THE CARDIOVASCULAR SYSTEM

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THE CARDIOVASCULAR SYSTEM
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VITAL FUNCTIONS

• pumps 7000 liters of blood / day
• carry O2 from the lungs to the bodys cells
• carry nutrients from the digestive system to the
  cells
• remove cellular waste
• form clots/coagulate (an anticoagulant prevents
  clotting)

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YOUR BLOOD FLUID TRANSPORT

• blood is a tissue made of
• fluid, cells, fragments of cells
• fluid plasma, 55 of the total volume of blood
• cells red white blood cells and platelets
  suspended in plasma
• usually 45 of the total volume of blood
• this percentage is called the hematocrit (HCT)
• For example, a hematocrit of 25 means that there
  are 25 milliliters of red blood cells in 100
  milliliters of blood.

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YOUR BLOOD FLUID TRANSPORT

• red blood cells (RBCs) erythrocytes
• round, disk-shaped cells
• make up 44 of the total volume of blood
• produced in the red bone marrow of the ribs,
  humerus, femur, sternum, and other long bones

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red blood cells (RBCs) Erythrocytes

• only have a nucleus in the early stages of
  development
• active about 120 days, then broken down in the
  spleen liver by macrophages via phagocytosis
• contain hemoglobin, an iron-rich protein molecule
  that binds to O2
• oxygenated RBCs carry oxygen from the lungs to
  the bodys cells

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Anemia

• too few RBCs or too little hemoglobin. Person
  is pale lacks energy. Caused by low iron
  intake.

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white blood cells (WBCs) leukocytes

• infection fighters
• play a major role in protecting you from foreign
  substances, and from invading bacteria
• make up 1 of total blood volume
• they are larger than RBCs they have a nucleus

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blood clotting

• platelets help blood to clot by linking together
  a sticky network of protein fibers called fibrin
• this forms a web over the wound to catch escaping
  RBCs
• platelets are produced in bone marrow last only
  1 week

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ABO BLOOD GROUPS

• blood surface antigens determine blood group
• antigen substances that stimulate an immune
  response
• antigens are on the
• surface of certain RBCs
• 2 types of antigens
• A B

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• blood plasma contains antibodies that are shaped
  to correspond with the different blood surface
  antigens
• the antibodies react with the matching antigen if
  they are brought together, resulting in clumped
  blood
• you dont have
• antibodies for your
• own antigen type

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Rh factor Rhesus factor

• another antigen which may be present (Rh) or
  absent (Rh-)
• Rh factor is an inherited characteristic
• only 15 of the U.S. population is Rh-

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• may complicate pregnancies
• an Rh- mother that is pregnant with a Rh baby
  will make anti-Rh antibodies when their blood
  mixes at birth
• if she gets pregnant again with another Rh baby,
  her anti-Rh antibodies will destroy RBCs in the
  fetus

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• prevention mom is treated with a substance to
  prevent the production of antibodies in her blood
  at 28 weeks again shortly after the birth of
  the first baby

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BLOOD VESSELS PATHWAYS OF CIRCULATION

• 3 main types arteries, veins, capillaries
• venules arterioles (smaller than veins and
  arteries, but bigger than capillaries)
• 62,000 miles of blood vessels in your body!

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arteries

• large, thick walled,
• muscular, elastic
• blood vessels
• carry blood away
• from the heart
• under great pressure
• main arteries divide into smaller arteries that
  divide into arterioles which eventually branch
  into capillaries

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capillaries

• microscopic blood vessels only 1 cell thick
• enables nutrients gases to diffuse easily
  between blood cells surrounding tissue cells
• form a dense network that reaches virtually every
  cell in the body
• join to form venules as
• blood leaves tissues

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veins

• carry blood from the tissues back to the heart
• less pressure than the arteries
• blood travels against gravity in some veins, so
  they are equipped with valves to prevent blood
  flowing backward

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HEART THE VITAL PUMP

• the heart
• a large organ made of cardiac muscle cells rich
  in mitochondria
• main function to keep blood moving constantly
  thru the body
• Myocardium thick layer
• of muscle in the walls of the
• heart
• Pericardium serous
• membrane that encloses the
• heart

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all mammalian hearts have 4 chambers

