1.Isovolumic (Isovolumetric)Contraction Phase:
•Time between ___ valves closing and ____ valve opening therefore both sets of valves are closed
• First heart sound occurs when ___ valves close.
• Onset of this phase linked to beginning of ventricular _____ (QRS—linked to peak of R)
• Associated with ______ volume of blood in ventricles (end diastolic volume or EDV)
• Linked to “c” wave of atrial pressure
• Ends with aortic valve opening which begins the next phase
AV
aortic
AV
systole
highest
2.Ejection Phase:
•Time between the opening of aortic (and pulmonary) valve and the closing of the
aortic (and pulmonary) valve.
•Aortic pressure increases from 80 mmHg to 120 mmHg during this phase (BP is highest)
•Rapid ejection of blood occurs in the first 1/3 of ejection phase and ___% of blood volume is ejected
• Slow ejection is the final ___% of the blood volume ejected and takes the remaining 2/3 of ejection time.
•Ends when ______ valves close
•2nd heart sound occurs when _________
valves close
70%
30%
semilunar
semilunar
T
lowest
v
incisura
4.Rapid Inflow (Filling) Phase:
•First ____of filling time— blood accumulating in the atria pushes the AV valves _____ and blood rapidly fills the ventricles
1/3
open
1/3
P
20
regulation of cardiac output:
1. Intrinsic Regulation: Frank-Starling Law- deals with relationship between ____ and Q.
•_____ _______ has the biggest impact on maintaining and increasing Q
•Other intrinsic factors that regulate Q are ___, SV and contractility.
preload
Venous Return (VR)
HR
2. Extrinsic Regulation: Autonomic NS A.Parasympathetic NS •\_\_\_\_\_\_ nerve primarily ↓ HR •Can ↓ SV •\_\_\_\_ binds to specific cholinergic (M2 muscarinic) receptors to \_\_\_\_ HR
B.Sympathetic NS
•Sympathetic nerves ↑ HR and ↑ SV
•_________ and Epinepherine
bind to specific (β1) receptors
Vagus
ACh
slow
Norepinepherine
normal conduction of the heart is:
SA node–>___ ____ –>bundle of his–> R and L bundle branches–> ______ fibers
AV node
purkinje
•S-A node-Dominant pacemaker with an
intrinsic rate of ___-__ beats/minute.
•A-V node-Back-up pacemaker with an
intrinsic rate of ___-___ beats/minute.
•Purkinje fibers-Back -up pacemaker with
an intrinsic rate of 15-40 beats/min.
70-80
40-60
velocity of action potentials: •SA node—0.3 to 0.5 m/sec •AV node—0.02 to 0.05 m/sec •Purkinje fibers—1.5 to 4.0 m/sec •Myocardium—0.3 to 0.5 m/sec
purkinje fibers (.06 sec??)
Atrial depolarization
QRS Compex
T
____ ______ represents the interval between atrial depolarization and the initiation of ventricular depolarization so the AV node
delay
PR Interval
__ _______ represents the beginning of
ventricular depolarization through the end of ventricular repolarization
QT Interval
__ ______ represents the time between the end of ventricular depolarization and the beginning of ventricular repolarization
ST Segment
the Three Layers of a blood vessel are:
1._____ _____- contains the endothelium that lines the lumen. Smooth layer that
minimizes friction.
2.Tunica media—circular smooth muscle and elastic fiber. Thickest layer. Regulates __________ and ___________
3. Tunica externa (adventitia)—collagen fibers that reinforce the vessel. Contains nerve fibers, lymph vessels, and blood vessels (____ ______) so the exterior of
the vessel is nourished.
Tunica intima
vasodilation and vasoconstriction.
vasa vasorum
8
quantity
volume
Four Sources of Resistance to Flow
Poiseuille’s
4
Parallel
resistance
flow = change in pressure over _________
if resistance goes up then flow goes down…
resistance
There are four primary forces (called starling forces) that determine if fluid will
move out of the blood into the interstitial space (filtration) or from the interstitial
space into the blood (absorption).
1.Capillary pressure (Pc)—tends to force fluid outward from the blood
2.Interstitial fluid pressure (Pif)—tends to force fluid into the blood when Pif is (+)
and outward if Pif is (-).
3.Plasma colloid osmotic pressure— tends to cause ______ of fluid into the
blood.
osmosis
edema
blood volume
Control of Blood Flow
I.Acute control—occurs within second to minutes (vasodilation or vasoconstriction) based on metabolic needs of tissue:
A.________ Theory—↑ metabolism or ↓ O2
concentration, causes a release of vasodilator substances (adenosine) which causes vasodilation
B. _______ Demand (Oxygen Lack) Theory— O2 is needed for smooth muscle to contract so if ↓O2 concentration then the smooth muscle of the blood vessels would simply relax causing vasodilation
Vasodilator
Oxygen
Control of Blood Flow
II. Autoregulation—maintaining BF when arterial pressure changes:
A._______ Theory—as MAP decreases, delivery of O2 and nutrients decrease
thus vasodilator substances are released.
B._______ Theory—when MAP decreases, arterioles vasodilate in response to a decrease in blood vessel wall tension
Metabolic
Myogenic
Control of Blood Flow
III. Long-term regulation—takes weeks or even months to establish new BF
A.Increase in tissue vascularity— angiogenesis is growth of new blood vessels; collateral circulation results from vessel ________
blockage