Unit 2 cardiovascular

• What are arteries responsible for?

  Carries oxygenated blood away from the heart at high pressure to the rest of the body.
• What are the characteristics of arteries?

  Thick muscular walls, narrow lumen and supporting connective tissue that provides strength.
• What are veins responsible for?

  Carries deoxygenated blood back to the heart at low pressure.
• What are the characteristics of veins?

  Thin walls and less muscular tissue and less connective tissue than arteries, wide lumen.
• What prevents the backflow of blood in veins?

  Veins contain valves to prevent the backflow of blood.
• What is vasodilation?

  When blood vessels dilate, increasing blood flow.
• What is vasoconstriction?

  When blood vessels constrict, limiting blood flow.
• What are capillaries?

  Capillaries connect the smallest branches of arteries and veins, they allow the exchange of molecules between the bloodstream and the bodys cells.
• What are the characteristics of capillaries?

  Capillaries are one cell thick to allow diffusion of molecules.
• What is the process of exchange of molecules?

  Oxygen diffuses through the capillary wall into the tissue fluid and then the cells.

  Carbon dioxide diffuses from the cells into the tissue fluid, then across the capillary walls into the blood plasma.

  Glucose diffuses from the blood plasma, across the capillary walls to the tissue fluid and then to the cells.

  The waste product urea diffuses from the cells of the liver to the tissue fluid and then across the capillary walls into the blood plasma.
• What does the right side of the heart do?

  Pumps deoxygenated blood to the lungs to be oxygenated.
• What does the left side of the heart do?

  Pumps oxygenated blood to the rest of the body.
• What does the atria (atrium for plural) of the heart do?

  Where blood collects when it enters the heart.
• What do the ventricles of the heart do?

  Pumps the blood out of the heart to the lungs or around the body.
• What does the septum of the heart do?

  Seperates the right side of the heart from the left side of the heart (seperates oxygenated and deoxygenated blood).
• Where is the tricuspid valve located in the heart and what is it responsible for?

  Located between the right atrium and right ventricle, opens up due to a build up of pressure in the right atrium.
• Where is the bicuspid valve located in the heart and what is it responsible for?

  Located between the left atrium and left ventricle, opens up due to a build up of pressure in the left atrium.
• What do the semilunar valves of the heart do?

  Stops the backflow of blood into the heart.
• Where are the semilunar valves of the heart located?

  One is located where the aorta leaves the left ventricle and another one is located where the pulmonary artery leaves the right ventricle.
• What does the aorta do?

  Largest artery in the body, carries oxygenated blood away from the ventricle to the body.
• What does the vena cava do?

  Largest vein in the body, carries deoxygenated blood from the body back to the heart.
• What does the pulmonary artery do?

  Carries deoxygenated blood away from the right ventricle to the lungs.
• What does the pulmonary vein do?

  Carries oxygenated blood from the lungs to the heart.
• What is cardiac output?

  The volume of blood pumped through each ventricle per minute.
• What is the cardiac output calculation?

  CO = SV x HR
• What is stroke volume?

  The volume of blood pumped out of each ventricle each time the heart beats.
• What does the term diastole mean?

  Relaxation of the heart.
• What does the term systole mean?

  Contraction of the heart.
• What are the 3 stages of the cardiac cycle?

  Atrial and ventricular diastole (chambers are relaxed and filling with blood).

  Atrial systole (atria contract and remaining blood is pushed into ventricles).

  Ventricular systole (ventricles contract and push blood out through the aorta and pulmonary artery).
• Where is the sino-atrial node (SAN) located and what does it do?


  Found in the top of the right atrium and it sets the rate at which the heart beats. It sends out electrical impulses which are carried through the muscular walls of both atria, these impulses causes atrial systole (contraction).
• Where is the atrioventricular node (AVN) located and what does it do?


  Located in the lower part of the right atrium, the impulse is passed from the SAN to the AVN, once the impulse reaches the AVN conducting fibres which travel down the central wall of the heart. The impulse then splits and travels up the left and right ventricles causing ventricular systole (contraction).
• What part of the brain regulates the rate of the sino-atrial node (SAN)?


  The medulla oblongata.
• What neurotransmitter does the sympathetic nervous system release and how does it affect heart rate?

  Noradrenaline is released, heart rate is increased.
• What neurotransmitter does the parasympathetic nervous system release and how does it affect heart rate?

  Acetylcholine is released, heart rate is decreased.
• What is used to measure blood pressure?

  Sphygmomanometer.
• What is hypertension?

  When blood pressure remains high even when resting >140/90mmHg.
• What is atherosclerosis?

  The build up of fatty material (cholesterol), this can result in an atheroma.
• What damage can an atheroma cause?

  The artery loses its elasticity.

  The blockage restricts blood flow due to the decreased diameter of the lumen.

  The restricted blood flow increases blood pressure.
• What is cardiovascular disease?

  A disease of the heart and blood vessels.

  Examples: angina, heart attacks (myocardial infarction), stokes, and peripheral vascular disease (PVD).
• What is a thrombosis?

  Formation of a blood clot.