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APK2105C > CH 13, Part 1-5 > Flashcards

CH 13, Part 1-5 Flashcards

1
Q

Pulmonary Circuit

A

blood vessels that take blood to and from the lungs
- main goal is to reoxygenate blood
- associated with the RIGHT side of the heart

PULMONARY ARTERIES
- take deoxygenated blood away from the heart to the lungs

PULMONARY VEINS
- take oxygenated blood from the lungs back to the left side of the heart

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2
Q

Systemic Circuit

A

blood vessels that take blood to and from all tissues of the body
- main goal is to deliver oxygenated blood to all tissues of the body
- associated with the LEFT side of the heart
- receives oxygenated blood from pulmonary circuit

SYSTEMIC ARTERIES
- takes oxygenated blood away from heart to tissues

SYSTEMIC VEINS
- takes deoxygenated blood from tissues back to right side of heart

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3
Q

Blood Flow through Heart

A

(1) Deoxygenated blood flows in through the superior and inferior vena cava
(2) Deoxygenated blood accumulates in the RA
(3) Deoxygenated blood travels through the tricuspid valve
- accumulating blood in RA generates pressure so valve will open
- blood flows from RA –> RV
(4) Deoxygenated blood accumulates in the RV
(5) RV contracts and pushes deoxygenated upwards
- when ventricle contracts, papillary muscles contracts, pulling on chordae tendineae, which pulls on tricuspid valve to keep it closed (prevents murmur)
(6) Deoxygenated blood travels up pulmonary trunk and will travel out pulmonary arteries
(7) Deoxygenated blood travels to lungs and is oxygenated
(8) Oxygenated blood returns through the pulmonary veins
(9) Oxygenated blood arrives in LA and accumulates while pressure builds
(10) Pressure opens the bicuspid valve and oxygenated blood flows into LV
(11) LV contracts and oxygenated blood travels upwards
(12) Oxygenated blood travels into the aorta and out to the rest of the body
- Aorta: largest vessel in body and beginning of systemic circuit
(13) Systemic veins will bring back deoxygenated blood to superior and inferior vena cava

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4
Q

Heart Sounds

A
  • “lub” is closing of the tricuspid and bicuspid valve
  • “dub” is closing of pulmonary semilunar valve and aortic semilunar valve
    • PSV: where RV contracts deoxygenated blood
    • ASV: where LV contracts oxygenated blood
  • Heart Murmur: whooshing sound due to retrograde blood flow
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5
Q

Systole

A
  • contraction of a chamber
  • Systolic BP: blood exerting maximal force against walls of a blood vessel
    • when LV contracts (systole) it very forcefully pushed blood out through aorta and to arteries of systemic circuit
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6
Q

Diastole

A
  • relaxation of a chamber
  • Diastolic BP: minimum pressure that the blood exerts against the wall of a vessel
    • when LV relaxes (diastole) and blood is being pushed out of aorta least forcefully
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7
Q

SA Node AP Generation

A
  • do not have resting membrane potential
  • peak negative potenital ~ -60 mV
    (1) Interior becomes more negative
    (2) Funny (F-type) channels (voltage-gated sodium channels) open and sodium shoots in (depolarization)
    (3) Sodium ions cause interior to reach threshold (-50 mV)
    (4) Funny channels close and voltage-gated calcium (L-type) channels will open
    (5) Calcium shoots in and drives interior up to +20 mV (depolarization)
    (6) AP propagates as positive calcium ions act as wave of positivity
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8
Q

SA Node AP Path

A
  • AP generation by SA nodes can happen about 70 times per minute
  • calcium ions (wave of positivity) will head into subsequently negative regions after AP has been generated
  • voltage-gated calcium channels exist down entire length of SA node fiber, so AP continues to travel down its entire length without decrementing
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9
Q

SA Node AP Repolarization

A

After every region of the SA node fiber is +20 mV:
- F-type closed
- L-type channels inactivation gates closed
- voltage-gated potassium channels open and allow K+ to shoot out of SA node fiber
- interior will begin moving back towards - 60 mV
- between -50 mV and -60 mV voltage-gated calcium channels reset and voltage-gated potassium channels close
REPOLARIZED
- at -60 mV funny channels reopen and rate at which sodium is entering exceeds rate at which potassium is leaving (depolarization) and process starts over

