Process of capillaries in cardiac muscles

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This essay will explain the dysfunctional process involving capillaries of the cardiac muscles, and the alveoli of the lungs specifically in relation to the Wellebaum's syndrome. Assessment details provided for the assignment states that, Capillaries in a healthy person have a diameter of between 4-10 microns compared to a person who suffers from Wellebaum's syndrome has a diameter between 15-20 microns. Using this information, I will attempt to answer the question, what will happen when these organs in the body are enlarged and the six likely symptoms that could happen to the body if the diameter of the capillaries and alveoli do enlarge. The six symptoms that will be discussed are Angina, Dyspnoea, Pneumothorax, Cor Pulmonale, Asthma and Chronic Obstructive Pulmonary Disease. At the conclusion of this essay I will look at the different types of damage each of the fore mentioned conditions and symptoms have on the organs and the body as a whole.

Capillaries in the Cardiac Muscle

Given my understanding and research, I would think that the blood pressure would decrease as well as its velocity. My reasoning is that, Capillaries are tiny blood vessels in which oxygen, nutrients and glucose supply the cells. When the capillaries diameter doubles in size, blood supplying the heart would not be able to match the heart rate. Therefore causing inadequate blood flow to the tissues that may result in shortness of breath, chest pains, angina, and/or death.

Marieb & Hoehn (2007, p. G-4) describes capillaries as the smallest vessels where the exchange of nutrients happens between the tissues and the blood occurs. Huether & McCane (2006, p. 1062) states ‘resistance is determined mainly by a change in the diameter of the arterioles'. Adequate flow of the blood throughout the body is dependent on the ability of the heart to pump the blood. Marieb & Hoehn (2007, p. 726) states ‘maintaining a steady blood flow is vital for the organs to function properly. Blood flow requires the heart and the blood vessels to work together, under the supervision of the brain'. Capillaries distribute blood to the tissues, other capillaries pick up the blood from the tissues and return it to the venules which then pass the blood to the veins; the veins then return the blood to the heart. If the capillaries have increased in diameter, as in the person with Wellebaum's syndrome, this will cause the velocity and the pressure of the blood to decrease: therefore the blood supply to the heart will not match the heart rate causing an insufficient blood flow to the tissues and in some parts of the heart, which could in turn lead to death. Additionally, to be able to live symptom free; a person must have free flowing blood, an unobstructed blood flow and supply for the cells to function effectively, so any disruption to this blood supply may have serious and devastating consequences. Huether & McCane (2006, p. 1058), confirms that the circulatory systems that has any disorders, have the potential to effect every tissue, organ and system in the body.

Alveoli of the Lungs

Lungs are organs in the body that perform respiration. Inhaled air is directed down the trachea into the bronchi, and distributed into the lungs which are protected in the chest by the ribs in the form of a cage (Marieb & Hoehn 2007, p. 842). The bronchi divide into smaller tubes called bronchioles, and further into tiny air sacs called alveoli (Marieb & Hoehn 2007, p. 842). Each alveolus has a small group of capillaries, through which the exchange of oxygen and carbon dioxide takes place (Marieb & Hoehn 2007, p. 842) the oxygen molecules dissolve and melt a thin film of moisture from the air sac to the bloodstream, oxygenated blood is sent to the heart, and then pumped around the body. At the same time, carbon dioxide in the blood crosses from the capillaries to the air sacs, using the same film of moisture (Marieb & Hoehn 2007, p. 842). The carbon dioxide is then exhaled from the mouth. Huether & McCane (2006, p. 1185) states the alveoli are the primary gas exchange units of the lung. The alveoli works closely with the capillaries, by exchanging oxygen and carbon dioxide. Marieb & Hoehn (2007, p. 468) describes the deprivation of blood supply to any living tissue results in a deficient quality of oxygen and nutrients being delivered to cells results in ischemia. From my studies, if the alveoli are damaged in any way for example an increase in diameter; this will cause the number of capillaries to decrease, which means that the heart has to pump harder to move blood through the lungs. Over time, this can place a considerable strain on the heart, resulting in cyanosis and an increased risk of respiratory infections. With all of these changes I feel it would damage or have very specific changes to the entire body.


Angina is chest pain caused by insufficient blood flow and oxygen to the heart muscle (Crisp & Taylor 2009, p. 959). The heart muscle is maintained by the coronary arteries. If these arteries are narrowed, the reduced blood flow; the heart muscle receives less oxygen than it requires to properly functioning (Marieb & Hoehn 2007, p. 686). A common cause of narrowed coronary arteries is atherosclerosis (Huether & McCane 2006, p. 1138), which is a condition characterised by fatty plaques, which develop in the artery walls (Marieb & Hoehn 2007, p. 709) Therefore, if a coronary artery becomes blocked, either by fatty material or a blood clot, part of the heart muscle is starved of oxygen, myocardial cells which are cells of the heart are then damaged, and the severity of the heart attack depends on how many myocardial cells are damaged or killed. I believe angina is often an early warning sign of a heart attack waiting to happen.


