Capillaries are the smallest blood vessels in the body and their walls are only one cell thick. They are very important in the exchange of water, carbon dioxide, oxygen, nutrients and waste products in the body. This happens between the blood in the capillaries and the body tissues, and the exchange happens through osmotic gradients (Wiederhielm, 1979, p. 5).
Capillaries are also very important in controlling blood flow through auto-regulation. This is important in blood pressure regulation. They can allow fluids to move out and reduce blood pressure or can allow fluids to move in and increase the blood pressure.
Therefore, it is important to consider the importance of permeability in the capillaries. Mainly because they are very important for the normal functioning of the body. They are selectively permeable—that is they allow some substances to pass through but not others. This property varies depending on the organs or tissues where they are found, and enables them to selectively exchange substances from different tissues in the body (Marshall, 1967, p. 54).
However, an experimental drug called Neostop, which is used to slow the growth and the spread of malignant gastrointestinal tumors, affects capillaries by reducing their permeability. The reduction in permeability of the capillaries has very detrimental effects on different organs and tissues in the body. Some of the organs that are highly affected by the reduction in permeability of the capillaries are the heart and the lungs.
Effect of Reduced Permeability of Capillaries in the Heart
The heart is a very important organ in the body. It is mainly involved in blood circulation: it is a muscular blood pump that distributes blood to all parts of the body. This circulation is important in maintaining a normalized body temperature, distributing nutrients to different organs in the body and removal of waste products form where they are produced to excretion organs.
For proper functioning of the heart, it require nutrients and oxygen, and at the same time, waste products must be removed from it. This is mainly because it is made up of muscles that respire a lot to produce enough energy for pumping blood; and respiration requires oxygen and other nutrients; and produces a lot of waste products such as carbon dioxide. This waste products must be removed from the heart, because if allowed to accumulate, they might damage the heart. Therefore the capillaries that cover the heart not only supply the much needed nutrients, but also remove the waste products of respiration (Rosdahl & Kowalski, 2008, p. 227).
The exchange of substances between the heart tissues and the capillaries takes place because they are permeable. If this permeability is reduced, it means the rate of exchange of substances also decreases. This in turn affects the normal functioning of the heart.
If for instance the rate at which oxygen is moving from the capillaries to the heart tissues is reduced, it means that the heart muscle tissues will be deprived of oxygen. This will reduce the rate of respiration, which in turn will reduce the energy required for pumping blood. The end result is weak blood pumping by the heart, which means the heart will not be able to pump blood to all parts of the body as it is supposed to do.
Also, if the permeability is reduced, the waste products of respiration will not be removed fast enough. This will lead to their accumulation in the heart tissues: a situation that might lead to heart poisoning, damage, and negatively affect its normal functioning.
Since blood is a fluid, any change in pressure at a given point is felt throughout the entire blood circulation system. As a result of reduced permeability of the capillaries, blood pressure within the capillaries will definitely change. This change in pressure in the capillaries will affect the normal functioning of the heart, as it tries to normalize the pressure.
All these stresses being subjected to the heart as a result of reduced permeability of the capillaries might lead to heat complications such as heart attacks, and affect the normal functioning of the heart.
Effect of Reduced Permeability of Capillaries in the Lungs
Lungs are very important organs in gaseous exchange. Their main functions is to absorb oxygen and remove carbon dioxide. This takes place between the capillaries and the alveoli through diffusion.
When capillaries permeability is reduced in in the lungs, capillary pressure reduces. This reduction in capillary pressure lead to structural changes in the capillaries, such as disruption of the capillary wall, alveoli wall or sometimes all the walls. This in effect affect the normal functioning of the lungs (West, 2007, p. 99).
Since capillaries in the lungs are important in gaseous exchange, reduced permeability of the capillaries will reduce the absorption of oxygen from the alveolus to the blood in the capillaries. Therefore, very little amounts of oxygen will be absorbed in the lungs. This will in-turn affect the rate of breathing, since most of the oxygen being inhaled is not absorbed. The person in this case might experience shortness of breath.
Reduced permeability of the capillaries in the lungs will also reduce the rate at which carbon dioxide is removed from the blood through the lungs. This will lead to an accumulation of carbon dioxide—which is a waste product—in the blood. This accumulated waste product is poisonous and might be detrimental to the health of the person if prolonged (Roberts, 1986, p. 244).
