When people talk about “plaque buildup,” they are often referring to atherosclerosis, the hardening and narrowing of arteries. This process involves the slow accumulation of material within the walls of the vessels that carry oxygen-rich blood from the heart to the rest of the body. Atherosclerosis develops silently, slowly transforming the interior structure of blood vessels. Arterial plaque is fundamentally different from other common types of buildup, such as the kind found on teeth.
The Physical Composition of Arterial Plaque
Arterial plaque is not merely a simple deposit of fat but a complex, hardened mixture that forms within the artery wall itself. The primary components of this mass include low-density lipoprotein (LDL) cholesterol, fatty substances, and cellular waste products. This debris is trapped within the arterial wall, where it triggers a chronic inflammatory response.
Immune cells, specifically macrophages, are recruited to the site to engulf the oxidized LDL particles, transforming into what are known as foam cells. The accumulation of these lipid-laden foam cells is a hallmark of the initial stages of plaque formation. As the process continues, the plaque mass incorporates other materials like fibrin, collagen, and elastin, which are part of the body’s attempt to repair and contain the damage.
Over time, calcium deposits accumulate within the plaque, leading to a process called calcification, which makes the entire structure rigid and hard. This hardening is why the condition is sometimes referred to as “hardening of the arteries”. The final composition is a dense, fibrous tissue capsule covering a core of lipids and cellular remnants.
The Appearance of Plaque Within the Artery Walls
The visual progression of atherosclerosis inside the artery is a slow transformation that begins with subtle changes. The earliest visible signs are known as fatty streaks, which appear as yellowish, minimally raised lesions on the inner lining of the artery. These streaks are essentially the initial clusters of foam cells accumulating just beneath the endothelial surface.
As the condition progresses, the lesion develops into a more advanced structure called a fibrous plaque. This mass is pale, firm, and significantly raised, pushing into the open space of the vessel. The advanced plaque features a soft, lipid-rich core—often described as a gruel-like or waxy substance—that is sealed off from the bloodstream by a protective layer called the fibrous cap.
Plaques are classified based on the thickness of the fibrous cap. A stable plaque has a thick, collagen-rich cap that maintains a smooth barrier between the core and the blood flow. In contrast, a vulnerable plaque (thin-cap fibroatheroma) has a fragile, thin cap that is prone to rupture. Rupture exposes the highly thrombogenic lipid core to the blood, leading to the rapid formation of a blood clot.
How Plaque Buildup Affects the Body
While the plaque grows internally, it often remains silent for decades because the arteries compensate by slightly enlarging at the site of the lesion. Symptoms only begin to appear when the plaque significantly narrows the artery or when a rupture occurs, severely impeding blood flow. The resulting symptoms depend entirely on which arteries are affected and how much oxygen delivery is restricted.
When the coronary arteries supplying the heart muscle are narrowed, individuals may experience angina, which is chest pain or discomfort often triggered by physical activity or stress. Blockage in these vessels can also lead to symptoms like shortness of breath, extreme weakness, or heart palpitations. If a plaque ruptures here and a clot forms, it can entirely block the artery, leading to a heart attack.
Atherosclerosis in the carotid arteries, which supply the brain, may lead to symptoms like sudden weakness, blurry vision, or difficulty speaking, often presenting as a transient ischemic attack (TIA) or stroke. When the arteries in the limbs, especially the legs, are affected, the resulting condition is called peripheral artery disease. This often manifests as claudication, which is pain, aching, or cramping in the legs that occurs during walking but fades with rest.
A Look at Dental Plaque
Dental plaque is a separate form of buildup that occurs in the mouth, having no connection to atherosclerosis. This material is a sticky biofilm, an organized community of microorganisms that adheres to the surfaces of teeth. It is primarily composed of bacteria, food particles, and an extracellular matrix made of polysaccharides and proteins.
Dental plaque typically appears as a colorless, pale yellow, or whitish deposit on the teeth, particularly along the gum line. If left undisturbed, this layer can eventually harden into dental calculus, also known as tartar. Unlike the complex mixture found inside arteries, dental plaque is directly related to oral health issues like cavities and gum disease.