Chapter 6 Textbook Notes

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Chapter 6: Aging of the Internal Organ System
Cardiovascular System
nutrients, hormones, oxygen, and antibodies to tissues in the body while at the same time removing
waste products such as carbon dioxide and hydrogen ions.
¾ The system is composed of the heart, blood vessels (arteries, arterioles, capillaries, veins, and venules),
and blood.
¾ In general, arteries carry blood away from the heart, and veins carry blood to the heart.
¾ Blood is highly complex fluid composed of water, red, and white blood cells, and platelets, as well as
nutrients such as fat globules, carbohydrates, and proteins.
¾ Blood also carries electrolytes, to help maintain the acid/base balance, and a host of other chemicals.
¾ The heart is the center of the circulatory system. It is located behind the chest wall, in slightly canted
position, with the midsection somewhat to the left of the sternum, or breastbone. It is enclosed in a
fibrous sac called the pericardium. The left and right sides of the heart each have two upper chambers
(atria), which collect the blood, and two lower chambers which pump the blood to the lungs and the
rest of the body.
¾ The blood from the aorta flows into the large arteries and then to the smaller arteries, arterioles, and
¾ The capillaries are very small, and ensure that all cells in the body have access to the bloodstream.
¾ Veins serve as a huge reservoir for the ERG\VEORRGVXSSO\
¾ Most people are familiar with the pulse of the carotid artery on the neck and the radial pulse on the
outer edge of the wrist. The pulse can be felt in other parts of the body as well, such as the top of the
foot (pedal pulse) and the back of the knee (popliteal pulse).
¾ To help keep blood moving up to the heart and to prevent it from pooling in extremities, some veins
have valves.
¾ These valves consist of tissue inside the vein wall that extends into the vein (like a flapper valve)
forcing the blood to flow in only one direction, toward the heart.
¾ The rate of blood flow is largely determined by physical demands on the body.
¾ The heart alters its rate of pumping depending on both external and internal demands.
¾ As well as delivering blood and nutrients to all tissues of the body, the cardiovascular system serves as
the conduit for communication among the organs.
¾ The health of the cardiovascular system, greatly affects the health of every other organ in the body.
¾ The first arteries to leave the aorta go to the heart muscle, ensuring that the heart has the most oxygen-
rich blood.
Age-Related Changes
¾ There are a few normal changes in the cardiovascular system with age.
¾ Some studies report enlargement of the heart due to increase in size of the muscle cells or myocytes.
¾ By age 75 only about 10% of pacemaker cells found in young people remain.
¾ There is an increase in the amount of fat tissue around the sinoatrial node, which interferes with the
conduction system (leads to bradycardia). This condition is often treated by giving the person an
artificial pacemaker that keeps the heart from falling below a preset rate.
¾ Changes in the collagen in the middle layer of the large arteries of the body cause them to thicken and
become stiff.
¾ Over time, the larger size and rigidity of these large arteries require the heart to work harder,
eventually increasing blood pressure.
¾ Overall, heart function is less efficient with age.
¾ There is a decrease in cardiovascular responsiveness to exercise and a reduction in the maximum heart
rate that can be reached.
¾ Cardiovascular disease is very much common in later life and results in the majority of disability and
deaths among older people.
¾ Optimal blood pressure for adults over the age of 18 is 120/80 or lower (the first number refers to the
systolic and the second to the diastolic).
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¾ Blood pressure is still considered normal at a reading of 130/85, but at 140/90 or greater, it is classified
as hypertension.
¾ Systolic hypertension increases throughout life, whereas an elevation in diastolic pressure tends to
level off in later years.
¾ High blood pressure affects all the major arteries of the body and organs and tissues that they serve.
¾ One of the dangers of hypertension is that the damage of the disease occurs without symptoms.
¾ Hypertension has a number of causes, including changes in kidney function, obesity, hormonal
changes, increased sensitivity to sodium, and genetic propensities.
¾ The first step in managing hypertension is to encourage lifestyle changes such as weight control, a
decrease in sodium intake, high calcium and magnesium intake and an increase in physical activity.
¾ Although they should be used cautiously, diuretics are the first drug of choice to control hypertension.
Arteriosclerosis and Atherosclerosis
¾ Arteriosclerosis refers to the thickening and loss of elasticity of arterial walls. Stiffened arteries tend to
be slightly contracted, raising blood pressure and leading to hypertension, which can create further
damage to the walls.
¾ Thus, high blood pressure both results from and is a cause of arteriosclerosis.
¾ The disease usually starts with an injury to the inner lining of an artery, which can be caused by
trauma, toxins, or viruses.
¾ Plaques are sticky; eventually they attract more dead cells, blood clots, and bacteria, further narrowing
the artery and creating an inflammatory process.
likely to adhere to the arterial walls.
¾ The first visible sign of atherosclerosis is a fatty streak on the inner wall of the artery.
