Question

Shonika has just donated a pint of blood. Mark each of the following "Increased", "Not changed", or "Decreased" to say what happens to each of the variables below. Use the codes exactly, and use each answer as often as is appropriate. (Hint: Remember Starling’s Law)

Her body has not had time to begin any intentional homeostatic attempts, but direct effects of reduced cardiac filling have begun:

Heart rate

Stroke volume

Cardiac output

Once her homeostatic systems have had a chance to make appropriate adjustments, compared to normal resting values:

Heart rate

Cardiac output

Answer 1

Her body has not had time to begin any intentional homeostatic attempts, but direct effects of reduced cardiac filling have begun:

Heart rate: Increased

Stroke volume: Decreased

Cardiac output: Decreased.

Stroke volume depends on EDV which correlates with VR. VR = CO under normal circumstances.

Significant reduction in mean arterial pressure, cardiac output, stroke volume, right atrial pressure and base deficit. On the other hand,  heart rate and total peripheral resistance show increase.

Normal resting values:

Heart rate: 60 to 100 beats per minute.

Cardiac output: 5-6 L/Min when resting.  It depends on weight, age and gender.