P1 Blood Pressure Flashcards
The Korotkoff sounds are heard when…
the cuff pressure is between systolic and diastolic pressures, because blood flow is turbulent
Stroke volume is likely to be highest when…
reclining. bc when you are lying down, the blood doesn’t have to work against gravity to get to the heart
Based on Frank-Starling law of the heart, what will happen when someone stands up from lying down?
The venous return decreases, which reduces the stretch in the ventricle and decreases the next stroke volume.
Exercise is one type of stressor. There are many others that you might experience, such as the stress of an exam, an injury or speaking in public. Which division of the autonomic nervous system is activated during a stressor?
Sympathetic nervous system.
The sympathetic division of the autonomic nervous system is ‘fight or flight’, and it is activated during times of stress.
Baroreceptor reflex influences blood pressure and pulse rate during times of stress. How do these results differ to those observed during changes in posture?
Increase blood pressure by constriction of arterioles and veins, increases heart rate and stroke volume
A deep inspiration increases the volume inside the thoracic cavity. This causes a decrease in thoracic pressure, including the CVP and right atrial pressure. This drop in pressure at the end of the venous circulation will increase the pressure gradient along the veins. How might this impact on venous return?
Venous return will increase.
Blood flow is directly proportional to the pressure gradient. Increasing the pressure gradient will increase blood flow back to the heart, and therefore increase venous return.
Explain why the blood volume drops in jugular vein during inspiration.
Greater pressure gradient so there is greater venous return and not as much blood pooling in the vein.
If stroke volume decreases on standing, how is the cardiac output maintained within homeostatic range?
Heart rate increases.
If the venous return (and stroke volume) decreases on standing, the heart rate must increase so that homeostasis is maintained.
