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002 - Organology > (01) Cardiac Muscle & Heart > Flashcards

(01) Cardiac Muscle & Heart Flashcards

1
Q
  1. What is Cardiac Muscle composed of?
  2. Striated or no?
  3. Under what kind of control?
  4. Majority for specialized for what?
  5. Modified ones whose main role is what?
A
  1. myocytes
  2. striated
  3. involuntary control (autonomic nervous system)
  4. contraction
  5. conduction
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2
Q

(Sarcomere)

(A bands - anisotropic)

  1. how do they refract polarized light?
  2. dark or light?

(I bands - isotropic)

  1. how do they refract polarized light?
  2. dark or light?
A
  1. differently
  2. dark
  3. same
  4. light
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3
Q
  1. A-bands are fixed in width by the length of what?
  2. Which band changes in length as the muscle contracts and relaxes? What area of the filaments is this?
  3. Which is the line that bisects the I-band and is the structure to which actin thin filaments are attached?
  4. What are the borders of the sarcomere?
A
  1. thick myosin filaments
  2. I-band; area of the thin filaments that does not overlap the thick filaments
  3. The z-line
  4. The z-lines
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4
Q

(Cardiac Myocyte)

  1. Cadiac myocytes in atria larger or smaller than those in ventricle?
  2. Do they branch?
  3. How many nuclei per cell? why?
  4. Myofibrils: banding same or different as skeletal muscle? striations more or less distinct? why?
A
  1. smaller
  2. yes
  3. 1-2; don’t fuse as much as skeletal muscle
  4. same; less distinct; variable arrangement of myofibrils within cells
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5
Q

( Cardiac Myocyte cont.)

  1. Organelles: these cells have many large what? Is SR more or less irregular? SR contacts tubules in what kind of relationship? What is this called? Juction of terminal cisternae with the T tubule is located where?
A
  1. mitochondria; more irregular; 1:1 relationship; diad; at the Z line
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6
Q

(Cardiac Myocyte cont)

  1. Does cardiac muscle have increased or decreased intercellular fibers for attaching to and coordinating contraction?
  2. What do the cells have to unify contraction?
A
  1. reduced
  2. intercalated disks joining cells end to end (desmosomes and fasciae adherentes) in long chains; lateral regions of disk (gap junction) - allow neighboring cells to communicate
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7
Q

what is this?

A

a gap juction

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8
Q

what are these?

A

adhesive junctions (zonula adherens)

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9
Q

What are these?

A
  • desmosomes
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10
Q

(Summary of Myocytes)

  1. many mitochondira surround _____
  2. T-tubules at what lines?
  3. Less extensive SR results in what rather than what?
A
  1. fassicles
  2. z lines
  3. dyads rather than triads
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11
Q

Cardiac Muscle vs. Skeletal Muscle

  1. length
  2. diameter
  3. fibers branch
  4. nucleus
  5. banding
  6. mitochondria
  7. location of t-tubules
  8. diads or triads (and makeup)
  9. juctions between cells?
A
  1. smaller 85-100 um long – larger 50 cm
  2. 10-20 um – 50-100 um
  3. branch – don’t
  4. central (1-2 per cell) – peripheral (many per cell)
  5. AI bands present (indistinct) – AI bands present (distinct)
  6. many – fewer
  7. at z-line – at A-I junction
  8. diads (= 1 t tubule + 1 SR) – triads (= 1 t tubule + 2 SR)
  9. intercalated disks – none
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12
Q

(Heart wall layers)

  1. completely lines the inner surface of the heart (atria, ventricles, and valves)

(Endocardium - these are both part of this!)

  1. endothelium is what?
  2. subendothelium composed of what parts?
  3. Inner subendothelium composed of what?
  4. Outer subendothelium composed of what? may have large amounts of what kinds of cells?
A
  1. endocardium
  2. simple squamous
  3. inner subendothelium and outer subendothelium
  4. dense irregular connective tissue composed of collagen, elastic fibers, and occasional smooth muscle cells
  5. loose connective tissue compose of collagen and elastic fibers; adipose
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13
Q

(Heart wall layers)

  1. the thickest layer of the heart
  2. What does it contain?
  3. Where is it thickest and why?
  4. How many layers is ventricular myocardium made up of and what are they?
  5. How are myocytes arrange in superfical and deep layers? What does contraction of these cells result in?
  6. Myocytes in middle layer circumscribe what? contraction results in what?
  7. atrial is thicker or thinner? how many layers?
A
  1. myocardium
  2. cardiac muscle, cardiac skeleton, part of the conduction system (purkinje cells)
  3. ventricles (esp left - more force to get blood into systemic circulation)
  4. three (superficial, middle, deep)
  5. from base to apex; ventricular shortening
  6. the lumen; narrowing of the ventricular lumen
  7. thinner; two layers
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14
Q

(Heart wall layers)

