AUTOREGULATION

AUTOREGULATION

MYOGENIC MECHANISM
TISSUE METABOLISM
H⁺ (LACTIC ACID & CO₂)
ADENOSINE & ADENINE NUCLEOTIDES
KREBS CYCLE INTERMEDIATES

ENDOTHELIAL CELL FACTORS:

EDRF ( nitric oxide or NO)
ENDOTHELIN ( peptide vasoconstrictor)
ADENSOINE AND RELATED ADENINE NUCLEOTIDES (vasodilators)

EDEMA

SWELLING OF THE TISSUES DUE TO FLUID ACCUMULATION FROM THE CAPILLARIES

INCREASED BP IN TISSUES

DECREASED VR
INCREASED TPR

CARDIOVASCULAR SHOCK

INADEQUATE SUPPLY OF O₂ TO THE TISSUES
RESULTS IN LOSS OF TISSUE FUNCTION AND LOSS OF CORRECTIVE REFLEXES

Note: especially the HEART & NERVOUS SYSTEM

PROBLEMS PRESENTED BY SHOCK

decreased cardiac output
decreased VR !!!

loss of sympathetic reflexes

tissue dehydration ( BP)

renal failure

SHOCK

ANAPHYLACTIC
CARDIOGENIC
EMOTIONAL STRESS
HEMORRHAGIC

ALSO BURNS

SYMPTOMS:

COLD, CLAMMY SKIN
RAPID SHALLOW PULSE
DILATED PUPILS
LOSS OF PUPILLARY REFLEX

TREATMENTS

ELEVATE FEET
KEEP WARM
PLASMA EXPANDERS
EPINEPHRINE

Reversible - NonReversible
Border:

Oxygen deficit of

> 120 ml/Kg

body weight

HYPERTENSION

INCREASED TPR
"ESSENTIAL" or IDIOPATHIC
ATHEROSCLEROSIS

decreased arterial compliance

ARTERIOSCLEROSIS

plaque deposit in major vessel

POSITIVE FEEDBACK

Increased TPR --> increased cardiac work

---> Increased cardiac muscle mass (hypertrophy)

---> Increased bv muscle mass & TPR

Increased cardiac O₂ demand !!!

Positive Feedback

Decreased BV compliance over time
Made worse by ‘re-setting’ of the baroreceptors as the BVs lose their compliance

POTENTIAL PROBLEMS

MYOCARDIAL DISEASE
HEART ATTACK AND INFARCT
---> INCREASED WORK FOR REMAINING HEALTHY TISSUE
DECREASED VR ----> EDEMA
LIVER
LUNGS
KIDNEY

Possible Treatments

Vasodilators

"False NTs" - a- methyl DOPA

Diuretics

b Blockers

Sedatives

Next: On to Blood