Circulatory System Notes

Transcription

1 Functions of Circulatory System A. Transports nutrients B. Transports gases C. Transports wastes D. Transports hormones E. Maintain balance of fluids F. Protection from disease G. Regulate body temperature H. Blood clotting Circulatory System Notes Characteristics of various blood vessels A. Arteries from the heart out, large to small, flexible, collect cholesterol B. Veins into the heart, small to large, valves to prevent backflow C. Capillaries from arteries to veins, one cell wide, responsible for the exchange of blood gases Heart Location, Size and Position A. Located between the lungs in lower part of chest B. Triangular organ about the size of your fist. Heart Chambers A. Hollow organ B. Upper two chambers = atria receiving chambers C. Lower two chambers = ventricles discharging chambers Atria are smaller and have thinner walls than ventricles D. Composed of cardiac muscle myocardium E. Interatrial spetum separates the atria F. Interventricular septum separates the ventricles G. Every chamber is lined with endocardium if this becomes inflamed= endocarditis. Endocarditis is abrasive to RBCs and a thrombosis (clot) can occur. Pericardium covering of heart consisting of two layers of fibrous tissue with space inbetween A. epicardium like skin on apple B. parietal pericardium loose baggy fit so heart can beat Heart action A. Muscular pumping device distributing blood to all parts of the body 1. Contraction = systole 2. Relaxation = diastole 3. Atria contract first (together) and then ventricles 1

2 Valves of heart A. Atrioventricular (AV) valves separates atria from ventricles 1. Bicuspid on left side 2. Tricuspid on right side B. AV valves prevent backflow of blood into atria when ventricles contract C. Chordae tendinae attach valves to wall of heart. D. Semilunar (SL) valves are located between the 2 ventricles and the large arteries 1. Pulmonary semilunar valve found at the beginning of the pulmonary artery (leads to lungs) and allows blood to go to lungs but not back into right ventricle 2. Aortic semilunar valve found at the beginning of the aorta and allows blood to flow out of left ventricle into aorta but prevents backflow. Sounds of heart A. Lub AV valves closing as the ventricles contract (longer and lower pitch) B. Dup SL valves closing as ventricles relax External Heart Diagram 1. Right Atrium 6. Inferior Vena Cava 11. Right Pulmonary Vein 2. Left Atrium 7. Aorta 12. Left Pulmonary Vein 3. Right Ventricle 8. Pulmonary Trunk 13. Coronary Artery 4. Left Ventricle 9. Left Pulmonary Artery 14. Apex 5. Superior Vena Cava 10. Right Pulmonary Artery 15. Ligamentum Arteriosum 2

3 Internal Heart Diagram Homework 3

4 Major Arteries of Humans Homework 4

5 Major Veins of Humans Homework 5

6 The heart acts as two separate pumps. The right and left sides work together but perform different functions. Pulmonary Circulation A. Blood enters right atrium through the superior & inferior vena cavas (O 2 poor blood from body). B. Blood pumped through AV (tricuspid) valve to right ventricle C. Right ventricle contracts and sends blood through the pulmonary artery to lungs (O 2 gained, CO 2 lost) Systemic Circulation A. O 2 rich blood returns to left atrium through pulmonary veins B. Blood pumped through AV (bicuspid) valve into left ventricle C. Left ventricle contracts and sends blood to rest of body through aorta Blood supply to heart A. Aorta s first two branches are the right and left coronary arteries B. Coronary thrombosis and coronary embolism blood clots that occlude some part of coronary artery. This causes a myocardial infarction (heart attack) you can recover if amount of damage to heart is minimal. C. Angina pectoris severe chest pain when myocardium is deprived of O 2 often a sign of blockage D. Coronary bypass surgery veins removed from another part of body to replace blocked coronary arteries 6

7 Hepatic Portal Circulation Veins from the spleen, stomach, pancreas, gallbladder and intestines do not pour blood directly into VC, they send their blood to liver via the hepatic portal vein. Blood must pass through the liver before it reenters the regular venous return path to heart. Blood leaves the liver by way of the hepatic veins which drain into the inferior VC This detour through liver serves valuable purpose: o When a meal is being absorbed, the blood in the portal vein has higher than normal glucose levels. The liver cells remove the excess glucose and store as glycogen o Liver cells also remove and detoxify various poisonous substances in blood. 7

8 Fetal Circulation o Specialized blood vessels must carry fetal blood to the placenta and return. Three vessels accomplish this purpose. 2 small umbilical arteries (O 2 poor blood) and a single, larger umbilical vein (O 2 rich blood) o Ductus venosus (a con t of umbilical vein) serves as a shunt allowing most of blood returning from placenta to bypass the liver and empty directly into inferior VC. o Two other structures allow most of blood to bypass developing lungs (collapsed until birth) o Foramen ovale shunts blood directly from the right atrium to the left atrium o Ductus arteriosus connects aorta and pulmonary artery o At birth, as baby takes its first deep breaths, the circulatory system is subjected to increased pressure. The result is the closure of the foramen ovale and rapid collapse of the umbilical bvs, ductus venosis and ductus arteriosis. 8

