IBHS 527 lecture 4

  1. 5 heart facts
    • 1. hardest ("heartest" ... I crack myself up) working muscle in the body
    • 2. heartbeats
    • - ~100,000 beats/day
    • - ~35,000,000 beats/year
    • - ~2,500,000 beats/lifetime
    • 3. moves blood
    • - ~5L of blood in body
    • -move ~8,000 L/day
    • 4. leading cause of death
    • - 700,000 deaths/year
    • 5. 60,800,000 with one or more CV diseases
    • (she's not a numbers person so I'm not putting this extra info in)
    • *just showing the good and the bad/ugly of the heart
  2. 4 functions of the heart
    • 1. routing blood
    • -heart separates pulmonary and systemic circulations
    • 2. ensuring one-way blood flow
    • -heart valves ensure one-way flow
    • 3. generating blood pressure
    • 4. regulating blood supply
    • -changes in contraction rate and force match blood delivery to changing metabolic needs
  3. 2 circuits of the cardiovascular system
    • 1. pulmonary circuit
    • 2. systemic circuit
  4. context: 2 circuits of the cardiovascular system
    pulmonary circuit
    • right atrium: deoxygenated blood from systemic circuit (body)
    • right ventricle: receives blood from right atrium and pumps to lungs
  5. context: 2 circuits of the cardiovascular system
    systemic circuit
    • left atrium: oxygenated blood from pulmonary circuit (lungs)
    • left ventricle: receives blood from left atrium and pumps to body or systemic circulation
  6. T/F
    arteries carry blood to the heart (always)
    FALSE. it should be "away" from the heart always
  7. T/F
    arteries always carry highly oxygenated blood
    FALSE. only "mostly" ... remember those pulmonary arteries carry deoxygenated blood to the lungs
  8. T/F
    veins carry blood to the heart mostly
    FALSE. veins "always" carry blood to the heart
  9. T/F
    veins mostly carry deoxygenated blood
    TRUE. they "mostly" do. except when???
  10. T/F
    capillaries just sit and do nothing all day except FB
    FALSE. they permit nutrient/gas/waste exchange.
  11. size of a heart
    • -size of a closed fist
    • -weighs less than a pound
  12. 2 parts of a heart's shape
    • 1. apex: rounded point of cone
    • 2. base: broader flat part of opposite of end of cone, great vessels
  13. location of the heart
    thoracic cavity in mediastinum (central core of thoracic cavity; everything in the thoracic cavity except lungs)
  14. 2 cavities in the thoracic cavity
    • 1. pericardial cavity: has heart
    • 2. pleural cavity: has lungs
  15. pericardium
    • lining of pericardial cavity (has heart)
    • 3 parts:
    • 1. visceral pericardium = epicardium
    • 2. pericardial fluid
    • 3. parietal pericardium (lines inner surface of pericardial sac)
  16. layers of the pericardium
    • pericardium: outer fibrous bad that surrounds a delicate
    • 1. fibrous pericardium (outside)
    • 2. serous pericardium contains:
    • a) parietal pericardium
    • b) visceral pericardium (epicardium)
    • Image Upload 1
  17. context: layers of the pericardium
    fibrous pericardium
    • tough fibrous outer layer
    • prevents over distention; act as anchor
  18. context: layers of the pericardium
    serous pericardium
    • thin, transparent inner layer
    • made of:
    • 1. parietal pericardium
    • 2. visceral pericardium (epicardium)
    • *the two are continuous and have a pericardial cavity between them filled with pericardial fluid ~15-50ml secreted by pericardial membranes- fluid acts as a lubricant to reduce friction between opposing surfaces
  19. context: layers of the pericardium: serous pericardium
    parietal pericardium
    lines the fibrous outer layer
  20. context: layers of the pericardium: serous pericardium
    visceral pericardium
    • aka epicardium
    • covers heart surface
  21. 2 problems with the pericardium
    • 1. pericarditis
    • 2. cardiac tamponade (plug/block)
  22. context: 2 problems with the pericardium
    • infection of pericardium
    • may lead to inflammation and swelling
  23. context: 2 problems with the pericardium
    cardiac tamponade (plug/block)
    • fluid build up between membranes that is life threatening (fatal) --> excess fluid results in pressure on heart (can't fill properly) and can result in dramatic drop in blood pressure
    • causes: viral, inflammation, or trauma
    • ex: car accident or unknown, but either excess fluid production, or thoracic injury
  24. 3 layers of tissue of the heart wall
    • 1. epicardium (visceral pericardium)
    • 2. myocardium (middle layer)
    • 3. endocardium (inner layer)
    • *in the pectinate muscle there are muscular ridges in auricles and right atrial wall
    • -muscular ridges and columns on inside of ventricle is the trabeculae carnae (The moderator band delivers the stimulus for contraction to the papillary muscles, so that they begin tensing the chordae tendineae before the rest of the ventricle contracts.)
