Test 1: Wk1: 1 Hemodynamics - Puri Flashcards
Systemic circulation
Oxygenated blood flows from the left heart into
the systemic circulation and, after passing through the capillary bed, flows back in
a deoxygenated state to the right atrium of the heart to restart the process.
Systemic circulation Flow
Left atrium → mitral valve → left ventricle → aortic valve
→ aorta→ arteries → arterioles → capillary beds → veins → superior vena
cava (SVC) and inferior vena cava (IVC) → right atrium
Pulmonary Circulation
Deoxygenated blood in the right heart flows into
the lungs, where it is oxygenated and returned to the left atrium.
Pulmonary Circulation Flow
Right atrium → tricuspid valve → right ventricle → pulmonary valve
→ pulmonary trunk → pulmonary arteries → lungs → four pulmonary
veins → left atrium
Flow of Blood Through the Heart
Inf and Sup Vena Cava > RA > Tricuspid Valve > RV > Pulmonary Valve > Pulmonary Artery > Lungs Capillary Bed > Pulmonary Veins > LA > Mitral Valve > LV > Aortic Valve > Aorta > Systemic Arteries > Systemic Capillary Beds > Systemic Veins > Vena Cava
cyanosis
bluish red discoloration of skin and mucosa
due to
deoxygenated blood circulating in the systemic circulation capillaries (usually seen
when oxygen saturation of hemoglobin drops below 85%)
As the pressure in the ventricles starts to --- during systole, it exceeds the pressure in the atria, which closes the ---- and the ---- valve. Closure of the valves causes turbulence that makes a sound–S1—the first heart sound is heard—“lub
As the pressure in the ventricles starts to rise during systole, it exceeds the pressure in the atria, which closes the mitral and the tricuspid valve. Closure of the valves causes turbulence that makes a sound–S1—the first heart sound is heard—“lub
S2 heart sound
closing of aortic and pulmonary valves
Flowing blood is key to homeostasis across organ-systems and to ensure: (4)
- Nutrient delivery & waste disposal
- Chemical signaling (think hormones)
- Thermoregulation (heat exchange in the skin)
- Defense mechanisms (innate and adaptive immunity travel to the site of injury
via the circulation)
rheumatic heart disease
the mitral valve is stenosed
valve opening is not supposed to make a sound, but
a stenosed valve opens with an audible snap→ the snap is after S2 and before S1
In atrial septal defect
blood flows from the left to the right atria during
diastole i.e. some volume of blood “bypasses” the LV and thus, LV output is NOT
equal to RV output.
— is the first step in restoring adequacy of circulation in the ER.
fluid infusion
distributive shock
all vascular beds dilate at the same time. This drops the
pressure in the system leading to severe under-perfusion of key organs
Pressure difference (ΔP)
required to generate flow, which is facilitated by
one-way valves—i.e. pressure upstream MUST be higher than pressure
downstream
what is the only purpose of the CV system
generating blood flow
where is pressure highest in circualtion
large arteries
blood reservoirs
veins
veins have — pressure and — volume
low; high
stop valves of circulation
arterioles
opening and closing controls flow of blood to capillaries
site of gas and nutrient exchange
capillaries
These are single-cell lined
tubes, which are freely permeable to gases and nutrients
arterioles are actively controlled by the
SNS
arborization
circulatory and respiratory systems are designed like a tree
the heart is a generator of
flow
Flow
vol/time
Q
Energy for flow
Force / Area
P
Measure of opposition to fluid movement
R
resistance
Flow, pressure and resistance are linked via
this equation
Q = ΔP/R
or
CO = ΔP/R
Cardiac output (CO) is defined as
volume pumped by the heart/min.
Stroke Volume (SV) is
volume ejected/beat ≈ 69 mL
Number of times the heart beats/min
HR = 72/min
CO =
CO = HR x SV = Flow (Q)
72 x 69 = 4950ml/min ≈ 5L/min
tachycardia is seen in — shock which is characterized by — stroke volume
hypovolemic; reduced
how to recover CO if SV is reduced
increase HR
cardiac output
can be regulated by changing either SV or HR or both depending on what the
“desired” outcome is.
blood pressure is
directly dependent
on the volume of blood in the major arteries which in turn is controlled by
cardiac output.
— refers to pressure in the aorta and its larger branches.
MAP
If RAP is 0, MAP = —
If RAP is 0, MAP = Driving pressure
MAP= 2/3 — + 1/3 — ≈ 100 mm
Hg
MAP= 2/3 Diastolic + 1/3 Systolic ≈ 100 mm
Hg
all organs are arranged in — to each other
parallel
1/TPR = 1/kidney + 1/liver + 1/upper limb + etc..
resistance to flow offered by an singular vascular bed is — than TPR
more
if an organ is removed what happens to TPR
increased
— have highest resistance to blood flow
arterioles
Adding resistance in —increases total resistance and adding resistance in — lowers it
Adding resistance in series increases total resistance and adding resistance in parallel lowers it
velocity of blood flow is highest
in the aorta
to calculate flow
or cardiac output—we
need three things—
- oxygen consumption/ minute
- arterial oxygen concentration
- Venous oxygen concentration
