Term
| What are the five functions of the circulatory system? |
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Definition
1) Carries blood.
2) Exchanges nutrients, gases and waste products with tissues.
3) Transports substances such as hormones.
4) Helps regulate blood pressure.
5) Directs blood flow to tissues to maintain homeostasis. |
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Term
| What are the three main types of blood vessels and their sub-divisions? |
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Definition
Arteries- elastic, muscular and arterioles
Capillaries
Veins- venules, small, medium and large |
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Term
| How many tunics (layers) are there in blood vessels? |
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Definition
| Three tunics, except for in venules and capillaries. |
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Term
| What are the three tunics, from innermost to outermost? |
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Definition
| tunica intima, tunica media and tunica adventitia |
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Term
| Describe the tunica intima. |
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Definition
| Consists of endothelium composed of simple, squamous epithelial cells, a basement membrane and a small amount of thin elastic tissue. |
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Term
| Describe the tunica media. |
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Definition
| Smooth muscle cells arranged circularly around the blood vessel- plus some elastic and collagen fibers. |
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Term
| Describe the tunica adventitia. |
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Definition
| Connective tissue. Dense when it is adjacent to the tunica media, but loose towards the outer portion of the blood vessel. |
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Term
| Describe elastic arteries. |
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Definition
The arteries with the largest diameter and the thickest walls.
Lots of elastic tissue, very little muscular tissue. |
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Term
| What are two examples of elastic arteries? |
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Definition
| The aorta and the pulmonary artery |
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Term
| How does the structure of elastic arteries play a role in the circulatory system? |
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Definition
| Their elastic nature allows them to maintain blood pressure. |
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Term
| Describe muscular arteries. |
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Definition
These include medium and small sized arteries.
Walls are relatively thick to the diameter of this artery. |
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Term
| Which arteries are also called "distributing arteries" and why? |
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Definition
| Muscular arteries. Their smooth muscle tissue allows them to control blood flood to different regions of the body via vasoconstriction and vasodilation. |
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Term
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Definition
| These transport blood from the small arteries to the capillaries. They are adapted for vasoconstriction and vasodilation. |
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Term
| What is the role of valves in the larger veins? |
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Definition
| They allow blood to flow towards the heart but not in the other direction. |
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Term
| What is the structure of valves in the larger veins? |
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Definition
| They are similar to semilunar valves in the heart. They consist of folds in the tunica intima that form two flaps. There are more valves in the lower limbs to compensate for the gravitational pull. |
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Term
| Describe pulmonary circulation. |
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Definition
| The system of blood vessels that carries oxygen-poor blood from the right ventricle of the heart to the lungs and oxygen rich blood back to the left atrium of the heart (via the pulmonary veins). |
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Term
| Describe the systemic circulation. |
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Definition
| The system of blood vessels that carry oxygen rich blood from the left ventricle of the heart to the tissues and oxygen poor blood back to the right atrium of the heart. |
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Term
| What do the right and left coronary arteries do? |
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Definition
| Arising from the base of the aorta, they supply oxygen rich blood to the heart. |
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