Circulatory System PDF

3.4 The Circulatory System Keep it Pumping! Functions of the Circulatory System ► Regulates body temperature ► Transports substances around the body ► Moves nutrients absorbed from intestine (digestive system) to all of body’s cells ► Blood picks up...

3.4 The Circulatory System Keep it Pumping! Functions of the Circulatory System ► Regulates body temperature ► Transports substances around the body ► Moves nutrients absorbed from intestine (digestive system) to all of body’s cells ► Blood picks up oxygen and delivers waste carbon dioxide at lungs (respiratory system) ► Blood carries other waste products from body tissues for disposal ► Moves disease-fighting white blood cells to location of invading viruses or bacteria Components of the Circulatory System ► The human circulatory system is made up of 3 main parts: ► Heart ► Blood vessels (arteries, veins, capillaries) ► Blood Human Heart ► The human heart is made of 3 types of tissues: ► Cardiac muscle tissue ► Nerve tissue ► Connective tissue Human Heart: Cardiac Muscle Tissue ► Cardiac muscle tissue is ONLY found in the heart ► All cardiac muscle tissues in each part of the heart contract at the same time ► Makes the heart contract in order to move blood around the body Human Heart ► Pumps with a regular beat ► Frequency of beat (heart rate) depends on physical activity, stress, age, health, etc. ► Smooth layer of epithelial tissue covers muscles and nerves ► Reduces friction and protects heart from damage when lungs expand and contract ► Inner surface also lined with smooth epithelial tissue ► Allows blood to flow freely Anatomy of the Human Heart ► It consists of 2 pumps which move blood through two different circuits at the same time: 1. PULMONARY – to the lungs 2. SYSTEMIC – to the body Anatomy of the Human Heart ► Each pump has 2 chambers: ATRIUM, VENTRICLE ► Atrium: thin-walled chamber that receives blood from the veins and pumps it at low pressure to the ventricle ► Ventricle: thick-walled chamber that receives blood from the atrium and pumps it at high pressure into the arteries septum ► The two sides of the heart are divided by the septum Blood travels: 1. from the heart to the lungs 2. back to the heart 3. then throughout the body 4. finally returning to the heart  Diagram of the Human Heart: Parts Semilunar valves Aorta Pulmonary artery Pulmonary artery Superior vena cava Pulmonary vein Pulmonary vein Left atrium Right atrium Tricuspid valve Bicuspid (mitral) valve Left ventricle Right Ventricle Septum Inferior vena cava  FYI - There are two paths through which blood circulates: Diagram of the Human Heart: Blood Flow 1. Blood that returns from the body to the heart is RED = oxygenated blood Aorta Blood to deoxygenated (oxygen has been the body removed by body cells) and BLUE = de-oxygenated blood carries carbon dioxide waste from cellular respiration. Blood to Blood from the lungs The blood goes from the heart’s right atrium to its right the body Blood from ventricle, which then pumps the the lungs blood through the pulmonary artery to the lungs. There, it eliminates the CO2 Left Atrium and picks up oxygen. 2. The oxygenated blood then goes Right Atrium back to the heart, to its left atrium, and then to the left ventricle. From here it is pumped out through the aorta, a huge artery, to the rest of the body. Left Ventricle Right Ventricle  Blood Vessels Capillaries ► There are 3 types of blood vessels: ► Arteries ► Veins ► Capillaries Artery Vein Arteries ► All arteries take blood AWAY from the heart ► Most arteries carry oxygenated blood (*shown as bright RED) ► Have a thick layer of smooth muscle and elastic tissue to withstand the large pressure generated by contraction of the heart Veins ► Veins always move blood TOWARD the heart ► Most veins carry de-oxygenated blood (*shown as BLUE) ► Have relatively thin walls compared to arteries because the blood is under a much lower pressure in the veins ► Contain valves to prevent backflow of blood Capillaries ► Capillaries are thin vessels, only one cell thick ► Have a diameter so thin that only ONE RBC (red blood cell) can pass through at a time!! ► Link arteries with veins ► Where blood exchanges materials (CO2, O2, water, etc.) with individual cells  Fig. 1 (pg. 83) Route of Blood Flow Through Blood Vessels ► Heart receives oxygenated blood from the lungs and pumps the blood through large arteries, which branch into smaller and smaller blood vessels ► Eventually, blood passes through the smallest blood vessels—capillaries ► In the capillaries, blood exchanges substances with the surrounding tissues ► O2 diffuses into body tissues, CO2 diffuses into blood vessels ► Then, blood flows into larger veins and eventually returns to the heart ► Heart pumps de-oxygenated blood to the lungs to become oxygenated once more, then blood goes back to heart Summary: Types of Blood Vessels Vessel Structure Function Diagram ARTERY Thick elastic Transports oxygenated walls blood AWAY from heart VEIN Thinner, less Transports de-oxygenated elastic walls; blood TOWARDS heart has valves CAPILLAR Very thin walls, Links arteries and veins; very small where materials are Y diameter exchanged between blood and body tissues Blood ► A specialized bodily fluid ► Contains tissues (blood cells) that deliver necessary substances TO the body's cells (such as nutrients and oxygen) ► Transports waste products (such as carbon dioxide) AWAY from the body's cells ► Also helps to regulate body temperature (heat exchange) Blood: Fun Facts! ► Average human has around 5 litres of blood: ► Females have 4.5L ► Males have 5.6L ► Are four main BLOOD TYPES: ► A, B, AB, O  Components of Blood Plasma: the liquid part of blood; makes up 54% of blood by volume White Blood Cells (WBC): also called “leukocytes”; make up < 1% of blood by volume ► Protein-rich liquid that carries the blood cells along ► Infection-fighting cells that make up the immune system ► Recognize and destroy invading bacteria/viruses Red Blood Cells (RBC): also called “erythrocytes”; make up 45% of blood by volume ► Are the only blood cells that DO have a nucleus ► Contain a protein called hemoglobin, which allows them to transport oxygen throughout the body Platelets: help with blood clotting; make up