basic cardiac principle Flashcards
What is the function of the circulatory system?
- maintain’s blood flow supply to the body
- delivers oxygen, nutrients and other needed substances to all of the body’s cells and removes the waste of metabolism
what is the interface between blood and the artery wall?
the endothelium
What are endothelial cells metabolic functions?
- maintain vessel tone
- hemostasis
- angiogenesis
- neutrophil chemotaxis
- hormone secretion
What produces nitric oxide & endothelin?
endothelium
injury to endothelium causes _____________
dysfunction
What is the outermost part of the heart?
pericardium
What is the muscle layer of the heart called?
myocardium
What is the innermost layer of the heart?
endocardium
What are the four valves of the heart?
aortic
pulmonic
tricuspid
mitral (bicuspid)
What are the two atrioventricular valves?
tricuspid
bicupid(mitral)
Where are atrioventricular valves located?
located between the atrial & ventricular chambers on each side
What prevents backflow into the atria when the ventricles contract?
AV valves
What does the bicuspid (mitral) valve consist of?
two flaps or cusps of the endocardium
What does the tricuspid valve consist of?
three flaps
What are the two semilunar valves?
pulmonic
aortic
What guards the bases of the two large arteries leaving the ventricular chambers?
semilunar valves
How does blood move from deoxygenated to oxygenated in the heart?
superior & inferior vena cava, rt atrium, tricuspid valve, rt ventricle, pulmonic valve, pulmonary arteries, lungs, pulmonary veins, lt atrium, mitral valve, lt ventricle, aortic valve, aorta
Which term is used to describe the amount of stretch on the myocardium at the end of diastole?
A. afterload
B. cardiac index
C. cardiac output
D. preload
D. preload
What 2 factors are used to calculate cardiac output? SATA
A. heart rate
B. blood pressure
C. stroke volume
D. mean arterial pressure
E. systemic vascular resistance
A. heart rate
C. stroke volume
Which statement best describes cardiac after load?
a. the volume amount that fills the ventricles at the end of diastole
b. the volume of blood the ventricles must pump out of the heart
c. the amount of blood the left ventricle pumps with each heart beat
d. the pressure the venticles must work against to open the semilunar valves so blood can be pumped out of the heart
d. the pressure the venticles must work against to open the semilunar valves so blood can be pumped out of the heart
a pt with hypovolemic shock is given Iv fluids. IV fluids will help ______________ cardiac output by ____________
a. decrease; decreasing preload
b. increase; increasing preload
c. increase; decreasing afterload
d. decrease; increasing contractility
b. increase; increasing preload
Which of the following is the main difference between unstable and stable angina?
a. stability of the plaque
b. age of the pt
c. type of activity bringing on chest pain
d. pain has never had chest pain before
a. stability of the plaque
Which catergory of beta blockers inhibit both beta 1 and beta 2 receptors?
a. selective beta blockers
b. non-selective beta blockers
b. non-selective beta blockers
What is the heart the size of?
a fist
How much does a heart weigh?
about a pound
What occurs during systole?
the heart contracts and pumps out blood; high pressure causes AV valves to open and ejects blood out of the heart
What are the 5 characteristics of metabolic syndrome?
- hypertension
- obesity
- abnormal cholesterol levels
- chronic inflammation
- insulin resistance
What two diseases does metabolic syndrome put someone at risk of?
heart disease
diabetes
What body shape puts someone at higher risk for metabolic disease?
apple shape
What happens in diastole?
the atria & ventricals relax allowing blood to flow into the heart; “filling phase”; 2/3 of the cardiac cycle
What is cardiac output?
the amount of blood the heart pumps per minute from the left ventricle
How is cardiac output measured?
heart rate x stroke volume
What is normal cardiac output?
4-8L per minute
What is stroke volume?
the amount of blood pumped by the ventricles with each heartbeat
Can stroke volume be measured?
no
What three factors impact stroke volume?
