The Circulatory System
Lesson 8, Page 10 of 12

The risk factors for stroke include all of the above.

Symptoms of Stroke

A stroke may be mildly incapacitating or may involve a sudden coma, followed by headache, nausea, confusion, and stupor. The symptoms of a stroke are sudden weakness or numbness of the face or limbs on one side of the body (hemiplegia); loss of speech or comprehension; dimness or loss of vision, particularly in one eye; and unexplained dizziness, unsteadiness, or sudden falls. Some strokes are preceded by transient ischemic attacks (TIAs), with similar effects that may last anywhere from one minute to several hours. Initially, the paralyzed muscles of a stroke victim are soft because of central nervous system shock, but spasticity occurs as spinal motor neurons resume function, tightening muscles and causing the limbs to contract.

Types of Strokes


A stroke can be caused by ischemia, which is a narrowing or blockage of an artery by means of atherosclerosis or by an embolus. About 63% of strokes are ischemic. Atherosclerosis, or progressive hardening of the arteries, produces ischemia by obstruction of vessels with fatty deposits.

Another form of ischemia is thrombosis, or blockage resulting from an embolus. An embolus produced by the carotid artery in the neck, which supplies blood from the heart to the brain, claims about one-third of stroke patients. A clot, or thrombus, can form in this artery and break off, producing a thromboembolus, which travels to the brain and becomes entrapped in a cerebral artery.


About 22% of all strokes are caused by cerebral hemorrhage or bleeding in the brain. The most common causes of spontaneous intracranial hemorrhage, commonly called apoplexy, are hypertension and aneurysm.

Heart Failure

Heart Failure is a condition in which the heart fails to maintain an adequate output, resulting in diminished blood flow and congestion in the circulation in the lungs and/or the body. The causes of heart failure are high blood pressure and heart disease. To properly manage heart failure the underlying heart disease must be treated. Common medical treatments include rest, restriction of salt intake, and drug treatment with digitalis which may improve the contractibility of the heart muscle and promote diuresis, or removal of fluid, to relieve tissue swelling.

The drug Digitalis is a powerful stimulant of heart muscle contractions. Digitalis is frequently prescribed for the treatment of congestive heart failure despite potentially serious side effects. The drug is a combination of ingredients derived from the foxglove plant, including digitoxin, the most active component. Foxglove was first brewed by American Indians to treat dropsy, fluid in the legs caused by heart problems (e.g., heart failure). This practice occurred for hundreds of years before it was discovered that foxglove contained the active ingredients now known as digitalis.

What herb was brewed by American Indians to treat dropsy (edema due to heart problems)?

Ginkgo biloba
Licorice root

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