Circulatory SystemCirculatory System

Circulatory SystemCirculatory System

• The circulatory system is made up of two chains of The circulatory system is made up of two chains of vesselsvessels• Lymphatic circulationLymphatic circulation• Drains interstitial fluid (in which cells of tissues are immersed)Drains interstitial fluid (in which cells of tissues are immersed)

• A liquid called A liquid called lymph lymph circulates through the vessels and circulates through the vessels and transports interstitial fluid, and moves without the help of any transports interstitial fluid, and moves without the help of any organorgan

• Blood circulationBlood circulation• Is responsible for transporting nutrients, oxygen, and waste. Is responsible for transporting nutrients, oxygen, and waste.

• The liquid, blood, circulates through the blood vessels, which The liquid, blood, circulates through the blood vessels, which are called are called arteries, veins, and capillaries arteries, veins, and capillaries

• The movement of blood is driven by the heartThe movement of blood is driven by the heart

BloodBlood

• Blood is the liquid that circulates through the blood Blood is the liquid that circulates through the blood vesselsvessels• Made up of a liquid part called Made up of a liquid part called plasma, plasma, as well as:as well as:• Red blood cells – Red blood cells – Most abundant. They are in charge of Most abundant. They are in charge of

transporting oxygen molecules combined with the hemoglobin transporting oxygen molecules combined with the hemoglobin molecules they have insidemolecules they have inside

• White blood cells White blood cells – These cells belong to the immune system – These cells belong to the immune system and use the blood circulation because blood vessels reach every and use the blood circulation because blood vessels reach every part of the body and it is fastpart of the body and it is fast

• Platelets - Platelets - Cellular fragments produced in the bone marrow. Cellular fragments produced in the bone marrow. Their purpose is to contribute to the formation of clots which Their purpose is to contribute to the formation of clots which cover woundscover wounds

Blood VesselsBlood Vessels

• Three types of blood vesselsThree types of blood vessels• Veins – Veins – These transport blood from the organs and parts of These transport blood from the organs and parts of

the body to the heartthe body to the heart

• Arteries – Arteries – These transport blood from the heart to the These transport blood from the heart to the organs and parts of the bodyorgans and parts of the body

• Capillaries - Capillaries - The arteries divide into The arteries divide into arterioles arterioles as the as the blood vessel branches offblood vessel branches off• Capillaries are the exchanging areas between the blood and the Capillaries are the exchanging areas between the blood and the

tissuestissues

• The capillaries begin to join together again in venules which The capillaries begin to join together again in venules which join others and return to the heartjoin others and return to the heart

HeartHeart

• The heart is a muscle divided into four chambers, two on the The heart is a muscle divided into four chambers, two on the left, two on the right, joined verticallyleft, two on the right, joined vertically• The upper chambers are called The upper chambers are called atria atria ((singular: singular: atriumatrium) ) and and and and

the lower chambers called the lower chambers called ventricles. ventricles. • The right atrium is connected to the right ventricle through the The right atrium is connected to the right ventricle through the

tricuspid valve. tricuspid valve. The left atrium is connected to the left ventricle The left atrium is connected to the left ventricle through the through the mitral valvemitral valve

• Pericardium – Pericardium – The membrane that covers external surface The membrane that covers external surface of the heart and protects itof the heart and protects it

• The heart has two basic movements:The heart has two basic movements:• Contraction Contraction (systole)(systole)• Relaxation Relaxation (diastole)(diastole)

HeartHeart

Cardiac CycleCardiac Cycle

• Both atria contract to finish filling their corresponding Both atria contract to finish filling their corresponding ventriclesventricles• This movement is called This movement is called atrial systoleatrial systole

• The ventricles contract and push blood through the main The ventricles contract and push blood through the main vessels leading from the heart (called vessels leading from the heart (called ventricular systole)ventricular systole)• These are the These are the aorta artery, aorta artery, which starts the circuit of taking which starts the circuit of taking

blood to the body, and blood to the body, and pulmonary artery, pulmonary artery, which transports which transports blood to the lungs to take oxygen and release carbon blood to the lungs to take oxygen and release carbon

• All the cardiac muscle relaxes and all four cavities fill with All the cardiac muscle relaxes and all four cavities fill with blood again (called blood again (called general diastolegeneral diastole))• To prevent the blood that has just left the heart from returning, To prevent the blood that has just left the heart from returning,

the aorta and the pulmonary artery have semilunar valvesthe aorta and the pulmonary artery have semilunar valves

Blood CirculationBlood Circulation

• Pulmonary circulation Pulmonary circulation • Blood returns from the tissues of the entire body through the Blood returns from the tissues of the entire body through the

two main veins, the two main veins, the superior vena cavasuperior vena cava and the and the inferior inferior vena cava. vena cava.

• The blood goes to the right atrium and then the right The blood goes to the right atrium and then the right ventricle, and from there, goes out the pulmonary artery to ventricle, and from there, goes out the pulmonary artery to exchanges gases (Carbon dioxide to oxygen)exchanges gases (Carbon dioxide to oxygen)• Once oxygenated, the blood returns to the heart through the Once oxygenated, the blood returns to the heart through the

pulmonary vein, which takes blood to the left atriumpulmonary vein, which takes blood to the left atrium

Blood CirculationBlood Circulation

• Systemic circulationSystemic circulation• The blood in the left atrium goes to the left ventricle during The blood in the left atrium goes to the left ventricle during

atrial systole, and then gets distributed throughout the body atrial systole, and then gets distributed throughout the body through ventricular systole through ventricular systole

• Exchange of substances in the tissuesExchange of substances in the tissues• The capillaries are the little branches that reach the tissuesThe capillaries are the little branches that reach the tissues• The blood plasma leaves the capillaries and mixes with the The blood plasma leaves the capillaries and mixes with the

interstitial liquid. interstitial liquid. • Then the cells take the oxygen and nutrients contained in the Then the cells take the oxygen and nutrients contained in the

plasmaplasma• The capillaries take back the liquid exiting the tissues and The capillaries take back the liquid exiting the tissues and

join the venules, and return to the heartjoin the venules, and return to the heart