptation, injury or cell death
Degree of injury to cell following severe changes in environment depends on what?
–Type of injury
–Severity of injury
–Type of tissue
How is the cell injury response part of a continuum?
Stimulus: Physiological –> Harmful
Response: Homeostasis –> Cellular Adaptation –> Cellular Injury –> Cell death
What kind of things can cause cell
injury? (7)
- Hypoxia
- Toxins
- Physical agents
- Radiation
- Micro-organisms
- Immune mechanisms
- Dietary insufficiency and deficiencies, dietary excess
Give examples of physical agents that can cause cell injury (4)
– Direct trauma
– Extremes of temperature
– Changes in pressure
– Electric currents
What is hypoxia?
Deficiency in the amount of oxygen reaching the tissues
Define cyanosis
A bluish discoloration of the skin due to poor circulation or inadequate oxygenation of the blood
What does frostbite most commonly affect?
Fingers, nose, toes
What can frostbite often result in?
Gangrene
What is cellulitis?
Inflammation of skin (subcutaneous connective tissue)
How can the worsening/improving of cellulitis be tracked?
Draw around affected area
What is the difference between hypoxia and ischaemia? Which is considered worse and why?
Hypoxia: Decreased oxygen supply
Ischaemia: Decreased blood supply
- Ischaemia deprives the cell of of oxygen but also many other things (e.g. sugars) that could impact metabolic processes.
What are the four main causes of hypoxia?
– Hypoxaemic hypoxia – arterial content of oxygen is low
• Reduced inspired p02
at altitude
• Reduced absorption secondary to lung disease
– Anaemic hypoxia – decreased ability of haemoglobin to carry oxygen
• Anaemia
• Carbon monoxide poisoning
– Ischaemic hypoxia - interruption to blood supply
• Blockage of a vessel
• Heart failure
– Histiocytic hypoxia – inability to utilise oxygen in cells due to disabled
oxidative phosphorylation enzymes
• Cyanide poisoning
Difference in sensitivity to hypoxia: brain vs skin
Neurones = few minutes Fibroblasts = few hours
What is urticaria?
Hives
How does the immune system damage the
body’s cells? (2)
• Hypersensitivity reactions - host tissue is
injured secondary to an overly vigorous
immune reaction, e.g., urticaria (= hives)
• Autoimmune reactions - immune system fails
to distinguish self from non-self, e.g., Grave’s
disease of thyroid.
Which cell components are most
susceptible to injury? (4)
- Membranes
- Nucleus
- Proteins
- Mitochondria
Why can different insults result in the same damage?
Sequence of events for other insults may be different
but as the cell has a limited responses to injury,
outcome often similar.
Two types of injury that damage membranes primarily
- Extreme cold (e.g. frostbite)
- Free radicals
- What is a free radical?
- What else is it often to referred to as?
- Comment on its reactivity.
- Single unpaired electron in an outer orbit
- Reactive oxygen species
- High reactivity: an unstable configuration hence react with other molecules, often producing further free radicals
What are the three free radicals that are of particular biological significance in cells?
- OH• (hydroxyl): the most dangerous
- O2 (superoxide)
- H2O2 (hydrogen peroxide)
What are the three free radicals that are of particular biological significance in cells?
- OH• (hydroxyl): the most dangerous
- O2- (superoxide)
- H2O2 (hydrogen peroxide)
