Cardiac Physiology Flashcards
Blood pathway
toe/finger ►inferior/superior vena cava►RA►tricuspid valve►RV►pulmonary valve►PA►lung
Pulmonary vein►LA►Mitral valve►LV►aortic valve►aorta►coronary arteries►body
S1
associated with ventricular contraction
sound when tricuspid and mitral valves close
S2
associated with ventricular relaxation (repolarization)
sound of aortic and pulmonic valve closing
Auscultation of the heart (4 areas)
- aortic
- pulmonic
- tricuspid
- mitral
auscultation of the heart
aortic area
2nd to 3rd right intercostal space
auscultation of the heart
pulmonic area
2nd to 3rd left intercostal space
auscultation of the heart
tricuspid area
lower left sternal border
auscultation of the heart
mitral valve
apex
A

aorta
B

right coronary artery
C

coronary vein
D

left main coronary artery
E

left circumflex coronary artery
F

left anterior descending coronary artery (LAD)
coronary arteries
right coronary artery
left anterior descending coronary artery
circumflex coronary artery
coronary arteries
RCA supplies:
right side of heart
coronary arteries
LAD supplies:
left anterior
coronary arteries
circumflex supplies:
left posterior
A

circumflex coronary artery
B

coronary sinus
C

right coronary artery
cardiac conduction pathway
- SA node
- AV node
- Bundle of His
- Right and left bundle branches
- Purkinje fibers
P wave

QRS complex
activation of the ventricles

T wave

3 layers of a blood vessel
- Tunica intima
- Tunica media
- Tunica adventitia
blood vessels
outer layer
tunica adventitia
contains:
- connective tissue
- vaso vasorum
- nerve
- lymph
vaso vasorum
blood supply to the blood vessels
Tunica media
smooth muscle cells
controlled by ACE
tunica media
ACE
Angiotensin Converting Enzyme
controls blood volume, kidneys
blood vessels
tunica intima
single epithelial layer
- prevents substance transfer from blood into vessel
- anti and prothrombotic secretions
- dilation metabolites
- constriction metabolites
How does the tunica intima prevent substance transfer from blood into the vessel?
acts as a barrier to cholesterol
tunica intima
dilation metabolites
NO
Prostaglandins
tunica intima
constriction metabolites
endothelin
superoxide
thromboxane
blood vessels
valves
only in veins,
prevent blood flow back to the extremities
blood vessels
decreased venous return
causes swelling in the feet due to fluid retention
must excrete or increase blood volume
A

