Heart And Circulatory System Flashcards
(31 cards)
What is the heart and its function?
The heart is a muscular organ that pumps blood through the circulatory system, keeping blood moving around the body. Its contractions generate pressure to push blood into arteries, delivering oxygen and nutrients to tissues and removing wastes.
Name the chambers of the heart.
The heart has four chambers: two upper atria (left atrium and right atrium) and two lower ventricles (left ventricle and right ventricle). The atria receive blood entering the heart, and the ventricles pump blood out of the heart.
Why are the walls of ventricles thicker than those of atria?
The ventricles have thicker muscular walls than atria because they pump blood out of the heart at higher pressure, whereas atria only pump blood a short distance into the ventricles.
Why is the left ventricle wall thicker than the right ventricle wall?
The left ventricle pumps blood to the entire body (systemic circulation) and must generate high pressure, so its wall is very thick and muscular. The right ventricle pumps blood a shorter distance to the lungs (pulmonary circulation) at lower pressure, so its wall is thinner.
What is the septum and what is its function?
The septum is the muscular wall separating the left and right sides of the heart. It prevents oxygenated blood on the left side from mixing with deoxygenated blood on the right side.
What are heart valves and why are they important?
Valves are flaps of tissue in the heart that ensure one-way flow of blood. They prevent backflow: when the atria contract, the atrioventricular valves (tricuspid on the right, bicuspid/mitral on the left) open to let blood into ventricles, then close as ventricles contract to stop blood from flowing back into atria. Similarly, the semilunar valves in the arteries (pulmonary artery and aorta) open when ventricles contract to let blood out, then snap shut to prevent blood from leaking back into the heart.
What are the coronary arteries?
Coronary arteries are the blood vessels that supply the heart muscle itself with oxygenated blood. They branch off from the aorta and spread over the heart’s surface.
What is a double circulatory system?
It is a circulatory system in which blood passes through the heart twice per complete circuit of the body. Mammals (including humans) have a double circulation: one circuit sends blood from the heart to the lungs and back (pulmonary circulation), and another sends blood from the heart to the rest of the body and back (systemic circulation).
Pulmonary vs. systemic circulation – what’s the difference?
The pulmonary circulation is the loop from the heart to the lungs and back. The right side of the heart pumps deoxygenated blood to the lungs via the pulmonary artery; blood picks up oxygen in the lungs and returns to the left side of the heart via the pulmonary vein. The systemic circulation is the loop from the heart to all other body tissues and back.
Advantages of double circulation?
Mammals’ double circulatory system is highly efficient. Blood can be pumped to the lungs at a lower pressure, protecting the delicate lung capillaries, but returned to the heart and boosted to a high pressure for the body. This means oxygenated blood reaches tissues more quickly and with greater pressure than in a single circulation system.
Major blood vessels in the human circulatory system?
The pulmonary artery carries deoxygenated blood from the right ventricle to the lungs, and the pulmonary vein carries oxygenated blood from the lungs back to the left atrium. The aorta is the main artery carrying oxygen-rich blood from the left ventricle out to all body organs.
Arteries – structure and function?
Arteries carry blood away from the heart at high pressure. They typically carry oxygenated blood (except the pulmonary artery, which carries deoxygenated blood to the lungs). Key features of arteries: they have thick, muscular, elastic walls and a narrow lumen.
Veins – structure and function?
Veins carry blood toward the heart at low pressure. They usually carry deoxygenated blood (except the pulmonary vein, which carries oxygenated blood from the lungs). Key features of veins: they have thinner walls and a wider lumen than arteries.
Capillaries – structure and function?
Capillaries are the tiniest blood vessels that connect arteries to veins throughout the tissues. They facilitate exchange of materials between the blood and body cells. Capillary walls are only one cell thick, and they have an extremely narrow lumen.
What is blood composed of?
Blood is a tissue consisting of four main components: red blood cells, white blood cells, platelets, and plasma.
What is coronary heart disease (CHD)?
Coronary heart disease is a condition in which the coronary arteries become narrowed or blocked by a buildup of fatty deposits on their walls. This reduces or blocks blood flow to parts of the heart muscle.
Why does a blockage of coronary arteries cause a heart attack?
If a coronary artery is narrowed by fatty plaque, blood flow to the heart muscle is reduced. A complete blockage cuts off blood supply to an area of the heart. Without oxygen, that part of the heart muscle cannot respire aerobically and muscle cells die.
Risk factors for CHD?
Several factors increase the risk of developing coronary heart disease. These include poor diet (high in saturated fat and cholesterol) and smoking.
What factors increase the risk of developing coronary heart disease (CHD)?
Several factors increase the risk of CHD, including poor diet, smoking, lack of exercise and obesity, stress, genetic predisposition, and age and gender.
How does a poor diet contribute to CHD?
A diet high in saturated fats and cholesterol can lead to fatty deposits in arteries, narrowing them and increasing the likelihood of blockage.
What role does smoking play in the risk of CHD?
Smoking damages blood vessels, contributes to artery narrowing, and accelerates plaque buildup, significantly increasing CHD risk.
How does lack of exercise affect the risk of CHD?
Inactivity can lead to obesity, high blood pressure, and poor lipid profiles, all of which strain the heart and increase CHD risk.
What is the connection between stress and CHD?
Long-term stress can raise blood pressure and stress hormones, damaging artery walls and speeding up plaque formation.
How does genetic predisposition influence CHD risk?
A family history of CHD can indicate genetic factors that predispose individuals to high cholesterol or high blood pressure.
