Heart and Blood Vessels Flashcards
Explain how the lungs are adapted for gaseous
exchange.
Capillaries cover 70% of the outside of alveoli, providing a large surface area for gases to diffuse across.
The walls of blood capillaries are one cell thick
Explain the role of the heart in a double circulatory
system.
The heart pumps blood through two circuits:
-the pulmonary circulation
-the systemic circulation
What is the pulmonary circulation?
The pulmonary circulation transports blood to the lungs. At the lungs:
-oxygen diffuses into the blood from the alveoli - the blood
becomes oxygenated
-carbon dioxide diffuses from the blood into the lungs
What is the systemic circulation
It transports:
-oxygen and nutrients to the body
-carbon dioxide and other wastes away from cells
Identify the three different types of blood vessel
present in the body.
Artery, Vein, Capillary
Identify the main blood vessels
associated with the heart.
From left to right:
Pulmonary artery, Vena cava, Pulmonary Vein, Aorta
Explain how the structure of arteries relates to their function
Arteries carry oxygenated blood away from the heart. They have a thick layer of muscles and elastic fibres. A type of supporting tissue called connective tissue provides strength. It has a small lumen. Arteries carry blood under high pressure.
Explain how the structure of veins relates to their function
Veins carry deoxygenated blood to the heart. They have a thin layer of muscle and elastic fibres. Veins carry blood under low or negative pressure. They have a wide lumen.
Explain how the structure of capillaries relates to their function
As blood enters the capillaries, the pressure falls. Capillaries have one cell thick walls and are permeable; this means that diffusion can occur. Oxygen and glucose diffuse in the cell for respiration. There are networks of capillaries to provide a large surface area.