• 2 upper chambers L R atria
• 2 lower chambers L R ventricles
• the atrial walls are thinner less muscular than
  the ventricles because they perform less work

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• the L ventricle works harder than the R, so its
  bigger making the heart lopsided
• a solid septum separates the whole R side from
  the L, so blood never mixes

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Valves of the heart

• - the tricuspid valve sits between the R atrium
  the R ventricle it permits blood to flow thru
  while preventing backflow
• the bicuspid (mitral) valve sits between the L
  atrium the L ventricle, does the same job as
  the tricuspid

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• the bicuspid tricuspid valves are called
  atrioventricular
• the pulmonary aortic valves are called
  semilunar because their cusps are shaped like
  half moons

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PATH OF BLOOD

• 
  pulmonary
• Blood ? superior/inferior ? Right ?
  Tricuspid ? Right ? semilunar ?
• from body vena cava Atrium
  Valve Ventricle valve
• Pulmonary ? To alveoli ? Blood ?
  pulmonary ? Left ? Bicuspid ?
• Artery of lungs from lungs
  veins Atrium Valve
• Aortic
• left ? Semilunar ? Aorta ? To body
• ventricle Valve
• http//www.youtube.com/watch?vrguztY8aqpk

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the heart acts as 2 separate pumps, following 2
pathways

• pulmonary circulation the right side of the
  heart pumps blood from the heart to the lungs
• systemic circulation the left side of the
  heart pumps blood from the heart to the rest of
  the body

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heartbeat regulation

• each heartbeat causes a surge of blood to flow
  from the L ventricle into the aorta then into
  the arteries pulse
• best felt in the arms radial artery or the
  necks carotid artery

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heartbeat regulation

• heart rate is set by the pacemaker in the top of
  the R atrium
• sends an impulse to the atria
• triggers another impulse to contract the
  ventricles
• electrocardiograph a machine
• that measures records these
• electrical signals

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heartbeat regulation

• electrocardiogram the reading produced by this
  machine
• the ECG is an important tool used to diagnose
  abnormal heart rhythms patterns

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blood pressure

• the force that the blood exerts on the blood
  vessels
• it rises falls as the heart contracts relaxes

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• it rises sharply when the ventricles contract
  systolic pressure / systole
• it drops dramatically as the ventricles relax
  diastolic pressure / diastole

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blood pressure

• hypertension high blood pressure persistently
  elevated arterial pressure. Can be caused by
  kidney disease, high sodium intake, obesity,
  psychological stress, or arteriosclerosis
  (hardening of the arteries)
• http//www.youtube.com/watch?v0L3hV-PLlC4
• http//www.youtube.com/watch?vtB8nISCEcs8feature
  PlayListp595A711C9A756527playnext_fromPL
• http//www.youtube.com/watch?v8e6qtnHa8ps
• http//www.youtube.com/watch?vPrRWkMoFNRcfeature
  channel

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control of the heart

• the medulla oblongata regulates the rate of the
  pacemaker
• sensory cells in the arteries become stretched
  when the heart beats too fast which sends a
  signal to the medulla oblongata

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control of the heart

• if the heart slows too much, blood pressure drops
  which signals the medulla oblongata to speed up
  the pacemaker

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RELEVANT VOCABULARY

• Pericarditis inflammation of the pericardium
• Pulmonary circulation a circuit transporting
  blood between the heart lungs
• Systemic circulation a circuit transporting
  blood between the heart body tissues
• Myocardial infarction a heart attack
• Tachycardia rapid heart rate (100 beats / min)
• Bradycardia abnormally slow heart rate (lt60)

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• Heart murmur abnormal or unusual heart sounds,
  can be due to valve incompetence
• Cardiac output the volume of blood pumped out
  by each side of the heart in 1 min
• Stroke volume the volume of blood pumped out a
  ventricle with each heartbeat
• Congestive heart failure a progressive
  condition occurring when the pumping efficiency
  of the heart is depressed so that circulation is
  inadequate to meet tissue needs

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• Pulmonary edema blood vessels leak fluid into
  the air sacs and tissues of the lungs
• Atherosclerosis fatty deposits / plaque clogs
  the blood vessels, leads to arteriosclerosis
  (hardening of the arteries)
• Leukemia cancer of the white blood cells