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10
Q

Intercalated Disks

A
  • attach SA node fibers and contractile fibers
  • made up desmosomes and gap junctions
    • Desmosomes: staples; physically attach fibers
    • Gap Junctions: tunnel (ion pore) between both cardiac fibers
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11
Q

AP Passage from SA Node to Contractile Fibers

A
  • contractile fibers have resting membrane potentials of -90 mV
    (1) Calcium ion AP (+20 mV) of SA node will get pulled through gap junction to contractile fiber
    (2) contractile fiber will depolarize to -70 mV (threshold)
    (a) voltage-gated sodium channels will open at -75 mV
    (3) voltage-gated calcium (L-type) channels will open at -50 mV and calcium will begin shooting in WITH sodium
    (4) Calcium AND sodium will work together to drive interior up to +20 mV
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12
Q

APs in Contractile Fibers

A
  • contractile fibers are all connected to each other through intercalated disks
  • if one generates an AP or contracts they ALL do
  • every time an SA node generated an AP, it will propagate throughout all of the left and right ventricular fibers –> heart contraction
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13
Q

Cardiac Muscle Fibers

A
  • just like skeletal muscle fiber, cardiac muscle fiber has an SR on either side of the t-tubule
  • unlike skeletal muscle fiber, cardiac muscle uses BOTH calcium and sodium to propagate an AP
  • as AP travels down cardiac muscle fiber, goes down t-tubule, and a similar process to that in skeletal muscle fiber occurs

(1) sodium and calcium drive inside up to +20 mV
- every single voltage-gated calcium channel is a DHP receptor
- in skeletal only exist in t-tubule attached to RR receptors
- in cardiac they are everywhere
- none attached to RyR receptors
- opening of DHP receptors will NOT open RyR receptors
- purpose of DHP receptors being everywhere is because calcium comes in from everywhere
(2) calcium will bind to RyR channels and cause them to open –> calcium will spill out SR
- Calcium-Induced Calcium Release
- calcium coming in from SR will directly participate in rxn: bind to troponin allowing for interaction of actin and myosin

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14
Q

Conduction Fibers

A
  • cardiac muscle branches
  • main job is to propagate excessively fast APs
    • passes of APs to contractile fibers
  • indirectly alllows for entire L and R ventricles to contract at same time
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15
Q

ECG Waves

A

P-WAVE
atrial depolarization

QRS COMPLEX
ventricular depolarization

T-WAVE
ventricular repolarization

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16
Q

End Diastolic Volume

A

volume of blood in LV after it is finished filling (end of diastole)

17
Q

End Systolic Volume

A

volume of blood in LV after it is finished contracting (end of systole)

18
Q

Stroke Volume

A

amount of blood that has been ejected out of LV in one contraction
SV = EDV - ESV

19
Q

Ejection Fraction

A
20
Q

Sympathetic Influence on SA Node Fibers

A

sympathetic autonomic neurons travel through thoracic nerves, out to vast majority of organs in body, and release neurotransmitters onto those organs
- releases norepinephrine onto SA fibers
- norepinephrine causes SA node to reach threshold faster, this produces more APs per min
- causes the heart to contract more, HR increases

21
Q

Parasympathetic Influence on SA Node Fibers

A
  • parasympathetic autonomic neurons travel through cranial nerves, to the same organs, releasing neurotransmitters
    • travel mainly through Vagus nerve
    • release acetylcholine (ACh) onto SA fibers
  • indirectly causes K+ channels to open, causing the interior to be more negative
    • increased time it takes to reach threshold
22
Q

Force of Contraction

A
  • sympathetic nervous system releases norepinephrine onto ventricular contractile fibers
    • more calcium channels open during AP than normal
      • increased intracellular calcium
      • increased stroke volume
  • when engaged in physical activity, muscles contract more, and increased respiratory rate
    • causes pressure changes that push more blood to return to the heart (venous return)
    • EDV and SV increase
23
Q

Frank-Starling Law

A
  • if cardiac muscle fibers are stretched, they generate more force
    • increased venous return
24
Q

Cardiac Output

A

sympathetic nervous system/frank starling mechanism

APK2105C (14 decks)

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