Coronary Heart Disease and Medical Interventions

Coronary arteries supply vital oxygen to heart muscle tissue. When these vessels become blocked by fatty deposits (atherosclerosis), it can lead to serious complications requiring medical intervention.

Example: Two main surgical approaches for treating blocked coronary arteries:

• Stent placement: A mesh tube inserted to hold open narrowed arteries
• Bypass surgery: Creating alternative routes for blood flow using blood vessels from other body parts

The CABG procedure (Coronary Artery Bypass Graft) involves taking healthy blood vessels from elsewhere in the body to create a bypass around blocked coronary arteries. While this is a major operation, bypass surgery survival rates are generally good, especially in younger patients.

Vocabulary: Life expectancy after bypass surgery varies but most patients experience significant improvement in quality of life and reduced risk of heart attacks.

Heart Valves and Pacemakers

The heart contains natural valves that ensure one-way blood flow through its chambers. When these valves fail, they can be replaced with either mechanical or biological alternatives.

Mechanical valves, made from titanium and polymers, offer excellent durability but require lifelong anticoagulation medication. Biological valves from animal sources provide more natural function without medication requirements but have shorter lifespans.

Definition: A natural pacemaker (sinoatrial node) controls heart rhythm by generating electrical impulses at about 70 beats per minute.

When the natural pacemaker malfunctions, an artificial pacemaker can be implanted. Modern devices are sophisticated, adjusting heart rate based on activity levels and only activating when needed.

Blood Vessel Structure and Function

Arteries, veins and capillaries each have unique structural adaptations that enable their specific roles in circulation. Understanding these differences is crucial for comprehending circulatory system function.

Highlight: Key differences between arteries and veins include wall thickness, presence of valves, and blood pressure levels.

The structure of veins includes:

• Wide lumens for low-pressure blood flow
• Valves to prevent backflow
• Thinner walls compared to arteries
• Large carrying capacity

Capillary function involves:

• Allowing substance exchange between blood and tissues
• Providing short diffusion distances
• Maintaining consistent blood flow to cells
• Supporting metabolic processes

Cardiovascular Health and Disease Prevention

Understanding cardiovascular health requires knowledge of how lifestyle choices affect our circulatory system. Blood vessels gcse biology curriculum emphasizes how poor dietary choices, particularly those high in bad cholesterol, can lead to blocked arteries and increased blood pressure.

The relationship between lifestyle and cardiovascular health is complex. Smoking directly damages arterial walls, while regular exercise helps lower blood pressure and reduces strain on the heart. Type 2 diabetes, often linked to obesity, affects the body's metabolism by releasing fat molecules into the blood, which interferes with cellular sugar uptake.

Highlight: Prevention strategies include maintaining a healthy diet, regular exercise, avoiding smoking, and limiting alcohol consumption to protect both cardiovascular and overall health.

Other significant health impacts include liver and brain function effects from alcohol consumption. Excessive alcohol leads to fatty liver disease and potential liver failure, while also damaging brain nerve cells. During pregnancy, both smoking and alcohol can severely impact fetal development, highlighting the importance of maternal health choices.