Cellular Tissue, Organ & Systemic Effects

Question 1

Describe common causes of cellular injury

Answer 1

• Hypoxia
• Chemical agents (pH, toxins)
• infectious agents (biological)
• Genetic factors (inherrited/acquired alle mutation)
• Nutritional imbalances

Question 2

What is Hypoxia

Answer 2

Hypoxia is a lack of sufficient oxygen.

• problem with O2 entering the blood
• problem transporting O2

Ischaemia is a reduction in blood supply to the cells.

• most common cause of Hypoxia
• gradual narrowing of arteries (arteriosclerosis)
• complete blockage by blood clot, thrombosis.
• progressive hypoxia hypoxia (better tolerated).
• anoxia = total lack of oxygen

Question 3

What is chemical injury to the cell?

Answer 3

When a toxic substance damages the cell membrane leading to increased permeability.

Two general mechanisms.

1. Direct toxicity caused by chemical reacting with part of the cell membrane/ organelles
2. Formation of substances that cause lipids in cell membrane to be damaged.

Question 4

What physical agents lead to cell injruy?

Answer 4

• Blunt force trauma
• Penetrating injuries
• environmental stressors
  
  • heat stress/
  • ionising radiation
  • temperature exposure
  • pressure sores and atmoshperic
  • sunlight causing cancer etc.

Question 5

What are some biological causes of Cellular injury?

Answer 5

• Infectious agents
  
  • infectious microrganisms enter the body, mulitply rapidly to cause disease
  • may enter the cell, like viruses or release toxins.
• immune responses
  
  • inflammatory response to infections or underwctive immune response
• Genetic causes
  
  • genetic abnormailities can produce defects in cellurlar metabolsim, alter structure & function of cells- making them more susceptible to injury
• Nutritional imbalance
  
  • lack of energy (starvation)
  • Metabolic malfunction caused by deficit or excess.

Question 6

What are the 4 major mechanisms of cellular injury?

Answer 6

1. ATP depletion
2. O2 and O2 derived free radicals
3. Intracellularbcalcium increased
4. Defects in cell membrane permeability.

Question 7

There are four types of tissue in the body. What are they?

Answer 7

Epithelial tissue
Connective tissue
Skeletal tissue
Nervous tissue