controlling heart rate

    Cards (13)

    • why is it essential that heart rate can be changed?
      • uncontrolled can cause high pressure which can cause damage to capillaries and organs
      • exercise - needs to be higher so you can get more oxygen
      • sleep - lower rate to not waste energy
    • what is an accelerator nerve?
      • a part of the sympathetic NS and delivers a higher than usual frequency of impulses to the sinoatrial node to increase the heart rate
    • what is a vagus nerve?
      • opposite to accelerator nerve, part of parasympathetic NS and works to decrease heart rate by delivering a lower than usual frequency of impulses to the sinoatrial node
    • what is a chemoreceptor?
      • detect chemical changes, e.g. oxygen concentration, carbon dioxide levels, pH of blood
    • what is a baroreceptor?
      • detects changes in blood pressure
    • what is the carotid artery?
      • primary vessels supplying blood to brain and face
    • where are chemoreceptors found?
      • aorta
      • carotid artery
      • medulla
    • what occurs when there is a lowered pH?
      • high CO2 concentration, carbonic acid is formed when CO2 interacts with water in the blood
      • chemoreceptors detect this and trigger increased heart rate
      • blood flows quickly to lungs so CO2 can be exhaled
    • where are baroreceptors located?
      • aorta
      • vena cava
      • carotid arteries
    • what is the negative feedback system of blood pressure?
      • too high, impulses sent to medulla oblongata, decrease heart rate, impulses sent along parasympathetic NS to SAN to decrease rate, back to normal
      • too low, impulses sent to medulla oblongata, increases heart rate, impulses send along sympathetic NS to SAN which increases rate, increases back to normal
    • what is the role of hormones in control of the heart rate?
      • times of stress, adrenaline and noradrenaline released
      • hormones affect pacemaker region of heart, speeding up heart rate by increasing frequency of impulses produced by SAN
    • what are the effects of exercise on heart rate?
      • blood pressure increases to supply cells with more oxygen and glucose
      • baroreceptor in carotid arteries detects and communicates to medulla oblongata
      • increases frequency of impulses down Vagus nerve (parasympathetic nervous system) to SAN
      • heart rate decreases
      • blood pressure returns to normal - so arteries don't sustain any unnecessary damage
    • what are effects of more CO2 in blood?
      • pH decreases as more CO2 released by aerobic respiration from cells, dissolves in blood forming carbonic acid
      • chemoreceptors in carotid arteries detects and communicates to medulla oblongata
      • increases frequency of impulses down accelerator nerve (sympathetic nervous system) to SAN
      • heart rate increases
      • increased blood flow allows increased CO2 to reach lungs to be removed quicker so CO2 levels decreases, and thus the pH returns to normal
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