As part of a blood drive on campus for the American Red Cross, you and your friends have just donated 500 ml of blood. You are now relaxing at the student lounge, waiting for A&P lab to begin. Unfortunately, even though you are thirsty, you haven't bothered to buy yourself a drink. Other than a little soreness of the skin and tissue around your median cubital vein, you feel fine. How has your 500 ml decrease in blood volume most likely affected your cardiac output, heart rate, and stroke volume?
A) no change in cardiac output, decreased heart rate, increased stroke volume
B) decrease in cardiac output, decreased heart rate, decreased stroke volume
C) increase in cardiac output, increased heart rate, increased stroke volume
D) no change in cardiac output, increased heart rate, decreased stroke volume

D) no change in cardiac output, increased heart rate, decreased stroke volume occurs after blood donation

Explanation:

When a person donates blood, there is a slight loss of blood volume or hypovolemia. This triggers the baroreceptors of the blood; although does not trigger the osmoreceptor.

The baroreceptor responses are according to the arterial pressure which rises momentarily and results in increased sympathetic activity with decreased vagal activity.

These changes will lead to vasoconstriction, reduced stroke volume, increased heart rate or tachycardia which helps to maintain the cardiac output.

The soreness at the venepuncture site on the skin is due to bruising which is common after any needleprick. applying cold pack, elevating and resting the arm.

In order to compensate for the fluid volume loss and avoid dehydration, one must take plenty of fluids before and after blood donation.

the answer that best describes the relative refractory period in the neuron is the resting membrane potential is restored, but concentrations of sodium and potassium are not restored to their original state.

the refractory period is the time during which another stimulus given to the neuron will not lead to a second potential. thus, because na+ channels are inactivated during this time, additional depolarizing stimuli do not lead to new action potentials.  

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it's the cell cycle, but cytokines is when the cell divides.

theres 3 stages interphase,mitosis,and cytokines.

interphase prepares the cell for division.

mitosis is the process of dividing the cell,it has 4 parts interphase,anaphase,metaphase,and telophase.

lastly there's cytokines,that's when the cell divides into 2 daughter cells