IGCSE Biology - Circulation and Gas Exchange

A collection of flashcards based on key topics related to Circulation and Gas Exchange in IGCSE Biology.

What structures make up the thorax in human anatomy?

The thorax includes the ribs, intercostal muscles, diaphragm, trachea, bronchi, bronchioles, alveoli, and pleural membranes.

How do intercostal muscles and diaphragm contribute to ventilation?

Intercostal muscles lift the ribcage, and the diaphragm contracts to change its shape, allowing air to move in and out of the lungs.

What is the primary role of alveoli in the lungs?

Alveoli are adapted for gas exchange by allowing oxygen to diffuse into the blood and carbon dioxide to diffuse out.

List two biological consequences of smoking on the respiratory and circulatory systems.

Smoking increases the risk of lung cancer and coronary heart disease.

What is the composition of blood?

Blood is made up of red blood cells, white blood cells, platelets, and plasma.

What is the role of plasma in the blood?

Plasma transports carbon dioxide, digested food, urea, hormones, and heat energy.

Describe how red blood cells are adapted for oxygen transport.

Red blood cells have a biconcave shape, lack a nucleus, and contain hemoglobin for efficient oxygen transport.

How does the immune system use white blood cells to fight pathogens?

White blood cells, like phagocytes, ingest pathogens, while lymphocytes release antibodies specific to pathogens.

What happens during the process of vaccination?

Vaccination triggers the manufacture of memory cells that enable quicker and stronger antibody production in response to future infections.

Describe the function of platelets in blood clotting.

Platelets help prevent blood loss and the entry of microorganisms by forming a clot at the site of an injury.

What are the key structural differences between arteries, veins, and capillaries?

Arteries have thick, muscular walls; veins have thinner walls and valves; capillaries are thin-walled for efficient gas exchange.

How does exercise affect heart rate?

During exercise, heart rate increases to supply more oxygen to muscles and remove carbon dioxide efficiently.

What is the significance of the coronary circulation?

Coronary circulation provides oxygenated blood to the heart muscle and removes waste products.

What are the major components of the cardiac cycle?

The cardiac cycle consists of systole (contraction) and diastole (relaxation) of the heart chambers.

How does adrenaline affect heart rate during stress?

Adrenaline increases heart rate and the force of cardiac contractions, preparing the body for 'fight or flight' response.

Explain how gas exchange occurs in the alveoli.

Gas exchange in the alveoli occurs through diffusion, where oxygen enters the blood and carbon dioxide leaves the blood.