CV function in pathology Flashcards
What are the consequences of circulatory shock?
Syncope after severe shock and inadequate blood to brain
Even after compensatory mechanism arterial pressure can be low
What is MAP?
Mean arterial pressure= CO*TPR
What are the 3 primary disturbances of circulatory shock?
- Severely depressed Myocardial function
- Grossly inadequate filling due to low mean circulatory filling pressure
- Profound systemic vasodilation
what volume of loss is considered hypovolemic shock?
> 20%
How do exotoxins create vasodilation?
Formation of nitric oxide synthase in endothelial cells
What is neurogenic shock?
Loss of vascular tone due to inhibition of normal tonic activity of sympathetic vasoconstrictor nerves
- Vasovagal syncope
- General anesthesia
What are the sx’s of compensatory circulatory shock?
Pallor Cold clammy skin Rapid HR Muscle weakness Venous constriction
What about when your compensatory response is weak?
Dizziness
Confusion
LOC
What are some other responses to circulatory shock?
Rapid breathing to increase VR
- Renin release (TPR)
- ADH release (TPR)
- Epi release
- Increase glycogenlysis of liver (rises extracellular osmolarity)
- reduced capillary hydrostatics–> resorption
How do we compensate for CAD?
Local metabolic vasodilation to reduced arterial resistance of coronaries
What is the definition of systolic dysfunction?
EF
What are some systemic alterations of systolic dysfunction?
Reduced Ca sequestration
- low affinity of trop for Ca
- Altered substrate metabolism from fatty acid and glucose oxidation
- Impaired respiratory chain activity- impaired energy production
What is the bad cause of long term compensation
Fluid retention leads to chronically high EDV
- increased O2 demand
- increased wall tension
What does high venous pressure cause?
Transcapillary fluid leading to filtration, edema and congestion
What is pulomonary HTN?
> 20mmHg
