9 1 circulatory systems heart and blood vessels

The circulatory system is a system of blood vessels with a pump and valves.

The circulatory system needs valves to ensure one-way flow of blood.

True. Fish have a single circulatory system.

Differences between single and double circulation include:

Mammals benefit from having double circulation because double circulation allows the heart to pump blood around the body at high pressure, so it supplies oxygen and glucose to the cells more quickly

The structures are:

Deoxygenated blood from the body passes through the heart and to the lungs as follows:

Valves in the heart prevent the backflow of blood, ensuring that blood flows in only one direction through the heart chambers and vessels.

Oxygenated blood returns to the heart from the lungs via the pulmonary vein.

The coronary arteries supply the cardiac muscle of the heart with oxygenated blood, ensuring it receives a constant supply of oxygen and glucose for aerobic respiration to release energy for muscle contraction.

False. Deoxygenated blood enters the right side of the heart from the body, via the vena cava.

The pulmonary vein is the only vein to carry oxygenated blood, returning blood to the heart after gas exchange has taken place.

True. Arteries carry blood away from the heart while veins carry blood into the heart.

The activity of the heart can be monitored as follows:

True. During physical activity the heart rate increases.

The effect of exercise on heart rate can be investigated by: This can be repeated several times at the same level of exercise, and could be extended by taking part in exercise at different intensity levels.

In an investigation into the effect of exercise on heart rate, the dependent variable is heart rate, e.g. in beats per minute

Variables that would need to be controlled when investigating the effect of exercise intensity on heart rate include:

Coronary heart disease (CHD) occurs when the coronary arteries narrow due to build-up of fatty deposits; this reduces the flow of blood through the coronary arteries of the heart.

Risk factors for CHD include:

A good diet can reduce blood cholesterol, reduce blood pressure and aid weight loss; these can all reduce the risk of CHD.

True. Exercise can reduce the risk of CHD because it lowers blood pressure and reduces stress.

The valves labelled X and Y are:

The left ventricle has a thicker muscle wall so that it can pump oxygenated blood at high pressure throughout the body, while the right ventricle pumps deoxygenated blood at lower pressure to the lungs.

False. The atria have thinner walls than the ventricles. This is because they only need to pump blood the short distance to the ventricles, so they do not need to generate high pressures.

The septum separates the left and right sides of the heart, preventing oxygenated and deoxygenated blood from mixing.

True. The muscular contractions of the atrial walls force blood downwards into the ventricles.

The heart valves enable forward flow of blood while preventing backflow as follows:

During exercise the heart rate increases because:

Arteries carry blood away from the heart.

The blood vessel in the diagram is an artery because:

Veins carry blood at low pressure towards the heart.

The blood vessel is a vein because:

The key feature of veins that is not visible in the diagram is the presence of valves.

The function of capillaries is to transport oxygenated blood from the arteries to the cells, and deoxygenated blood from the cells to the veins. In doing so they supply the cells with oxygen and nutrients, and remove waste products from the cells.

The blood vessels are:

The blood vessel that carries deoxygenated blood to the lungs from the heart is the pulmonary artery.

False. The pulmonary vein carries oxygenated blood to the heart from the lungs.

False. The renal vein carries deoxygenated blood away from the kidneys.

Arteries are adapted for their function as follows:

Veins are adapted to their function as follows:

Capillary adaptations shown include: Note that while capillaries also have gaps between the cells in their walls to increase permeability, this feature cannot be seen in this image.

Blood vessels A-C are:

The main components of blood are:

Structures X and Y are:

The function of red blood cells is to transport oxygen (via haemoglobin) to tissues and organs.

White blood cells are involved in the immune response; they carry out:

False. Platelets are involved in the blood clotting process. Red blood cells transport oxygen.

Substances transported in the plasma include:

Blood clotting is important because it:

Blood cell types A-C are:

False. Lymphocytes produce antibodies. *Phagocytes *engulf and destroy pathogens.

The function of phagocytes is to engulf and destroy pathogens during phagocytosis.

False. Soluble fibrinogen proteins are converted to insoluble fibrin proteins during the blood clotting process.

Fibrin forms an insoluble mesh across the wound, trapping red blood cells to form a clot, which eventually dries to become a scab.