The Cardiovascular System

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The Cardiovascular System

• Your Heart and Stuff

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The Cardiovascular System

• includes the heart, blood vessels, and blood.
• Cardiology- the study of the heart and the
  diseases associated with it.

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Functions

1. to supply cells tissues with oxygen
2. to circulate substances nutrients
3. to remove wastes (CO2 urea) from cells and
   tissues.

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Heart Coverings

• Pericardium covers the heart, has 3 layers
• Fibrous pericardium - outermost
• Parietal pericardium - middle
• (Pericardial cavity)
• Visceral pericardium (continuous with epicardium)
  - innermost

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The Heart Wall (3 layers)

1. epicardium (visceral pericardium) reduces
   friction
2. myocardium - cardiac muscle tissue (bulk of
   heart)
3. endocardium smooth inner lining of heart
   chambers and valves.

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Heart Chambers

• The upper chambers atria (atrium) blood flows
  here 1st. Pumps to ventricles
• The lower chambers ventricles, pump blood out
  to body or lungs.
• The right side of your heart receives blood
  (deoxy) from the body and pumps it to the lungs.
• The left side of the heart receives blood (oxy)
  from the lungs and pumps it out to the body
• A solid wall-like septum separates the atrium and
  ventricle on the right from those on the left
  so blood on one side never mixes with blood on
  the other side

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Why is this the right side? And this the left?
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Heart Valves

• Tricuspid Valve btwn RA and RV
• Pulmonary Valve allows blood to leave RV
• Pulmonary means lungs.
• Bicuspid (mitral) Valve btwn LA and LV
• Aortic Valve allows blood to leave LV

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What color is blood?

• Blood when oxygenated is red
• However, deoxygenated is not blue as believed. It
  is actually a redish purple.
• It appears blue because the color is diffused
  looking through the skin
• This is also why veins typically appears almost
  green in African-Americans.

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Blood Flow

• Blood low on O2 (deoxygenated) enters Right
  Atrium through the superior and inferior venae
  cavae and coronary sinus
• Right Atrium wall contracts, and blood passes
  thru tricuspid valve into Right Ventricle (only
  adds 30 of vol. to RV)
• Right Ventricle contracts, and blood is forced
  thru pulmonary valve into pulmonary trunk?
  divides into pulmonary arteries(left right)?to
  lungs

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Blood Flow cont.

• pulmonary arteries take blood to lungs gas
  exchange occurs between blood and air in alveoli
• Carbon Dioxide is released. Oxygen is taken in.
  Blood goes from deoxygenated to oxygenated
• Freshly oxygenated blood returns to heart thru
  the pulmonary veins that lead to Left Atrium

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Blood Flow cont.

• Left Atrium wall contracts, and blood moves thru
  bicuspid valve into Left Ventricle
• Left Ventricle contracts, blood moves thru aortic
  valve and into the aorta?aorta carries oxygenated
  blood to tissues
• Oxygen to tissues, Carbon Dioxide made in tissues
  released into blood
• Deoxygenated blood is sent back to heart thru
  superior and inferior vena cava

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Heart Sounds

• Heart sounds are produced by vibrations in the
  tissue associated with the closing of the valves.
• The first part of the heart sound (lubb) is heard
  during ventricular contraction when the valves
  between the Atrium Ventricles closes.
• The closing causes the blood to stop flowing or
  back up causing a sound almost like waves
  crashing on a beach. They do not make a sound
  until they crash. Blood does not make a sound
  when flowing only when it is stopped and crashes
  into heart valve.

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Heart Sounds contd

• The second part of the heart sound (dubb) happens
  during ventricular relaxation when the pulmonary
  and aortic valves snap shut
• Heart sounds give doctors an indication of how
  well the valves are functioning (ex murmurs)
• Mitral Valve prolapse is usually identified by
  lubb-dubb-squish. The squish is the valve closing
  improperly and some blood still is leaking
  through.

