The Circulatory System
The Circulatory System
Functions of the Circulatory System Transports nutrients and oxygen to body cells Transports waste products away from body cells Fights infection
Blood Flow through the BODY HEART LUNGS HEART CELLS
STRUCTURE of the Circulatory System HEART (pump) BLOOD (fluid) BLOOD VESSELS (pipes)
HEART pump composed of cardiac muscle tissue Contains four chambers that separate O2-rich blood from O2-poor blood (left atrium, right atrium, left ventricle, right ventricle)
The Heart
The Heart
Blood Plasma Red Blood Cells White Blood Cells Platelets Liquid portion of the blood 92% H2O Makes up 54.3% of blood volume Red Blood Cells Contain hemoglobin; Carry O2 Produced in bone marrow Live about 4 months No nuclei; 45% of blood vol. White Blood Cells Immune system cells Help fight infection and disease Move from blood to tissues–form pus Produced in bone marrow Help repair injured blood vessels Produce clots (scabs); stop bleeding Platelets
Blood
Blood is RED. Oxygen-rich blood is bright red. Oxygen-poor blood is dark red.
FACTOIDS: A tiny drop of blood contains approx. 5 million RBCs. It takes about 20 seconds for one RBC to circle the whole body. Your heart will beat about 3 billion times during your lifetime.
BLOOD VESSELS Arteries Veins Capillaries Carry blood away from the heart Contain thick walls (smooth muscle) Found deep within the body Veins Carry blood back to heart Contain thin walls (smooth muscle) Valves prevent backward flow of blood Located near surface of the body Capillaries Tiny vessels which join arteries to veins Site of gas exchange (CO2 and O2) in the lungs Site of nutrient and waste exchange at cells Microscopic, thin-walled
The Heart
Blood Circulation
Blood Circulation
Blood Flow through the Heart Blood comes into the heart via the superior and inferior vena cava Blood enters the right atrium; goes through a valve to the right ventricle Blood leaves the right ventricle through the pulmonary artery (away from heart) Blood goes to the lungs to pick up oxygen Blood comes back to the heart through the pulmonary vein (to the heart) Blood goes into the left atrium; goes through a valve into the left ventricle Blood leaves the heart for the rest of the body through the aorta
Normal blood pressure is 120/80 Terms to Know Pulse – throbbing of arteries due to heart contractions Blood Pressure – pressure in arteries when ventricles contract (systolic number – top #) pressure in arteries when ventricles relax (diastolic number – bottom #) Normal blood pressure is 120/80
MALFUNCTIONS Disease Problem Effect on Body Atherosclerosis Fatty material (cholesterol) builds up in blood vessels causing them to become more narrow Causes hypertension (high blood pressure), heart attack Heart Attack Arteries become blocked Some heart tissue dies
Troubled Hearts
Atherosclerosis
Heart after a Heart Attack
Heart attack
Heart attack
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