Aortic Disease And Congestion & Oedema

Question 1

What are the 3 layers of the thoracic aorta?

Answer 1

Tunica intima
Tunica media
Tunica adventitia

Question 2

What are the features of the tunica intima?

Answer 2

Layer of endothelial cells
Subendothelial layer - collagen and elastic fibres
Separated from the tunica media internal elastic membrane

Question 3

What are the features of the tunica media

Answer 3

Smooth muscle cells

Secrete elastin in the form of sheets (lamellae)

Question 4

What are the features of the tunica adventitia

Answer 4

Thin connective tissue layer
Collagen fibres and elastic fibres (not lamellae)
- prevents elastic arteries from stretching beyond physiological limits during systole

Question 5

What is an aneurysm?

Answer 5

Localised enlargement of artery caused by weakening of the vessel wall

Question 6

What is a true aneurysm?

Answer 6

Aneurysm bound by all 3 layers of the vessel wall which weakens and bulges

Question 7

What are the 2 types of true aneurysm?

Answer 7

Saccular - aneurysm only bulges out on one side of the vessel
Fusiform - bulges out on all sides of the vessel (more common)

Question 8

What is a false aneurysm?

Answer 8

Blood vessel wall is injured and leaking blood collects in the surrounding tissue

Question 9

What is a dissecting aneurysm?

Answer 9

Injury to intima allows blood to flow between layers of the aortic wall forcing the layers apart

Question 10

What is congestion?

Answer 10

Relative excess of blood in vessels of tissue of organ

Active hyperaemia

Question 11

What are the causes of vascular congestion (3)? With examples

Answer 11

Local acute congestion (e.g. DVT - blood backed up in veins, venules, capillaries)
Local chronic congestion (e.g. hepatic cirrhosis - serious liver damage blocking portal blood flow - haemorrhage risk)
Generalised acute congestion (e.g. congestive cardiac failure - heart unable to clear blood - R and L ventricles)

Question 12

What is transudate?

Answer 12

Alterations in haemodynamic forces which act across capillary wall
(Cardiac failure, fluid overload)

Question 13

What is exudate?

Answer 13

Part of inflammatory process due to increased vascular permeability (tumour, inflammation, allergy)

Question 14

What is an oedema?

Answer 14

Accumulation of abnormal amounts of fluid in extravascular compartment

Question 15

What is heart failure?

Answer 15

clinical syndrome comprising of dyspnoea, fatigue or fluid retention due to cardiac dysfunction, either at rest or on exertion, with accompanying neurohormonal activation

Question 16

Why isn’t heart failure a final diagnosis?

Answer 16

There is underlying structural abnormality and cause

Question 17

What are underlying causes to heart failure (2)?

Answer 17

Heart failure due to left ventricular systolic dysfunction

Heart failure due to severe aortic stenosis (narrowing of aortic valve)

Question 18

How does frank-starling law relate to heart failure?

Answer 18

If the muscle of the heart is stretched it will contract with greater force and pump out more blood

In failing damage heart this is lost
Circulatory volume increases and heart dilates, force of contraction weakens and cardiac output drops further

Question 19

What is the neurohormonal hypothesis of heart failure?

Answer 19

Systemic disorder - multiple organ dysfunction

Renin-angiotensin-aldosterone system - salt and water retention, LV hypertrophy/remodelling and fibrosis