STRUCTURES OF THE CARDIOVASCULAR SYSTEM

Transcription

1 STRUCTURES OF THE CARDIOVASCULAR SYSTEM

2 CARDIOVASCULAR SYSTEM Also called the circulatory system Consists of the heart, arteries, veins, and capillaries Main function is to pump/circulate oxygenated blood to the body s tissues (muscles, organs, brain) and deoxygenated blood to the lungs

3 FUN FACT! Deoxygenated blood is not blue. That s a MYTH! It s really just a deeper, less vibrant red than oxygenated blood. The reason some people s veins look blue through their skin is because blue light can more easily penetrate the skin than red light. oxygenated deoxygenated

4 HEART Four chambered muscular organ Comparable to the size of a closed fist Located in the center of the chest Behind sternum Between 2 nd and 6 th ribs

5 COVERINGS OF THE HEART Pericardium loose fitting sac surrounding the heart made of: Fibrous pericardium Serous pericardium owith parietal and visceral layers Pericardial space: between parietal and visceral layers of serous pericardium Filled with 10-15ml of pericardial fluid Decreases friction

6 WALLS OF THE HEART Epicardium outer layer = visceral pericardium Myocardium thick layer composed of cardiac muscle cells Endocardium interior of cardiac wall

7 CHAMBERS OF THE HEART Atria two superior chambers Receiving chambers Blood from veins enters atria Ventricles two inferior chambers Pumping chambers Thick muscular walls to increase force of pumping action Separated by interventricular septum

8 VALVES OF THE HEART Permit blood flow in one direction during circulation Atrioventricular valves (AV valves) Between atria and ventricles Tricuspid valve on RIGHT Bicuspid valve on LEFT Semilunar valves (SL valves) Pulmonary valve between right ventricle and pulmonary arteries Aortic valve between left ventricle and aorta

9 CONDUCTION SYSTEM OF THE HEART 1) Electrical impulse travels from the sinoatrial node (SA node) Pacemaker of the heart 2) To the atrioventricular node (AV node) 3) Through the bundle of His 4) Splits up and becomes Purkinje fibers 5) To make muscles in the left and right ventricles contract

10 This Video Shows a Heart Contraction and How it Correlates to an EKG Reading:

11 FUN FACT! You might think a heart attack happens when the heart stops pumping. In actuality, a heart attack is caused by the heart pumping so fast that the ventricles are unable to refill with blood, stopping circulation. Using a defibrillator (shock pads) on a patients does not start their heart, it STOPS and RESTARTS it (like restarting

12 STRUCTURE OF BLOOD VESSELS Tunica adventitia - outermost layer Fibrous connective tissue Holds vessels open; prevents tearing of vessels walls during body movements Larger in veins than arteries Tunica media middle layer Smooth muscle and elastic CT Helps vessels constrict and dilate Larger in arteries Tunica intima innermost layer Composed of epithelium Semilunar valves present in veins One cell thick in capillaries Semilunar valve

13 TYPES OF BLOOD VESSELS Artery carries oxygenated blood away from the heart Arteriole = small artery Aorta = the largest artery in the body, which receives blood from the left ventricle

14 TYPES OF BLOOD VESSELS Vein carries deoxygenated blood towards the heart Great ability to stretch (constrict and dilate) Function as reservoirs: blood pools in the valves then is pushed forward from the pumping pressure Venules = small veins

15 TYPES OF BLOOD VESSELS Capillaries Primary exchange vessels Transport materials to and from the cells Speed of blood flow decreases to increase contact time Microcirculation = blood flow between arterioles, capillaries and venules

16 CIRCULATORY ROUTES Blood follows in a figure 8 pattern through the body Oxygenated blood flows from the left ventricle to the body & back to the right atrium Deoxygenated blood flows from the right ventricle to the lungs and back to the left atrium