Sam wakes suddenly realising they have slept through their alarm and quickly moves from laying down to standing up. Sam feels dizzy upon standing up so quickly and needs to sit down to prevent themselves from fainting. After a few seconds Sam feels okay to stand back up and continues getting ready for university.
a) Sam’s dizziness is caused by a drop in mean arterial blood pressure due to their positional change. Describe how a drop in blood pressure is detected and signaled to the brain. (3 marks)
b) Later in the day Sam looks at the data from their heart rate monitor and notices that their heart rate increased during the time that they sat down to recover from their dizzy spell. Describe the mechanisms that would have resulted in Sam’s increase in heart rate during this time (3 marks)
c) Describe how an increase in heart rate can help correct the initial drop in blood pressure and discuss one other cardiovascular change that might be occurring to return blood pressure to normal. (4 marks)
Sample Solution