Circulatory System

Circulatory SystemHonors Biology

1Circulatory SystemHeartBloodBlood Vessels2

Heart

Approximately the size of your fist

Weighs less than a pound

5 Liters of blood is pumped through 60 000 miles of blood vessels per minute

Beats ~100 000 times a day3

Heart CoveringPericardium Protects and anchors heart Prevents overfilling

Heart WallEpicardium - visceral layer of the serous pericardium

Myocardium cardiac muscle layer forming the bulk of the heart

Endocardium lines the heart chambers and continues with endothelial lining of blood vessels4External Heart: Major Vessels of the Heart Superior & inferior venae cava

Right and left pulmonary veins

Pulmonary trunk (splits into right & left pulmonary arteries)

Ascending aorta (3 branches) brachiocephalic, carotid, & subclavian arteries

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6Heart ChambersAtria of the HeartAtria are the receiving chambers of the heart Blood enters right atria from superior & inferior venae cava & coronary sinus Blood enters left atria from pulmonary veins

Ventricles of the Heart Ventricles are the discharging chambers Papillary muscles mark ventricular walls Interventricular septum separate ventricles

Right ventricle pumps blood into the pulmonary trunkLeft ventricle pumps blood into the aorta

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9Pathway of Blood through the Heart and Lungs (Pulmonary & Systemic Circuits)

Pulmonary Circuit Right atrium tricuspid valve right ventricle Right ventricle pulmonary semilunar valve pulmonary arteries lungs

Systemic Circuit Lungs pulmonary veins left atrium Left atrium bicuspid valve left ventricle Left ventricle aortic semilunar valve aorta Aorta systemic circulation

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Microscopic Heart Muscle Anatomy Cardiac muscle is striated, short, fat, branched, and interconnected Intercalated discs anchor cardiac cells together & allow free passage of ions Heart muscle behaves as a functional syncytium 13Cardiac Cycle

Cardiac cycle refers to all events associated with blood flow through the heart

The cardiac cycle has two phases: Systole (contraction) Diastole (relaxation) 14

Cardiac Conduction15Electrocardiography (ECG or EKG)Electrical activity is recorded by electrocardiogram (EKG)P wave corresponds to depolarization of SA node & atria (ATRIAL SYSTOLE)QRS complex corresponds to ventricular depolarization (VENTRICULAR SYSTOLE & ATRIAL DIASTOLE)T wave corresponds to ventricular repolarization (VENTRICULAR DIASTOLE)Atrial repolarization record is masked by the larger QRS complex

16Abnormal ECG Deflection Wave PatternsSinus Bradycardia

Rate = 40-59 b.p.m.17

Sinus TachycardiaRate = 101-160 b.p.m.CausesCHF, hypoxia, pulmonary edemaIncreased temperature Stress or response to pain

18Sinus Arrest

CausesMyocarditis MI Digitalis toxicity

19Atrial Flutter

Rate = 250-350 b.p.m.Precipitates CHF

20Atrial Fibrillation (afib)

CausesCOPD CHF

21Ventricular Tachycardia(V-tac)

CausesCAD Acute MI Digitalis toxicity CHF

Rate = 100-220 b.p.m.22Ventricular Fibrillation (V-fib)

CausesAcute MI23Asystole

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Coronary Bypass25The 3 major types of vessels

Arteries carry blood away from the heart

Veins carry blood toward the heart

Capillaries contact tissue cells (Serving cellular needs)

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Capillaries

Very narrow (10 m diameter, the red blood cells that travel through capillaries are 6 m in diameter). Capillaries are made of thin endothelial cells (one layer thick) 27

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29Hydrostatic & Osmotic PressuresThe high hydrostatic pressure on the arterial side squeezes water and nutrients out of the capillaries.

Water leaving the capillaries builds up the osmotic pressure because the blood components have become more concentrated.

Towards the venal end, water and waste materials are sucked into capillaries by the osmotic pressure.

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35Varicose veins

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What Causes Varicose Veins?37How to treat varicose veins

Compression Stockings

Sclerotherapy

Ablation or Laser treatment(Both use heat)38BloodCardiovascular System

39Blood Functions1. Transports Dissolved gasses Nutrients Waste products to lungs and kidneys Enzymes Hormones from endocrine organs2. RegulatespHElectrolyte concentration of body fluidsBody temperature3. Restricts fluid loss4. Defends pathogens and toxins

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41Blood Composition1. Formed elementsErythrocytesLeukocytesPlatelets

2. Plasma

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43Overview of Blood Circulation

Blood leaves the heart via arteries that branch repeatedly until they become capillaries

Oxygen (O2) and nutrients diffuse across capillary walls and enter tissues

Carbon dioxide (CO2) and wastes move from tissues into the blood

Oxygen-deficient blood leaves the capillaries and flows in veins to the heart

This blood flows to the lungs where it releases CO2 and picks up O2

The oxygen-rich blood returns to the heart44Blood Physical Characteristics and Volume

Sticky, opaque fluid with a metallic taste

Color varies from scarlet (oxygen-rich) to dark red (oxygen-poor)

pH of blood is 7.357.45

Temperature is 38C, slightly higher than normal body temperature

Blood accounts for approximately 8% of body weight

Average volume of blood is 56 L for males, and 45 L for females

45PlasmaPlasma accounts for 55 % of the volume of whole blood. 92% of plasma is water, the rest consists of electrolytes and dissolved organic compounds.

Blood plasma contains over 100 solutes, including: Proteins albumin, globulins, clotting proteins, etc Non-protein nitrogenous substances lactic acid, urea, creatinine Organic nutrients glucose, carbohydrates, amino acids Electrolytes sodium (Na+), potassium (K+), calcium (Ca++), chloride (Cl-), bicarbonate (HCO3-) Respiratory gases oxygen and carbon dioxide

46ErythrocytesBiconcave discs

RBCs have no nuclei or organelles (anucleate) allow for a huge surface area to volume ratio

Hematocrit % of RBCs out of the total blood volume. (Ave) 46 adult men & 42 adult women.

There are roughly 5 million RBCs in each microliter of blood

Erythrocytes are unable to perform normal maintenance operations and usually degenerate after about 120 days in the circulation.

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49Blood TypeRh TypePercentA+34 %-6 %B+9 %-2 %AB+3 %-1 %O+38 %-7 %

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51Erythroblastosis Fetalis

52LeukocytesNormal response to bacterial or viral invasion

Move through tissue spaces

Granular leukocytes include neutrophils, eosinophils , and basophils.

Neutrophils are abundant, highly mobile phagocytes.

Eosinophils are attracted to foreign compounds coated with antibodies.

Basophils migrate into damaged tissues and release histamine, aiding in the inflammation response.

Monocytes migrating into peripheral tissues become free macrophages.

Lymphocytes, cells of the lymphatic system, include T cells and B cells. T cells migrate to peripheral tissues and attack foreign or abnormal cells; B cells produce antibodies.

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55Blood Clotting The coagulation process requires calcium ions, and Vitamin K must be available for the synthesis of five of the clotting factors.

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