Cardiovascular System: the heart and the vessels

Transcription

1 Cardiovascular System: the heart and the vessels Mar 25 3:05 PM heart parts: apex: bottom, pointed region of the heart; points to the left hip base: top, broad region of the heart; points to the right shoulder base apex Mar 25 3:09 PM 1

2 heart parts: pericardium: double layered membrane surrounding the heart visceral pericardium: membrane that lies on the heart parietal pericardium: membrane that lines the region of the thoracic cavity that the heart is in (called the mediastinum) Mar 25 3:13 PM heart parts: The Heart Wall Epicardium the thin serous membrane comprising the outer surface of the heart (the epicardium is the same structure also called the visceral pericardium) Myocardium the thick middle layer comprised of cardiac muscle tissue pumps Endocardium smooth inner surface of the heart chambers; reduces friction for smooth flow Mar 25 7:57 PM 2

3 heart parts: septum: wall on the interior of the heart that separates the right and left sides Mar 25 8:11 PM heart parts: chambers: hollow areas of the heart right atrium: receives deoxygenated blood from the vena cava (from the body); small; not very muscular, because it simply holds blood right ventricle: receives deoxygenated blood from the right atrium; muscular to pump blood to the lungs left atrium: receives oxygenated blood from the pulmonary veins (from the lungs); small; not very muscular, because it simply holds blood left ventricle: receives oxygenated blood from the left atrium; very muscular to pump blood to the body **compare the thickness of the right and left ventricles where the arrows are pointing why the difference? Mar 25 8:15 PM 3

4 heart parts: chordae tendineae: the heart strings; anchor the valve flaps **notice the position that the valve is in when it is closed and the chordae tendineae are pulled tight (arrow) Mar 25 8:15 PM heart parts: valves: prevent backflow right atrioventricular valve (tricuspid) has 3 flaps; empties the right atrium into the right ventricle left atrioventricular valve (bicuspid; mitral valve) has 2 flaps; empties the left atrium into the left ventricle right semilunar valve (pulmonary semilumar valve) 3 flaps; allows the blood to pass from the right ventricle into the pulmonary artery left semilunar valve (aortic semilunar valve) 3 flaps; allows blood to pass from the left ventricle to the aorta Mar 25 8:15 PM 4

5 valves of the heart Mar 25 9:02 PM vessels: transport blood throughout the body veins: carry deoxygenated blood from the body to the heart (*exception the pulmonary vein carries oxygenated blood from the lungs to the heart) arteries: carry oxygenated blood from the heart to the body (*exception the pulmonary artery carries blood to the lungs from the heart) capillaries: where gas exchange takes place; connects arteries to veins venule smallest vein arteriole smallest artery vena cava largest vein aorta largest artery blood leaves the heart through the: aorta arteries arterioles capillaries venules veins vena cava heart largest smallest smallest largest Mar 25 8:15 PM 5

6 Mar 25 9:26 PM vessel layers: tunica intima: innermost layer; membranous and smooth to reduce friction of the blood (only layer found in capillaries) tunica media: middle layer; muscular to contract or dilate tunica externa: outermost layer; fibrous to support *note the difference in diameter and thickness of the 2 vessel types Mar 25 9:28 PM 6

7 blood flow through the heart Mar 25 9:37 PM Mar 25 9:38 PM 7

8 flow of blood through the body: aorta arteries arterioles capillaries of the body venules veins vena cava right atrium tricuspid right ventricle pulmonary semilunar valve pulmonary artery capillaries of the lungs pulmonary veins left atrium bicuspid left ventricle aortic semilunar valve aorta **underlined areas above are the parts of the pulmonary circuit that goes to the lungs (can be extended to a couple areas of the heart); the parts above not underlined are the systemic circuit **no matter where you start, you will end up back at that location; it is a cycle Mar 25 9:39 PM cardiac circulation: The heart is supplied with blood through the coronary circuit. These vessels are found on the outer surface of the heart and are in the muscle of the heart. These vessels directly supply the heart with oxygen and nutrients and remove wastes. The heart takes nothing from the blood as it moves through the chambers. Mar 27 10:02 AM 8

9 lubb dupp (the heart sounds) lubb is from the AV valves closing; it is a longer and louder sound dupp is from the SL valves closing; it is a shorter and softer sound Mar 27 10:10 AM intrinsic conduction system: the pumping of the heart is controlled by the intrinsic conduction system in conjunction with the autonomic nervous system. parts: (nervous system cells) sinoatrial node (SA node): the pacemaker; jump starts the impulse that makes the heart beat; located on the right atrium atrioventricular node (AV node): between the right atrium and right ventricle Bundle of His: leaves the AV node and leads to the septum bundle branches: divisions of the Bundle of His that travel down the septum of the heart purkinje fibers: smaller divisions that travel throughout the heart ***as the impulse leaves the purkinje fibers, the heart muscle contracts from the bottom up Bundle of His (purkinje fibers) Mar 27 1:48 PM 9

10 Mar 28 10:00 AM Nov 13 10:48 AM 10

11 fetal circulation: in the umbilical cord between the mom and the baby, there is one large umbilical vein and two small umbilical arteries. The vein carries nutrient rich blood and oxygen to the baby and the arteries carry wastes and carbon dioxide from the baby. Mar 27 2:36 PM pulse: the expansion and recoil of the arteries with each beat of the left ventricle; average adult pulse is beats per minute at rest common pulse points: temporal artery: in the temple on the side of the head (1) carotid artery: in the neck (3) brachial artery: in the upper arm (4) femoral artery: in the upper leg (6) popliteal artery: behind the knee (7) Mar 27 2:40 PM 11

12 blood pressure: pressure exerted by the blood on the inner wall of the vessel; it is highest in the aorta and lowest in the vena cava; this is why cut arteries spurt blood and cut veins flow Mar 27 3:20 PM systolic pressure is from the ventricles contracting diastolic pressure is from the ventricles relaxing average blood pressure: 120/80 (top # is systole; bottom # is diastole) Mar 27 3:29 PM 12

13 factors that affect blood pressure: friction in the vessels (from plaque build up) age weight exercise/activity emotions diet body temperature drugs Mar 27 3:30 PM disorders/conditions: hypotension: low blood pressure; systolic below 100 hypertension: high blood pressure; systolic above 140 ***alcohol is a vasodilator nicotine and caffeine are vasoconstrictors Mar 27 4:01 PM 13

14 atherosclerosis: narrowing of the arteries on the inside, due to deposits on the inner walls (early arteriosclerosis) arteriosclerosis: reduced elasticity of the arteries hardening of the arteries Mar 27 4:12 PM aneurysm: ballooning of a vessel can rupture and cause death Mar 27 4:16 PM 14

15 varicose veins: weakening of the valves in a vein causing backflow and blood pooling; causes sagging of the vessel and weakening of the vessel wall Mar 27 4:21 PM fibrillation: rapid shaking of the heart muscle, that makes it useless as a pump; can lead to heart attack Mar 27 4:24 PM 15

16 tachycardia: rapid heart rate (usually more than 100 beats per minute); symptoms include sweating, palpitations, chest pain bradycardia: slow heart rate (usually less than 60 beats per minute); symptoms include dizziness, tired, short of breath Mar 28 8:58 AM angina: pain from the myocardium being deprived of oxygen myocardial infarction: heart attack; death of heart cells from severe angina Mar 28 9:24 AM 16

17 congestive heart failure: heart gets worn out from: old age; hypertension; arteriosclerosis; heart attack Mar 28 9:29 AM 17