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The Cardiovascular System

The Cardiovascular System. Circulating fluid (blood) The Heart Blood vessels. Physical Characteristics of Blood. Sticky, opaque fluid Color varies from scarlet (O2 rich) to dark red (O2 poor) More dense than water, slightly alkalinic (7.35-7.45) Temperature:(38C or 100F)

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The Cardiovascular System

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  1. The Cardiovascular System • Circulating fluid (blood) • The Heart • Blood vessels

  2. Physical Characteristics of Blood • Sticky, opaque fluid • Color varies from scarlet (O2 rich) to dark red (O2 poor) • More dense than water, slightly alkalinic (7.35-7.45) • Temperature:(38C or 100F) • 8% of body weight, 5-6L(volume)

  3. FunctionsDistribution • Deliver oxygen from lungs & nutrients from GI tract to cells • Transport metabolic wastes from cells to elimination sites (lungs, kidneys) • Transport hormones

  4. FunctionsRegulation • Maintenance of body temperature • Maintenance of pH;proteins act as buffers • Maintenance of adequate fluid volume in circulatory system

  5. FunctionsProtection • Prevention of blood loss • Prevention of infection

  6. Blood CompositionBlood Plasma • 90% water; 55% of whole blood volume • 100 dissolved solutes (nutrients, gases, hormones, wastes, cell activity products • Plasma proteins: (1)Albumin accounts for 60% of plasmic proteins; (2) immunoglobulins, transport proteins (35%); (3) fibrinogen (4%) clotting reaction

  7. Blood CompositionFormed Elements • Erythrocytes, leukocytes, platelets • Two of the three are not true cells • Most of the formed elements short life spans • Amitotic (renewed by bone marrow)

  8. Formed ElementsErythrocytes • Biconcave shaped (maintained by spectrin) ideal for gas transport • Anucleate, no organelles • 97% Hb • Hemocytoblast>proerythroblast>early erythroblast>late erythroblast >normoblast> reticulocyte>erythrocyte • Blood typing:A, B, AB, O

  9. Formed ElementsLeukocytes • Provide immunity • Less than 1% of total blood volume • Diapedesis • Amoebid motion • Positive chemotaxis • Leukopenia,leukocytosis • Granulocytes, agranulocytes

  10. Granulocytes • Neutrophils-Most numerous(70%);granules contain peroxidases and hydrolytic enzymes; polymorphonuclear; 1st line of immune attack;defensins • Eosinophils-(1-4%); bilobed red nucleus;lack bacteriolytic enzymes;parasitic infections; inactivate allergic reactions • Basophils-(0.5%);U or S shaped nucleus; release histamine/contain heparin

  11. Agranulocytes • Monocytes-(4-8%); largest WBC; kidney shaped nuclei;metamorphose into macrophages • Lymphocytes-(20-30%); 2nd most numerous leukocyte;scant cytoplasm;lymphatic system component;specific immunity T cells-attack foreign cells directly; B cells-change into plasma cells that secrete antibodies;NK cells-immune surveillance

  12. Platelets • Cytoplasmic fragments of megakaryocytes • Anucleate • Regulated by thrombopoietin • Hemostasis

  13. The Cardiovascular System:The HeartOverview • Heart chambers:Atria,ventricles • Pulmonary circuit • Systemic, coronary circuit • Arteries, veins, capillaries

  14. The Heart Size, Location, and Orientation • Weighs between 250-350 grams • Located in mediastinum(extends obliquely from 2nd rib to 5th intercostal space) • Base, apex

  15. Coverings of the Heart • Fibrous pericardium-(1) protection;(2) anchors to surroundings (diaphragm,great vessels); (3) prevents blood overfill. • Serous pericardium-(1) parietal layer lines inner fibrous pericardium;(2)visceral layer (epicardium);(3) Pericardial cavity-in between

  16. Layers of the Heart Wall • Epicardium-often infiltrated with adipose • Myocardium-layered cardiac muscle tissue(contractile), CT, blood vessels, & nerves • Endocardium-glistening white endothelial layer resting on CT;continuous with endothelium

  17. Cardiac Muscle Tissue • Cardiocytes-central nucleus,myofibrils, intercalated discs,aerobic respiration;high myoglobin [ ];glycogen/lipid reserves • Circulatory supply more extensive vs.red muscle tissue • Cardiocyte membranes bound together by intercalated discs (desmosomal cell junctions); functional syncytium.