tunica intima
B

elastin
C

tunica media
D

tunica externa
common causes of atrial clots
atrial fibrillation
bruits
bifurcations
A-fib
multiple messages, sporadic contractions in the atria
can lead to clotting
venous clots cause
- stasis of blood
- lack of movement
medication to break up a clot
TPA
risks associated with DVT
pulmonary embolus
flows through the heart into the increasingly smaller airways
What medication should someone with a DVT be on?
blood thinners (Coumadin/Warfarin, Heparin)
needed to prevent platelet aggregation
SV
stroke volume
amount (in L) of blood pumped in one beat
what is SV a measure of?
preload (venous return)
x
contractility (how hard the muscle is squeezed)
CO
cardiac output
HR x SV
BP
CO x TPR
- *TPR = total peripheral resistance**
- whether vasodilated or vasoconstricted affects
What regulates blood pressure? (3)
- Heart-pumping pressure
- Blood vessel tone
- Kidney
3 layers of blood vessels
- Tunica adventitia
- Tunica media
- Tunica intima
vaso vasorum
blood supply to the blood supply
Tunica adventitia components
- nerve
- lymph
- connective tissue
- vaso vasorum
Tunica media
smooth muscle cells
angiotensin converting enzyme (ACE) controls
Tunica intima
actions
- prevents substance transfer from blood into the vessels
- antithrombotic and prothrombotic secretions
- dilation metabolites
- constriction metabolites
dilation metabolites
NO
prostaglandins
dilation constrictors
endothelin
superoxide
thromboxane
tunica intima
turbulent blood flow
can damage tunica indica
turbulent blood flow at bifurcation points can cause scarring over time
valves
only present in the veins
prevent backflow into the extremities
fluid retention
decreased venous return causes swelling in the extremities
how to decrease fluid retention
increase blood volume
excrete fluid
DVT
deep vein thrombosis
blood clot in a vein
risk of DVT
pulmonary embolus
flows through the heart to increasingly smaller pathways of the lungs
Why is there a greater risk of DVT after surgery?
caused by stasis of blood and lack of movement
stroke volume =
preload (venous return) x contractility (how hard the muscle is squeezed)
Cardiac output =
stroke volume x HR
BP =
cardiac output (SV x HR) x TPR
TPR = total peripheral resistance
blood pressure regulation
3 factors
- heart pumping pressure
- blood vessel tone
- kidney
Frank Starling Mechanism
The heart pumps all blood that comes to it within the physiologic limits
What controls heart pumping pressure?
sympathetic and parasympathetic control of HR and CO
blood vessel tone
systemic resistance to flow
What does blood vessel tone rely on?
- compliance of vessels
- arteries
- veins
- capillaries
Blood vessel tone
What happens when sympathetic stimulation is increased?
see an increase in BP
*atherosclerosis and aging altered vascular compliance, PVD, hypertension, etc.
How do kidneys regulate blood pressure?
Blood volume control
Local factors
- interstitial pressure
- hormones
- local control
Local control of blood pressure by the kidneys
removal of water
removal of salt
pressure diuresis
removal of water
pressure natriuresis
removal of salt
ejection fraction in normal adults
60-75% of blood expelled
Hypertension
3 stages
- 140-159 SBP, 90-99 DBP
- 160-179 SBP, 100-109 DBP
- greater than 180, greater than 110
hypertension
two major categories
- essential hypertension (EH)
- secondary hypertension
essential hypertension
unknown cause in 95% of cases
- genetics or stress possibly causes
secondary hypertension
result of a known cause
i.e. kidney or bladder infection, arterial disease, Cushing’s syndrome, etc
LVEDV
left ventricular end diastolic volume
occurs after atrial kick
ejection fraction
amount you spit out divided by total amount of blood in the ventricle
SV/EDV
60-75% is normal
muscle contraction in the heart
delays?
muscles need to contract simultaneously in the heart
renin
released by kidney due to decrease in pressure
angiotensin I
released systemically due to renin in circulation
Angiotensin I is converted to (1) in the (2) by (3)
- Angiotensin II
- lungs
- ACE (Angiotensin Converting Enzyme)
Angiotensin II causes
- causes vasoconstriction and decreased excretion of salt and water by the kidneys
- due toincreased release of aldosterone
aldosterone
(1) Result
(2) Drug
produces reabsorption of salt and water
(1) Result: Elevated BP (hypertension and potential long term CHF)
(2) Drug: ACE inhibitor
Sleep Apnea and Acute Hypertension
chemoreflexes
influence cardiac, vascular, and breathing control
Sleep Apnea and Acute Hypertension
What do chemoreflexes respond to?
hypoxia
hypercapnia
Sleep Apnea and Acute Hypertension
Stimulation of chemoreceptors leads to what response?
sympathetic response of vasoconstriction
sleep apnea and acute hypertension
peripheral chemoreceptors
carotid bodies of carotid artery
respond to hypoxia
sleep apnea and hypertensives
central chemoreceptors
brain stem and respond to hypercapnia
How do hypertensives respond to hypoxia or hypercapnia?
exaggerated response
renal artery stenosis
- Fibromuscular dysplasia (FMD)
- Atherosclerosis
Who does fibromuscular dysplasia (FMD) typically affect?
young women
S/S renal artery stenosis
atherosclerosis
hypertension
renal failure
refractory angina
recurrent episodes of CHF
flash pulmonary edema
S/S renal artery stenosis
treatment
stent of renal artery
angioplasty
What is this condition?

FMD
fibromuscular dysplasia
What is heart failure?
“the inability of the heart to pump blood forward at a sufficient rate to meet the metabolic demands of the body (forward failure),
or the ability to do so only if the cardiac filling pressures are abnormally high (backward failure), or both.”
preload
amount of blood filling along with stretch
afterload
what heart is pumping against
- hypertension
- blood volume
- vascular compliance