Download cardiovascular system ppt

Biology 2

THE CARDIOVASCULAR SYSTEM

CARDIOVASCULAR SYSTEM https://www.youtube.com/watch?v=gVY04NQU pxk  How does this video relate to the heart?  What happens to the man in the video? 

SCHEME OF BLOOD CIRCULATION 

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

CIRCULATION 

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

HEART SIZE & LOCATION 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 2nd rib  The apex (distal point of the heart) extends downward and to the left to the intercostal space between the 5th & 6th rib

HEART LOCATION

COVERINGS OF THE HEART 

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 

AKA epicardium

 Parietal



pericardium = innermost layer of sac pericardium = inner lining of fibrous pericardium

Pericardial cavity- space between the visceral and parietal layers 

Contains fluid that reduces friction as heart contracts

PERICARDIUM

PERICARDITIS 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. 

3 LAYERS OF THE HEART’S WALLS 

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

3 LAYERS OF HEART WALLS

3 LAYERS OF HEART WALLS

DOUBLE PUMP 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 

CHAMBERS OF THE HEART

VALVES OF THE HEART 

Atrioventricular valves (A-V valves)ensure one way flow of blood between atria and ventricles  Tricuspid

valvelocated between the right AV  Bicuspid valve (AKA mitral valve)- located between the left AV

THE VENTRICLES 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 

BLOOD FLOW 

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

BLOOD FLOW 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 arterieslead to lungs 

BLOOD FLOW 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

SEMILUNAR VALVES 

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

MITRAL VALVE PROLAPSE (MVP) 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 

MITRAL VALVE PROLAPSE https://www.youtube.com/watch?v=AHBzu5zh FuA  https://www.youtube.com/watch?v=KmhKufTS 0wQ 

BLOOD SUPPLY TO THE HEART 

Right & Left Coronary Arteries- 1st 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 sinusempties directly into the right atrium