1Cardiovascular System: Anatomy Review: Blood Vessel Structure and Function
Name the three layers or tunics of the blood vessel wall and what they are composed of. Location
Smooth muscle cells and sheets of elastin Outer
Collagen fibers that protect and reinforce the blood vessels and anchor it to surrounding structures
In the following list of characteristics, put “A” for artery, “C” for capillary, and “V” for vein: v contain the lowest pressure
a contain the highest pressure a has thick tunica media
v thin tunica media
c smallest of the blood vessels
a carries blood away from heart v largest lumen—blood reservoir
c has only one tunic (intima) v carries blood toward the heart
c site of exchange of nutrients
Name the three groups of arteries:
Elastic arteries have a thick tunica media with the greatest amount of elastin. They also experience the greatest pressure and the widest variation in pressure. The best example is the aorta.
Compared to the arteries above, the muscular arteries have more smooth muscle but less Elastin. They deliver blood to specific organs. The renal artery delivers blood to the kidney and would be an example of this type of artery.
Small changes in the diameter of these blood vessels greatly influence blood flow and blood pressure. Stimulation of vasomotor fibers would cause (vasoconstriction or vasodilation) of the blood vessels.
The smallest arteries are called aterioles. The steepest drop in blood pressure occurs in these vessels, thus they offer the greatest resistance to flow.
An increase in blood flow through a feeder arteriole will (increase or decrease) blood flow through the capillary.
The shunt is a short vessel that directly connects the arteriole and venule. When blood flows through this vessel, there is no exchange of materials.
The precapillary sphincter controls blood flow into the true capillaries. Exchange of materials takes place from these capillaries.
Compared with blood pressure in the arteries, blood pressure is (high or low) in the capillaries.
The smallest venules are formed when capillaries unite. They consist mainly of endothelium around which a few fibroblasts congregate. Blood flow continues to (increase or decrease) in the venules.
Veins have three distinct tunics, with the tunica exteria being the heaviest. Veins have thinner walls and longer lumens than arteries.
Because pressure is lower in the veins, special adaptations are necessary to return blood to the heart. These three structural adaptations are: 1.
Venous Valve. Here, one way prevent backflow as blood travels toward the heart. 2.
Muscle pump. Here, contractingskeletal muscles press against veins, forcing blood through #1 above. 3.
respiratory pump. During inspiration, pressure (increases or decreases) in the thoracic cavity and (increases or decreases) in the abdominal cavity. This results in an upward “sucking” effect that pulls blood toward the heart.
Cardiovascular System: Measuring Blood Pressure
Blood flow is generated by the cardiac output . Blood pressure results when that flow encounters systolic pressure from the vessel walls.
Blood pressure is expressed in millimeters of mercury and is written as mmHg.
Blood flows in layers within the lumen of blood vessels, with the layers in the ¬middle of the lumen flowing fastest. This is known as laminar flow.
Blood pressure fluctuates with each heartbeat. The pulse you feel in your wrist is a/an pressure wave created by the contracting heart ejecting blood.
The maximum pressure exerted by blood against the artery wall is known as systolic pressure (SP) and is the result of ventricular systole
Normal SP is about 120 mmHg.
What does the dicrotic notch represent?
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