GCSE Biology: The Circulatory System, the Heart, and Cardiovascular Disease

Comprehensive practice flashcards covering the anatomy of the heart, components and functions of the blood, blood vessel structures and adaptations, mathematical calculation of blood flow rate, and the causes, treatments, and evaluations of cardiovascular diseases.

What are the four chambers of the human heart, and how are they arranged?

The heart has two small upper chambers called atria (right atrium and left atrium) and two lower muscular chambers called ventricles (right ventricle and left ventricle).

Which heart valves are located on the right side of the heart, and which are on the left side?

The tricuspid valve and pulmonary valve are on the right side; the mitral valve and aortic valve are on the left side.

What is the difference in function between the superior vena cava and the inferior vena cava?

The superior vena cava delivers deoxygenated blood to the heart from the superior parts of the body (head, neck, arms, chest), whereas the inferior vena cava delivers deoxygenated blood from the inferior parts (abdomen, legs, feet).

How do the pulmonary artery and the pulmonary vein differ in blood oxygenation and direction of transport?

The pulmonary artery carries deoxygenated blood away from the heart to the lungs, while the pulmonary vein carries oxygenated blood from the lungs into the left atrium of the heart.

What are two structural adaptations of red blood cells that assist in their function?

They lack a nucleus to allow more space for hemoglobin and oxygen, and they have a biconcave disc shape to provide a large surface area for absorbing and releasing oxygen rapidly.

What three actions do white blood cells perform to defend the body against pathogens?

They engulf and consume microorganisms via phagocytosis, produce antibodies that bind to and help destroy pathogens, and produce antitoxins that neutralize toxins released by pathogens.

What are platelets, and what is their role in the circulatory system?

Platelets are small fragments of cells without nuclei that trigger blood clotting at wounds, acting like glue to prevent excessive blood loss and stop microorganisms from entering the body.

What is blood plasma, and what substances does it transport?

Plasma is a pale straw-colored liquid making up just over half of blood volume; it carries blood cells, platelets, nutrients (glucose, amino acids), waste products (carbon dioxide, urea), hormones, proteins, antibodies, and antitoxins.

What is artificial blood, and what is its major limitation compared to a donor blood transfusion?

Artificial blood is a salt water blood substitute that adds volume to keep vessels full and the heart pumping, but it contains no red blood cells to transport oxygen, meaning it can only replace up to one-third of a patient's blood.

Why is the human circulatory system described as a double circulatory system?

It consists of two separate circuits where blood passes through the heart twice: the pulmonary circuit pumps blood to the lungs and back to collect oxygen, and the systemic circuit pumps oxygenated blood around body tissues and back.

Why does the left ventricle have a thicker muscular wall than the right ventricle?

The left ventricle must generate greater force to pump blood around the entire body, whereas the right ventricle only pumps blood a short distance to the lungs.

What is the primary drawback of a single circulatory system, such as that found in fish?

Blood loses significant pressure as it passes through the gills, causing it to travel to the organs relatively slowly and limiting the rate of oxygen delivery to cells.

Where is the natural pacemaker of the heart located, and how can its malfunction be treated?

The natural pacemaker is a group of cells located in the right atrium that controls resting heart rate; if it malfunctions, doctors can implant an artificial pacemaker, which is an electrical device that corrects heart rate irregularities.

What structural adaptations allow arteries to withstand and sustain high blood pressure?

Arteries have thick muscular walls to withstand high blood pressure, and thick layers of elastic fibers that stretch during heart contractions and recoil between surges to keep blood flowing.

How are capillaries adapted for rapid exchange of substances with body tissues?

Their walls are permeable and only one cell thick, creating a very short diffusion pathway; additionally, their large total cross-sectional area lowers blood pressure and slows flow, giving time for substance exchange.

What structural features enable veins to return blood to the heart under low pressure?

Veins have large lumens with relatively thin walls to minimize resistance, and they contain valves that open in the direction of blood flow and shut if blood begins flowing backwards.

If $2560\,\text{ml}$ of blood passes through the aorta in $8\,\text{minutes}$, what is the rate of blood flow in milliliters per minute?

The rate of blood flow is $320\,\text{ml/minute}$, calculated by dividing $2560\,\text{ml}$ by $8\,\text{minutes}$.

What are two risks associated with donor blood transfusions?

The patient's immune system may reject the transfused blood if it is not the matching blood type, and there is a potential risk of transmitting blood-borne infections.

What causes coronary heart disease, and what is its physiological consequence?

Layers of fatty material build up inside the coronary arteries, narrowing the lumen and reducing blood flow; this starves the heart muscle of oxygen and glucose, potentially causing a heart attack.

How do statins work to manage cardiovascular disease, and what is a potential disadvantage?

Statins decrease bad LDL cholesterol and increase good HDL cholesterol in the blood to slow fatty deposit formation, but they require continuous long-term use and can cause side effects like headaches or liver and kidney issues.

What is a stent, and what are its advantages and disadvantages?

A stent is an expandable tube inserted into a coronary artery to hold it open and restore blood flow; it works effectively for a long time, but surgery carries risks of infection, heart attack, or local blood clot formation (thrombosis), and it does not treat the underlying cause.

What are the trade-offs between mechanical and biological replacement heart valves?

Mechanical valves are made of metal and can last a lifetime, but they require anti-clotting medication; biological valves (from pigs, cattle, or humans) do not require anti-clotting drugs, but they wear out faster and may need replacement.

What is an advantage of an artificial heart compared to a donor heart, and what are its main limitations?

Artificial hearts are made of plastic and metal so the patient's immune system will not reject them; however, they significantly increase the risk of blood clotting and serve only as a temporary fix while awaiting a donor transplant.

What lifestyle factors increase the risk of developing coronary heart disease?

High blood pressure, smoking, drinking excessive alcohol, and a diet high in saturated fats that leads to elevated cholesterol levels.