Cardio- Nicely Flashcards
4 layers of the heart
Pericardium- loose-fitting sac that surrounds the heart
Epicardium is the outer layer of the heart (visceral layer)
Myocardium is the muscle layer
Endocardium lines the chambers of the heart (smoother layer)
positioning of the heart in the chest- right side is more ____ while left is more _____
oblique position: right is more anterior and left is more posterior
Myocardium beats as one unit due to ________ in cardiac muscle that allow for easy passage of _______ and _____
Contains ____and ____ (like skeletal muscles)
low-resistance gap junctions
ions and electrical impulses
actin and myosin
cardiac muscle action is regulated by what proteins? what are the three subtypes? what do they do?
troponin, troponin myosin complex
types: T, I, and C
- regulate calcium- mediated muscle contraction
______ can be measured during muscle injury to diagnose myocardial infarction
troponin T and I
what are the three layers that all vessels (besides capillaries) possess? what is the purpose of each?
- Tunica externa or tunica adventitia: (outermost layer);collagen fibers ; Protect and anchor the vessels
- Tunica media- middle: Smooth muscle; Allows constriction of vessels
- Tunica intima:
Single layer of flattened endothelial cells with minimal underlying connective tissue
–>Provides slippery surface to prevent platelet adhesion and blood clots
which vessel type has Highest blood volume resistance AND
Extensive smooth muscle that is tonic (constantly contracted)?
arterioles
what are the main properties of capillaries pertinent to their function?
- Single layer endothelial cells surrounded by basal lamina
- Exchange of gas, nutrients, water, solutes, waste
- Low velocity allows for increased time for exchange
- selective perfusion based on metabolic demand (fight or flight, rest/digest) - shutting down or opening more where needed
how do lipid-soluble vs water-soluble substances move in and out of capillaries?
Lipid-soluble substance – dissolve in endothelial cell membranes and diffusing across
Water-soluble substance – through water-filled cleft between endothelial cells or large pores in walls (fenestrations)
what are splanchnic arterioles?
arterioles that feed gut/GI system
A1 vs B2 on the vascular system?
A1- excitatory = vasoconstrict
B2- inhibit = vasodilate
(do so by opening (excite) or closing (inhibit) Ca channels in smooth muscle)
AV valves are _____ unless diseased
one way!
systemic circulation path
Left heart Systemic Arteries (Arterioles) Systemic Capillaries – greatest surface area (Venules) Systemic Veins
pulmonary circulation path
Right heart
Pulmonary Arteries
Pulmonary Capillaries
Pulmonary Veins
what is stroke volume?
Volume ejected by ventricle with each heart beat
SV = (End-diastolic volume) – (End-systolic volume)
what is ejection fraction?
Fraction of end-diastolic volume ejected in each stroke volume
Measuring efficiency of ventricular contraction
Normal = ~55%
EF= SV/End-diastolic volume
what is cardiac output?
Total volume of ventricular ejection over a unit of time
CO = SV x HR (bpm)
end-diastolic volume can be thought of as synonymous with …?
preload
what is the frank-starling relationship?
venous return = cardiac output (in a normal heart) - aka more stretch/ volume = more output = more venous return (cycle)
positive vs negative ionotrope effect
agents that alter muscle contraction force:
Positive inotropes - increases contractility
-Increases SV and CO
-Increases EF
Negative inotropes – decreases contractility
-Decreases SV and CO
- Decreases EF
Percentage of Cardiac output flow to different areas increases or decreases based on_____
O2 demands
what are the different percentages of CO to different parts of the body?
Cerebral 15% Coronary 5% Renal 25% GI 25% Skeletal Muscle 25% Skin 5%
what are CO distribution alterations? 3 types…
- CO constant but redistribution of flow
-Selective arteriolar pressure resistance
=Change flow to one organ at expense of others - CO increases or decreases but distribution of flow is constant
- combo of 1 and 2
how does venous size effect blood flow velocity?
an inverse relationship between velocity and cross sectional area of a vessel.
skinnier vessel = more pressure on it (higher velocity), larger diameter = less pressure on it (b/c more surface area)
what is the principle of the poisuielle equation?
Blood flow depends on resistance, vessel diameter, blood viscosity
Higher viscosity = higher resistance
Longer vessel = higher resistance
Bigger radius = lower resistance by 16 fold!! (4th power)
resistance is affected by vessel arrangement… series vs parallel
series: Total resistance = sum of individual resistances in the circuit because total flow is the same
parallel: Total resistance = less than any individual resistances b/c it is expressed as a fraction
1/Rtotal = 1/R1 + 1/R2 + 1/R3 + ….
Increasing resistance in the circuit = decreased total resistance
what is laminar flow?
what is normal —>smooth vessel- less resistance in the center of the vessel so that flows faster
what is turbulent flow?
what results from laminar flow being disrupted by valvular irregularity or clot (hear murmur or bruit)
what is “shear” in terms of flow through the vessels?
the resistance of flowing blood on the sides vs the center of the vessel:
-Highest at the wall of a vessel because the greatest difference in velocity is between the motionless layer at the vessel wall and the moving layer of blood next to it
(Breaks up plaques and decreases viscosity)
-Lowest in center of vessel = velocity highest
which vessels would have the lowest compliance?
Aged arteries : requires the arteries to operate under higher pressure to contain an appropriate amount of volume
(Stenosed/sclerosed)
diastolic pressure
lowest arterial pressure
Ventricular relaxation
systolic pressure
highest arterial pressure
Systolic ejection
dicrotic notch in curve
Dicrotic notch in curve – slight backward flow of blood with closure of aortic valve
pulse pressure
Systolic pressure minus diastolic pressure
-Pulse pressure diminishes as blood moves from large arteries to absence in the capillaries and beyond (due to increased resistance in arterioles and increased compliance in veins)
Pressures within the system have to _____ in order to _____
differ in order to drive flow
Equal pressures throughout would not create this driving force.
formula for mean arterial pressure (MAP)
MAP = diastolic + 1/3 pulse pressure
when is MAP highest and lowest?
Mean pressure is highest in aorta and decreases throughout the system to being the lowest in the veins
what is the mean aortic pressure?
100mmHg
Minimal energy is lost as blood flows from aorta to large arteries due to ______
arterial elastic recoil - so the pressure remains high
RV wall is ____ than LV wall due to ______ pressure work on R
thinner, decreased
pulmonary vs systemic resistance
Pulmonary resistance is lower than systemic resistance to achieve the same amount of flow
CO of RV = CO of LV
3 types of pathology that can alter compliance of vessels?
ateriosclerosis, aortic stenosis, aortic regurg.
what are the effects of arteriosclerosis?
Plaque decreases diameter
Decreased compliance
Increased SBP, PP, and MAP