THE HEART LUNGS: Gas exchange http://www.sumanasinc.com/webcontent/animations/content/human_heart.html

Structure of the Heart

the external surface of the heart is covered with blood vessels – the coronary arteries and veins these provide food and oxygen for the muscle of the heart

there are 4 chambers inside the heart

there are 4 chambers inside the heart 2 atria (singular atrium)

RA LA there are 4 chambers inside the heart 2 atria (singular atrium)

RA LA there are 4 chambers inside the heart 2 atria (singular atrium) 2 ventricles

RA LA RV LV there are 4 chambers inside the heart 2 atria (singular atrium) 2 ventricles

RA LA valves RV LV there are also valves that ensure the blood flows in the correct direction

RA LA RV LV four blood vessels connect to the chambers of the heart

pulmonary vein RA LA RV LV four blood vessels connect to the chambers of the heart 2 veins carrying blood to the heart

vena cava pulmonary vein RA LA RV LV four blood vessels connect to the chambers of the heart 2 veins carrying blood to the heart

vena cava pulmonary vein RA LA RV LV four blood vessels connect to the chambers of the heart 2 veins carrying blood to the heart 2 arteries carrying blood from the heart

vena cava aorta pulmonary vein RA LA RV LV four blood vessels connect to the chambers of the heart 2 veins carrying blood to the heart 2 arteries carrying blood from the heart

vena cava pulmonary artery aorta pulmonary vein RA LA RV LV four blood vessels connect to the chambers of the heart 2 veins carrying blood to the heart 2 arteries carrying blood from the heart

RA LA RV LV if we just look at the left side of the heart as it beats..

pulmonary vein RA LA RV LV

pulmonary vein RA LA oxygenated blood from the lungs enters the left atrium via the pulmonary vein RV LV

pulmonary vein RA LA oxygenated blood from the lungs enters the left atrium via the pulmonary vein RV LV

pulmonary vein RA LA the left atrium contracts forcing blood through the valve into the left ventricle RV LV

pulmonary vein RA LA the left atrium contracts forcing blood through the valve into the left ventricle RV LV

pulmonary vein RA LA the left atrium contracts forcing blood through the valve into the left ventricle RV LV

pulmonary vein RA LA the left atrium contracts forcing blood through the valve into the left ventricle RV LV

pulmonary vein RA LA the left atrium contracts forcing blood through the valve into the left ventricle RV LV

aorta pulmonary vein RA LA the left ventricle contracts forcing blood out of the aorta to the body the valve stops the blood flowing back into the left atrium RV LV

aorta pulmonary vein RA LA the left ventricle contracts forcing blood out of the aorta to the body the valve stops the blood flowing back into the left atrium RV LV

aorta pulmonary vein RA LA the left ventricle contracts forcing blood out of the aorta to the body the valve stops the blood flowing back into the left atrium RV LV

aorta pulmonary vein RA LA the left ventricle contracts forcing blood out of the aorta to the body the valve stops the blood flowing back into the left atrium RV LV

aorta pulmonary vein RA LA the left ventricle contracts forcing blood out of the aorta to the body the valve stops the blood flowing back into the left atrium RV LV

RA LA RV LV

RA LA the left side of the heart receives oxygenated blood from the lungs and pumps it around the body RV LV

RA LA the right side of the heart receives deoxygenated blood from the body and pumps it to the lungs to be oxygenated RV LV

The heart is divided into right and left sides RIGHT SIDE of heart Receives and pumps DEOXYGENATED BLOOD LEFT SIDE of heart Receives and pumps OXYGENATED BLOOD 4 chambers ATRIA receive blood from VEINS VENTRICLES pump blood away from heart in ARTERIES

Blood Vessels The blood circulates around the body more than a thousand times a day Arteries Arterioles Capillaries Venules Veins

Blood Vessels: Arteries Carry blood Away from the heart Carry oxygenated blood – except for the pulmonary artery which is going to the lungs to be re-oxygenated Have thick, elastic walls to withstand high blood pressure The blood moves in pulses due to the pumping action of the heart

Arterioles Smallest arteries Made mostly of smooth muscle This means the diameter can vary, so blood can be diverted to where it is most needed.

Blood Vessels: Veins Carry blood back to the heart – gravity means this is not an easy job! Carry deoxygenated blood Have thin walls because the blood travels at low pressure Muscles around the veins contract to help move the blood back towards the heart Veins have one-way valves to stop blood flowing backwards

Veins & Valves

Artery vs. Vein Structure Thick muscular & elastic wall – gradually reduces the harsh surge of blood to a steadier flow Larger Lumen (space in middle) – less resistance to blood flow

Blood Vessels: Capillaries Join arteries to veins Very tiny blood vessels that reach all the cells of the body – thin permeable walls Capillaries provide cells with “food”, oxygen & water and remove wastes like carbon dioxide

Capillaries & transfer of materials