CTB7 Cell Biology Of The Cardiovascular System Flashcards
What are the three layers blood vessels are made of?
- Tunica intima
- Tunica media
- Tunica adventitia
What does the thickness and composition of the three layers of blood vessels depend on?
the type of vessel and the vessel’s position in the vascular tree – veins are thinner and less muscularised than arteries.
What happens to the muscular medial layer found in larger vessels, in capillaries?
It disappears and capillaries consist of only endothelial cells
What’s the intima made up of?
a monolayer of endothelial cells which are smooth and non-adhesive for platelets or leukocytes
What to the endothelial cells in the intima do?
adhere tightly to one another in order to form a selective barrier between the blood and vascular wall components
What is the surface area of the lung endothelium?
~130m squared
What does the large surface area of the lung endothelium ensure?
effective exchange of gas and nutrients throughout the body
In smaller vessels, what morphology do endothelial cells adopt?
‘Cobblestone’
What happens to endothelial cells in larger vessels? Why? How?
the blood flow is stronger so the endothelial cells flatten out and elongate in the direction of flow to minimise mechanical forces acting on their surface. The cells also overlap in order to increase junctional area and strengthen barrier function.
What changes to the environment do endothelial cells respond to?
oxygen tension, blood flow, circulating cytokines and growth factors by producing vasoactive mediators
What vasoactive mediators do endothelium cells respond to?
- Endothelin-1
- Norepinephrine
- Angiotensin 1
- Thromboxane
- Prostacyclin (PGI2)
- Endothelial derived relaxing factor nitric oxide (NO)
How do endothelium cells maintain vascular homeostasis?
by relaying environmental changes to smooth muscle cells via chemical messages
What functions do endothelium cells exhibit to maintain vascular homeostasis?
- Regulation of vascular tone
- Barrier function – regulates the exchange of fluids and nutrients to tissues
- Inflammatory responses – blood cells are trafficked to the injury site
- Thrombogenesis
- Angiogenesis
What does media consist of? What is it separated from and how?
vascular smooth muscle cells surrounded by a mesh of collagen and elastin which contribute to the strength and compliance of the blood vessel wall. The media is separated from the intima by the internal elastic lamina.
What is the aorta composed of? Why is this needed?
many layers of smooth muscle, with a greater abundance of collagen and elastin to withstand the arterial pressure.