- preload
- afterload
- contractility
What does preload refer to?
the stretching of muscle fibers in the ventricles to the greatest of their ability
The bigger the stretch the more ________ you have, therefore the more ______ you have in the left ventricle.
preload; blood
The biggest stretch is the blood in the ventricle at the ____ of diastole; when the ________ valve is still closed.
end; mitral
What is starling’s law?
the more the heart muscles stretch during diastole the more forcefully it will contract during systole
during ______, the more blood I get in, the more blood I get out.
preload
What 4 things does preload help with?
- accommodating greater blood volume
- increasing sacromere length
- increasing sensitivity of Ca++
- encouraging strong contractions
When you have more preload you are increasing ______ _______
cardiac output
What are the 8 things that can increase preload?
- increased central venous pressure
- reduced heart rate
- valvular regurgitation
- increased aortic pressure
- ventricular systolic heart failure
- increased circulating volume
- mitral insufficiency
- aortic insufficiency
What are the 7 ways preload can be decreased?
- decreased central venous pressure
- increased heart rate
- decreased circulating volume
bleeding
third spacing - mittral stenosis
- vasodilator use (nitro)
- atrial fib
- cardiac tamponade
What is contractility?
ability of the myocardium to contract normally (squeezing of the ventricles)
What does increased contractility cause?
an increase in stroke volume
What is contractility influenced by?
preload
What is positive inotropy?
increased force of contraction; decreased preload & afterload
What is negative inotropy?
decreased force of contraction
If the stretch during preload is not strong, there is not as strong of a ____________
contraction
Are there medications that can moderate the force of contraction?
yes there are meds to increase or decrease force of contraction
What is afterload?
refers to the amount of resistance the heart must pump against when ejecting blood
to eject blood out of the ventricles the ___ valves must be pushed open
AV valves
What is the example used for afterload?
overcoming the kink in the hose
In what condition is heart contractility not great and the heart has to work harder to open up the valves?
heart failure
What happens when afterload is low?
ventricles do not have to exert much effect to get the blood out of the heart; easy workload
What happens when afterload is high?
increased due to increased systemic vascular resistance; think HTN; vasoconstriction
What is ejection fraction?
how much blood the left ventricle pumps out with each contraction
How is ejection fraction measured?
stroke volume/ preload; expressed in a %
What is the normal & abnormal measurement for ejection fracture?
normal - 55 to 70%
abnormal - below 40%
What does an abnormal ejection fraction tell us?
the heart is not putting out a lot of oxygenated blood to the rest of the body
What happens in the heart during sympathetic nervous system response?
- HR & BP increase
- preload decreasd & afterload increased to get blood oxygenated more quickly
- epinephrine & norepinephrine are secreted to increase blood flow
- heart increased output & vasodilation occurs to oxygenate tissues more quickly
What are beta 1 receptors responsible for?
signaling sympathetic nervous system
Beta 1 is involved in response of what organ?
the heart
When beta 1 is activated what 4 things occur?
- increase force of contraction
- increased rate of contraction (HR)
- increased HR & contractility will increase stroke volume & cardiac output
What can happen when there is too much activation of beta 1 receptors?
abnormal arythmia
What happens when we block the activation of beta 1 receptors (use beta blockers)?
HR & force of contractions decrease
What does beta 2 do?
act as a vasodilator
- play a role in glucose metabolism
- more involved in resp & GI systems
What is the RAAS?
a hormone signaling system that regulates blood volume, BP, fluid & electrolytes, and systemic vascular resistance
What are the three main substances involves in RAAS?
renin (enzyme)
aldosterone (hormone)
angiotensin II (hormone)
What do renin, aldosterone & angiotensin II help regulate and how?
