Lecture 5&6- Cardio I, II

Question 1

Characteristics of endothelial cells in the Endocardium (t. intima) layer.

Answer 1

• simple squamous with tight and gap junctions
• flattened cells aligned with their long axes in the direction of blood flow
• express receptors and surface adhesion molecules on luminal surface

**endothelial activation- change in functional properties in response to various stimuli

Question 2

Functions of endothelial cells in the Endocardium (t. intima) layer

Answer 2

1. permeability: controls composition of interstitial fluid
2. movement of inflammatory cells into tissues
3. VEGF (vascular endothelial growth factor): provides of angiogenesis in the embryogenesis
4. provides signals that control blood pressure
5. contain rod-shaped inclusions: Wiebel Palade bodies

Question 3

What are Wiebel Palace bodies?

Answer 3

rod-shaped inclusions

• store vWF that binds clotting factor VII, platelet adhesion to site of endothelial injury
• *present in heart, elastic, and muscular artier, small arteries and arterioles (but not present in capillaries)

Question 4

Explain the different signals released by the endothelial cells of the t. intima endothelium that controls blood pressure

Answer 4

• vasoconstriction: endothelin, ACE- decrease luminal diameter
• vasodilation: NO; increase smooth muscle relaxation
• anticoagulants: thrombomodulin- decreases lately attachment and aggregation
• antithrombogenic: prostacyclin- prevents aggregation of platelets and release of clotting factors
• Prothrombogenic: vWF- promotes clot formation
• Pulmonary endothelial cells: ACE- converts angiotensin I to II