Dyspnea also called breathlessness is a sign of a serious disease of the airway, lungs or the heart Breathlessness, also can be known as hypoxia (Crisp & Taylor 2009, p. 963). Dyspnea refers to the sensation of shortness of breath, difficulty breathing or a sign that there is not enough air p.436). This happens when the body is unable to ventilate enough to sufficiently meet the body's needs (Crisp & Taylor 2009, p. 963). Dyspnea may occur when there is increased breathing demand such as during exercise. Whereas the opposite effect which is an extremely common symptom, is the reduced ability to breathe enough due to respiratory muscle weakness (Crisp & Taylor 2009, p. 963). Breathlessness may occur in conjunction with other symptoms such as a cough, fever and chest pain. Therefore, dyspnea can be caused by a variety of conditions effecting the lungs, heart and or general circulation. In many cases, breathlessness occurs due to a fall in the levels of oxygen in the blood, which then increases the levels of carbon dioxide. This is frequently seen in people who suffer from emphysema, pneumonia, asthma, heart failure, dementia and multiple sclerosis (Crisp & Taylor 2009, p. 966).


Asthma is an illness which affects the narrowing of the airways of the lungs (Health institution, 2009). People who suffer from asthma have very susceptible airways (Health institution, 2009). This narrowing is a response to certain reactions or triggers that leads to breathing difficulties. The airway narrowing is caused by inflammation and swelling of the airway lining, the tightening of the airway muscles and the production of excess mucus (National Asthma Organisation, 2009). Huether & McCane (2006, p. 1223) confirms that when the airway is obstructed it causes an increase in resistances to the airflow, which includes the expired air flow. As a consequence, airflow into and out of the lungs is reduced, however, this condition is reversible. The release of histamine and cysteinyl- leukotrines cause the bronchi to constrict which then enables a asthma attack to be treated and managed (National Asthma Organisation, 2009).


Pneumothorax is an accumulation of gas or air, in the pleural space. This creates positive pressure and prevents the lungs from properly inflating (Kamg, Kim, Pyo et al 2009). If this build up of air is too great the lungs will probably collapse. Pneumothorax can also occur as a result of trauma or pre-existing pulmonary disease such as tuberculosis malignancy and emphysema. This trauma can allow gas into the pleural space. The pleura are made up of thin films of connective tissue, which lines both the outer surfaces of the lungs, and the inside of the chest cavity (Kamg, Kim, Pyo et al 2009). This inner surface of the thoracic cage is adjacent to the outer surface of the lung; this space contains a small amount of fluid and is normally under negative pressure compared to the alveoli (Kamg, Kim, Pyo et al 2009).

Cor Pulmonale

Cor pulmonale is defined as the main disorder of the respiratory system and the most common dysfunction between the heart and the lungs (Huether & McCane 2006, p. 1686). The two most common cause of Cor pulmonale is pulmonary vasoconstriction due to hypoxia and emphysema (Huether & McCane 2006, p. 1236). This effect causes an increase in pulmonary arterial pressure. Normally, the left side of the heart produces a higher blood pressure in order to pump blood to the body. The right side of the heart pumps blood through the lungs under much lower pressure. When the right ventricle is unable to properly pump against these abnormally high pressures cor pulmonale occurs (Huether & McCane 2006, p. 1686).

Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary Disease (COPD) is a progressive disease that makes it hard to breathe (Huether & McCane 2006, p. 1221). COPD can cause coughing which produces large amounts of mucus, wheezing, shortness of breath and chest tightness (Australian Lung Foundation, 2009). A person, who does not suffer from COPD, breathes in air which goes down the windpipe into tubes in your lungs called bronchial tubes. Theses elastic airways are shaped like an upside-down tree with many branches. At the end of the branches are tiny air sacs called alveoli (Australian Lung Foundation, 2009).When you breathe in, each air sac fills up with air. When you breathe out, the air sac deflates and the air goes out. In COPD, air flows in and out of the airways are reduced because the airways and air sacs lose their elastic properties or are destroyed (Australian Lung Foundation, 2009). The walls of the sacs then make the airways more mucus than usual, which then tends to clog the airway making it more difficult to breathe.


This essay has discussed what could occur when capillaries feeding into the heart and lungs, have an enlarged diameter. From this enlargement, the body could suffer from Angina, Dyspnoea, Pneumothorax, Cor Pulmonale, Asthma and Chronic Obstructive Pulmonary Disease. Within these conditions the body seems to have a common factor, a shortness of breath caused by insufficient airflow and oxygen to the heart muscle as well as the lungs. Respiration supplies the cells in the body with oxygen and rids the body of excess carbon dioxide. If our organs or organ systems fails to fulfil their own function or the ability to meet the adequate needs of our body the effects could be life changing or even cause death.


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