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Blood and the Cardiovascular System

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Title: Blood and the Cardiovascular System


1
Blood and the Cardiovascular System
  • Chapters 17-19

2
Blood Functions
  • Distribution
  • Delivery of oxygen and nutrients to all body
    cells Transport of wastes to lungs and excretory
    organs Transport of hormones
  • Regulation
  • Maintenance of body temperature, pH, and adequate
    fluid volume
  • Protection
  • Prevention of blood loss via clotting prevention
    of infection with the immune system

3
Blood
  • Only fluid tissue in the body with both cellular
    and liquid components
  • Specialized connective tissue where the living
    blood cells are suspended in the non-living
    plasma
  • Parts of the blood
  • Plasma (55)
  • Erythrocytes (42-45)- Red Blood Cells
  • Leukocytes (1)- White Blood Cells
  • Platelets

4
Plasma
  • Composed largely of water (90), but also has
    over 100 dissolved solutes (gases, nutrients,
    wastes, proteins, etc.)
  • Most common plasma protein is albumin
  • Aids in carrying molecules through circulation,
    is a blood buffer, and helps to keep water in the
    bloodstream

5
Erythrocytes (RBCs)
  • Shaped like flattened disks with depressed
    centers giving it a high surface area good for
    gas exchange
  • Have no nucleus and very few organelles
  • Contains proteins such as hemoglobin that aid in
    carrying oxygen (do not go through aerobic
    respiration so none of this oxygen is consumed by
    the RBC)
  • Protein spectrin gives the cell flexibility so
    that it can move through capillaries

6
Erythrocytes (RBCs)
  • Functions in oxygen and carbon dioxide gas
    exchange
  • Production of RBCs is called hematopoiesis or
    hemopoiesis and occurs in the red bone marrow
  • In adults this generally occurs in the axial
    skeleton and girdles and in the proximal
    epiphyses of the humerus and femur

7
Erythrocyte Disorders
  • Anemia
  • An insufficient number of red blood cells
  • Possibly due to blood loss, bone marrow failure,
    excessive RBC destruction
  • Ex hemorrhagic anemias, hemolytic anemias,
    aplastic anemias
  • Low hemoglobin content
  • Often related to nutrition (may be diet or
    inability of the body to absorb certain
    nutrients)
  • Ex Iron-deficiency anemia, pernicious anemia
  • Abnormal hemoglobin
  • Globin is misshaped due to genetic variation
  • Ex Thalassemias, sickle-cell anemia

8
Erythrocyte Disorders
  • Polycythemia is an excess of erythrocytes that
    increases blood viscosity
  • Polycythemia vera often caused by bone marrow
    cancer
  • Secondary polycythemia often caused by
    prolonged exposure to high altitudes and is a
    response by the body to get more oxygen
  • Can be treated with blood dilution
  • Some athletes do this on purpose (called blood
    doping) to increase oxygen carrying capabilities

9
Leukocytes (WBCs)
  • Are complete cells who function in the bodies
    defense system
  • The circulatory system is their highway and means
    of transportation to where they are needed
  • They are able to leave blood vessels in a process
    known as diapedesis
  • Once out of the bloodstream, they move through
    the tissue spaces by amoeboid motion following
    chemicals released by damaged cells (called
    positive chemotaxis)
  • The body speeds up WBC production when needed
    therefore, having a WBC count over 11,000 tends
    to signify an infection

10
Leukocytes (WBCs)
  • 2 groups of leukocytes
  • Granulocytes
  • Neutrophils contain hydrolytic enzymes and are
    active phagocytes (bacterial slayers)
  • Eosinophils contain digestive enzymes that tend
    to work against parasitic worms also phagocytize
    inflammatory chemicals related to allergic
    reactions
  • Basophils release histamine causing an
    inflammatory response
  • Agranulocytes
  • Lymphocytes composed of T cells which function
    in immune response and B cells which give rise to
    plasma cells that produce antibodies
  • Monocytes aka macrophages defend against
    viruses, bacterial parasites and chronic
    infections

11
Leukocyte Disorders
  • Leukemias a group of cancerous conditions
    involving WBCs
  • The type of cancer will depend on the type of WBC
    involved
  • The bone marrow becomes occupied by cancerous
    leukocytes and immature WBCs flood into the
    bloodstream
  • This in turn can cause anemia and bleeding
    problems
  • Infectious Mononucleosis caused by the
    Epstein-Barr virus
  • Causes excessive numbers of agranulocytes, often
    atypical
  • Typically runs its course in a few weeks

12
Platelets
  • Cytoplasmic fragments of large cells called
    megakarocytes
  • Function in the clotting process by sticking to
    the damaged site and creating a temporary seal
  • This process is called hemostasis and involves 3
    phases
  • Vascular spasms (vasoconstriction)
  • Platelet plug formation
  • Coagulation or blood clotting

