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Biology 2.  pxk pxk  How does this video relate to the heart?  What.

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Presentation on theme: "Biology 2.  pxk pxk  How does this video relate to the heart?  What."— Presentation transcript:

1 Biology 2

2  pxk pxk  How does this video relate to the heart?  What happens to the man in the video?

3  Pulmonary circulation  Eliminates carbon dioxide via the lungs and oxygenates the blood  Contains deoxygenated blood  Systemic circulation  Delivers oxygen to all body cells and carries away wastes  Contains oxygen-rich blood


5  Without circulation, tissues would lack a supply of oxygen and nutrients, and wastes would accumulate  Necrosis = death of body tissue that occurs when not enough blood is flowing to the tissue

6  Average adult heart size is 14 centimeters long and 9 centimeters wide (fist size)  Housed within the mediastinum – location behind the sternum  Bordered laterally by the lungs  The base of the heart lies beneath the 2 nd rib  The apex (distal point of the heart) extends downward and to the left to the intercostal space between the 5 th & 6 th rib


8  Pericardium- encloses the heart and the proximal ends of the large blood vessels to where it attaches  Outer fibrous pericardium attaches heart to surroundings  Double-layered sac  Visceral pericardium = innermost layer of sac  AKA epicardium  Parietal pericardium = inner lining of fibrous pericardium  Pericardial cavity- space between the visceral and parietal layers  Contains fluid that reduces friction as heart contracts


10  Swelling and irritation of the pericardium  Pericarditis often causes chest pain and sometimes other symptoms. The sharp chest pain associated with pericarditis occurs when the irritated layers of the pericardium rub against each other.

11  Epicardium- outer layer  Also part of the visceral pericardium  Made of connective & adipose tissue  Protects heart by reducing friction  Myocardium- middle layer  Thick cardiac muscle tissue  Pumps blood out of the heart chambers  Endocardium- inner layer  Epithelial and connective tissue layer  Contains elastic fibers, blood vessels, & Purkinje fibers



14  The heart is divided into 4 hollow chambers  Atria- upper chambers have thin walls and receive blood returning to heart  Ventricles- lower chambers that receive blood from the atria and contract to force blood out of the heart into arteries  Septum- solid wall that separates the atrium and ventricle on the right from the atrium and ventricle on the left


16  Atrioventricular valves (A-V valves)- ensure one way flow of blood between atria and ventricles  Tricuspid valve- located between the right AV  Bicuspid valve (AKA mitral valve)- located between the left AV

17  The right ventricle has thinner muscular walls as it only pumps blood a short distance to the lungs  The left ventricle is thick and must force the blood to all parts of the body against a greater resistance to flow

18  The right atrium receives blood from 2 large veins: superior vena cava and inferior vena cava  Superior vena cava- returns blood to heart from upper body  Inferior vena cava- returns blood to heart from lower body

19  Muscular wall of RV contracts, blood in chamber is under pressure, closing the tricuspid valve and forcing the blood out the pulmonary trunk, which divides into the pulmonary arteries  Pulmonary arteries- lead to lungs

20  The LA receives blood from 4 pulmonary veins (2 from each lung)  The LV contracts, closing the bicuspid valve and pushing blood through the aortic valve into the aorta  Aorta – large artery that delivers blood to the body

21  The pulmonary and aortic valves are called semilunar valves due to their half moon shape of their cusps

22  One or both of the cusps of the mitral valve stretches and bulges into the left atrium during ventriclar contraction  Sometimes blood flows back into the left atrium  Chest pain, palpitations, fatigue, anxiety  Sounds like a “click and a murmur”  6% of the population  More susceptible to endocarditis, which can be caused by Streptococcus

23  FuA FuA  0wQ 0wQ

24  Right & Left Coronary Arteries- 1 st two branches of the aorta that supply blood to heart tissue  Feed the many capillaries of the myocardium  Cardiac veins- drain the blood that has passed through the myocardial capillaries (deoxygenated blood)  These veins join an enlarged vein on the heart’s posterior surface called the coronary sinus- empties directly into the right atrium

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