The Circulatory System

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					The Circulatory System

  The Heart, Blood, and Blood Vessels
The Circulatory System
 The circulatory system is
  also known as the
  cardiovascular system.
   Often referred to as the
    ―transportation system‖ of
    the body. It consist of the
    heart, blood vessels, and
    the blood.
The Heart

  It is a muscular hollow organ
   often called the pump of the
  It’s approx. the size of a closed
  Located in the mediastinal
   cavity, between the lungs,
   behind the sternum, and above
   the diaphragm.
The Heart
 Three Layers of Tissue form
  the Heart.
   Endocardium—Smooth layer of
    cells that line the inside of the
   Myocardium—the muscular
    middle layer.
   Pericardium—double layered
    membrane or sac that covers
    the outside of the heart.
The Heart
 The Septum– A muscular wall
  that separates the heart into a
  right and left side. It prevents
  blood from moving between the
  right and left side of the heart.
   Interatrial septum– upper part of
    the septum.
   Interventricular septum– lower part
    of the septum.
The Heart
 Heart Chambers.
   Atria– Two upper
   Ventricles– two lower
The Heart
 Right Atrium– receives blood as it
  returns from the body cells.
 Right Ventricle– receives blood
  from the right atrium and pumps
  the blood into the pulmonary
The Heart
 Left Atrium– receives
  oxygenated blood from the
 Left Ventricle– receives blood
  from the left atrium and pumps
  the blood into the aorta for
  transport to the body cells.
Heart Valves
 Tricuspid valve– located between the
  right atrium and the right ventricle. It
  closes when the right ventricle
  contract allowing blood to flow to the
  lungs and preventing blood from
  flowing back into the right atrium.
Heart Valves
 Pulmonary valve– located between
  the right ventricle and the pulmonary
  artery, a blood vessel that carries
  blood to the lungs. It closes when the
  right ventricle has finished
  contracting, preventing blood from
  flowing back into the right ventricle.
Heart Valves
 Mitral Valve.
   Located between the left
    atrium and left ventricle.
   It closes when the ventricle is
    contracting, allowing blood to
    flow into the aorta and
    preventing backflow into the
    left atrium.
Heart Valves
 Aortic Valve.
   Located between the left
    ventricle and the aorta.
   It closes when the left ventricle
    is finished contracting, allowing
    blood to flow into the aorta and
    preventing backflow into the
    left ventricle.
Heartbeat Cycle
 Although separated by a septum, the
  right and left side of the heart work
  together in a cyclic manner.
   Diastole—brief period of rest.
   Systole—period of ventricular
Electrical Impulses
 Electrical Impulses originating in the
  heart cause the cyclic contraction of
  the muscles.
   Sinoatrial node (SA)—or pacemaker sends
    out an electrical impulse, which spreads
    out over the muscles in the atria.
   Atrioventricular node (AV)– a group of
    nerve cells located between the atria and
Blood Vessels
 Arteries—carry blood away from the
   Aorta—the largest artery in the body
   The smallest branch of arteries are called
Blood Vessels
 Capillaries—connect arterioles with
  venules, the smallest veins.
  Capillaries have thin walls to allow
  oxygen and nutrients to pass through
  to the cells and allow carbon dioxide
  and metabolic products from the cells
  to enter capillaries.
Blood Vessels
 Veins—carry blood back to the heart.
  Veins are thinner and have less
  muscle tissue than arteries.
   Two Largest Veins
     Superior Vena Cava—brings blood from the
      upper part of the body
     Inferior Vena Cava—brings blood from the
      lower part of the body.
The Blood

 It transports oxygen and
  nutrients to the body cells.
 It transport carbon dioxide and
  metabolic materials away from
  body cells.
 Often called a tissue because it
  contains many kinds of cells.
 There are approx. four to six
  quarts of blood in the average
 Made of fluid called plasma and
  solid elements called blood
   Plasma is approx. 90% water with
    many dissolved or suspended
Blood Cells
 Three main kinds of blood cells.
   Erythrocytes or red blood cells.
     The erythrocytes contain hemoglobin.
        Hemoglobin carries both oxygen and
         carbon dioxide.
        When carrying oxygen, hemoglobin
         gives blood it’s red color.
Blood Cells
 Leukocytes– white blood cells.
   Their main function is to fight
   Five types of leukocytes
       Basophils
       Eosinophils
       Neutrophils-
       Lymphocytes
       Monocytes
Blood Cells
 Thrombocytes—also called
   They contain an enzyme required
    for the clotting process.
Diseases and Abnormal
 Anemia– inadequate number
  of red blood cells,
  hemoglobin or both.
   Symptoms include pallor
    (paleness), fatigue, dyspnea
    (difficult breathing), and rapid
    heart rate.
Diseases and Abnormal
 Types of Anemia.
   Iron deficiency anemia—results when
    there is inadequate amounts of iron
    to form hemoglobin in erythrocytes.
   Aplastic anemia– caused by injury to
    or destruction of the bone marrow,
    resulting in poor or no formation of
    red blood cells. Usually fatal if
    damage cant be reversed.
Disease and Abnormal
 Types of anemia.
   Pernicious anemia– results in the
    formation of abnormally large and
    inadequate number of erythrocytes.
   Sickle cell anemia– chronic, inherited
    anemia. It results in the production
    of abnormal crescent shaped
    erythrocytes that carry less oxygen,
    breaks easily, and block blood
Diseases and Abnormal
 Aneurysm– ballooning out of, or
  saclike formation on an artery
 Arteriosclerosis– hardening or
  thickening of the arterial walls,
  resulting in a loss of elasticity
  and contractility.
 Atherosclerosis– occurs when
  fatty plaque are deposited on the
  walls of the arteries.
Diseases and Abnormal
 Congestive Heart Failure– occurs
  when the heart muscles do not
  beat adequately to supply the
  blood needs of the body. It may
  involve the right or left side of
  the heart.
 Embolus– foreign substance
  circulating in the bloodstream. It
  can be air, a blood clot, bacterial
  clumps, a fat globule, or other
  similar substances.
Diseases and Abnormal
 Hemophilia– an inherited
  disease that occurs almost
  exclusively in males but can
  be carried by females.
 The blood is unable to clot
  due to a lack of plasma
 Hypertension– high blood
Diseases and Abnormal
 Leukemia– malignant disease of the
  bone marrow or lymph tissue.
 Myocardial Infarction– Heart attack
  occurs when blockage in the
  coronary artery cut off blood supply
  to the heart.
 Phlebitis—inflammation of a vein,
  frequently in the leg. If a thrombus
  or clot forms the condition is termed
Diseases and Abnormal
 Varicose veins– dilated,
  swollen veins that have
  lost elasticity and cause
  stasis or decreased blood
Diseases and Abnormal Conditions
 Stroke-occurs when a blood clot
  blocks the flow of blood in a vessel,
  or when a vessel bursts in the brain.
 Coronary artery disease-is the
  narrowing of the coronary arteries
  that supply blood to the heart.
The Circulatory System