Biology Chapter 5: Section 7-Cardiovascular Disorders

If a small cranial arteriole bursts or is blocked by an embolus, this can lead to a(n) ______, which causes brain tissue to die.

stroke

The majority of arteries and veins transport blood to all the body systems and are therefore part of the______circuit.

systemic

An embolus that becomes completely stationary when it lodges in a small blood vessel is called a

thromboembolism

To lower the possibility of clot formation in a person who has shown symptoms of angina or stroke, ______ may be prescribed.

aspirin

What is an aneurysm?

ballooning of a blood vessel

A cerebrovascular accident (CVA)

A cerebrovascular accident (CVA), also called a stroke,often results when a small cranial arteriole bursts or is blocked by an embolus. Lack of oxygen causes a portion of the brain to die, and paralysis or death can result. A person is sometimes forewarned of a stroke by a feeling of numbness in the hands or the face, difficulty in speaking, or temporary blindness in one eye.

The surgical procedure in which a blood vessel (usually) from a patient's leg is used as a substitute for a heart patient's obstructed coronary artery(ies) is called a coronary ______operation.

bypass

A myocardial infarction (MI)

A myocardial infarction (MI), also called a heart attack, occurs when a portion of the heart muscle dies due to lack of oxygen. If a coronary artery becomes partially blocked, the individual may then suffer from angina pectoris. Characteristic symptoms of angina pectoris include a feeling of pressure, squeezing, or pain in the chest. Pressure and pain can extend to the left arm, neck, jaw, shoulder, or back. Nausea and vomiting, anxiety, dizziness, and shortness of breath may accompany the chest discomfort. Nitroglycerin or related drugs dilate blood vessels and help relieve the pain. When a coronary artery is completely blocked, perhaps because of a thromboembolism, a heart attack occurs.

A stent

A stent is a small metal mesh cylinder that holds a coronary artery open after a blockage has been cleared. When the balloon inside the stent is inflated, the stent expands, locking itself in place.

Heart Transplants

Although heart transplants are now generally successful, many more people are waiting for new hearts than there are organs available. Today, only about 2,300 heart transplants are done annually, though many thousands of people could use them. Genetically altered pigs may one day be used as a source of hearts because of the shortage of human hearts. Also, bone marrow stem cells have been injected into the heart. Once in the heart, these cells have been able to form new cardiac muscle tissue to replace tissue damaged by a heart attack.

Why use aspirin if you have angina or stroke symptoms?

Aspirin lowers the probability of clot formation. There is evidence that aspirin protects against first heart attacks, and it may have other health benefits when taken at low doses.

The formation of lesions called plaques on the inside walls of blood vessels is most characteristic of which disease?

Atherosclerosis

Atherosclerotic plaque

Atherosclerotic plaque is an irregular accumulation of cholesterol and fat. When fat is present in a coronary artery, a heart attack is more likely to occur because of restricted blood flow.

Atherosclerotic plaques

Atherosclerotic plaques can cause a clot to form on the irregular, roughened arterial wall. As long as the clot remains stationary, it is called a thrombus. If the thrombus dislodges and moves along with the blood, it is called an embolus.

Cardiovascular disease (CVD)

Cardiovascular disease (CVD) is the leading cause of early death in Western countries. In the United States, CVD is responsible for more than 33% of all deaths. Modern research efforts have resulted in improved diagnosis, treatment, and prevention.

The medical term for a stroke is

Cerebrovascular Accident (CVA)

Summarize the treatments available for cardiovascular disorders.

Common treatments include giving drugs to lower blood pressure, giving nitroglycerin at onset of heart attack, replacing diseased/damaged portion of the vessel, opening clogged arteries, stents, dissolving clots, and performing a heart transplant.

atherosclerosis

Condition in which fatty substances accumulate abnormally beneath the inner linings of the arteries. Atherosclerosis is caused by the formation of lesions, or atherosclerotic plaques, on the inside of blood vessels. The plaques narrow blood vessel diameter, choking off blood and oxygen supply to the tissues. In most instances, atherosclerosis begins in early adulthood and develops progressively through middle age, but symptoms may not appear until an individual is 50 or older. To prevent the onset and development of atherosclerosis, the American Heart Association and other organizations recommend a diet low in saturated fat and cholesterol but rich in omega-3 polyunsaturated fatty acids.

Which of the following involves attaching a blood vessel to the aorta and to the other side of a blockage to treat a clogged coronary artery?

Coronary bypass

When doctors are considering treating a person for hypertension, which blood pressure reading is more important?

Diastolic.

Hypertension

Elevated blood pressure, particularly the diastolic pressure.

Disorders of the Blood Vessels

Hypertension and atherosclerosis often lead to stroke or heart attack, due to an artery blocked by a blood clot or clogged by plaque. Treatment involves removing the blood clot or prying open the affected artery. Another possible outcome is a burst blood vessel, or aneurysm. An aneurysm can be prevented by replacing a blood vessel that is about to rupture with an artificial one.

