Cardiovascular and Lymphatic System

Question 1

What are different types of blood vessels in the cardiovascular system?

Answer 1

• The elastic artery (high content of elastic tissue) –> the muscular artery (high content of smooth muscle and collagen) –> arteroid –> capillary beds

Question 2

There are changes in the structure and layering of blood vessels as blood travels from the heart to the capillary bed, describe these changes in a couple of sentences and explain how these changes affect the elasticity of the bloood vessels and how this affect the transportation of blood and the absorption of nutrients?

Answer 2

• The blood vessels become less and less elastic approaching the capillary beds. The number of layers also decreases. This is because we need to preserve the pressure generated by the heart to have blood flow to different parts of the body. The elasticity of the blood vessels plays a key role in preserving this pressure.
• However, at the capillary beds, the body is more concerned about diffusion (pushing fluid (nutrient) out – while the cells (blood) stay) than the transporting of blood. The blood vessels in the capillary bed consist of only one layer of epithelial cells to maximize the diffusion. This is also the reason that there is a loss in blood pressure after it passes through the capillary bed.

Question 3

What structure in the veins that maintain a unidirectional blood flow?

Answer 3

• Vein has valves.

Question 4

is there a difference in elasticity between veins and arteries? How do they differ structurally?

Answer 4

• Remember that arteries have layers of smooth muscle, elastic tissue and collagen layer?

yea Veins do not have layers of smooth muscle and elastic tissue. I mean they do but very minimal. Vein acts as tubes that transport fluid passively.

Because of its lack of elasticity, once a vein is stretched, it will not be able to return to its original form. This causes problems with the overall blood flow, blood starts to pool into one area of the circulatory system. People whose work requires standing for a prolonged period of time are at risk of this issue – co giang tinh mach.

Question 5

When we think of blood we think of red blood cells, but is that all there is in blood? What is the composition of blood and What exactly leaves the blood vessels at the capillary beds?

Answer 5

• Contrast to average people understanding of blood, red blood cells only make up around 30-50% of the blood volume. 4% is white blood cell (the guard) and 55% is plasma (water, proteins, nutrients and hormones)
• What is small enough to pass through a layer of epithelial cells and the basement membrane that make up the blood vessels of the capillary bed?
• water, nutrients and hormones.
• Where do these things go after they are being pushed out?
• Interstitial fluid – tissue fluid.

Question 6

We know that osmosis drives the outward flow of nutrients, water, and hormones into the interstitial fluid (tissue fluid), which reduces the overall blood volume. If the blood pressure drops too low, blood flow would be disrupted. What needs to happen to compensate for the loss of blood volume after it passes the capillary beds?

Answer 6

• After the blood passes the capillary beds, it will be overconcentrated. Some of the interstitial fluid will be drawn back, but that still is not enough to restore the blood pressure.
• the lymphatic system will supply the interstitial fluid back to the veins to maintain blood pressure. However, there are waste products in the interstitial fluid and so the fluid needs to be filtered before it can enter the blood flow again. This is done through lymph nodes ( kidney-shaped small encapsulated bodies of white blood cells and macrophages) that take out dangerous stuff from the fluid.