Wk2-Cardiovascular System

Transcription

1 Wk2-Cardiovascular System Overview: 1. Cardiovascular system general overview. 2.Circula=on: Artery, arterioles, capillary, venules, veins 3. Capillary Exchange 5. Systemic and Pulmonary Circula=on 6. The Heart-flow of blood through the heart. 7. Conges=ve heart failure 8. Angina pectoris 9. Cardiac arrest 10. Thrombosis. 1

2 Summary! The purpose of the les atrium and ventricle in the heart is to receive oxygenated blood from the lungs & to pump it out to the body. The purpose of the right atrium and ventricle in the heart is to receive deoxygenated blood from the body & distribute it to the lungs for oxygena=on (to get oxygen). Septum is the thick muscular wall that separates the les and right side of the heart. The aorta is the largest artery connected to the heart. The 2 blood flow systems though the heart are called Systemic & Pulmonary. Valves in the heart are there to make sure the blood flows one way. 2

3 Summary con+nues!.. The pericardium is a series of sacs that surround/cover the heart The sino-atrial node= the series of specialised cells in the heart that set the frequency of the heart s rhythm. Angina pectoris is pain in the chest due to lack of oxygen to the heart caused by blocked arteries (atherosclerosis). Palpita=ons=heart beats rapidly or irregularly (subjec+ve sensa=on i.e the client themselves feels this sensa=on) Thrombosis=forma=on of blood clot in a blood vessel. 3

4 Summary con+nues!.. The pericardium is a series of sacs that surround/cover the heart The sino-atrial node= the series of specialised cells in the heart that set the frequency of the heart s rhythm. Angina pectoris is pain in the chest due to lack of oxygen to the heart caused by blocked arteries (atherosclerosis). Palpita=ons=heart beats rapidly or irregularly (subjec+ve sensa=on i.e the client themselves feels this sensa=on) Thrombosis=forma=on of blood clot in a blood vessel. 4

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6 1. Cardiovascular system-general overview The cardiovascular system transports oxygen, carbon dioxide, waste products, nutrients and hormones to and from various parts of the body. The cardiovascular system is made up of: - the heart - the blood vessels (arteries, veins and capillaries) & blood. The heart has major vessels that supply it with deoxygenated blood (travels back to the heart from the body), and major vessels that carry oxygenated blood away from the heart to all the parts of the body. 6

7 The major vessels that carry blood to and from the heart are: (please see page 4 s picture) inferior vena cava takes deoxygenated blood (blood low in oxygen) from the lower extremi=es of the body to the heart superior vena cava takes deoxygenated blood from the upper extremi=es of the body to the heart aorta takes oxygenated blood (blood high in oxygen) away from the heart This informa=on is important so that you can gain an understanding of how the heart works and some of the condi=ons that may affect the func=oning of the heart. 7

8 2. Circula=on: Closed system of tubes that carries blood around the body (please see page 7 s picture) Arteries = carry blood from heart to =ssues. There are 3 types of arteries, categorised based on their sizes (diametre): 1. Elas+c Arteries - conduc=ng arteries, the largest, e.g: Pulmonary arteries, aorta. 2. Muscular Arteries - distribu=ng arteries, medium-sized, e.g : arteries in the leg. 3. Arterioles - small in size, take blood to capillaries Capillaries are: -microscopic (very small) vessels -connects arterioles to venules thin walls that allow exchange of fluids and small molecules eg oxygen and nutrients 8

9 Circula=on Venules : merge together to form veins Veins : carry blood back to the heart 9

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11 The big picture 11

12 4. Microcircula=on-capillary network Capillaries =+ny (microscopic) vessels that connect arterioles to venules. It is located near every cell in the body Increase demand-> Increase network.in highly ac=ve =ssue such as muscles, kidney, brain & liver, there are more capillary network. Not found in cornea, lens of the eye, car=lage and epithelia. Capillary wall has no muscle layer. It is made up of a single layer of simple squamous epithelium (slide 7) and its basement membrane Capillary s func+on= exchange of oxygen, nutrients and waste between blood and inters==al fluids. 12

13 5. Systemic & Pulmonary Circula=on Systemic circula=on: carries oxygenated blood to the body. LeS side of the heart->aorta->systemic Arteries (all branch from Aorta)-> Capillaries->Systemic Veins (they all merge into Vena Cavas)->Superior/Inferior Vena Cava->Right side of the heart 13

14 Pulmonary circula=on: carries deoxygenated blood from the heart (right side) ->lungs. ->Blood is oxygenated (at the lungs) and then ->the heart (les side). Pulmonary Trunk -> right/les pulmonary arteries -> arteries / arterioles -> capillaries -> venules / veins ----> 4 pulmonary veins (2 on each side) Note: compared to systemic circula=on, pulmonary arteries are shorter, larger, and have thinner walls 14

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16 The Heart-flow of blood through the heart The heart is a hollow organ about the size of a fist and is composed of special muscle =ssue (cardiac muscle). It lies under the breast bone in the centre of the cardiothoracic cavity. In the average life=me the heart beats 250 million =mes and pumps 340 million litres of blood. The heart is a sophis=cated pump that is controlled by an electrical current that is ini=ated in the brain. The heart is divided into a les and right side by a muscular wall called the septum and has four chambers. The heart is covered in pericardium sac-like (protects and anchors the heart) 16

17 Heart chambers and valves 4 chambers of the heart: 2 atria (upper chambers) 2 ventricles (lower chambers) Note: atria is plural form for atrium 17

