Transport in Humans & Respiration Flashcards
What does the heart do?
It provides the pressure to pump blood through the circulatory system. This pressure is generated by the squeezing of the walls of the heart against the blood which is possible because these walls are made of muscle, and the muscle contracts rhythmically.
What is the left atrium?
It is the part of the left side of the heart that receives oxygenated blood returning from the lungs through the pulmonary vein.
What is the right atrium?
It is the part of the right side of the heart that receives deoxygenated blood from the vena cava returning from the tissues in the body.
What are the semi lunar valves?
They are the valves found in the pulmonary artery and aorta that prevent blood running back into the left and right ventricle when pressure falls during relaxation
What are the tricuspid valves?
They are the valves found between the right atrium and ventricle that prevent blood flowing back from the right ventricle to the right atrium during contraction, forcing the blood through the pulmonary artery.
What are the bicuspid valves?
They are the valves found between the left atrium and ventricle that prevent blood running back from the left ventricle to the left atrium during contraction, forcing the blood out through the aorta.
What is the aorta?
It is the main artery of the body. It carries oxygenated blood from the left ventricle out to the tissues. Blood pressure is at its highest in the aorta, and the strongest pulse is felt here.
What is the pulmonary artery?
It carries deoxygenated blood from the right ventricle to the lungs.
What is the pulmonary vein?
It returns oxygenated blood from the lungs to the left atrium. A vein from each lung join before entering the left atrium.
What is the vena cava?
It is the main vein of the body. It returns deoxygenated blood from the head and lower body to the right atrium.
What is the septum?
It is the wall between the left and right sides of the heart. This separates oxygenated and deoxygenated blood.
What special characteristic does the wall of the left ventricle have?
It is thick and muscular since it must force blood through the aorta and other arteries to all the tissues of the body.
Why isn’t the wall of the right ventricle as thick and muscular as the wall of the left ventricle?
Since it need only force blood along the pulmonary arteries to the lungs.
What are the atriums?
They receive blood at low pressure from the veins.
What are the ventricles?
They pump blood at high pressure out to the arteries.
What are the valves?
These pocket-like flaps make sure that the blood flows in the right direction.
What side of the heart deals with deoxygenated blood? Which deals with oxygenated blood?
The right side of the heart deals with deoxygenated blood whilst the left side deals with oxygenated blood.
Describe how blood flows through the right side of the heart.
- Blood travels through the vena cava
- Blood enters the right atrium
- The right atria contracts
- Blood travels through the tricuspid valve
- Blood enters the right ventricle
- The right ventricle contracts (the tricuspid valves close)
- Blood travels through the semilunar valves and into the pulmonary artery
- Blood travels to the lungs to collect O2 and deposit CO2
Describe how blood flows through the left side of the heart.
- Blood travels through the pulmonary veins
- Blood enters the left atrium
- The left atria contracts
- Blood travels through the bicuspid valve
- Blood enters the left ventricle
- The left ventricle contracts (the bicuspid valves close)
- Blood travels through the semilunar valves and into the aorta
- Blood travels to the body
What are arteries?
They always carry blood away from the heart to the tissues. Blood in the arteries is at high pressure, rich in oxygen and low in carbon dioxide (except in pulmonary artery).
What are some of the important characteristics of arteries?
- Thick outer wall withstands the high pressure of the blood
- Thick layer of rings of muscles (narrow or widen the artery and control the blood flow in it according to the body’s needs)
- Elastic fibers (expand and relax as blood is forced out the heart, help to squeeze blood through – causes the pulse you can feel if you press an artery against a bone a bone, e.g. in the wrist)
- Smooth lining (no obstruction to the flow of blood)
- Narrow central tube (lumen)
What are veins?
They always carry blood towards the heart. Blood in the veins is at low pressure, low in oxygen and high in carbon dioxide (except in pulmonary vein).
What are some of the important characteristics of veins?
- Thin walls reduce resistance to blood flow and allow skeletal muscles to squeeze the blood along
- Large diameter reduce resistance to the flow of blood and ensures transport of large volume of blood
- Valves prevent backflow of blood.
What are capillaries?
They link arteries and veins. They are present in all organs and tissues and are the site of exchange of materials between blood and tissue fluid (by diffusion): oxygen and nutrients diffuse into cells and CO2 and wastes diffuse into the blood from the cells. Very thin walls (one cell thick) allow for a short diffusion distance, speeding up the process. Networks or beds of capillaries extend through all the tissues, so every body cell is near to a capillary
What are arterioles?
They connect arteries to capillaries.
What are venules?
They connect capillaries to veins.
What are shunt vessels?
They provide an alternative pathway for the blood (e.g. shunt vessels in skin allow less heat to be lost by redirecting blood away from the skin surface)
What does the hepatic artery do?
It carries oxygenated blood to the liver.
What does the hepatic vein do?
It returns blood with a regulated, optimum concentration of food substances to the circulation.
What does the hepatic portal vein do?
It carries blood containing variable amounts of the absorbed products of digestion from the digestive system to the liver.
What does the renal artery do?
It carries oxygenated blood with a high concentration of urea to the kidneys.
What does the renal vein do?
It returns blood with reduced urea concentration to the circulation.