1 Circulatory System https://www.youtube.com/watch?v=p-N_DKvAHRk

2 The Mammalian Heart

3 A hollow muscular organ that contracts repeatedly without fatigueIt is located between the lungs in the thoracic cavity the heart is protected by a protective layer of thin tissue called the pericardium

4 Heart consist of two pumps One pump on the left Right ‘Pump’ Left ‘Pump’ Heart consist of two pumps One pump on the left One on pump on the right Pumps are separated by the septum which is a a wall of muscle that separates the right heart pump from the left Septum

5 CHAMBERS OF THE HEART Left ventricle Left atrium Right atriumRight ventricle

6 It is divided into 4 chambers: the right and left atria (singular atrium) and right and left ventricles: The right side pumps blood to the lungs (pulmonary) and the left side pumps blood to the body (systemic) atria are collecting chambers that receive blood from the lungs and body, and then pump blood to ventricles. ventricles have a thick muscular wall and are the pumping chambers that push blood out through blood vessels and into capillary beds (in lungs and body).

7 Heart Valves The valves: In order to prevent backflow of blood and make sure blood flows in the correct direction through the heart, there are valves at a few points: Semilunar valves Atrioventriclar valves Semilunar Valves Atrioventricular Valves

8 The left atrioventricular (AV) valve (bicuspid valve or mitral valve) is located between the left atrium and left ventricle. It has two parts flaps The right atrioventricular valve (tricuspid valve) is located between the right atrium and right ventricle. It contains three flaps. The aortic semilunar valve is located between the left ventricle and aorta – allows blood to flow to the rest of the body. The pulmonary semilunar valve allows blood to travel from right ventricle to the lungs.

9 Left Semilunar Valve Left Semilunar Valve Left Atrioventricular Valve Bicuspid Valve Mitral Valve Right Atrioventricular Valve Tricuspid Valve

10 Lub sound = Atrioventricular valves shutting Dub sound = Semilunar valves shutting https://www.youtube.com/watch?v=tn1Chu23dl0

11 Systole and Diastole: “lubb-dubb, lubb-dubb”-Contraction of the ventricles (blood is pushed out of the heart) -AV valves shut to prevent blood from going back up into the atria -Shutting of these valves produces a “lubb” sound Diastole: -Relaxation of the heart (heart fills with blood) - SL valves shut to prevent blood from going back into the ventricles from the arteries -Shutting of these valves creates a “dubb” sound

12 Aorta Pulmonary Artery Superior Vena Cava Pulmonary Vein Inferior Vena Cava

13 Deoxygenated blood from the body collects in a vein called the vena cava:The superior vena cava returns deoxygenated blood from the upper portion of the body the inferior vena cava returns deoxygenated blood from the lower portion of the body and legs. Deoxygenated blood is transported to the lung through the pulmonary arteries Oxygenated blood is returned to the heart through the pulmonary veins

14 Pathway of blood through the heart:Vena cava  right atrium  atrioventricular valve  right ventricle  semi-lunar valve  pulmonary arteries  lungs  pulmonary veins  left atrium  atrioventricular valve  left ventricle  semi-lunar valve  aorta

15 Flow of Blood Through the Heart:Blood from the vena cava collects in the right atrium of the heart. When the atria contracts, blood flows from the right atrium, through the left atrioventricular valve into the right ventricle. When the right ventricle contracts, it pumps blood out through the pulmonary semilunar valve into the pulmonary artery which carries the deoxygenated blood towards the lungs. Oxygenated blood returns to the left atrium of the heart, through the pulmonary veins. When the left atrium contracts, blood flows through the right atrioventricular valve into the left ventricle. When the left ventricle contracts, blood flows through the aortic semilunar valve into the systemic circulatory system (aorta).

16 https://www.youtube.com/watch?v=Rj_q D0SEGGk

17 Homework Read pages Answer: Pg # 4-6 Pg. 488 # 2,