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National geographic website

• Here the heart Hit next twice

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Cardiac Muscle fibers

• Cardiac fibers are highly branched, so when any
  part of the network is stimulated, the whole unit
  contracts (called a functional syncytium)
• There are 2 syncytia the atrial syncytium and
  the ventricular syncytium

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Conduction of a cardiac impulse

• Starts at the sinoatrial (S-A) node located in
  the RA
• The S-A node is self-exciting (no outside
  stimulation needed) and is rhythmic (initiates
  70-80 impulses/min. in an adult)
• Called the pacemaker

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Conduction of a cardiac impulse

• impulse generated by the S-A node causes the
  atrial syncytium to contract
• impulse then travels to the atrioventricular
  (A-V) node located in the septum that separates
  the atria

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Conduction of a cardiac impulse

• impulse is delayed as it passes thru the A-V
  node, allowing time for the atria to empty and
  the ventricles to fill with blood
• impulse then travels thru a bundle of fibers
  called the bundle of His located in the
  interventricular septum.

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Conduction of a cardiac impulse

• The bundle of His gives rise to Purkinje fibers
• The Purkinje fibers extend down into the apex of
  the heart and curve upward thru the walls of the
  ventricles
• As impulse passes thru Purkinje fibers it
  stimulates the ventricular syncytium to contract
• Ventricles squeeze up from the bottom of V to
  squeeze blood out of heart.

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Blood vessels

• Arteries
• carry blood away from heart strong, thick carry
  blood under high pressure composed of mainly
  smooth muscle tissue
• Not always oxygenated blood. Pulmonary artery
  takes deoxygenated blood to lungs away from
  heart.
• Are typically deeper than veins
• Arteries subdivide into smaller tubes called
  arterioles.

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Blood vessels contd

• Capillaries
• are the smallest blood vessels. They connect the
  arterioles with the venules.
• Capillary walls are thin enough to allow
  substances to pass through such as O2 CO2
• Capillaries are microscopic and are only big
  enough for one red blood cell to go through at a
  time. If you can see it it is not a capillary.
• 10-40 billion capillaries in your body
• No cell is 1/100 of cm from a capillary

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Blood vessels contd

• Veins
• Venules are small vessels that merge to form
  veins parallel to arterioles
• these vessels carry blood back to heart and are
  not always deoxygenated.
• Venules and veins have thinner walls than
  arteries because the blood pressure is less.

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The Cardiac Cycle

• The series of events that constitute a heartbeat
• The atrial walls contract the ventricle walls
  are relaxed
• The ventricle walls contract the atrial walls
  relax
• Both the atria and the ventricles relax
• Ventricle contractions control blood pressure
• Contracting systole
• Relaxation - diastole

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Blood Pressure

• The force blood exerts against the inner walls of
  blood vessels
• Usually refers to the pressure in the arteries
  supplied by the aorta
• When the ventricles contract blood moves into the
  aorta and pulmonary trunk, increasing pressure
• maximum pressure during ventricular contraction
  is called the systolic pressure

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Blood Pressure

• When ventricles relax, arterial pressure drops
• The lowest pressure before the next ventricular
  contraction is called the diastolic pressure
• If theres a drop in blood pressure, walls of
  veins constrict, helping to maintain blood
  pressure by returning more blood to heart. (Less
  blood in veins if veins are smaller)
• This ensures a nearly normal blood flow even when
  as much as 25 of blood volume is lost.

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Taking Blood Pressure

• Normal Blood Pressure 120/80.
• Increase blood pressure until can not hear any
  flow because artery closed. Cuff pressure is
  greater than systole diastole so blood vessels
  closed all the time. (Contraction Relaxation)

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Taking Blood Pressure

• Let blood pressure come down until under 120.
  During Systole (contraction), pressure in
  arteries is greater than cuff, so artery open
  only during systole
• But during diastole (relaxation) pressure of cuff
  is greater than pressure in blood vessels so
  blood vessels are closed.

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Taking Blood Pressure

• The walls of the blood vessels go in and out
  causing turbulent flow of blood.
• Can hear turbulent flow because walls of arteries
  going in and out do to change in pressure.
• Under 80 silent because cuff pressure less
  diastole pressure so arteries stay open.
• Blood pressure always recorded as systolic 120
  
• diastolic 80

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Pulse Rate

• The pulse rate is equal to the rate at which the
  ventricles contract or equal to heart rate.
• The pulse is the alternate expanding and
  recoiling of the artery walls.