  25. context: 3 layers of tissue of the heart wall
    • smooth outer surface of heart
    • serous membrane consists of connective tissue covered by epithelium
    • includes blood and lymph cap and nerve fibers
  26. context: 3 layers of tissue of the heart wall
    • function: responsible for muscle contracting
    • composition:
    • 1. cardiac muscle tissue
    • 2. some connective tissue
    • 3. nerves and blood vessels
  27. context: 3 layers of tissue of the heart wall
    • epithelium and connective tissue
    • squamous epithelia which is continuous with blood vessels
  28. 4 chambers of heart and respective vessels
    • 1. right atrium (pulmonary circuit):
    • -superior and inferior vena cava
    • 2. right ventricle (pulmonary circuit):
    • -pulmonary arteries
    • 3. left atrium (systemic circuit):
    • -pulmonary veins
    • 4. left ventricle (systemic circuit):
    • -aorta
    • *2 atria:
    • -"auricles" = ear
    • -floppy and thin
    • *2 ventricles:
    • -thick
  29. context: internal anatomy of the heart
    parts of the atria section
    • 1. right atria
    • 3 major openings to receive blood returning from the body:
    • -superior vena cava
    • -inferior vena cava
    • -coronary sinus
    • 2. left atria
    • -four openings that receive blood from pulmonary veins
    • 3. interatrial septum
    • wall between the atria. contains a depression, the foramen ovale, a remnant of the fetal opening between the atria
  30. context: internal anatomy of the heart
    parts of the ventricles section
    • 1. atrioventricular canals: openings between atria and respective ventricles
    • 2. right ventricle opens to pulmonary trunk
    • 3. left ventricle opens to aorta
    • 4. interventricular septum between the two
    • 5. papillary muscle, chordae tendineae, trabeculae carnae
  31. Blood flow through heart
    Image Upload 2
  32. Fetal circulation comparison
    • lungs are non-functional so blood by-passes them
    • 1. blood goes through inferior vena cava --> enters right atrium --> majority shunted directly to left atrium via opening which is the Foramen Ovale (FO)
    • *in adults, the foramen ovale closes and becomes the fossa ovalis
    • 2. ligamentum arteriosum is a fibrous band that is a remnant of an important fetal blood vessel (ductus arteriosus) that once linked the pulmonary and systemic circuits.
    • -!some of the blood from right atrium --> right ventricle --> small amount enters pulmonary trunk but because lungs are collapsed and resist flow --> more blood bypasses lung --> enters ductus arteriosus from pulmonary trunk --> enters descending aorta
  33. right vs left ventricle
    • demands are different for the ventricles
    • left:
    • more muscular than right; thicker to generate 4-6x as much pressure to go through systemic vs pulmonary circuit because it's not as hard to push through the pulmonary circuit
    • *right vs left atria are similar in design
  34. 4 types of valves
    • 1. right atrio-ventricular (AV) valve/tricuspid valve
    • 2. pulmonary semilunar valve
    • 3. aortic valve
    • 4. left atrio-ventricular (AV) valve/biscupid valve/mitral valve
  35. T/F
    valves are designed for 2 way flow
    FALSE. they are designed for "1" way flow
  36. context: heart valves
    what occurs when ventricles are relaxed?
    chordae tendineae is loose when papillary muscles are relaxed = no resistance --> (1) AV valves open, (2) semilunar valves closed
  37. context: heart valves
    what occurs when ventricles contract?
    papillary muscles contract --> tenses Chordae tendineae --> stoping cusps from swinging into atria --> (1) AV valves close, (2) semilunar valves open
  38. 3 problems with valves
    • 1. stenosis
    • 2. regurgitation or insufficiency
    • 3. combination
  39. context: 3 problems with valves
    • problems opening:
    • valve doesn't open all the way --> restricting the forward flow of blood
    • valve may have become hardened or stiffened with calcium deposits or scarring
  40. context: 3 problems with valves
    regurgitation or insufficiency
    • problems closing:
    • valves doesn't close properly or tightly allowing blood to flow backwards
    • valves may be loose, torn, or have been stretched too tight or too thin
    • heart has to work harder to re-pump blood through heart
    • ex: heart murmurs - valve not properly closed and regurgitation of blood makes sound
  41. context: 3 problems with valves
    combination of problems with closing and opening
    • valve neither opens or closes properly or leaking heart valve
    • causes:
    • may be caused by infection
    • ex: rheumatic fever, birth defects failure, heart failure, or unknown reasons
  42. 2 steps in rheumatic fever and heart disease
    • 1. step 1: rheumatic fever
    • 2. step 2: rheumatic heart disease
  43. context: 2 steps in rheumatic fever and heart disease
    rheumatic fever
    • step 1
    • -rare complication of untreated streptococcal infection in childhood (5-15 yr old)
    • -less likely to occur because of use of antibiotics
    • -can progress to Rheumatic fever (2-4 weeks later)
    • symptoms:
    • joint pain; fever, abdominal pain, skin rash, writhing, jerky movements (affect basal ganglia)
  44. context: 2 steps in rheumatic fever and heart disease
    rheumatic heart disease
    • step 2
    • -permanent damage 10-20 years later
    • -antibodies may cross reacting with cardiac tissue
    • -stenosis of mitral or aortic valve:
    • (a) valves have increased susceptibility to infections
    • (b) valves do not close properly which result in backflow, regurgitation, heart failure (rare cases)
    • -too much damage require replacement
    • *most common: mitral stenosis
  45. 2 types of valve replacements
    • too much damage requires a valve replacement (90,000/yr)
    • 1. biologic:
    • -human cadavers
    • -modified animal (pig, cow) placed in synthetic rings
    • -lasts 10-15 years (may require second surgery)
    • 2. mechanical/artifical:
    • -50% of replacements - half!
