Heart: Study Guide on Cardiovascular System

The Blood Blood compostion- 55% Plasma, 45% (Erythrocytes, Leukocytes and cell fragments) Physical Characteristics- alkaline PH 7. 35, 5-6 liters in men, e-5 in woman Functions of Blood- Transportation, Regulation, Protection Erythroppietin- Hormone that stimulates RBC production/ Anemia- too low RBC Polycythemia- Too high RBC Hemopoiesis- Process by which formed elements develop Red Blood Cell (erythrocytes)- Contain hemoglobin, leave marrow and are destroyed at 2 mil per second RBC Physiology- Specialized for Oxygen transport, atp anaerobically, globin-protien, heme-pigment

Erythropoieses- Production of RBC’s BLOOD GROUPS- Antigen A on RBC= Type A Antigen B on RBC= Type B Both Antigens on RBC= Type AB Niether Antigens on RBC= Type O Whatever antigen is in the blood there will be the opposite Anti body in the plasma. White Blood Cells(leukocytes)- have nucleus, no hemoglobin Granular- Eosinophils-combats effects of histamine Basophils-Release heparin,hystomine, and serotonin- Intensifying allergic response Neutrophils- Release lysozyme, antibiotic activity against fungi Agranular- Monocytes- cleanup cellular debris, develop into macrophages

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Lymphocytes- B-cells differentiate into cells that produce antibodies T-cells- Attack viruses, cancers, bacteria, etc Hemostasis- Sequence of responses that stops bleeding. Hemostasis sequence- Vascular spasm, platelet plug forming, blood clotting Chapter 19- The Heart Location- Heart is located in the mediastinum, apex is at tip of left ventricle, base is posterior surface Pericardium- Membrane surrounding and protecting the heart. Fibrous Pericardium- tough, inelastic, irregular connective tissue. Serous pericardium- thinner more delicate. Double layer Partiel layer and visceral layer

Layers of Heart Wall- Epicardium- outer layer, Myocardium, Endocardium=inner layer The heart chambers- 2 atria- recieveing chambers, 2 ventricles- pumping chambers Right atrium- receives blood from the coronary sinus, vena cava, has fossa ovalis Right ventricle- blood enters through the tricuspid to the right ventricle go to the pulmonary circuit Left atrium- receives blood from the lungs Left ventricle- Recieves blood from the left atrium via mitral valve goes to the systemic circuit Semilunar valves- aortic and pulmonary valves, valves open when pressure is exceeded.

Coronary circulation- Myocardium has its own network of blood vessels. Coronary veins empty in right atrium. Cardiac Muscles- autorhythmic fibers-self excitable, act as pacemaker, form conduction system. Contractile fibers-Provide contractions that propel blood. Conduction system- Begins in Sinoatrial (SA) node, reaches atrioventicular (AV)node enters AV bundle, enters right and left bundle branchesehich extends through interventricular septum toward apex. Purkinje fibers conduct action potential to remainder of ventricle myocardium. Ventricles contract. Nerve impulses from autonomic system and hormones modify timing.

Electrocardiogram- EKG- composite record of action potentials produced by all the heart muscle fibers. 3 recognizable waves- p, QRS, T Correlation of ECG waves- Systole-contraction/ dystole-relaxtion. Cardiac potential apperars –p wave, Action potential reaches av bundle-QRS wave, repolarization of ventricule fibers- t wave. Action potential and Contractions- repolarization- recovery of resting membrane potential, refractory period- time interval during which second contraction cannot be triggered, depolarization- contractile fibers have stable resting membrane potential, plateu- period of maintaining depolarization.

Cardiac Cycle- All events associated with one heartbeat. In each cycle, atria and ventricle alternately contract and relax. Forces blood from higher pressure to lower pressure. During relaxation period both atria and ventricles are relaxed Heart sounds- Auscultation Lubb-Av valves close Dupp SL Valves close Cardiac Output- CO- volume of blood ejected from left ventricle into aorta each minute. Cardiac reserve- difference between maximum CO and CO at rest. Chemical Regulation of heart rate- Hormones- epinephren and norepinehrine increase heart rate. Cations- Ionic imbalance can compromise pumping effectiveness.

Chapter 20- Blood vessels Introduction- Blood vessels transport material throught the body. Nutrient to/ waste out. Pathway- Goes from heart- ateries- aterioles-capillaries-venules-veins-heart Tissue Layers- Three coats- Tunic Interna, Tunica Media, Tunica externa Main Blood Vessels- Artery- blood carried away from heart. Vein- vessel carrying blood to the heart. Capillaries- exchange of waste and nutrients in the body. Anastomoses- the union of the branches of two or more arteries supplying the same body region. Collatrel circulation- the alternative circulatory route of blood flow to a body part.

End arteries- arteries that do not anastomose Arterioles- Muscular arteries divide into smaller arteries the smaller arteries divide into arterioles. Arterioloes feed capillaries. Capillaries- Microscopic vessels that connect arterioles to venules. Fed by metraterioles. Three capillary types- Continuous, fenestrated, sinusoids- from least leaky to most leaky. Capillary exchange- exchange mechanisms include- diffusion, trancytosis, bulk flow. Filtration and reabsorbtion- Filtration- pressure driven movement of fluid and solutes from blood into interstitial fluid.

Reabsorption- pressure driven from interstitial fluid into blood vessels. Net filtration pressure- difference between filtration and reabsorbtion pressure. Blood reservoirs- about 64% of blood is in systemic veins and venules at any given moment. Venous return- mechanisms that “pump blood from lower body to heart. Respitory pump- during inhalation the diaphragm moves downward increasing pressure in abdominal cavity and decreasing pressure in the thoracic cavity Blood Flow- the volume of blood that flows through any tissue in a given time period.

Blood pressure- Hydrostatic pressure exerted by blood on walls of blood vessel. Systolic blood pressure- highest pressure, diastolic blood pressure-lowest blood pressure Blood pressure regulation- in medulla oblongata Neural regulation of BP- baroreceptor reflexes- pressure sensitve sensory receptors in aorta, carotid arteries in neck and chest Hormonal regulation of BP- rennin-angiotensin-aldosterone system- endocrine response. Epi and norepinephrine- sympathetic nervous system, antidiuretic hormone- causes increase blood pressure, Atrial natriuetic peptide- lowers blood vessels.