IBHS 527 lecture 4

• 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

• 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

• 1. pulmonary circuit
• 2. systemic circuit

• right atrium: deoxygenated blood from systemic circuit (body)
• right ventricle: receives blood from right atrium and pumps to lungs

• left atrium: oxygenated blood from pulmonary circuit (lungs)
• left ventricle: receives blood from left atrium and pumps to body or systemic circulation

FALSE. it should be "away" from the heart always

FALSE. only "mostly" ... remember those pulmonary arteries carry deoxygenated blood to the lungs

FALSE. veins "always" carry blood to the heart

TRUE. they "mostly" do. except when???

FALSE. they permit nutrient/gas/waste exchange.

• -size of a closed fist
• -weighs less than a pound

• 1. apex: rounded point of cone
• 2. base: broader flat part of opposite of end of cone, great vessels

thoracic cavity in mediastinum (central core of thoracic cavity; everything in the thoracic cavity except lungs)

• 1. pericardial cavity: has heart
• 2. pleural cavity: has lungs

• lining of pericardial cavity (has heart)
• 3 parts:
• 1. visceral pericardium = epicardium
• 2. pericardial fluid
• 3. parietal pericardium (lines inner surface of pericardial sac)

• pericardium: outer fibrous bad that surrounds a delicate
• 1. fibrous pericardium (outside)
• 2. serous pericardium contains:
• a) parietal pericardium
• b) visceral pericardium (epicardium)
• 

• tough fibrous outer layer
• prevents over distention; act as anchor

• 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

lines the fibrous outer layer

• aka epicardium
• covers heart surface

• 1. pericarditis
• 2. cardiac tamponade (plug/block)

• infection of pericardium
• may lead to inflammation and swelling

• 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

• 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.)

• smooth outer surface of heart
• serous membrane consists of connective tissue covered by epithelium
• includes blood and lymph cap and nerve fibers

• function: responsible for muscle contracting
• composition:
• 1. cardiac muscle tissue
• 2. some connective tissue
• 3. nerves and blood vessels

• epithelium and connective tissue
• squamous epithelia which is continuous with blood 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

• 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

• 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

• 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

• 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

• 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

FALSE. they are designed for "1" way flow

chordae tendineae is loose when papillary muscles are relaxed = no resistance --> (1) AV valves open, (2) semilunar valves closed

papillary muscles contract --> tenses Chordae tendineae --> stoping cusps from swinging into atria --> (1) AV valves close, (2) semilunar valves open

• 1. stenosis
• 2. regurgitation or insufficiency
• 3. combination

• 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

• 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

• 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

• 1. step 1: rheumatic fever
• 2. step 2: rheumatic heart disease

• 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)

• 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

• 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

• 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

• 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

FALSE. behaves as "single" unit

supplies blood to muscle tissue of heart

• 1. right coronary artery
• 2. left coronary artery
• *originate at base of ascending aorta

• 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

• 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

• 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

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)

• 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%

• 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)

not enough real hearts