BP by increasing sodium absorption, water reabsorption, & vascular tone(how much vasoconstriction)
What do kidneys play a role in?
cardiac output; account for 20% of cardiac output
What do the kidneys do in response to low BP?
release renin
How is angiotensin converted into angiotensin I?
via renin
How does angiotensin I become angiotensin II?
angiotensin I goes to the lungs where angiotensin converting enzymes (ACE) converts angiotensin I to angiotensin II
What does Angiotensin II cause?
vasoconstriction causing an increase in BP
- causes adrenal glad to release aldosterone & pituitary gland to release ADH
What is the role of aldosterone & ADH in the RAAS system?
causes sodium retention and fluid retention causing BP & blood volume to increase
What do aldosterone & angiotension II stimulate?
sympathetic nervous system
What is a big issue with angiotensin II?
it sheds our blood vessels
What happens when RAAS is constantly activated?
leads to shredding of blood vessels & the development of atherosclerosis; Causes the heart to lose the ability to expand & contract normally due to remodeling
What happens in the heart when angiotensin II is activated?
increased preload & afterload
What prevents angiotensin I from becoming angiotensin II?
ACE inhibitors
What can inappropriate RAAS activation cause?
endothelial dysfunction
vascular remodeling
elevated BP
artherosclerosis
plaque
impaired adipogenesis
glucose intolerence
What is insulin resistance?
When cells fail to make effective use of insulin
What happens to glucose levels in those with insulin resistance?
blood sugar increases; insulin is not able to reduce blood sugar; pt remains hyperglycemic
where is insulin secreted from?
beta cells in the pancreas
Should insulin be in circulation?
no; we want it in the cell; if it is in circulation this means it is not being used by the cells
What can insulin resistance cause?
- increased catecholamine
- stimulates sodium reabsorption (increases BP)
- endothelial dysfunction
- RAAS & SNS dysfunction
- increase smooth muscle proliferation which leads to hypertrophy & targeted organ damage
What improves high BP related to insulin sensitivity?
meds that improve insulin sensitivity; ACEI
What do you need to make nitric oxide?
insulin
What role does insulin play in the vascular system?
plays a role in vascular protection; increases endothelial cell production of nitric oxide
What puts someone in a state of low-grade chronic inflammation?
obesity
What 4 things can a low-grade chronic inflammatory state cause?
CVD (increased thrombosis)
type 2 diabetes
hypertension
hyperlipidemia
What can target organ damage increase the risk of?
dementia; decreased circulation meaning decreased O2 to the brain
What target organ damage is caused by HTN?
brain damage (may cause stroke)
renal damage
retinopathy
PAD
left ventricular hypertrophy
atherosclerotic cardiovascular disease
What are the risk factors that lead to endothelial dysfunction and therefore atherogenesis?
HTN
genetic susceptibility
hyperlipidemia
diabetes
physical inactivity
obesity
smoking
stress
aging
How are FOAM cells formed?
macrophages ingest deposited cholesterol from LDLs; making “plaque”
What does the build up of plaque lead to?
hypertrophy
What does LDL do?
deposits cholesterol
What happens when plaque ruptures?
a blood clot forms at the site & the muscle in that area of the blocked artery starts to die
What causes things like CVD, PVD, & cerebral issues?
inadequate tissue perfusion; disruption of supply & demand
What are the symptoms of inadequate tissue perfusion?
coronary issues
- stable angina
- unstable angina
peripheral disease
- claudication
cerebral
- TIA
- CVA
What is present in stable angina?
a significant fixed lesion?
What is present in unstable angina?
unstable plaque that could break off causing clotting and an acute MI; AKA acute coronay syndrome (ACS)
What are the three main reperfusion strategies when an MI has occurred?
- pharmacologic agents (fibrinolytic therapy)
- percutaneous coronary intervention
- CABG
What are the types of PCIs that can be performed?
- percutaneous transluminal coronary angioplasty (PTCA)
- stents
- artherectomy
- thrombectomy
What is a CABG?
Coronary Artery bypass graft; a healthy blood vessel is attached to the aorta to bypass a blockage
What is a stent?
a small device that is put into a vein or artery to keep it open
