Term
| The Five aspects of the Cardiovascular System are: |
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Definition
1. A Fluid - Blood Plasma
2. A Pump - the Heart
3. Arteries for carrying blood away from the heart
4. Veins for draining capillaries and returning blood to the heart
5. Capillaries - For supplying O2 and nutrients as well as removing CO2 and metabolic wastes. |
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Term
| What are the three layers of a blood vessel's wall? (internal to external) |
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Definition
1. Tunica Intima
2. Tunica Media
3. Tunica Adventitia |
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Term
What is the general microstructure of:
Tunica Intima |
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Definition
Has three main regions:
A. Endothelium
B. Basla Lamina
C. Subendothelial Layer (Loose CT) (In arteries and arterioles there is a sheet like layer of lamella called the internal elastic membrane)
In arteries and arterioles, the subendothelial layer may contain some smooth muscle. |
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Term
What is the general microstructure of:
Tunica Media |
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Definition
Extends from the Internal Elastic Membrane to the External Elastic Membrane.
Mainly composed of circumfrentially arranged layers of smooth muscle.
Variable amounts of elastin, reticular fibers, and glycoproteins are found surround the smooth muscle from the bordering membranes. |
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Term
What is the general microstructure of:
Tunica Adventitia |
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Definition
| Longitudinally arranged collagenous tissue. This layer contains small vessels called vasa vasorum that supply blood to the vessel walls and nervi vascularis that innervates the smooth muscle of the wall. |
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Term
Describe the wall and size of:
Capillaries |
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Definition
Small, red blood cell (RBC)‑sized endothelial tube
No other components |
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Term
Describe the wall and size of:
Postcapillary Venule |
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Definition
Large Endothelial Tube
No other componenets |
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Term
Describe the wall and size of:
Muscular Venule |
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Definition
Small sized vessel
Media with one or two layers of smooth muscle
Lots of adventitia |
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Term
Describe the wall and size of:
Arteriole |
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Definition
Small vessel
Media with one or two layers of smooth muscle
Little adventitia |
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Term
Describe the wall and size of:
Artery |
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Definition
Large vessel
Thick media with lots of elastin |
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Term
Describe the wall and size of:
Muscular Artery |
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Definition
large vessel
Thick media (lots of smooth muscle)
Thinner adventitia |
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Term
Describe the wall and size of:
Vein |
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Definition
large vessel
Thin media
Thicker adventitia |
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Term
| What type of vessels do you expect to find a vasa vasorum and why? |
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Definition
| Vasa Vasorum is present within large artieries and veins only. It is only present within these types of vessels because in the smaller types of vessels nutrient and wastes can readily diffuse from the blood to the layers of the vessels. |
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Term
| Why do large artieries have so much elastin within their walls? |
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Definition
| In order to maintain constant blood flow throughout the body, the elastin allows major arteries to distend during systole and recoil during diastole. This maintains constant blood flow through the vessels and initially during recoils forces a small amount of blood back towards the heard and forces closing of the pulmonary and aortic valves. |
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Term
| What are the three main types of capillaries? |
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Definition
1. Continuous Capillaries
2. Fenestrated Capillaries
3. Discontinuous Capillaries |
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Term
| What are the six major functions of endothelial cells? |
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Definition
1. Maintaines a selectively permeable barrier
Simple Diffusion, Active Transport, Pinocytosis, Receptor Mediated Endocytosis.
2. Maintenance of a nonthrombotic barrier
Secretion of Antiocadulants, Antithrombogenic Agents, and Prothrombogenic Agents
3. Modulation of blood flow and vascular resistance
Secretion of vasconstrictors and vasodilators
4. Regulation and modulation of immune responses
Regulates leukocyte migration by expression of adhesion molecules
5. Hormonal Synthesis
Growth factor secretion
6. Modification of lipoproteins
Production of free radicals |
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Term
| Why is the tunica media of veins typically less prominent than that of similarly sized arteries? |
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Definition
| The tunica media is less prominant because the veins do not need to dilate and recoil. Instead the vein has semilunar valves that only allow blood to flow in one direction (towards the heart) |
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Term
| Apart from blood flow, what other function do arterioles and muscular arteries have? |
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Definition
| They have the ability to constrict between 60% and 100% of their size to direct the flow of blood to where it is most needed by stopping blood flow to some capillaries. |
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Term
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Definition
| Arterioles which give rise and have capillaries connected to them. |
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