Question

TRUE OR FALSE

1.The sympathetic nervous system increases blood pressure in the short term by increasing cardiac______output¬¬¬¬¬____and___bloodpressure.

2. The rapid depolarization phase of the contractile cell action potential is due to the opening of voltage-gated potassium ion channels.

3. The buffy coat is the fraction of an anticoagulated blood sample that contains most of the leukocytes and thrombocytes.

4. Erythrocytes are biconcave discs with prominent nuclei. The main function of erythrocytes is to transport O2 on the molecule hemoglobin.

5. The plateau phase in cardiac cell is due to the influx of calcium ions through calcium ion channels

Answer 1

1. True; Stimulation of sympathetic nervous system causes release of epinephrine and norepinephrine leading to vasoconstriction and increased heart rate which results in increased blood pressure and cardiac output.

2. False; The rapid depolarization phase of the contractile cell action potential is due to opening of voltage gated sodium channels.

3. True; centrifugation of blood sample after adding anticoagulant results in three different layers. The lower layer is red containing red blood cells and the upper layer is yellow which is plasma and there is a buffy coat between both layer containing leukocytes and thrombocytes.

4. False; Mature RBC do not contain nuclei.

5. True; the plateau phase of action potential is due to increased permeability of calcium ions which maintain depolarization and prolong the action potential.