List the cardiovascular disorders that are common in humans.

Hypertension, stroke, heart attack, aneurysm, heart failure.

What helps lower blood pressure?

If hypertension is present, prescription drugs can help lower blood pressure. Diuretics cause the kidneys to excrete more urine, ridding the body of excess fluid. In addition, hormones (the body's chemical messengers) that raise blood pressure can be inactivated. Drugs called beta blockers and ACE (angiotensin-converting enzyme) inhibitors help control hypertension caused by hormones.

vascular endothelial growth factor (VEGF)

Important for angiogenesis involved in tissue regeneration and repair

angioplasty

In the past, angioplasty involved inserting a plastic tube into an artery of an arm or a leg and then guiding it through a major blood vessel toward the heart. When the tube reached the region of plaque in an artery, a balloon attached to the end of the tube was inflated, forcing the vessel open. The procedure now uses the same procedure to deliver a stent to the blocked vessel

Discuss why CVD is the leading source of death in Western countries.

Mainly due to diet, lack of exercise, and lifestyle choices.

Prevention of Cardiovascular Disease

Many of us are predisposed to cardiovascular disease (CVD) due to factors beyond our control. Having a family history of heart attacks under age 55, being male, or being African American increases the risk. Other risk factors for CVD are related to our behavior. The Don'ts Smoking: When a person smokes, the drug nicotine, present in cigarette smoke, enters the bloodstream. Nicotine causes arterioles to constrict, including those that supply the heart itself. It also increases blood pressure, and the tendency of blood to clot. These factors may explain why about 20% of deaths from CVD are directly related to cigarette smoking. Drug Abuse: Stimulants, such as cocaine and amphetamines, can cause an irregular heartbeat and lead to heart attacks even when using the drugs for the first time. Obesity: People who are obese have more tissues that need to be supplied with blood. To meet this demand, the heart pumps blood out under greater pressure. Being overweight also increases the risk of type 2 diabetes, in which glucose damages blood vessels and makes them more prone to the development of plaque. The Do's Reduce Fat in Diet: Diet influences the amount of cholesterol in the blood. Cholesterol is ferried by two types of plasma proteins, called LDL (low-density lipoprotein) and HDL (high-density lipoprotein). LDL (the "bad" lipoprotein) takes cholesterol from the liver to the tissues, and HDL (the "good" lipoprotein) transports cholesterol out of the tissues to the liver. When the LDL level in blood is high or the HDL level is too low, plaque accumulates on arterial walls (Fig. 5.15). Eating foods high in saturated fat (red meat, cream, and butter) or trans fats (most margarines, commercially baked goods, and deep-fried foods) increases LDL cholesterol. Replacement of these harmful fats with monounsaturated fats (olive and canola oil) and polyunsaturated fats (corn, safflower, and soybean oil) is recommended. Most nutritionists also suggest eating at least five servings of antioxidant-rich fruits and vegetables a day to protect against cardiovascular disease. Antioxidants protect the body from free radicals that can damage blood vessels. The American Heart Association (AHA) recommends eating at least two servings of cold-water fish (e.g., halibut, sardines, tuna, and salmon) each week. These fish contain omega-3 polyunsaturated fatty acids that can reduce plaque. However, some studies suggest that farm-raised fish (such as tilapia) contain low levels of these beneficial fatty acids and may, in fact, be detrimental to heart health. Cholesterol Profile: Starting at age 20, all adults are advised to have their cholesterol levels tested at least every five years. Specific guidelines for cholesterol levels are no longer used. Instead, physicians now evaluate your cholesterol levels based on other risk factors for stroke or heart disease. However, as general guidelines, an LDL level above 160 mg/100 ml and an HDL level below 40 mg/100 ml are matters of concern. Resveratrol: The "French paradox" refers to the observation that levels of CVD are relatively low in France, despite the common consumption of a high-fat diet. One possible explanation is that wine is frequently consumed with meals. In addition to its alcohol content, red wine contains an antioxidant called resveratrol. This chemical is mainly produced in the skin of grapes, so it is also found in grape juice, and supplements are available at health food stores. Exercise: People who exercise are less apt to have cardiovascular disease. Exercise not only helps keep weight under control, but may also help minimize stress and reduce hypertension. And short bursts of exercise may be superior to longer sessions. In one study, as few as three 10-minute workout sessions a day reduced triglyceride levels in blood better than one 30-minute session. Anxiety and Stress: Mental stress can increase the odds of a heart attack. Within an hour of a strong earthquake that struck in 1994 near Los Angeles, 16 people died of sudden heart failure (compared to the average of about 4 per day). Over the next several days, the number of heart-related deaths declined, suggesting that emotional stress had triggered fatal complications in those who were already predisposed to them. Obviously, it is difficult to avoid earthquakes, but we can learn healthy ways to avoid and manage stress. Can Alcohol Benefit the Heart? Alcohol abuse can destroy just about every organ in the body, the heart included. Based on several large research studies, however, the AHA notes that people who consume one or two drinks per day have a 30% to 50% reduced risk of CVD compared to nondrinkers. Importantly, because of the potential downsides of alcohol consumption, the AHA does not recommend nondrinkers start using alcohol.

