Pathological Processes: Overall Flashcards Preview

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Flashcards in Pathological Processes: Overall Deck (22):
1

What can severe changes in the environment of a cell lead to?

Cell adaptation, injury or cell death

2

Degree of injury to cell following severe changes in environment depends on what?

–Type of injury
–Severity of injury
–Type of tissue

3

How is the cell injury response part of a continuum?

Stimulus: Physiological --> Harmful

Response: Homeostasis --> Cellular Adaptation --> Cellular Injury --> Cell death

4

What kind of things can cause cell
injury? (7)

• Hypoxia
• Toxins
• Physical agents
• Radiation
• Micro-organisms
• Immune mechanisms
• Dietary insufficiency and deficiencies, dietary excess

5

Give examples of physical agents that can cause cell injury (4)

– Direct trauma
– Extremes of temperature
– Changes in pressure
– Electric currents

6

What is hypoxia?

Deficiency in the amount of oxygen reaching the tissues

7

Define cyanosis

A bluish discoloration of the skin due to poor circulation or inadequate oxygenation of the blood

8

What does frostbite most commonly affect?

Fingers, nose, toes

9

What can frostbite often result in?

Gangrene

10

What is cellulitis?

Inflammation of skin (subcutaneous connective tissue)

11

How can the worsening/improving of cellulitis be tracked?

Draw around affected area

12

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.

13

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

14

Difference in sensitivity to hypoxia: brain vs skin

Neurones = few minutes
Fibroblasts = few hours

15

What is urticaria?

Hives

16

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.

17

Which cell components are most
susceptible to injury? (4)

- Membranes
- Nucleus
- Proteins
- Mitochondria

18

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.

19

Two types of injury that damage membranes primarily

- Extreme cold (e.g. frostbite)
- Free radicals

20

- 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

21

What are the three free radicals that are of particular biological significance in cells?

- OH• (hydroxyl): the most dangerous
- O2 (superoxide)
- H2O2 (hydrogen peroxide)

22

What are the three free radicals that are of particular biological significance in cells?

- OH• (hydroxyl): the most dangerous
- O2- (superoxide)
- H2O2 (hydrogen peroxide)