¾ The growth of this plaque into the middle layer of the artery causes it to stiffen and weaken. With time,
the artery becomes narrower and less elastic, reducing the flow of blood to vital areas of the body
including the brain, heart, and legs.
¾ Blood clots and hemorrhaging can occur in these damages blood vessels.
¾ Risk factors for both arteriosclerosis and atherosclerosis include bring male, having a family history of
the disease, smoking, a diet high in saturated fat, diabetes, hypertension, obesity, and leading a
sedentary lifestyle.
¾ Atherosclerosis process may begin at a young age, but the incidents increase with age.
¾ The primary treatment for atherosclerosis includes a decrease in dietary cholesterol and exercise, as
well as lipid-lowering medications such as the statins.
Peripheral Vascular Disease
¾ Atherosclerosis can also damage peripheral blood vessels.
¾ In peripheral arterial disease (PAOD), arteries that carry blood to the legs and feet are partially or
completely blocked by atherosclerosis, resulting in a decrease in the supply of oxygen and nutrients to
these areas.
¾ Symptoms of PAOD include pain, a pale or bluish colour to the skin of the feet and legs, and a lack of
hair growth in these areas.
¾ Lack of blood flow causes severe leg pain when walking or exercising.
¾ Anything that slows the flow of blood to the legs exacerbates PAOD. This includes smoking, diabetes,
and physical activity.
¾ One of the primary ways of treating peripheral vascular disease is to encourage exercise. The person
with PAOD is encouraged to walk until limited by pain and to rest until pain diminishes. This
improves blood circulation to the area and increases muscle strength.
¾ The most important treatment for PAOD is to stop smoking.
Coronary Heart Disease
¾ Coronary heart disease (CHD) results from atherosclerosis of the coronary arteries of the heart.
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¾ Risk factors for coronary artery disease include smoking, high blood pressure, high cholesterol, being
overweight, and having an inactive lifestyle. Abdominal and chest fat are especially dangerous risk
factors for the disease.
¾ Angina pectoris is a common symptom of coronary heart disease.
¾ It develops when the demand for blood to the heart muscle is greater than what can be supplied.
¾ It can be a temporary, although painful, condition that resolves when the person is resting or relaxed.
¾ Angina pectoris is one of the symptoms of an impending heart attack, especially among older people.
¾ Generally, angina is felt as pain that radiates to the left shoulder and down the left arm or to the jaw or
¾ Treatment may also include nitroglycerin or other pharmaceuticals, carefully monitored.
¾ Coronary heart disease can lead to a myocardial infarction (MI) of hear attack. This occurs when an
artery in the heart is blocked because of blood clot.
¾ Among older people MI can be silent or occur while sleeping or at rest.
¾ The initial goal for caring for someone with an MI is to reduce further heart damage and the risk of
heart failure.
¾ Treatment includes the administration of medications to thin the blood and control the rhythm of the
¾ Changes in health behaviour habits such as quitting smoking, improving diet and beginning an exercise
program are the keys to successful post-MI rehabilitation.
¾ One of the most popular therapies to reduce reoccurrences of MIs is to take a low dose of aspirin daily
or even weekly to reduce blood clotting.
Heart Failure
¾ One definition of heart failure is the cessation of a heartbeat, with death imminent.
¾ Another use of the term heart failure describes a heart that is no longer able to pump blood to meet the
PHWDEROLFQHHGVRIWKHERG\s tissues (this is the type used here).
¾ In heart failure, the left ventricle is less able to pump blood out through the aorta and into the arteries
of the body, so the supply of oxygen and nutrition to the body tissues are reduced.
¾ Overt symptoms of heart failure include shortness of breath, fatigue, confusion, and lethargy.
¾ About 10% of those over the age of 80 have some degree of heart failure.
¾ A number of factors can exacerbate heart failure, including anything that causes fluid retention, such as
a diet high in sodium and the use of estrogens.
¾ Treatment of heart failure includes smoking cessation, change in diet, and exercise, as well as
medications (antihypertensives ad diuretics) to reduce the edema or swelling caused by fluid intake.
Promoting Optimal Aging
¾ Folic acid may be particularly important in preventing cardiovascular disease.
¾ We are beginning to recognize that cardiovascular disease is an inflammatory process, and antioxidants
such as vitamin E may also be helpful.
¾ Exercise decreases weight, lowers cholesterol, strengthens heart muscles, etc.
¾ Alleviating stress is also important.
Respiratory System
¾ The primary function of the respiratory system is to transfer oxygen from the air into the bloodstream
and to remove carbon dioxide.
¾ The breathing process is highly complex and involves not only the respiratory tract but also the
muscles of the abdomen, chest and diaphragm.
¾ Air travels from the nasal cavities into the naspharynx, the trachea, and the bronchi.
¾ The respiratory system processes the air before it enters the bloodstream, warms and moisturizes the
air in the nose and trachea, and guards the body against invasion of germs, viruses, and other toxins.
germs and viruses.
¾ Total lung capacity consists of the vital capacity and the residual volume.
Age-Related Changes
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