t-PA

Medical treatment for a thromboembolism includes the use of tissue plasminogen activator (t-PA), a biotechnology drug that converts plasminogen, a protein in blood, into plasmin, an enzyme that dissolves blood clots. Tissue plasminogen activator is also being used for stroke patients, but with less success. Some patients experience life-threatening bleeding in the brain. A better treatment might be new biotechnology drugs that act on the plasma membrane to prevent brain cells from releasing and/or receiving toxic chemicals caused by the stroke.

thromboembolism

Obstruction of a blood vessel by a thrombus that has dislodged from the site of its formation. A thromboembolism consists of a clot first carried in the bloodstream that then becomes completely stationary when it lodges in a small blood vessel. If a thromboembolism is not treated, life-threatening complications can result.

A ballooning of the wall of a blood vessel is called a(n)

aneurysm

Possible causes of atherosclerosis

Research has suggested several possible causes for atherosclerosis aside from hypertension. Chief among these are smoking and a diet rich in lipids and cholesterol. Research also indicates that a low-level bacterial or viral infection that spreads to the blood may cause an injury that starts the process of atherosclerosis. Surprisingly, such an infection may originate with gum diseases or be due to Helicobacter pylori. People who have high levels of C-reactive protein, which occurs in the blood following a cold or an injury, are more likely to have a heart attack.

aneurysm

Saclike expansion of a blood vessel wall. An aneurysm is a ballooning of a blood vessel, most often the abdominal artery or the arteries leading to the brain. Atherosclerosis and hypertension can weaken the wall of an artery to the point that an aneurysm develops. If a major vessel, such as the aorta, bursts, death is likely. It is possible to replace a damaged or diseased portion of a vessel, such as an artery, with a plastic tube. Cardiovascular function is preserved because exchange with tissue cells can still take place at the capillaries. Research is under way to use blood vessels made in the laboratory by injecting a patient's cells inside an inert mold or generating them using stem cells.

Are statins safe?

Statins are a class of drug that reduces blood cholesterol level by reducing the amount of cholesterol produced by the liver. In doing so, they reduce the risk of cardiovascular disease associated with elevated cholesterol levels. While there have been reports that statins may cause health problems, such as liver disease, diabetes, and muscle damage, the FDA has not found any evidence that these drugs elevate these risk factors in most people.

A partial blockage of a coronary artery can cause the feeling of pressure, squeezing, and pain in the chest, left arm, and shoulder. This condition is called

angina pectoris

A coronary bypass operation

Therapy for blocked coronary arteries in which part of a blood vessel from another part of the body is grafted around the obstructed artery. A surgeon takes a blood vessel—usually a vein from the leg—and stitches one end to the aorta and the other end to a coronary artery located past the point of obstruction.

Heart failure

When a person has heart failure, the heart no longer pumps as it should. Heart failure is a growing problem, because people who used to die from heart attacks now survive but are left with damaged hearts. Often the heart is oversized not because the cardiac wall is stronger but because it is sagging and swollen.

The major barrier to heart transplantation to treat people with heart failure in the U.S. is

a shortage of available donor organs.

Treatments for atherosclerotic plaque in coronary arteries

a. Improvements in surgery techniques can assist in coronary bypass operations. b. In this procedure, blood vessels (leg veins or arteries placed in the chest) are stitched to coronary arteries, bypassing the obstruction. c. In a stent procedure, a balloon-tipped catheter guides the stent (a cylinder of expandable metal mesh) to the obstructed area. When the balloon is inflated, the stent expands and opens the artery.

Treating clogged arteries

bypass surgery, stents, angioplasty. Now, bypass surgery can be assisted by using robotic technology. A video camera and instruments are inserted through small cuts, while the surgeon sits at a console and manipulates interchangeable grippers, cutters, and other tools attached to movable arms above the operating table. Looking through two eyepieces, the surgeon gets a three-dimensional view of the operating field. Robotic surgery is also used in valve repairs and other heart procedures.

The drug t-PA works as a treatment for thromboembolism because it

converts plasminogen into plasmin.

Angina pectoris is caused by decreased blood flow through what specific blood vessels?

coronary arteries

A clot that is moving through the bloodstream is called a(n)

embolus

A myocardial infarction is commonly called a

heart attack

One group of drugs used to treat hypertension are the diuretics, which mainly have what specific effect?

increase urine production

The medical term for a heart attack is

myocardial infarction (MI).

Atherosclerosis is the build up of fatty deposits in the arteries. These lesions are specifically called atherosclerotic______.

plaques