Hemodynamics
Card 1
Define hemodynamics
the mechanism of blood flow
What do hymoynamic disorders do?
interrupt blood flow
Formation of a mass of platelets, blood cells and fibrin that can
occlude a blood vessel. Is a description of what?
Thrombosis
Region of necrosis caused by oxygen deficiency due to a vessel blockage.
Infarction
An abnormal mass traveling in the bloodstream that occludes a blood vessel
Embolism
This kind of occlusion is not commonly developed in vessels with
fast, laminar, smooth blood flow.
Thrombosis
what are the three factors that cause higher chance for thrombus formation?
1. Endothelial damage
2. Altered blood flow
3. Blood hypercoagulation
What are varicose veins?
Vessels that can show large alterations to normal blood flow as they
are regions where the vein wall muscle is weakened allowing irregular
bulges to form
Where do 90% of venous thrombi develop?
Veins of the legs
A thrombi that starts to form and does not continue to develop
Resolution
Phagocytic digestion of a thrombus and replacement with fibrous
connective tissue
Organization
Endothelium forms over the replacement tissue and channels can form
through the thrombus
Recanalization
Thrombus narrows or occludes a vessel such that downstream tissues no
longer receive oxygen
Infacrtion
Growth of a thrombi along a vessel
Propagation
When talking about infarction what are we almost always talking about?
Arterial NOT venous
Why are infarcts due to arterial blockage?
Because arteries deliver oxygen and the loss of oxygen delivery is
what causes the infarct
What is an embolism?
any abnormal mass moving in the bloodstream
What is a thromboembolism?
part of a thrombus that breaks away from the vessel wall and is
carried by the bloodstream
What are arterial thromboemboli formed from?
Cardiac valve thrombi, aneurysm sites, any area with endothelial irregularities
What is the most common emboli?
Thromboembolism
Where would a venous thromboembolism get stuck?
can become trapped in the small vessels of the pulmonary system
What promotes the development of Deep vein thrombosis?
Venous stasis
vessel damage
hypercoagulation
What are the dangers of DVT?
portion of the thrombus will embolize to the lungs resulting in
pulmonary embolus.
What are the signs and symptoms of DVT?
often asymptomatic
skin dscolouration
edema
pain at the site of occlusion
What is the treatment for DVT?
anticoagulants and clot busters.
What is used for anti-coagulation therapy?
heparin
what is used for anti-platelet/clotting therapy?
asprin
what is used to increase the fribrinolytic system?
tPA
What drugs suppress the liver's synthesis of several clotting factors?
Dicumarol
Phenprocoumon
Warfarin
What drug blocks the last 2 steps of the coagulation cascade?
Heparin
What drug is used to inhibit platelet aggregation?
Aspirin
What three drugs are used to promote the fribrinolytic cascade and
plasmin formation?
Streptokinase
Urokinase
Alteplase
This type of emboli is usually due to bone fractures
Fat emboli
Start of Cardiovascular
...
Systole
Ejection of blood from the ventricles
Diastole
Filling period
Cardiac Output
amount of blood ejected by the heart in 1 minute (HR x SV)
Inotropy
contractility of the cardiac muscle
Dromotropy
Velocity of the conduction of the electrical signals
Chronotropy
Rate of heart beats
Lusitropy
relaxation functions of the cardiac muscle and chambers
Transmural
across the entire wall
stenosis/stenotic
abnormal narrowing or construction of a passageway (narrowed valves)
Sinus rhythm
SA node controls the cardiac rhythm
Mean arterial pressure (MAP)
pressure that propels blood to the tissues
What is a voltage gated ion channel?
open and closes in response to changes in membrane potential
What is a receptor gated ion channel?
open and closes in response to chemical signals operating through
membrane receptors.
What is the primary activation of non-pacemaker action potentials?
Primarily initiated through influx of sodium into the cell
During what phase does rapid depolarization through increased
movement of sodium into the cell through fast sodium channels occur in
non-pacemaker cells?
Phase 0
Name the event, Ion, direction of movement and other associated
activities in Phase 0 (non-pacemaker)
Initiatial Depolarization
Sodium (Na+)
Into the cardiac cells
Not applicable
Name the event, Ion, direction of movement and other associated
activities in Phase 1 (non-pacemaker)
Initial repolarization
Potassium (K+)
Slow movement out of the cardiac cells
Na+ channels close
Name the event, Ion, direction of movement and other associated
activities in Phase 2 (non-pacemaker)
Plateau
Calcium
Into the cardiac cells
Transient potassium channels close
Name the event, Ion, direction of movement and other associated
activities in Phase 3 (non-pacemaker)
Repolarization
Potassium
Out of the cardiac cells (rapid)
calcium channels close
Name the event, Ion, direction of movement and other associated
activities in Phase 4 (non-pacemaker)
Resting potential reset
Potassium, sodium, and calcium
K+ pumped into the cells, Na+ pumped out of the cells and
Ca2+ pumped out of the cells
All channels close while pumps are activated
In pacemaker cells what do they depolarize primarily through?
Activity of L-type calcium channels
What node is the primary pacemaker?
SA node
Name the activity, ion, direction of movement and other associated
activities of the pacemaker cell's actions potentials in Phase 4
Spontaneous initiation
Na+ and Ca2+ (T-type channels)
Into the cardiac pacemaker cells
Closure of K channels
Name the activity, ion, direction of movement and other associated
activities of the pacemaker cell's actions potentials in Phase 0
Full depolarization
Ca2+ (through L-type channels)
Into the cardiac pacemaker cells
closure of Na+ channels
Name the activity, ion, direction of movement and other associated
activities of the pacemaker cell's actions potentials in Phase 3
Repolarization
K+
Out of the pacemaker cells
closure of L-type calcium channels
Full depolarization of non-pacemaker =
Na+ influx
Full depolarization of pacemaker cells =
Ca2+ influx
Both pacemaker and non-pacemaker require ____ efflux for
repolarization and both require _____ activity to re-set ion concentrations.
K+
ATPase