heart bio Flashcards
Describe the structure of the heart and its main chambers.
The heart has four chambers:
Right atrium: Receives deoxygenated blood from the body through the superior and inferior vena cava.
Right ventricle: Pumps deoxygenated blood to the lungs through the pulmonary artery.
Left atrium: Receives oxygenated blood from the lungs via the pulmonary veins.
Left ventricle: Pumps oxygenated blood to the rest of the body through the aorta.
The heart also has valves to ensure the unidirectional flow of blood, such as the tricuspid, bicuspid (mitral), and semilunar valves.
What is the difference between the pulmonary circulation and systemic circulation?
Answer:
Pulmonary circulation: Carries deoxygenated blood from the right ventricle to the lungs for oxygenation and then returns oxygenated blood to the left atrium.
Systemic circulation: Transports oxygenated blood from the left ventricle to the body and returns deoxygenated blood to the right atrium.
Explain the role of heart valves.
Heart valves (tricuspid, bicuspid, and semilunar valves) ensure that blood flows in only one direction through the heart. They prevent backflow of blood when the ventricles contract and ensure efficient circulation. For example, the bicuspid valve prevents blood from flowing back into the left atrium when the left ventricle contracts.
Describe the sequence of events in the cardiac cycle.
Atrial systole: The atria contract, pushing blood into the ventricles.
Ventricular systole: The ventricles contract, pushing blood through the pulmonary artery to the lungs (right ventricle) and through the aorta to the body (left ventricle).
Diastole: The heart relaxes, and the chambers fill with blood as the atria and ventricles expand.
How is the heart rate controlled?
The heart rate is controlled by the pacemaker (sinoatrial node, or SA node) located in the right atrium. This node sends electrical signals that trigger the heart to contract. The medulla in the brain also regulates heart rate based on factors such as physical activity and stress. The autonomic nervous system, via the sympathetic and parasympathetic nerves, can increase or decrease the heart rate.
What is the role of coronary arteries?
The coronary arteries supply oxygenated blood to the heart muscle (myocardium). If these arteries become blocked (due to plaque buildup), it can lead to a heart attack (myocardial infarction) because the heart muscle is deprived of oxygen.
How is oxygen transported in the blood?
Oxygen is primarily transported in red blood cells bound to hemoglobin. In the lungs, oxygen binds to hemoglobin to form oxyhemoglobin, which is carried to tissues. In tissues, oxygen is released from hemoglobin and diffuses into cells for respiration.
Explain how the heart functions as a double pump.
The heart functions as a double pump because it has two circuits:
The right side pumps deoxygenated blood to the lungs for oxygenation (pulmonary circulation).
The left side pumps oxygenated blood to the rest of the body (systemic circulation). Both sides work simultaneously to ensure efficient circulation.
How does exercise affect heart rate?
During exercise, the body’s demand for oxygen increases. The medulla detects this and sends signals to the pacemaker (SA node) to increase the heart rate. This allows the heart to pump more blood, delivering oxygen and nutrients to muscles. After exercise, the heart rate gradually returns to resting levels.
What is the role of the atria in the heart?
The atria are the upper chambers of the heart. The right atrium receives deoxygenated blood from the body through the vena cava and pumps it into the right ventricle. The left atrium receives oxygenated blood from the lungs via the pulmonary veins and pumps it into the left ventricle.
How does the vena cava function in the circulatory system?
The vena cava is the large vein that carries deoxygenated blood from the body back to the right atrium of the heart. It consists of the superior vena cava (carrying blood from the upper body) and the inferior vena cava (carrying blood from the lower body).
Describe the role of the ventricles in the heart.
The ventricles are the lower chambers of the heart. The right ventricle pumps deoxygenated blood through the pulmonary artery to the lungs for oxygenation. The left ventricle pumps oxygenated blood through the aorta to the rest of the body, supplying organs and tissues with oxygen and nutrients.
What is the function of the aorta in the circulatory system?
The aorta is the largest artery in the body and carries oxygenated blood from the left ventricle to the body. It branches into smaller arteries that deliver oxygenated blood to all parts of the body.
What is the role of the pulmonary artery and pulmonary vein in blood circulation?
The pulmonary artery carries deoxygenated blood from the right ventricle to the lungs for oxygenation.
The pulmonary vein carries oxygenated blood from the lungs to the left atrium of the heart.
What is a stent, and how does it help people with heart conditions?
A stent is a small mesh tube that is inserted into a narrowed or blocked artery. It helps to keep the artery open, allowing blood to flow more freely, which is particularly helpful in treating coronary artery disease.
