Heart Revision Notes

The heart is divided into left and right sides by a muscular septum.

Each side contains an atrium (upper chamber) and a ventricle (lower chamber).

• Septum separates the heart into two sides.
• Atria receive blood returning to the heart.
• Ventricles pump blood out of the heart.

The muscular wall contracts to pump blood through the heart and body.

One-way valves prevent blood from flowing backward, ensuring unidirectional flow.

• Muscular wall generates force for blood circulation.
• Valves ensure blood flows in the correct direction.
• Coronary arteries supply oxygenated blood to the heart muscle.

Coronary arteries provide the heart muscle with its own blood supply, essential for its function.

They ensure the heart receives oxygen and nutrients to maintain its activity.

• Coronary arteries are vital for heart health.
• They prevent heart muscle fatigue by supplying oxygen.
• Blockage can lead to heart problems.

Arteries are blood vessels that carry blood away from the heart.

They usually transport oxygen-rich blood to the body's tissues.

• Arteries deliver oxygen and nutrients to tissues.
• Pulmonary artery carries oxygen-poor blood to the lungs.
• High pressure in arteries aids in efficient transport.

Veins are blood vessels that return blood to the heart.

They usually carry oxygen-poor blood from the body's tissues.

• Veins collect blood from tissues and return it to the heart.
• Pulmonary vein carries oxygen-rich blood from the lungs.
• Valves in veins prevent backflow of blood.

Continuous blood circulation is vital for delivering oxygen and nutrients and removing waste products.

It supports cell survival and overall body function.

• Ensures efficient transport of oxygen and nutrients.
• Removes waste products from tissues.
• Maintains homeostasis and supports metabolism.

An ECG records the electrical signals that control the heartbeat.

It provides detailed information about the heart's rhythm and electrical activity.

• Shows the rhythm and strength of heartbeats.
• Detects irregular heart rhythms or electrical issues.
• Non-invasive method to assess heart function.

Pulse rate measures the number of heartbeats per minute.

It indicates how fast the heart is beating and can reflect heart health.

• Counts heartbeats per minute.
• Simple method to assess heart rate.
• Can indicate stress or heart conditions.

Heart sounds are produced by the closing of heart valves during the heartbeat cycle.

Using a stethoscope, these sounds can be heard to assess valve function.

• 'Lub-dub' sounds indicate valve closure.
• Stethoscope is used to listen to heart sounds.
• Abnormal sounds can suggest valve problems.

Physical activity causes muscles to work harder, increasing their need for oxygen and nutrients. To meet this demand, the heart rate rises, pumping more blood per minute.

The heart rate increase during exercise is regulated by the nervous system and hormones, which respond to the level of activity.

• Muscles require more oxygen during exercise.
• Heart rate increases to supply more oxygenated blood.
• Nervous system and hormones regulate heart rate changes.

Heart rate can be measured before, during, and after exercise to observe changes.

Using a heart rate monitor or counting pulses are common methods to measure heart rate.

• Measure resting heart rate before exercise.
• Record heart rate immediately after exercise.
• Repeat measurements to ensure reliability.

The nervous system and hormones play a crucial role in adjusting heart rate during physical activity.

Signals from the brain and hormones like adrenaline increase heart rate to meet the body's demands.

• Nervous system signals adjust heart rate.
• Hormones like adrenaline increase heart rate.
• Regulation ensures efficient oxygen delivery during exercise.

Coronary heart disease occurs when the coronary arteries, which supply oxygen-rich blood to the heart muscle, become blocked or narrowed. This blockage is mainly caused by the build-up of fatty deposits (atherosclerosis) inside the artery walls. As the arteries narrow, less blood reaches the heart muscle, which can cause chest pain (angina) or heart attacks if blood flow is severely reduced.

• Coronary arteries supply blood to the heart muscle.
• Fatty deposits build up inside artery walls, causing blockages.
• Blocked arteries reduce oxygen supply to the heart muscle.
• Reduced oxygen can cause chest pain or heart attacks.

Several factors increase the likelihood of developing coronary heart disease. These include lifestyle choices and biological characteristics. A diet high in fats can lead to fatty deposits in arteries. Lack of exercise weakens heart health. Stress raises blood pressure and damages arteries. Smoking harms artery walls and promotes blockages. Genetic factors inherited from parents can predispose individuals to the disease. Older age increases risk as fatty deposits accumulate over time. Males generally have a higher risk than females due to hormonal differences.

• Poor diet high in fats contributes to fatty deposits.
• Lack of exercise reduces heart strength.
• Stress increases blood pressure and artery damage.
• Smoking damages arteries and promotes blockages.
• Genetic factors can increase susceptibility.
• Older age raises risk due to gradual artery blockage.
• Males are at higher risk than females.

Understanding these risk factors helps in preventing coronary heart disease. Maintaining a healthy diet low in saturated fats, engaging in regular physical activity, managing stress, and avoiding smoking can reduce risk. Awareness of family history and regular health checks are important, especially as age increases. Early intervention can prevent artery blockage and protect heart health.

• Healthy diet and exercise reduce risk.
• Stress management protects arteries.
• Avoiding smoking prevents artery damage.
• Know family history and monitor health regularly.
• Early action can prevent disease progression.

A diet low in saturated fats and cholesterol helps reduce fatty deposits in arteries, lowering the risk of coronary heart disease.

Fruits, vegetables, and whole grains provide essential nutrients and fiber that support heart health.

• Low saturated fat diet reduces artery blockage.
• Fruits and vegetables provide heart-protective nutrients.
• Whole grains offer fiber that lowers cholesterol.

Regular exercise strengthens the heart muscle, improves blood circulation, and helps maintain a healthy weight.