    • -lasts longer - but need anticoagulation therapy
    • *Alain Carpentier - won award for pig valves
  46. heart skeleton
    • 1. plate of fibrous connective tissue between atria and ventricles
    • 2. fibrous rings around valves provide structural support around valves and great vessels
    • 3. serves as electrical insulation between atria and ventricles
    • 4. provides site for muscle attachment
  47. cardiac muscle
    • elongated, branching cells containing 1-2 centrally located nuclei
    • contains:
    • 1. actin and myosin myofilaments
    • 2. intercalated disks:
    • specialized cell-cell contacts --> cell membrane interdigitate, desmosomes hold cells together, gap junctions allow action potentials to move from one cell to the next
  48. T/F
    electrically, cardiac muscle of the atria and of the ventricles behaves as separate units
    FALSE. behaves as "single" unit
  49. function of coronary circulation
    supplies blood to muscle tissue of heart
  50. 2 coronary arteries
    • 1. right coronary artery
    • 2. left coronary artery
    • *originate at base of ascending aorta
  51. context: 2 coronary arteries
    right coronary artery
    • exits aorta and lies in coronary sulcus
    • 2 branches:
    • 1. right marginal branch: to lateral wall of right ventricle
    • 2. posterior interventricular branch/artery: lies in posterior interventricular sulcus, supplies posterior and inferior aspects of heart
  52. context: 2 coronary arteries
    left coronary artery
    • 2 main branches:
    • 1. circumflex branch/artery
    • 2. anterior interventricular branch/artery:
    • -arterial anastomoses: interconnect anterior and posterior interventricular arteries to stabilize blood supply to cardiac muscle
  53. 5 cardiac veins in the coronary circulation
    • 1. great cardiac vein:
    • -drains blood from area of anterior interventricular artery into coronary sinus
    • 2. anterior cardiac vein:
    • -empties into right atrium
    • 3. posterior cardiac vein:
    • -empty into great cardiac vein or coronary sinus to right atrium
    • 4. middle cardiac vein:
    • -empty into great cardiac vein or coronary sinus to right atrium
    • 5. small cardiac vein:
    • -empty into great cardiac vein or coronary sinus to right atrium
  54. problems with coronary blood supply can lead to what disease?
    coronary artery disease (CAD)
  55. context: disease/problems with coronary blood supply
    coronary artery disease (CAD)
    • areas of partial or complete blockage of coronary circulation (ex-blockage of the vessels that carry blood to the myocardium with narrowing due to plaque or thrombus) --> ischemia (reduced circulatory supply = reduced blood/nutrients/oxygen to cells)
    • risk factors:
    • 1. age
    • 2. family history
    • 3. smoking - which can be controlled
    • 4. high blood pressure
    • 5. high cholesterol levels
    • 6. diabetes
    • 7. obesity
    • 8. physical inactivity
    • 9. high stress (uh oh)
    • causes:
    • 1. formation of a fatty deposit
    • 2. blood clots can narrow passageway and reduce flow
    • symptoms: first symptom is usually Angina Pectoris (pain chest) typically during exercise (exertion) --> may trigger pain due to vessel spasms --> heart failure (if untreated)
    • *ischemia is not a myocardial infarction (MI)
  56. context: disease/problems with coronary blood supply
    treatments for angina pectoris and coronary artery disease (CAD)
    • 1. alter behavior:
    • diet (lower fat), control stress, stop smoking, medication
    • 2. surgical treatment: catheter inserted and blockage removed with laser
    • -catheter/small flexible tube inserted into artery (usually near groin of wrist) --> remove blockage with laser or mechanical grinding (roto rooter) or press plaque against vessels with balloon catheter which has inflatable balloon at tip (works best for small plaques) --> stent can be inserted to maintain patentcy (also so not redevelop)
    • *stats: <1% mortaility and outpatient and 90% success rate
    • 3. balloon angioplasty: expands vessel and stent inserted (used to open blocked arteries with over 1 million per year in the U.S.)
    • 4. coronary bypass surgery (last resort): damaged vessels replace (up to 4) with healthy vessel. create detour around obstruction
    • *stats: 1-2% mortality, 70% success relief/partial 20%
  57. history: heart transplants for when heart is too damaged to function properly
    • first human heart transplanted in 1967 (lasted 18 days) and then 1984 (lasted 20 days)
    • then in 2005, 2006 = greater than 2000 transplants
    • june 2007 had > 85% survival rate (lasted 1 year mark) then ~70% survival rate (lasted 5 year mark)
  58. history: why the use of artificial hearts?
    not enough real hearts
Card Set
IBHS 527 lecture 4
ibhs heart: anatomy and physiology intro . skacel