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3. Similar in some ways to the combined use of intravenous Alfa1- and ß adrenergic blockers -Decreased heart rate and blood pressure -Sympathectomy causes venous and arterial vasodilation

4. -Blockade of the Cardioaccelerator fibers arising T1–T4 Decrease heart rate because of fall in right atrial filling,deacrease out flow from intrinsic Chrono tropic stretch receptors Located in the right atrium and great veins

5. -Decrease in mean arterial pressure of 26% (155 to 115mmHg) accompanied by only a 12% (52to46ml/100gr/min ) decrease in CBF -Higher Level than T4 in normotensive and hypertensive patient, arterial pressure decreased by 32% and 50%

6. - Although CBF was unchanged in the normotensives group and 19% decrease in untreated hypertensive patient - -During T10 block 22% decrease in mean arterial pressure cerebral and myocardial block flow was insingnificantly altered

7. Respiratory effect -Little Clinical Consequence -TV unchanged during high Spinal -Vital capacity is decrease a small amount from 4- 3/7L -This decrease result ERV related to paralysis of the abdominal

8. -Respiratory arrest result hypoperfusion of the respiratory centers in the brainstem -focus on the expiratory muscle are important

9. Gastrointestinal function - Nausea and vomiting up to 20% patient -Primarily related parasympathetic Vagal activity - - Atropine is effective on nausea associated with high (T5) subarachnoid anesthesia - The decrease in hepatic blood flow during Subarachnoid may accrued

10. -Urinary retention -avoid administration of excessive of crystalloid solution