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Chapter 11

Chapter 11. The Cardiovascular System. Heart (Cardiac Muscle). General continuous, rhythmic beating delivers: to cells thru blood oxygen nutrients hormones electrolytes pump to lungs exchange CO2 for O2. Heart. Anatomy of the Heart lies in the mediastinum medial cavity of the chest

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Chapter 11

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  1. Chapter 11 The Cardiovascular System

  2. Heart(Cardiac Muscle) • General • continuous, rhythmic beating • delivers: to cells thru blood • oxygen • nutrients • hormones • electrolytes • pump to lungs • exchange CO2 for O2

  3. Heart • Anatomy of the Heart • lies in the mediastinum • medial cavity of the chest • big as fist 2nd rib and 5th rib • pericardium • sac around heart • film of serous fluid friction free • Pericarditis - inflammation • heart wall • epicardium - visceral pericardium • myocardium - thick cardiac muscle and connective tissue • endocardium • endothelial lining of heart chambers

  4. Chambers of the Heart • right atrium • recieves blood “deoxygenated” • superior & inferior vena cava • tricuspid valve • right ventricle • pumps blood to lungs • pulmonary artery • semilunar valve “pulmonary” • left atrium • recieves blood “oxygenated” • pulmonary veins bicupsid(mitral) valve • left ventricle • pumps blood to body • aorta • semilunar valve “aortic”

  5. Septum • divides chambers (wall) • Auricles • wrinkled flap like appendages on atria • musculi pectinati • muscle bundles in atria • Valves • prevent backflow • atrioventricular valves • tricupsid valve • mitral valve “bicuspid” • chordae tendinae • white cords anchor flaps of valves attached to papillary muscles • semilunar valves • pulmonary • aortic

  6. Cardiac Circulation • coronary arteries - O2 and nutrients • arise from aorta • coronary veins take CO2 & wastes • coronary sinus ---> right atrium

  7. Cardiac Function • General • 70 beats/min • its own conduction system • contracts independently • Conduction • sinoatrial (SA) node “pacemaker” • in right atrium ---> depolarization • atrical contract • internodal fiber bundles • depolarization node to node • atrioventricular (AV) node • junction of atria & ventricle • ventricular contraction

  8. Atrioventricular Bundle • purkinje fibers • rapid impulses • failed pacemakers • slow h.r. – bradycardia < 60 beats/min • rapid h.r. -tachycardia > 100 beats/min • fibrillation • rapid uncoordinated heart beat

  9. Cardiac Cycle • initiated by the SA node • Cycle • Systole -contraction ventricles • Diastole -relaxed atria fill • Heart Sounds • auscultation • ‘lubb dubb’ • Lubb AV valves close • Dubb semilunar valves close • murmurs • abnormal heart sound • incompetent valve swishing sound • Stenosed- narrow valves

  10. Cardiac Output • stroke volume • volume of blood pumped w/ each beat • cardiac output • 4900 ml/min ---> 4.9 l/min • SV x VR 70 ml/ beat x 70 beats/ min • exercise • increase SV increase venous return • cardiac reserve • ability of heart to increase cardiac output • Stroke Volume Regulation • healthy heart increase SV • Starling’s Law of the Heart • more cardiac muscle stretches greater stroke volume

  11. Regulation of Heart Rate • autonomic nervous system • parasympathetic innervation • vagus nerve ---> ACH • slows h.r. • sympathetic innervation • speeds h.r. stimulate SA node • norepinephrine • AV cardiac muscle • hormones and ions • epinephrine speeds up h.r. • Ca++ levels down - h.r. down • thyroxine levels up -h.r. up • K + levels drop causes abnormal heart rate

  12. temperature, gender, exercise, & age • fetus 140 - 160 • heat h.r. goes up • congestive heart failure • hypertension • worn out and weak • age & coronary atherosclerosis

  13. Electrocardiogram • three basic features of ECG • atria • P wave- depolarization of atria- atria contract • ventricle • QRS complex depolarization of ventricles • T wave repolarization of ventricles • shapes of the waves and the time intervals

  14. Disturbances in Heart Rate & Rhythm • myocardial infarction- heart attack • Ischemia- lack of oxygen • Fibrillation- irregular heart beat • Atherosclerosis- narrowing of arteries • Artherosclerosis- scar tissue Ca build up

  15. Systemic & PulmonaryCirculation • Capillaries ----> cells ----> capillaries ---->venuoles ---> veins ---> superior or inferior vena cava ---> right atrium ---> tricuspid valve --> right ventricle ---> pulmonary valve ---> pulmonary artery ---> lungs---> pulmonary veins ---> left atrium ---> bicuspid valve --> left ventricle ---> aortic valve ---> aorta --->arteries ---> arterioles----

  16. Blood Vessels • General • closed system • blood in vessels • principal types of blood vessels • arteries • blood away from heart • arterioles • capillaries • exchange materials w/ cells • capillary beds • veins • venuoles • blood toward heart

  17. Blood Vessel Wall • tunica interna ~ simple squamos • tunica media ~ smooth muscle • tunica adventitia ( externa) ~ connective • Major Arteries • aorta ~ largest artery • head and neck • carotid, brachiocephalic, subclavian • upper limbs and thorax • brachial, radial, ulnar • abdomen • hepatic • pelvis and lower limbs • renal - kidneys

  18. Major Veins • superior vena cava • head and neck • jugular & subclavian • upper limbs and thorax • brachial & radial • inferior vena cava • abdomen • hepatic and mesentaric • pelvis and lower limbs • renal and femoral • saphenous (LONGEST VEIN) • Capillaries • wall only one layer thick • exchange between blood & tissues • nutrients, oxygen, CO2, & wastes

  19. Special Circulation • brain • Circle of Willis • brain blood barrier • hepatic • digestive organs • liver • mesenteric • intestine

  20. Physiology of Circulation • Pulse • expansion and recoiling of artery • carotid, brachial, and radial • Blood Pressure • general • systolic / diastolic • pressure against walls of artery • Gradient auscultatory method • 120 mm Hg / 80 mm Hg brachial artery • Measuring Ventricular pressure • Systolic- contraction • Diastolic- relaxation

  21. Factors Effecting Blood Pressure • resistance • directly related to cardiac output • vasoconstriction ~ sympathetic • chemicals , temperature, diet • Kidneys- blood volume • autonomic nervous system • Blood viscosity- > resistance • variations in pressure • hypotension • systolic < 100 mm Hg • diet • hypertension • > 140 / 90 sustained • myocardium enlarged

  22. Cardiovascular Disease • Developmental • con genital • heart defects • Aging • atherosclerosis ~ narrowing of veins • cholesterol “LDL’s” ~ form plaque • ischemic heart disease ~ lack of oxygen • angina pectoris ~ heart pains • myocardinal infarction ~ heart attack • varicose veins ~ venous valves weaken thrombophlebitis

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