9 Physiology of Circulation A. Cardiac muscle fibers can contract rhythmically on their own, but need electrical impulses to be effective (coordination) B. Intercalacted disks are the electrical connectors 1. Both atrial walls contract together 2. Both ventricular walls contract together C. Synoatrial (SA) node = pacemaker, located in right atrial wall near opening of Superior VC. Impulse usually begins here, then spreads throughout atria causing atrial fibers to contract. D. Atrioventricular (AV) node found in right atrium along lower part of interatrial spetum. When the impulse reaches the AV node, it relays the message via the AV bundle. E. AV bundle (bundle of HIS) originates in AV node and extends into interventricular septum continues as purkinje fibers. AV bundle together with Purkinje fibers causes ventricles to contract. F. Normally, ventricular beat follows atrial beat however endocarditis or myocardial infarction can cause disruptions in this cycle. G. Heart block impulses blocked to ventricles causing heart to beat much slower than usual treated with artificial pacemaker. Electrocardiogram measurement of the electrical current in graphic form. 3 waves A. P Wave occurs with depolarization of atria electrical activity triggering contraction B. QRS Wave depolarization of ventricles this masks the repolarization wave of atria C. T Wave repolarization of ventricles just before the relaxation phase. D. Damage to the cardiac muscle causes skewed ECG and point to diagnosis/treatment. Blood Pressure General Info A. Pressure (push) of blood exists in all bv. (higher in arteries than veins) B. Pressure is necessary for circulation otherwise blood wouldn t move. Factors influencing BP A. Blood volume the higher the volume of blood in arteries = higher pressure on art walls. B. Strength of heart contractions each time the heart contracts, a certain volume of blood is released. The stronger the contraction, the higher the more blood. C. Heart rate if the heart rate is up, it usually means that blood volume is down so instead of 70 ml x 70 beats (4900 ml/min) you get 40 ml x 100 beats (4000 ml/min) D. Blood viscosity thin blood = lower bp E. Normal bp is 120/80 Pulse 9 major pulse points in body A. Superficial temporal artery F. Radial artery B. Facial artery G. Femoral artery C. Carotid artery H. Popliteal D. Axillary artery I. Dorsalis pedis E. Brachial artery 9

10 Circulatory problems explain each of the following: Ischemia Lack of blood supply to heart muscle Hypertension high blood pressure (anything consistently over 140/90) Fibrillation rapid uncoordinated beating of heart muscle Congestive Heart Failure heart in such bad shape that circulation is totally inadequate Tachycardia rapid heart rate (over 100 beats/minute) Angina Pectoris chest pain caused by lack of oxygen to heart muscle Bradycardia slow heart rate (less than 60 beats/minute) Varicose veins weak venous valves gravity forces blood downward, causing stretching of veins (particularly in lower leg) Incompetent valve valve doesn t close properly Myocardial infarction heart attack death of a part of the heart. Pericarditis inflammation of the pericardium Murmur abnormal heart sounds caused by valve problems. Cerebrovascular accident stroke results from brain not receiving O 2 lack of blood flow Atherosclerosis damming up process of blood vessels Cardiopulmonary resuscitation procedure used to circulate blood in a person whose heart has stopped. Angioplasty opening up of blood vessels without surgery 10

11 Definitions Anatomy Blood Lecture Plasma liquid portion of the blood Serum clotting proteins found in blood Composition and functions of blood 1. Granular Leukocytes (BEN) Large granule in cytoplasm and lobed nucleus 2. Nongranular leukocytes (LM) granules not visible, normal shaped nucleus 3. Hematocrit Erythrocyte % of blood (40) will be variable according to O 2 content Blood Disorders Polycythemia excess RBC produced by red bone marrow. Anemia inability of blood to carry enough O 2 due to the number of RBCs or an RBC problem Leukopenia very low WBC count often occurs during cancer treatment Leukocytosis excess WBC usually die to a bacterial or viral infection 11

12 Leukemia way too many WBCs are being made too quickly blood cancer. WBCs can t do their job Sickle Cell Anemia sickle shaped RBCs, clogs capillaries and don t carry enough O 2 to cells Pernicious Anemia lack of Vit B 12 absorption this results in fewer but larger RBCs that don t live long Neutropenia low neutrophil count Blood types indentified by certain antigen on RBC Antigens protein that can stimulate body to make antibodies Antigens are different in persons with different blood types Antibodies proteins found in plasma. They are produced by the body to destroy specific substances (antigens) that have entered the body. Complete the following table: Blood Type Agglutinogens or antigens Agglutinins or antibodies in plasma Can donate blood to type Can receive blood from type Type A A Anti B A, AB A, O Type B B Anti-A B, AB B, O Type AB A and B NONE AB All Type O None Anti A and B All O Rh factor (antigen D) an extra blood protein is present = Rh +, no extra blood protein = Rh - Hemostasis (blood clotting) Homework Prothrombin and Fibrinogen are blood proteins Vitamin K stimulates liver cells to make prothrombin A. Break B. Erythrocytes C. Fibrin D. Fibrinogen E. Platelets F. Prothrombin G. Serotonin H. Thrombin I. Thromboplastin Clotting begins when a (1). occurs in a blood vessel wall. Almost immediately, (2), cling to the blood vessel wall and release (3), which helps to decrease blood loss by constricting the vessel. (4). is also released. This chemical substance causes (5). to be converted to (6). Once present, thrombin acts as an enzyme to attach (7). molecules together to form long, threadlike strands of (8), which then traps (9). flowing by in the blood. 1. A break 6. H Thrombin 2. E Platelets 7. D Fibrinogen 3. G Serotonin 8. C Fibrin 4. I Thromboplastin 9. B Erythrocytes 5. F Prothrombin 12

13 Additional Blood related Problems Homework Thrombus clot in an unbroken blood vessel Embolus floating clots in blood vessel, problems only occur when they get stuck. Agglutination clumping of RBCs when incorrect blood types are mixed Hemophilia factor(s) necessary for clotting are missing 13