  18. Fibrous Heart Skeleton • Collagen & elastic fibers • Encircle bases of pulmonary trunk/aorta and heart valves • Functions:(1) stabilizes cardiocyte/valve positionings; (2) reinforcement of blood vessels & nerves;(3) elasticity

  19. Anatomical Orientation and Superficial Heart Anatomy • Borders: Superior, Right, Inferior, Left • Sternocostal surface-rt.atrium & ventricle • Diaphragmatic surface-post./inf.wall of left ventricle • Auricles • Coronary sulci • Interventricular sulci(ant.,post.)

  20. Internal Anatomy/Organization of the Heart • Right atria-superior/inferior vena cavae,coronary sinus;pectinate muscles, interatrial septum, fossa ovalis • Tricuspid valve • Right ventricle-chordae tendineae, papillary muscles,trabeculae carneae, pulmonary semilunar valve, pulmonary trunk

  21. Internal Anatomy/Organization of the Heart(cont’d) • Left Atrium-Lt./Rt. Pulmonary veins • Bicuspid valve • Left ventricle-Aortic semilunar valve,aortic sinuses, ascending aorta • Vestigial structures:Ligamentum arteriosum(pulm.trunk, aortic arch),fossa ovalis

  22. Coronary CirculationArterial Supply • Left coronary artery:anterior interventricular art.(supplies intervent. septum & ant.walls of rt./lt. ventr.) and circumflex art.(lt. atrium & post.walls of lt. vent.) • Right coronary artery: marginal art. (supplies myocardium of lateral part (rt.side) and post.intervent.art.(post.ventr.walls) • Anastomoses-fusing collateral routes

  23. Coronary CirculationVenous Supply • Coronary sinus-receives blood from great, middle, and small cardiac veins

  24. Cardiac Cycle • Systole-chamber contraction (atrial 0.1s, ventricular 0.3s) • Diastole-chamber relaxation(0.4 s) • (1)Period of ventricular filling(mid-to-late diastole); (2) Ventricular systole (isovolumetric contraction, ventricular ejection phases);(3)Isovolumetric relaxation (early diastole)

  25. Cardiac CycleHeart Sounds • 1st (“lubb”) sound- beginning ventricular systole • 2nd (“dupp”)sound-beginning ventricular diastole • 3rd/4th sounds associated with ventricular blood flow & atrial contractions

  26. Cardiac CycleCoordination of Cardiac Contractions • Nodal cells-establish contraction rates(SA, AV nodes) • Conducting fibers-distribute contractile stimuli to myocardium(AV bundle, Purkinge fibers) • Bradycardia, Tachycardia

  27. The Cardiovascular System:Blood Vessels • Blood vessels-closed delivery system that begins and ends at the heart • Heart>arteries>arterioles>capillary bed> venules>veins>heart

  28. Structure of Blood Vessel Walls • All blood vessels (except capillaries), are composed of three tunics surrounding a central blood-containing lumen. • Tunica intima (interna)-endothelium (continuum of endocardium) • Tunica media-Circular smooth muscle & elastin; regulated by vasomotor nerve fibers of ANS; vasoconstriction/vasodilation;thickest layer

  29. Structure of Blood Vessel Walls (cont’d) • Tunica externa (adventitia)-loose collagen fibers that protect/reinforce blood vessel;infiltrated with nerve fibers, lymphatic vessels, elastin fibers; vasa vasorum.

  30. Arterial System • Elastic (conducting) arteries; located near heart-aorta & major branches;diameters range from 2.5cm to 1 cm; contain elastin. • Muscular(distributing) arteries-deliver to target organs and account for named arteries in human body; middle tunic has more smooth muscle;active in vasoconstriction.

