Circulatory System Notes

Transcription

1 Circulatory System Notes Functions of Circulatory System A. Transports B. Transports C. Transports D. Transports E. of fluids F. G. Regulate temperature H. Blood clotting 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 C. Lower two chambers = ventricles discharging chambers D. Composed of cardiac muscle myocardium E. separates the atria F. Interventricular septum separates G. Every chamber is lined with endocardium if this becomes inflamed= endocarditis. Endocarditis is abrasive to RBCs and a 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 to all parts of the body 1. Contraction = 2. Relaxation = 3. Atria contract (together) and then ventricles 1

2 Valves of heart A. Atrioventricular (AV) valves separates atria from ventricles Tricuspid on B. AV valves prevent backflow of blood into atria when ventricles contract C. attach valves to wall of heart. D. Semilunar (SL) valves are located between the 2 ventricles and the large arteries 1. 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. 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

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 (O 2 poor blood from body). B. Blood pumped through AV (tricuspid) valve to C. Right ventricle contracts and sends blood through the to lungs (O 2 gained, CO 2 lost) Systemic Circulation A. O 2 rich blood returns to B. Blood pumped through valve into left ventricle C. and sends blood to rest of body through aorta Blood supply to heart A. Aorta s first two branches are the right and left B. 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 is deprived of O 2 often a sign of blockage D. Coronary bypass surgery veins removed from 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. can contract rhythmically on their own, but need electrical impulses to be effective (coordination) B. are the electrical connectors 1. Both atrial walls contract together 2. Both ventricular walls contract together C. Synoatrial (SA) node =, 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. When the impulse reaches the AV node, it relays the message via the AV bundle. E. AV bundle ( ) originates in AV node and extends into interventricular septum continues as. AV bundle together with Purkinje fibers causes ventricles to contract. F. Normally, 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 Hypertension Fibrillation Congestive Heart Failure Tachycardia Angina Pectoris Bradycardia Varicose veins Incompetent valve Myocardial infarction Pericarditis Murmur Cerebrovascular accident Atherosclerosis Cardiopulmonary resuscitation Angioplasty 10