13
Platelets
  • After 30-60 minutes, the clot goes through clot
    retraction
  • This processes squeezes serum (plasma) from the
    clot and compacting the clot, drawing the edges
    closer together
  • Fibrinolysis also occurs to remove unneeded clots
    when healing has occurred

14
Disorders of Hemostasis
  • Thromboembolytic conditions
  • A clot or thrombus forms in an unbroken blood
    vessel
  • This can block circulation or break away and move
    through the bloodstream (embolus) where it can
    obstruct blood flow through a vessel
  • Embolism often become lodged in the lungs or
    brain
  • This may be more prevalent when there is
    arteriosclerosis, burns, or inflammation or when
    the blood is flowing more slowly due to lack of
    movement
  • This can be treated using aspirin, heparin,
    dicumarol, or warfarin / coumadin

15
Disorders of Hemostasis
  • Bleeding Disorders
  • Thrombocytopenia
  • Too few platelets causes spontaneous bleeding
    from small blood vessels
  • Impaired liver function
  • Liver cannot / does not produce the procoagulants
    thus causing bleeding often related to vitamin K
    deficiency
  • Hemophilias
  • Genetic sex-linked conditions resulting in the
    inability to clot correctly bleeding is often
    caused by normal activity
  • Different kinds associated with deficiencies in
    specific factors

16
Blood Groups
  • People have different blood types because the
    RBCs have specific glycoproteins associated with
    the plasma membranes
  • If the glycoproteins of an RBC are seen as
    foreign by the body, the cells may be
    agglutinated (clumped together)
  • There are 30 varieties of naturally occurring
    RBC antigens that are common in humans
  • Approximately 100 others are familial
  • These are used to put everyones blood into blood
    groups such as ABO and Rh

17
ABO Blood Groups
  • Based on the presence or absence of the
    agglutinogens A and B
  • Their presence or absence gives rise to A, B, AB
    and O blood
  • O which means neither is present is the most
    common blood type
  • Preformed antibodies called agglutinins will form
    against those antigens not present
  • A person with type O blood will have both anti-A
    and anti-B antibodies

18
Rh Blood Groups
  • There are at least 8 different types of
    agglutinogens called Rh factors
  • Only C, D, and E are common
  • 85 of Americans are positive for Rh factors
  • Anti-Rh antibodies do not form spontaneously, but
    will form if a Rh- person receives Rh blood
  • This can also occur in Rh- women pregnant with
    Rh babies

19
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20
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21
The Heart
  • Is about the size of a fist and generally weighs
    250-350 grams
  • Is located more centrally in the chest between
    the lungs above the diaphragm. The sternum sits
    in front of the heart.

22
The Cardiovascular System (cont
  • The Heart
  • Covered by the pericardium.
  • Has two sides with two chambers.
  • Blood flows through the heart in one direction.
  • Valves control the blood flow.
  • The cardiac conduction system controls the
    electrical impulses that cause the heart to
    contract.

23
Layers of the Heart Wall
  • The heart wall is composed of 3 layers
  • Epicardium the visceral layer of the serous
    pericardium
  • Often becomes fatty in older people
  • Myocardium the contracting layer of the heart
    which is composed mainly of cardiac muscle
  • Endocardium endothelium cells that line the
    inner myocardial surfaces (chambers of the heart
    and valves)

24
Chambers
  • The heart has 4 chambers
  • 2 superior atria
  • 2 inferior ventricle

25
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26
Atria
  • The atria are receiving chambers for blood
    returning to the heart
  • Relatively small, thin-walled chambers and
    responsible for very little pumping (blood moves
    from atria to ventricle)
  • Blood enters the R. atrium via
  • Superior vena cava returns blood from areas
    superior to the diaphragm
  • Inferior vena cava returns blood from below the
    diaphragm
  • Coronary sinus collects blood draining from the
    myocardium
  • Blood enters the L. atrium via 4 veins from the
    lungs

27
Ventricles
  • Make up the bulk of the heart
  • These are the discharging chambers. When the
    ventricles contract, blood is propelled out of
    the heart.
  • The R. ventricle pumps blood to the pulmonary
    trunk which sends blood to the lungs where gas
    exchange occurs
  • The L. ventricle ejects blood into the aorta
    which sends blood out to the body

28
Path of blood through the heart
29
Pathway of Blood
  • The heart consists of two circuits
  • Pulmonary circuit the blood vessels that carry
    blood to and from the heart
  • The pump is the right side of the heart
  • Systemic circuit the blood vessels that carry
    blood to and from the body
  • The pump is the left side of the heart
  • Deoxygenated blood returning from the body will
    enter the R. atrium, enters the R. ventricle
    where it pumps to the lungs via the pulmonary
    arteries. Oxygenated blood then returns to the
    L. atrium via the pulmonary veins, enters the L.
    ventricle where it pumps to the body via the
    aorta.

30
The Cardiovascular System (cont.)
  • Circulation
  • Coronary circulation the circulation of blood
    within the heart.
  • Pulmonary circulation the flow of blood between
    the heart and lungs.
  • Systemic circulation the flow of blood between
    the heart and the cells of the body.

