Misc

Question 1

Outcomes of AI

Answer 1

• Resolution
• Abscess formation
• Organisation and repair
• Chronic inflammation

Question 2

Abscess

Answer 2

Localised accumulation of pus

- Liquefactive necrosis

Question 3

Abscess Pathogenesis

Answer 3

• Presence of bacteria -> potent neutrophil response
• Neutrophils phagocytose the bacteria and in doing so release ROS and other damaging proteases, which results in liquefactive necrosis
• This leads to a localised accumulation of dead and dying neutrophils and necrotic debris

Question 4

Granulomatous inflammation

Answer 4

• Specific type of chronic inflammation, which involves activated macrophages (epitheloid cells)

Question 5

Layers of BV Wall

Answer 5

1. Intima
2. Media
3. Adventitia

Question 6

Pathogenesis of MI

Answer 6

Atherosclerotic narrowing of coronary artery with an underlying occlusive thrombus leading to infarction of the myocardium to which that particular vessel supplies

Question 7

Thrombus formation on plaque

Answer 7

• if a fibrous cap over an atheromatous plaque bd, collagen fibres in the intima are exposed to the circulating blood and this initiates the formation of a thrombus
  Virchows triad:
• it is the injury to the endothelium by ulceration or fissuring of the plaque which stimulates the thrombogensis
• Sometimes also the turbulence or stasis around the plaques can lead to thrombosis

Question 8

What is an embolus

Answer 8

Intravascular solid, liquid or gaseous mass carried in the blood stream to a site remote from its origin or point of entrance into the blood stream

Question 9

Types of embolus

Answer 9

• Thrombo-embolus
• Athero-embolis
  (these two may result from atherosclerosis)
• Tumor-embolus
• Fat embolus

Question 10

Ventricular Fibrillation

Answer 10

VF is an arrhythmia (abnormal rhythm). The left ventricle contracts in an uncoordinated chaotic way (fibrillates) and has no effective output. Acute injury to myocytes, usually caused by acute ischaemia, leads to electrical instability as insufficient ATP is generated to maintain normal ion pumps. Myocytes automatically fire and abnormal impulses travel erratically around the left ventricle preventing normal contraction and relaxation. There is no effective cardiac output and no cerebral blood flow leading to irreversible brain damage or death unless successful resuscitation occurs.

Question 11

Type of necrosis in MI

Answer 11

Coagulative necrosis

Question 12

When is a MI rupture likely to occur?

Answer 12

Mostly it occurs between 4-10 days after the MI. This is when the muscle is maximally necrotic and weak. It does not generally occur later as after this time there is more collagen being laid down in healing that adds strength.

Question 13

Cardiac tamponade

Answer 13

Blood filling the confined space of the pericardial cavity outside the heart constricts the heart and severely impairs diastolic filling, thus its output is significantly reduced leading to severe cerebral and myocardial ischaemia and death. This external constriction of the heart is known as tamponade.