The main function of the lungs is gaseous exchange. This function is highly aided by the capillaries that are efficiently permeable. This permeability enhance the exchange of gases between the lungs and the blood: carbon dioxide which is a byproduct of respiration is removed from the blood through the capillaries, and oxygen is absorbed into the blood through the capillaries. Therefore, if the permeability of the capillaries is reduced, the normal functioning of the lungs is highly compromised and the rate of gaseous exchange highly reduced.
The Effects of Reduced Permeability of Capillaries on a Person’s Health
Since capillaries are very important in the removal of waste products from tissues, reduced permeability of the capillaries means that the rate of waste removal from the tissues will be reduced. Therefore, waste products accumulate in the tissues, and in extreme cases damage them. This negatively affects the affected person’s health.
For example, the accumulation of carbon dioxide in the blood as a result of reduced permeability of capillaries in the lungs, can cause the body to increase the rate and depth of breathing so as to compensate for the reduced carbon dioxide removal. The person may also suffer from a “flapping tremor” which is an uncontrollable flapping of hands when they are bent backwards at the wrists. The lips under a person’s tongue might turn blue due to high levels of carbon dioxide in the blood. High levels of carbon dioxide in the brain can also lead to brain hypoxia—due to carbon dioxide poisoning (van den Brink et al., 2000, p. 9).
When the permeability of the capillaries is reduced, it means there will be less oxygen uptake in the lungs. This can lead to less oxygen flowing to the brain. Another situation that might lead to less oxygen being supplied to the brain is when the capillaries in the brain are less permeable, therefore less oxygen is diffusing to the brain cells. The deprivation of oxygen might lead to a headache in the affected person. Prolonged lack of oxygen might also lead to brain hypoxia (van den Brink et al., 2000, p. 7). The person might also feel dizzy or drowsy due to lack of oxygen.
Another important organ that is affected by loss of capillary permeability is the heart. As discussed above, the heart muscle tissues requires enough oxygen in order to function properly. In case the permeability of the capillaries that provide this vital substance is reduced, it means less oxygen will be supplied to the heart tissues. In case they are deprived of oxygen, the person might get a heart attack: the death of heart muscles due to lack of oxygen. This can lead to heart failure which has no cure, and the health of the person is compromised (Reisner, 2008, p. 142).
Heart failure is very serious because it affects other parts of the body. The heart pumps blood to other parts of the body, which in turn distributes nutrients and removes waste products. If the heart fails, the blood will not be pumped properly and the body parts will not be able to receive nutrients and remove waste. This condition is very serious because the affected person might even die. The health of a person depends on the proper functioning of all the body organs. If any one of the organs or tissues is not functioning properly, the health of the person is compromised.
The experimental drug Neostop is very useful in the treatment of malignant gastrointestinal tumors. But it affects the capillaries in the lungs and heart negatively by reducing their permeability. Capillaries are very important in exchanging substances between them and body tissues. They are specialized to carry out this function by being permeable and allowing substances to pass across their one cell thick epithelia.
If this permeability is compromised by a drug such as Neostop, their functionality is highly compromised. And since they are the main site of substance exchange between the blood and the surrounding tissues, tissues will not be able to function properly. Waste products will not be removed from the tissues, and they will also not be provided with nutrients and oxygen.
This has been discussed at length in the above subheadings, and shows that the continued use of the drug might have more devastating health impacts to the affected person, compared to its beneficial effect. Therefore, the use of this drug should highly be discouraged.
Marshall, P. T. (1967). Physiology of Mammals and Other Vertebrates: A Text Book for Schools and Colleges. CUP Archive.
Reisner, D. E. (2008). Bionanotechnology: Global Prospects. CRC Press.
Roberts, M. B. V. (1986). Biology: A Functional Approach. Nelson Thornes.
Rosdahl, C. B., & Kowalski, M. T. (2008). Textbook of Basic Nursing. Lippincott Williams & Wilkins.
van den Brink, W. A., van Santbrink, H., Steyerberg, E. W., Avezaat, C. J. J., Suazo, J. A. C., Hogesteeger, C., … Maas, A. I. R. (2000).
West, J. B. (2007). Pulmonary Physiology and Pathophysiology: An Integrated, Case-based Approach. Lippincott Williams & Wilkins.
Wiederhielm, C. A. (1979). Dynamics of capillary fluid exchange: A nonlinear computer simulation. Microvascular Research, 18(1), 48–82.