1 Where would you expect to find fenestrated capillaries Mor

1. Where would you expect to find fenestrated capillaries? (More than one answer may be correct)

-Thyroid

-Skeletal muscle

-Cardiac muscle

-Spleen

2.. Explain why veins need specific mechanisms for blood return.

3. A patient has calcification in the left gastric artery. What organs will have impaired blood flow?

4. Describe the pathway taken by blood in the feet to get back to the heart.

Solution

1. Fenestrated capillaries are found in endocrine organs,pancreas,kidneys and small intestine. Fenestrated capillaries have pores in the endothelial cells.

2. Unliike arteries, veins are not muscular and they cannot control the diameter of the vessels. In the arteries, blood flows by the push provided by the heart, whereas in veins, the blood has to flow by the negative pressure created by heart and the muscle pump.

3. Left gastric artery supplies blood to the lower curvature of the stomach and lower part of the oesophagus. These organs will have impaired blood flow if the left gastric artery has calcification.

4. Once the blood has passed from the arteries through the capillaries, it is flowing at a slower rate because little pressure remains to move the blood along. Blood flow in the veins below the heart is helped back up to the heart by the muscle pump. The walls of the veins are thin and somewhat floppy. To compensate for this many veins are located in the muscles. Movement of the leg squeezes the veins, which pushes the blood toward the heart. When the muscles contract the blood within the veins is squeezed up the vein and the valves open. When the muscle is at rest, the valves close helping to prevent the backward flow of blood. This is referred to as the muscle pump.

Healthy legs have veins with smooth, elastic walls that are perfectly designed to adapt to the changes in pressure within a vein. Veins have valves that keep blood moving in one direction: back toward the heart. As the leg muscles are activated, the venous valves open to allow one-way flow in the direction of the heart. When the muscles relax, the valves close to stop any back-flow.