Exercise lowers blood pressure and increases levels of good cholesterol (HDL), which removes bad cholesterol (LDL) from the bloodstream.

• Exercise strengthens the heart and improves circulation.
• It helps lower blood pressure and maintain healthy weight.
• Increases HDL cholesterol, reducing LDL cholesterol.

Combining a healthy diet with regular exercise significantly reduces the risk factors for coronary heart disease.

These lifestyle changes manage cholesterol levels, blood pressure, and body weight, contributing to overall heart health.

• Diet and exercise together lower heart disease risk.
• Manage cholesterol, blood pressure, and weight.
• Support overall cardiovascular health.

Atrioventricular (AV) valves are located between the atria and ventricles, controlling blood flow from atria to ventricles.

The right AV valve is the tricuspid valve, and the left AV valve is the bicuspid or mitral valve.

• Right AV valve: tricuspid valve.
• Left AV valve: bicuspid (mitral) valve.
• Control blood flow from atria to ventricles.

Semilunar valves are located at the bases of the large arteries leaving the heart, controlling blood flow out of the heart.

The pulmonary semilunar valve is at the base of the pulmonary artery, and the aortic semilunar valve is at the base of the aorta.

• Pulmonary valve at pulmonary artery base.
• Aortic valve at aorta base.
• Control blood flow out of the heart.

Heart valves ensure one-way blood flow through the heart chambers, preventing backflow.

Recognizing valve positions in diagrams helps understand heart function and blood circulation.

• Valves prevent backflow and ensure one-way flow.
• Recognizing valve positions aids understanding of heart function.
• Valves open and close in response to pressure changes.

The left ventricle has the thickest muscle wall because it pumps blood to the entire body, requiring more force.

The right ventricle has a thinner wall as it only pumps blood to the lungs, which requires less force.

• Left ventricle: thickest muscle wall.
• Right ventricle: thinner wall than left ventricle.
• Thickness relates to the force needed to pump blood.

Atria have thinner muscle walls than ventricles because they only receive blood and push it into the ventricles.

Ventricles need thicker walls to pump blood out of the heart, requiring more force.

• Atria: thinner muscle walls.
• Ventricles: thicker muscle walls.
• Ventricles pump blood out, needing more force.

The thickness of muscle walls in heart chambers reflects the different pressures needed for blood circulation.

Thicker walls generate higher pressure to pump blood further, ensuring efficient circulation.

• Thickness reflects pressure needed for circulation.
• Thicker walls generate higher pressure.
• Ensures efficient blood circulation.

The septum is a muscular wall that divides the heart into left and right sides, preventing mixing of oxygenated and deoxygenated blood.

This separation is crucial for efficient circulation, ensuring oxygen-rich blood is delivered to the body and oxygen-poor blood is sent to the lungs.

• Septum divides heart into left and right sides.
• Prevents mixing of oxygenated and deoxygenated blood.
• Ensures efficient circulation and oxygen delivery.

Keeping oxygenated and deoxygenated blood separate allows the heart to pump blood effectively to the lungs and body.

Without the septum, mixing of blood types would reduce oxygen delivery efficiency, impairing body function.

• Separation allows effective blood pumping.
• Prevents mixing, maintaining oxygen delivery efficiency.
• Essential for proper body function.

The septum's role in separating blood types is vital for maintaining high oxygen levels in blood delivered to body tissues.

This separation supports the heart's ability to pump blood efficiently, ensuring proper circulation.

• Maintains high oxygen levels in blood.
• Supports efficient heart pumping.
• Ensures proper circulation and body function.

The heart contains four chambers: two atria and two ventricles. The pumping action begins with the contraction of the atrial muscles, which pushes blood into the ventricles. Following this, the ventricular muscles contract, pumping blood out of the heart to the lungs and the rest of the body. This coordinated sequence ensures efficient filling and emptying of the heart chambers.

• Atrial muscles contract first to push blood into ventricles.
• Ventricular muscles contract next to pump blood out of the heart.

Valves are located between the atria and ventricles (atrioventricular valves) and at the exits of the ventricles (semilunar valves). These valves open and close in response to pressure changes during the heart cycle. When atria contract, atrioventricular valves open to allow blood flow into ventricles. When ventricles contract, these valves close to prevent blood flowing back into the atria. Semilunar valves open during ventricular contraction to allow blood to leave the heart and close when ventricles relax to prevent backflow from arteries.

• Atrioventricular valves open during atrial contraction and close during ventricular contraction.
• Semilunar valves open during ventricular contraction and close when ventricles relax.
• Valves ensure blood flows in one direction through the heart.

The opening and closing of valves prevent blood from flowing backwards, maintaining efficient circulation. This one-way flow is essential for the heart to function effectively as a pump, ensuring oxygenated and deoxygenated blood move correctly through the circulatory system.

• Valves prevent backflow of blood.
• One-way flow maintains efficient circulation.
• Valve operation is synchronized with muscle contractions.

When a person exercises or performs physical activity, their muscles work harder and require more oxygen and nutrients to produce energy. This increased demand triggers physiological responses to meet the needs of active muscles.

• Muscles need more oxygen and glucose during activity.
• Energy production increases in muscle cells.

To supply the increased demand, the heart beats faster, raising the heart rate. This faster heartbeat pumps more blood, carrying oxygen and nutrients, to the muscles more quickly.

• Heart rate increases during physical activity.
• Increased blood flow delivers more oxygen and nutrients to muscles.

Once physical activity stops, the muscles' demand for oxygen decreases. Consequently, the heart rate gradually slows down, returning to its normal resting level.

• Heart rate decreases after activity ends.
• Resting heart rate is restored over time.