CSIM 1.2 Introduction to Disease - Cell Injury

Question 1

What is clinical pathology?

Answer 1

The laboratory diagnosis of disease

Question 2

Which autoimmune diseases are associated with HLA antigens? Which antigen does each depend on?

Answer 2

• ankylosing spondylitis B27
  
  • coeliac disease DR3
  • Graves’ disease DR3
  • insulin-dependent diabetes DR3, DR4
  • rheumatoid disease DR4

Question 3

Define pathogenesis

Answer 3

The mechanism by which etiological agents cause disease manifestations

Question 4

Define pathology

Answer 4

The study of the causes and effects of disease

Question 5

Define disease

Answer 5

Abnormal variation in the structure or function of any part of the body

Question 6

Define morbidity

Answer 6

Sum of the effects of a disease

Question 7

What does HLA stand for (antigen)?

Answer 7

Human leukocyte antigen

Question 8

In what ways can cells become damaged by disease?

What can cause each?

Answer 8

Cell membrane injury
• Chemicals
• Physical injury
• Toxins from bacteria

Nuclear injury
  •  Inherited genetic disease
  •  Irradiation
  •  Free radicals
  •  Carcinogens

Question 9

What immune system mechanisms damage cell membranes of cells containing foreign antigens?

Answer 9

• Complement fixation - these consist of proteins which stick to bugs so you know they’re foreign
  
  • Perforin-mediated injury - cytotoxin t cells find cells which have virus antigens on them and punch a hole in them

Question 10

What does nuclear injury result in?

Answer 10

• Loss of nuclear function

* Neoplasia

Question 11

What causes neoplasia?

Answer 11

Non-lethal damage of genes controlling:
  •  cell division
  •  apoptosis
  •  DNA repair 
leads to unregulated proliferation

Question 12

How can one DNA mutation give rise to more?

Answer 12

Can occur if the mutation is on a protein responsible for DNA repair

Question 13

What can cause reduced energy production?

Answer 13

Hypoxia
Hypoglycaemia
Toxins (cyanide)

Question 14

How are free radicals formed?

Answer 14

As a bi-product of aerobic respiration in mitochondria

Through ionising radiation

Question 15

How are free radicals removed?

Answer 15

Antioxidant mechanisms:
• Catalase
• Peroxidase
• SOD

Question 16

What are the two main types of cell death? Do these require energy?

Answer 16

Necrosis - no energy needed

Apoptosis - requires ATP

Question 17

What is the role of mitochondrial dysfunction in the two types of cell death?

Answer 17

Permeability in mitochondria membrane causes loss of H+ gradient –> CAUSES NECROSIS

Within the mitochondria there is cytochrome c, which can trigger APOPTOSIS

Question 18

What causes cell death?

Answer 18

Failure of a cell to adapt to injury

Question 19

What are the morphological types of necrosis?

Where does each occur and what does it look like?

Answer 19

• Coagulative (heart and kidney, yellow fibrosis)
  
  • Liquefactive (brain, liquified and falls to bits)
  • Caseous (lung, looks like cheese)
  • Gangrenous (black)

Question 20

Describe the process of necrosis?

Answer 20

• Loss of membrane integrity
  
  • Cell contents leak out
  • Cell is degraded and digested by lysosomal enzymes
  • This generates an inflammatory response

Question 21

What is gangrene

Answer 21

Black coloured infarction and infection

Question 22

How is apoptosis carried out?

Answer 22

• Enzymatic destruction of DNA and cytoskeleton
  
  • Cell membrane remains intact
  • Fragments of cell break away and are phagocytosed

Question 23

What two types of apoptosis are there?

Answer 23

• Physiological (normal cell turnover)

* Pathological (elimination of potentially harmful cells e.g. infected cells)

Question 24

Where are the ‘triggers’ for apoptosis?

Answer 24

Cell membrane receptors and mitochondrial cytochrome c

Question 25

What is pathogenesis of bacterial diseases dependent on/come about as a result of?

Answer 25

• Exotoxins and endotoxins

* Consequences of immune response