ARTERY

Artery

An artery is an elastic blood vessel that transports blood away from the heart. There are two main types of arteries: pulmonary arteries and systemic arteries.

Pulmonary arteries carry blood from the heart to the lungs where the blood picks up oxygen. The oxygen rich blood is then returned to the heart via the pulmonary veins. Systemic arteries deliver blood to the rest of the body. The aorta is the main systemic artery and the largest artery of the body. It originates from the heart and branches out into smaller arteries which supply blood to the head region (brachiocephalic artery), the heart itself (coronary arteries), and the lower regions of the body.

The smallest arteries are called arterioles and they play a vital role in microcirculation. Microcirculation deals with the circulation of blood from arterioles to capillaries to venules (the smallest veins). The liver, spleen and bone marrow contain vessel structures called sinusoids instead of capillaries. In these structures blood flows from arterioles to sinusoids to venules.

Structure of the Artery Wall

The artery wall consists of three layers:

·         Tunica Adventitia - the strong outer covering of arteries and veins. It is composed of connective tissue as well as collagen and elastic fibers. These fibers allow the arteries and veins to stretch to prevent overexpansion due to the pressure that is exerted on the walls by blood flow.

·         Tunica Media - the middle layer of the walls of arteries and veins. It is composed of smooth muscle and elastic fibers. This layer is thicker in arteries than in veins.

·         Tunica Intima - the inner layer of arteries and veins. In arteries this layer is composed of an elastic membrane lining and smooth endothelium (special type of epithelial tissue) that is covered by elastic tissues.

Aneurysm

An aneurysm is a bulge or "ballooning" in the wall of an artery. Arteries are blood vessels the carry oxygen-rich blood from the heart to other parts of the body. If an aneurysm grows large, it can burst and cause dangerous bleeding or even death.

Most aneurysms occur in the aorta, the main artery traveling from the heart through the chest and abdomen. Aneurysms also can happen in arteries in the brain, heart and other parts of the body. If an aneurysm in the brain bursts, it causes a stroke.

Aneurysms can develop and become large before causing any symptoms. Often doctors can stop aneurysms from bursting if they find and treat them early. Medicines and surgery are the two main treatments for aneurysms.

Syncope

Syncope is defined as a transient, self-limited loss of consciousness with an inability to maintain postural tone that is followed by spontaneous recovery. The term syncope excludes seizures, coma, shock, or other states of altered consciousness.

Syncope is a prevalent disorder, accounting for 1-3% of emergency department (ED) visits and as many as 6% of hospital admissions each year in the United States. As much as 50% of the population may experience a syncopal event during their lifetime. Although many etiologies for syncope are recognized, categorization into reflex (neurally mediated), orthostatic, and cardiac (cardiovascular) may be helpful during the initial evaluation. Cardiac syncope is associated with increased mortality, whereas noncardiac syncope is not. Syncope may result in significant morbidity due to falls or accidents that occur as a result. In the United States alone, an estimated $2 billion annually is spent on patients hospitalized with syncope.

Although most causes of syncope are benign, this symptom presages a life-threatening event in a small subset of patients. It is unclear whether hospital inpatient admission of asymptomatic patients after syncope affects outcomes. No current criterion standard exists for diagnosing undifferentiated syncope. Many physicians continue to admit patients because of perceived risk. Recent reviews of the 2001 American College of Emergency Physician (ACEP) clinical policy suggest that evidence-based criteria may decrease admission rates by nearly half by identifying cardiac causes of syncope. Inpatient admission should be reserved for patients in whom identification of specific immediate risk, such as those with structural heart disease or history of ventricular arrhythmia, is needed. Outpatient management can be used for patients who are low risk for a cardiac etiology in order to define a precise cause in order to effect mechanism-specific treatment.

Orthostatic Hypotension

Orthostatic hypotension is a sudden fall in blood pressure that occurs when a person assumes a standing position. It is due to a lesion of the baroreflex loop, which senses a change in blood pressure and adjusts heart rate and activates sympathetic nerve system fibers to cause the blood vessels to narrow and correct blood pressure. It may also be caused by hypovolemia (a decreased amount of blood in the body), resulting from the excessive use of diuretics, vasodilators, or other types of drugs, dehydration, or prolonged bed rest. The disorder may be associated with Addison's disease, diabetes, and certain neurological disorders including Multiple System Atrophy with Orthostatic Hypotension (formerly known as Shy-Drager syndrome), autonomic system neuropathies, and other dysautonomias. Symptoms, which generally occur after sudden standing, include dizziness, lightheadedness, blurred vision, and syncope (temporary loss of consciousness).

When orthostatic hypotension is caused by hypovolemia due to medications, the disorder may be reversed by adjusting the dosage or by discontinuing the medication. When the condition is caused by prolonged bed rest, improvement may occur by sitting up with increasing frequency each day. In some cases, physical counterpressure such as elastic hose or whole-body inflatable suits may be required. Dehydration is treated with salt and fluids.  More severe cases can be treated with drugs, such as midodrine, to raise blood pressure.

The prognosis for individuals with orthostatic hypotension depends on the underlying cause of the condition.

Varicose Veins

Varicose veins are enlarged veins that are swollen and raised above the surface of the skin. They can be dark purple or blue, and look twisted and bulging. Varicose veins are commonly found on the backs of the calves or on the inside of the leg. They develop when valves in the veins that allow blood to flow toward the heart stop working properly. As a result, blood pools in the veins and causes them to get larger.

Varicose veins affect 1 out of 2 people over age 50. They are more common in women than men. Hemorrhoids are a type of varicose vein. Spider veins are like varicose veins, but they are smaller.

Exercising, losing weight, elevating your legs when resting and not crossing them when sitting can help keep varicose veins from getting worse. Wearing loose clothing and avoiding long periods of standing can also help. If varicose veins are painful or you don't like the way they look, your doctor may recommend procedures to remove them.

Stroke

Also called: Brain attack, CVA 

A stroke is a medical emergency. Strokes happen when blood flow to your brain stops. Within minutes, brain cells begin to die. There are two kinds of stroke. The more common kind, called ischemic stroke, is caused by a blood clot that blocks or plugs a blood vessel in the brain. The other kind, called hemorrhagic stroke, is caused by a blood vessel that breaks and bleeds into the brain. "Mini-strokes" or transient ischemic attacks (TIAs), occur when the blood supply to the brain is briefly interrupted.

Symptoms of stroke are

• Sudden numbness or weakness of the face, arm or leg (especially on one side of the body)
• Sudden confusion, trouble speaking or understanding speech
• Sudden trouble seeing in one or both eyes
• Sudden trouble walking, dizziness, loss of balance or coordination
• Sudden severe headache with no known cause

If you have any of these symptoms, you must get to a hospital quickly to begin treatment. Acute stroke therapies try to stop a stroke while it is happening by quickly dissolving the blood clot or by stopping the bleeding. Post-stroke rehabilitation helps individuals overcome disabilities that result from stroke damage. Drug therapy with blood thinners is the most common treatment for stroke.