31
The Heartbeat
  • Each heartbeat is called a cardiac cycle.
  • When the heart beats, the two atria contract
    together, then the two ventricles contract then
    the whole heart relaxes.
  • Systole is the contraction of heart chambers
    diastole is their relaxation.
  • The heart sounds, lub-dup, are due to the closing
    of the atrioventricular valves, followed by the
    closing of the semilunar valves.

32
Heart Valves
  • Blood flows through the heart in one direction
    enforced by 4 valves
  • 2 atrioventricular (AV) valves located at each
    atrial-ventricular junction
  • R. AV valve (tricuspid valve)
  • L. AV valve (bicuspid or mitral valve)
  • 2 semilunar (SL) valves
  • Aortic SL valve located at junction between L.
    ventricle and aorta
  • Pulmonary SL valve located at junction between R.
    ventricle and pulmonary trunk

33
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34
Heart Sounds
  • During each heartbeat, 2 sounds can be
    distinguished
  • Described as lub-dup, pause, lub-dup, pause, etc.
  • Sounds associated with closing of heart valves
  • 1st sound AV valves close
  • 2nd sound SL valves close (generally do not
    close at the same time making this sound less
    defined)

35
Heart Sound Link
  • http//www.med.ucla.edu/wilkes/intro.html
  • Normal Sounds
  • Murmurs
  • Wheezing
  • Crackles

36
Disorders of the Heart
  • Asystole situation in which the heart fails to
    contract
  • Commotion cordis situation in which a
    relatively mild blow to the chest causes heart
    failure and sudden death
  • Occurs during a vulnerable time during the heart
    repolarizing
  • Endocarditis inflammation of the endocardium
    often caused by bacterial infection

37
Disorders of the Heart
  • Heart palpitation a heartbeat that is unusually
    strong, fast, or irregular
  • Can be caused by drugs, emotional pressures or
    heart disorders
  • Hypertrophic cardiomyopathy (HCM) cardiac
    muscle cells enlarge, thickening the heart wall.
    The heart pumps well, but doesnt relax well
    during diastole when the heart is filling
  • Leading cause of death among young athletes

38
Disorders of the Heart
  • Mitral valve prolapse the mitral valve does not
    close properly, allowing blood regurgitation.
  • Affects up to 10 of the population often seen
    in young women may be genetic
  • Often treated with valve replacement
  • Myocarditis inflammation of the myocardium may
    weaken the heart and its ability to pump
  • Often caused by untreated strep infection

39
Diseases and Disorders (cont.)
  • Diseases and Disorders
  • Hypertension.
  • Stroke.
  • Arteriosclerosis.
  • Aneurysm.
  • Coronary artery disease (CAD).
  • Heart attack (Myocardial Infarction)
  • Congestive heart failure (CHF).
  • Anemia, hemophilia, and leukemia.

40
BLOOD VESSELS
41
ARTERIES
  • FUNCTION CARRY BLOOD AWAY FROM THE HEART
  • CHARACTERISTICS
  • VERY THICK, MUSCULAR WALLS (WHY).
  • VERY HIGH BLOOD PRESSURE
  • CARRIES OXYGENATED BLOOD
  • EXAMPLES CORONARY, AORTA, CAROTID, FEMORAL

42
ATHEROSCLEROSIS
43
ARTERIES
44
CORONARY ARTERIES
45
ARTERIES IN BRAIN
46
VEINS
  • FUNCTION AFTER BLOOD MOVES THROUGH THE ARTERIES
    IT ENTERS BLOOD VESSELS CALLED VEINS, WHICH CARRY
    BLOOD BACK TO THE HEART.
  • CHARACTERISTICS
  • THINNER WALLS WITH LESS MUSCLE
  • HAVE VALVES
  • CARRIES DEOXYGENATED BLOOD (1 EXCEPTION)
  • EXAMPLES VENA CAVA, JUGULAR,
  • LOCATION NEAR MUSCLES

47
VEINS
48
VEINS VS. ARTERIES
49
Vein Valves
  • Allows flow of blood in only ONE DIRECTION

50
VEINS
51
SPIDER VEINS
52
RETICULAR VEINS
53
VERICOSE VEINS
54
VERICOSE VEINS
55
CAPILLARIES
  • FUNCTION WHERE MATERIAL (OXYGEN, NUTRIENTS,
    CARBON DIOXIDE, ENERGY) IS EXCHANGED BETWEEN
    BLOOD AND CELLS
  • CHARACTERISTICS
  • VERY SMALL
  • WALLS ARE ONLY ONE CELL THICK
  • DIFFUSION TAKES PLACE
  • MOST ABUNDANT
  • FOUND NEAR MUSCLE CELLS, ORGANS, ETC.

56
CAPILLARIES
http//www.innerbody.com/htm/body.html
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