  31. Arterial System (cont’d) • Arterioles-diameter ranges from 0.3mm to 10 μm; larger arterioles/3 tunics • Capillaries-smallest of blood vessels;single tunic(intima)

  32. Arterial System (cont’d)Types of Capillaries • Continuous-abundant in skin and muscles;complete lining with tight junctions • Fenestrated-have porous walls due to incomplete endothelium • Sinusoids-highly modified leaky capillaries common in liver, bone marrow, lymphoid and endocrine organs • Capillary Beds-microcirculation

  33. Venous System • Venules-range from 8 to 10 µm in diameter;porous • Veins-65% of total blood supply; collect blood from all tissues;vein walls less elastic than arteries;sparse tunica media, thick adventitia;valves

  34. The Pulmonary Circuit • Left/Right Pulmonary Arteries • Pulmonary Arterioles • Capillaries, alveoli • Venules • Pulmonary veins

  35. The Systemic CircuitSystemic Arteries • Ascending aorta • Aortic arch • Brachiocephalic trunk (rt. common carotid, rt. subclavian) • Left common carotid • Left subclavian

  36. Subclavian Arteries and Branches • Thyrocervical trunk-neck, shoulder & upper back • Internal thoracic-pericardium/ant.thoracic wall • Vertebral artery-brain/spinal cord • Axillary artery-pectoral region/axilla • Brachial artery-upper limb • Radial/ulnar arteries-antebrachium • Superficial/deep palmar arch-palm • Digital artery-thumb/fingers

  37. The Carotid Arteries and Brain Blood Supply • External carotid artery-neck, pharynx, esophagus, larynx, mandible, & face • Internal carotid artery-brain • (IC branches):Ophthalmic artery-eyes;anterior cerebral artery-frontal/parietal;middle cerebral-midbrain, lat.cerebrum • Vertebral>basilar>posterior cerebral>posterior communicating arteries>middle cerebral> anterior communicating>anterior cerebral

  38. The Descending AortaThoracic Aorta & Branches • Visceral branches-Bronchial, pericardial, mediastinal,esophageal arteries. • Parietal branches-Intercostal,superior phrenic.

  39. The Descending AortaAbdominal Aorta & Branches Unpaired arteries : • Celiac trunk-liver, stomach, spleen; Branches-left gastric,splenic, & common hepatic arteries. • Superior mesenteric-pancreas, small intestine, most of large intestine. • Inferior mesenteric-terminal colon & rectum

  40. Abdominal Aorta & Branches (cont’d) Paired arteries: • Inferior phrenic • Suprarenal • Renal • Gonadal • Lumbar

  41. Arteries of the Pelvis & Lower Limbs • Right/Left Common Iliacs • Internal Iliac-urinary bladder, int.,ext. walls of pelvis, genitalia • External Iliac-lower limbs

  42. Arteries of Thigh & Leg • Femoral • Deep femoral • Popliteal • Post., Ant. tibial • Peroneal

  43. Arteries of the Foot • Dorsalis pedis • Medial, Lateral plantar

  44. Systemic CircuitSystemic veins • Cranial venous return-Superior cerebral veins, superior sagittal sinus, great cerebral vein,straight/sigmoid sinus,internal jugular. • Vertebral veins empty into brachiocephalic veins. • Temporal, facial, & maxillary empty into the external jugular

  45. Systemic Veins Brachium venous return- • Digital veins • Superficial/deep palmar • Palmar venous arches • Cephalic • Median antebrachial • Basilic • Median cubital (cephalic, basilic) • Axillary (basilic, brachial)

  46. Systemic Veins SVC formation • Subclavians • Brachiocephalics(vertebrals,ext/int jugulars) • Azygos(hemiazygos)-chief blood collectors of thorax

  47. Systemic VeinsTributaries of the IVC Pelvic limb venous drainage • Plantar/dorsal venous arch • Anterior/ posterior tibial • Peroneal • Popliteal • Femoral • Great/small saphenous • External iliac

  48. Systemic VeinsVeins Draining the Pelvis • Internal iliac-pelvic organs • Common iliac Veins Draining the Abdomen • Lumbar • Gonadal • Hepatic • Renal • Suprarenal • Phrenic

  49. Hepatic Portal System Tributaries • Inferior mesenteric • Splenic • Superior Mesenteric * Hepatic portal vein formed by fusion of superior mesenteric and splenic

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