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Pulse
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Blood vessel disorders

• Arteriosclerosis- degenerative disease in which
  the arteries loose elasticity the vessels become
  brittle and can rupture easily associated with
  fatty diet, genetics, lack of exercise, cigarette
  smoking, etc.
• Go to Heart Attack Then Blocking the Artery to
  watch video

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Arteriosclerosis
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Blood vessel disorders

• Aneurysm- a bulge in a blood vessel this area of
  the blood vessel then weakens and may burst can
  result from trauma, high blood pressure,
  infections, or genetic defects

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Aneurysm
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Blood vessel disorders contd

• Varicose veins- irregular dilations in
  superficial veins, especially of the legs
  associated with prolonged increased back
  pressure, also with crossing legs.

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Blood vessel disorders contd

• Hypertension high b.p. caused by kidney
  disease, high Na intake, obesity, stress,
  arteriosclerosis left ventricle works overtime
  so myocardium thickens, enlarging heart?coronary
  vessels cant feed overgrowth so parts of heart
  die

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Disorders, cont.

• Anemia condition in which the oxygen carrying
  capacity of the blood is reduced symptoms
  fatigue, intolerance to cold, and paleness.
• Nutritional Anemia inadequate diet, especially
  lacking in iron and vitamin B12
• Sickle-Cell Anemia abnormal kind of hemoglobin
  results in cells shaped like a sickle (bent)
  they can rupture easily and often get stuck
  together (genetic)

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Types of Anemia
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Pericarditis

• Inflammation of the pericardium and therefore an
  enlargement of the pericardial sac.
• This causes an increase in pressure on the
  outside of the heart and causes the heart to have
  to work harder
• Can cause heart attack
• Treatment typically the fluid is drained with a
  needle into the pericardial sac.

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Pericarditis
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Blood

• Connective tissue with liquid matrix.
• Carries oxygen, protects against infection,
  promotes clotting, and carries other vital
  substances
• Plasma
• clear, straw-colored (yellowish)
• mixture of water (95), amino acids, proteins,
  carbs, lipids, vitamins, hormones, electrolytes,
  and cellular wastes
• Red Blood Cells (Erythrocytes)
• contain hemoglobin (a protein that carries
  oxygen) made of Iron loves oxygen what causes
  blood to change colors. Red to purplish
• Also the chemical when changed which causes urine
  to be yellow and feces to be brown.
• formation of RBC (hematopoiesis) in red marrow

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Blood continued

• 3. White Blood Cells (Leukocytes)
• Can squeeze through vessel walls and move through
  interstitial spaces via amoeboid movement
• Many kinds of white blood cells all have
  different jobs.
• Protect against disease in 2 ways
• Phagocytize bacteria (eat up bacteria like
  pacaman)
• Produce antibodies (proteins that destroy or
  disable foreign particles)
• 4. Platelets (Thrombocytes)
• Cell fragments that help close breaks in vessels
  and initiate formation of blood clots -
  (coagulation)
• Causes scabs and stops bleeding.

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5 Types of White Blood Cells
Red Blood Cells are erythrocytes
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ABO Blood Types

• Antigen- protein or carb on RBC surface
• Presence or absence of antigens is an inherited
  trait
• 2 major antigens Antigen A and Antigen B
• 4 possible antigen combinations A only, B only,
  A and B, or neither A nor B

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ABO Blood Types

• Antibodies- proteins in the plasma that destroy
  foreign substances
• Antibodies develop about 2-8 months after birth
• If antigen A is absent a person develops anti-A
  antibody
• If antigen B is absent a person develops anti-B
  antibody

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ABO Blood Types, cont
Blood Type Antigen Antibody
A A Anti-B
B B Anti-A
AB A and B Neither Anti-A nor Anti-B
O Neither A nor B Both Anti-A and Anti-B
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ABO Blood Types, cont.

• An antigen and an antibody of the same type react
  to clump RBC so such combos must be avoided
• Type AB universal recipients (lacks antibodies
  anti-A and anti-B)
• Type O universal donors (lacks antigens A and
  B)
• However, the preferred donor is one with the
  matching blood type

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Rh Blood Type

• Blood type a person is either positive or
  negative.
• It takes only 1 gene to be positive.
• erythroblastosis fetalis When a mother is RH
  and her baby is RH . During their first
  pregnancy some blood is transferred from baby to
  mother. The mother then develops antibodies
  against RH blood.

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erythroblastosis fetalis

• Next pregnancy some of the blood from the mom
  gets in the baby and the antibodies cause the
  blood to agglutinate. Can cause fatality because
  of lack of oxygen (severe anemia)
• Treated by massive transfusions of Rh blood for
  the baby and removal of blood containing Rh
  antibodies.