18 In detail. Right atrium which receives deoxygenated blood (low in oxygen) from all over the body Right ventricle receives blood from the right atrium and sends it to the lungs via the pulmonary artery to become oxygenated and get rid of carbon dioxide LeS atrium receives oxygenated blood from the lungs and sends it to the les ventricle LeS ventricle receives blood from the les atrium and sends it out to the body via the aorta. 18

19 The heart wall The heart wall has 3 layers - the endocardium is the inner lining, the myocardium is the muscle layer and the pericardium is the outer covering. 19

20 The chambers of the heart are separated by valves: (see page 23) tricuspid valve is located between the right atrium and right ventricle bicuspid or mitral valve is located between the les atrium and les ventricle pulmonary valve is between the right ventricle and the pulmonary artery aor+c valve is between the les ventricle and the aorta 20

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22 The Heart-flow of blood through the heart. The correct term for contrac=on of the heart is systole. This is followed by relaxa=on of the heart called diastole. One systole and diastole form the cardiac cycle. A cardiac cycle takes only 0.8 seconds and during this =me the following events occur. hip:// 22

23 hip:// The rate and rhythm of the heart is regulated by the conduc+on system that is made up of specialised neuromuscular +ssue that sends out impulses. The impulses begin at the Sino-Atrial (SA) node in the right atrium and spread across the two atria. The atria then contract and the impulses from the SA node reach the Atrio-Ventricular (AV) node in the right atrium. Messages from the AV node then travel down the Bundle of His in the septum and con=nue through the Purkinje fibres to the walls of the ventricles. 23

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25 A deoxygenated blood cell arrives into the right atrium and passes into the right ventricle through the tricuspid valve 25

26 The blood cell leaves the heart through the pulmonary valve into the pulmonary artery where it travels to the lungs to be oxygenated. 26

27 The oxygenated blood cell returns to the heart through the pulmonary vein into the les atrium. The blood cell moves into the les ventricle through the mitral valve. The blood cell then moves from the heart into the body through the aorta passing through the aor=c valve. 27

28 Cardiovascular problems. 1.Conges=ve heart failure 2. Angina pectoris 3. Cardiac arrest 4. Deep Vein Thrombosis. 28

29 1. Conges=ve heart failure aka LeS heart failure What is a failure? =not strong enough to keep up the workload. Conges=ve heart failure or les heart failure happens when the les side of the heart is badly impaired in its func=on. A backup of congestsion in the pulmonary circuit leads to the seepage of fluid back into the alveoli (lung), if untreated, à pulmonary edema. Symptoms: severe shortness of breath stubborn coughing may be with blood in sputum Complica=on: Pneumonia (serious, par=cularly in the elderly). 29

30 2. Angina pectoris This is a descrip=on of the symptoms that can happen when the heart muscle is not receiving enough oxygen, such as from the coronary arteries been sererely blocked. Note: other causes of chest pain can be from severe aneamia or hyperthyroidism Symptoms may include: heavy pressure around the chest like a truck on chest, pain radia=ng to les shoulder and arms, into the jaw and back. 30

31 Heart Aiack:(or myocardial infarc=on)= death of heart muscle =ssue due to the loss of blood supply, not necessarily resul=ng in the death of the heart aiack vic=m. 31

32 3. Cardiac arrest Is Cardiac arrest & heart aiack the same thing? NO. Note: while a heart aiack may cause a cardiac arrest & sudden death, the terms don t mean the same! Cardiac arrest=abrupt loss of heart func=on in a person who may or may not have diagnosed heart disease. The =me and mode of death are unexpected. It occurs instantly or shortly aser symptoms appear. 32

33 So how does the heart suddenly lose its func=on? This happens when the heart's electrical system doesn t func=on properly. This may be caused by abnormal, or irregular, heart rhythms (this is called arrhythmias). A common arrhythmia in cardiac arrest is ventricular fibrilla1on. This is when the heart's lower chambers suddenly start bea=ng chao=cally and don't pump blood. 33

34 4. Deep Vein Thrombosis Thrombosis= a blood clot. The clot may block a blood vessel, leading to serious health effects. DVT= a blood clot that forms in the deep veins of the leg. DVT in the thigh carries a risk of pulmonary embolism. Thrombus=Clot The clot can come off the vein, leaves the leg s veins and lodges in the pulmonary artery, the main blood vessel to the lungs. If the clot is big enough, it can block that artery à death. So what causes the clot in the first place? Anything that slows the flow of blood through the deep veins can cause DVT. Examples: injury, surgery or long periods lying and sipng, perhaps 'economy-class syndrome'. Blood flow through the leg veins tends to need some physical help, because it 'flows' up instead of down. Example: working calf muscles act as a pump. The contrac=ng muscles compress the veins àblood in these veins move upwards to the heart. Of course, valves are there to help! 34

35 The symptoms of a deep vein thrombosis (DVT) may be the following: pain and tenderness in the leg pain on extending the foot swelling of the lower leg, ankle and foot skin that is red and warm. 35

36 Ques=ons 1. What is the purpose of the les atrium and ventricles in the heart? 2. What is the purpose of right atrium and ventricle in the heart? 3. What is the name of the thick muscular wall separa=ng the les and right side of the heart? 4. What is the name of the largest artery connected to the heart? 5. What are the two blood flow system thought the heart called? 6. What is the purpose of the valves in the heart? 7. What is the pericardium? 8. What are the series of specialised cells in the heart that set the frequency of the heart s rhythm called? 9. What is angina pectoris? 10. What are palpita=ons? 11. What is thrombosis? 36