Heart Brain Link

Question 1

What node in the heart contributes the greatest to HRV? why?

Answer 1

SA node - stimulates the heartbeat

Question 2

What are the main SA node inputs that contribute to HRV?

Answer 2

SNS, PNS and humoral factors

Question 3

What conditions affect SA node and HRV?

Answer 3

baroreceptor reflex, change in posture, physical activity, stress, thermoregulation, hormones, sleep-wake-cycle, meals

Question 4

What is respiratory sinus arrhythmia?

Answer 4

slow deep breathing

Question 5

Why does standing after laying down increase SNS and how does it affect frequency in HRV?

Answer 5

• SNS increases to tone vessels in legs and pump blood up to brain
• LF power increases to represent the SNS component

Question 6

Why does the vasodilator nitroglycerine increase SNS and how does it affect frequency in HRV?

Answer 6

• during vasodilation, blood vessels increase and BP drops, so SNS must increase to raise BP
• LF power increases to resemble SNS activity

Question 7

Why does coronary artery occlusion increase SNS and how does it affect frequency in HRV?

Answer 7

• the artery block causes a lack of oxygen so chemoreceptors increase SNS to compensate
• LF peak increases to resemble chemoreceptor SNS activity

Question 8

Why does exercise increase SNS and how does it affect frequency in HRV?

Answer 8

• stress increases SNS activity due to greater need of blood flow and O2
• HF decreases and LF increases

Question 9

Why does mental arithmetic stress increase SNS and how does it affect frequency in HRV?

Answer 9

• SNS increased due to stress of fight or flight

- LF peak increases

Question 10

What are the 4 ways the heart communicates with the brain?

Answer 10

neurological (NS), biophysical (pulses), biochemical (hormones), energetic (electromagnetic fields)