central ischemic response severe drop in brain map > increase in flow to brain & brain map,...

Central Ischemic ResponseSevere drop in Brain MAP > increase in flow to brain & brain MAP,

shunt blood away from other organs (vasoconstriction via sympathetic)

HOWEVER, long term O2 deprivation shuts down brainstem…lose the integrator

Causes systemic vasodilatation and further drop in MAP…… DEATH!

Lose systemic sympatheticResults in severe vasodilation

HR and contractility DROPReduced Cardiac Output

MAP = CO x R

Capillary Anatomy

Continuous Capillaries Fenestrated Capillaries

Transcytosis via vesicles

Large Proteins & Solutes

Diffusion directly through capillary wall

O2 & CO2, Ions

Movement through capillary walls

Capillary Hydrostatic Pressure (CHP)

Colloid Osmotic Pressure (COP)

Fluid Movement = CHP - COP

Fluid Moves out to ISF

FILTRATIONFILTRATION

Fluid Moves in to Capillary

ABSORPTIONABSORPTION

BLOOD FLOWArterial side Venous side

Filtration drives Fluid into ISF

O2, Ions, Nutrients, Glucose!

Absorption drives Fluid into Capillary

CO2, Metabolic wastes,recycled molecules

COP > CHP

CHP

COP

COP > CHP

Arterial side Venous side