CARDIOVASCULAR SYSTEM

Transcription

1 CARDIOVASCULAR SYSTEM

2 CARDIOVASCULAR SYSTEM Close your hand into a fist look at it! Your fist is +/- the same size as your heart, around 12 cm long, 9cm wide & 6 cm thick It is located behind the sternum & tilted to the left. The heart is made up mainly of cardiac muscle, which is also known as the myocardium. Myocardium cardiac muscle layer forming the bulk of the heart

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5 ANATOMY OF THE HEART The heart is divided into right and left hand side by the septum. Septum The 2 sides are separate & have no communication with each other.

6 ANATOMY OF THE HEART Each side is further divided into 2 chambers. Atrium the upper chamber. Smaller chamber. It receives blood from the veins. Ventricle lower chamber. A pump which drives blood into the arteries. The connection between the 2 chambers is through the atrio-ventricular valve.

7 ANATOMY OF THE HEART Left Atrium Septum Right Atrium Left Ventricle Right Ventricle

8 ANATOMY OF THE HEART Blood circulation is dependent upon the action of the myocardium, which varies in thickness: it is thickest in the left ventricle (to produce power to pump oxygenated blood around the body), thinner in the right ventricle and thinnest in the atria.

9 ANATOMY OF THE HEART The walls of the atria & ventricles are lined with a smooth, shiny membrane called the endocardium, which is a single layer of cells. The outside of the heart is covered by the 2 layers of the pericardium, which covers the blood vessels of the heart (coronary arteries). The inner layer of the pericardium is called the epicardium.

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11 VALVES OF THE HEART The heart uses valves to ensure blood flows in the right direction. There are 4 main valves: Right artio-ventricular valve Left atrio-ventricular valve Aortic valve Pulmonary valve

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13 RIGHT ATRIO-VENTRICULAR VALVE Called the tricuspid valve. Opens up to allow blood to flow from the right atrium to the right ventricle. Valve consists of cusps made of muscle & fibrous tissues Are attached to several fine, tendinous cords called chordae tendious Prevent the valves being forced back into the atrium.

14 LEFT ATRIO-VENTRICULAR VALVE Called the Mitral or Bicuspid Valve. Similar to the tricuspid valve, although smaller. Acts to prevent the backflow of blood into the left atrium from the left ventricle as it contracts.

15 AORTIC VALVE Opens up to allow blood to flow from the left atrium into the aorta. The coronary arteries which supply the blood to the heart muscle (myocardium) are positioned just above the aortic valve.

16 PULMONARY VALVE Allows blood to flow from the right ventricle into the pulmonary artery to take deoxygenated blood to the lungs.

17 SUMMARY & FUNCTIONS Right Atrium (RA) receives deoxygenated blood from the organs of the body. Right Ventricle (RV) pumps deoxygenated blood to the lungs. Left Atrium (LA) receives oxygenated blood from the lungs. Left Ventricle (LV) pumps oxygenated blood to all organs of the body larger & stronger than RV as it pumps blood through the body.

18 SUMMARY & FUNCTIONS Valves: there are 4 one way valves in the heart that open or close in response to pressure of blood flow: Bicuspid Valve: separates the left atrium from the left ventricle. Tricuspid Valve: separates the right atrium from the right ventricle. Aortic Valve : separates the left ventricle from the aorta. Pulmonary Valve: separates the right ventricle from the pulmonary artery.

19 SUMMARY & FUNCTIONS Blood vessels leading to and from the heart are as follows: Aorta carries oxygenated blood out of the left ventricle to the body. Superior Vena Cava returns deoxygenated blood to the right atrium from the head & upper body. Inferior Vena Cava returns deoxygenated blood to the right atrium from the lower body. Pulmonary Vein carries oxygenated blood from the lungs to the left atrium. Pulmonary Artery carries deoxygenated blood from body to lungs.

20 PULMONARY CIRCULATION Right ventricle pumps blood through the pulmonary artery to the lungs. Here, blood picks up oxygen & carbon dioxide is released into the lungs. From the lungs, oxygenated blood is carried to the left atrium. This short loop is called the pulmonary circulation.

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22 SYSTEMIC CIRCULATION From the left atrium, blood flows down to the left ventricle. Left ventricle pumps oxygenated blood through the aorta to all tissues of the body. Oxygen & nutrients are released from the blood to nourish cells Carbon dioxide & other waste products are carried back to the heart via the 2 venae cavae. Blood enters the right atrium. Carbon dioxide is carried to the lungs & removed from the body.

23 Arteries: BLOOD VESSELS Arteries carry blood away from the heart. Thick muscular walls. Carry predominantly oxygenated blood, except pulmonary artery. Arterioles are small branches off arteries.

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25 Capillaries: BLOOD VESSELS Tiny blood vessels one cell thick. Small spaces in the walls to allow for diffusion. Oxygen & nutrients diffuse into the cells. Carbon dioxide & lactic acid flow from the cells into capillaries.

26 Veins & Venules: BLOOD VESSELS Veins always take blood towards the heart. Veins have thin, muscular walls. They have non-return valves to prevent backflow. Predominantly carry deoxygenated blood, except the pulmonary vein. Venules are smaller branches which feed into veins.

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28 BLOOD The medium in which all cells are carried to transport nutrients & oxygen to cells. Blood transports the following, among other things: Oxygen Glucose Proteins Fats Vitamins Hormones Enzymes Platelets Carbon dioxide Electrolytes

29 Blood is made up of 4 components: Red blood cells White blood cells Platelets Plasma Blood can be described: as thick gloopy substance due to the high concentration of solids it carries. Blood is made up of 55% plasma & 45% solids.

30 Erythrocytes. RED BLOOD CELLS +/- 99% of blood cells are red blood cells. Red in colour due to presence of haemoglobin. Main role to take on & transport oxygen to cells.

31 RED BLOOD CELLS

32 WHITE BLOOD CELLS Leucocytes, colourless or transparent. +/- 1:700 ratio white to red blood cells. Role to fight infection & form part of body s immune system. Destroy bacteria & other dangerous organisms & thus remove disease from the body.

33 WHITE BLOOD CELLS

34 PLATELETS Thrombocytes. Not full cells, but rather parts of cells. Become sticky when contact air to form initial stage of repair to damaged tissue. Need substance called factor 8 to enable them to clot. A haemophiliac is a person whose blood doesn t clot.

35 PLATELETS

36 PLASMA Liquid part of blood. Straw-coloured in appearance. Solution in which all solids are carried. Also carries: Fats Amino acids Glucose Hormones Enzymes

37 PLASMA