  1. is a serous membrane (mesothelium) covering the external surface of the heart
A
  1. epicardium (visceral pericardium)
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15
Q
  1. What is the cavity between the epicardium (visceral pericardium) and the parietal pericardium?
  2. These 2 layers become continuous in what areas?
  3. What does the pericardial sac contain? to do what?
A
  1. pericardial sac
  2. areas where larg vessels exit/enter the heart
  3. fluid; to reduce friction between these two layers
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16
Q
  1. What is a support system within the muscle framework?
  2. area serves as a site for anchoring what?
  3. composed of what?
  4. Depending of species may also contain what?
    a. cat and pig
    b. dog
    c. horse
    d. large ruminants
A
  1. “Skeleton” of the heart
  2. valves, atria musculature, and ventricular musculature
  3. dense fibrous connective tissue
  4. a. dense irregular connective tissue
    b. fibrocartilage
    c. hyaline cartilage
    d. bone “os cordis” (esp around aorta)
17
Q

(components)

  1. Fibrous rings surrounding the 4 valves of the heart
  2. fibrous triangle between the valves
  3. fibrous connective tissue in the interventricular septum
A
  1. annuli fibrosi
  2. trigonum fibrosum
  3. septum membranaceum
18
Q
  1. What are endocardial folds with an inner connective tissue core that ties into the “skeleton” of the heart
  2. Composition of endothelium?
  3. Composition of central layer?
  4. What extend from the atrioventricular valves? What is it? continuous with what? covered with what? What do they help prevent?
A
  1. Valves of the heart
  2. simple squamous
  3. collagenous connective tissue with elastic fibers
  4. chordae tendinae; a fibrous cord; central connective tissue of the valve; endothelium; the valves from evulsing (to extract forcibly) during contraction
19
Q
  1. Conduction sytem of the heart composed of what?
  2. The wave of depolarization begins where? extends through to where?
  3. When depolarization reaches the AV node there is delay in what?
  4. Depolarization progresses rapidly through what? which is composed of what?
A
  1. a series of cells specialized for conduction
  2. SA nodal cells; the atrial cardiac muscle cells
  3. a delay in progression when passing through the “skeleton” components of the heart
  4. the AV bundle; specialized impulse-conducting fiber (Purkinje fibers) arranged in series
20
Q

(Nodes)

  1. The pacemaker of the heart
  2. located where?
  3. What are these nodal cells (what do they look like)? What does this allow them to do?
  4. Do they have myofibrils? intercalated disks?
  5. What surrounds this area?
  6. Parasympathetic terminals release what to accomplish what?
  7. Sympathetic fibers release what to accomplish what?
A
  1. SA node
  2. right atrium
  3. small, branching cardiac muscle fibers ; depolarize/repolarize more rapidly than other cells allowing it to assume pacemaker role
  4. a few; no
  5. many autonomic nerve endings
  6. Acetylcholine; decreases rate of depolarization (slows the heart rate)
  7. norepinephrine; increase heart rate
21
Q

(Nodes)

  1. made up of cells similar in morphology to the SA nodal cells
  2. Continuous with what?
A
  1. AV node
  2. atrial myocardial fibers and cardiac muscle cells specialized for conduction (Purkinje cells)
22
Q
  1. Has large impulse-conducting muscle fibers (Purkinje cells) arranged in series
  2. Do cells have myofibrils? T tubules?
  3. What are there between the cells? what purpose do they serve? What do these conducting fibers connect with? what do they lack?
A
  1. AV bundle (Bundle of His)
  2. few; none
  3. large gap juctions; act as a tissue synctium allowing AP to spread from cell to cell; smaller transitional cells; intercalated disks
23
Q

(Purkinje Fibers)

  1. Modified whats?
  2. how many myofibrils? how do they stain?
  3. mitochondria and SR?
  4. intercalated disks?
  5. cheddar cheese?
A
  1. myocyte (very large cell)
  2. few; pale
  3. present
  4. present
  5. not present
24
Q

(Moderator Band)

  1. Fancy name for this?
  2. extension of what?
  3. carries what from where to where?
A
  1. trabeculae septomarginalis
  2. endocarium and myocardium of ventricular wall
  3. impulse conducting muscle fibers (Purkinje fibers) from interventricular septum to lateral wall of ventricle
25
Q

(Flow of conduction/coordination of contraction - sequence)

PUT THESE IN ORDER

(a) av nodal delay (which does what?)
(b) atria contract following depolarization of SA node (blood pushed where?)
(c) AV bundles speed the impulses to apex and allow the wave of contraction to go from apex to heart base (what happens to blood here?)

A

(b) blood pushed into ventricles
(a) facilitates max ventricular filling before initation of contraction
(c) blood ejected from ventricles into pulmonary trunk and aorta

26
Q

(Myogenesis/hypertrophy/repair)

  1. Myogensis - cardiac muscle develops from what? What do cells do?
  2. Can cardiac muscle regenerate after birth?
  3. Hypertrophy of individual muscle cells results in what only?
  4. What is damaged cardiac muscle replaced with?
A
  1. splachnic mesoderm surround the endocardial heart tube; differenteate and grow into single cardiac muscle cells
  2. not really (limited ability)
  3. increase in size only
  4. connective tissue

002 - Organology (16 decks)

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