Short term control of blood pressure Flashcards
How do you find MAP?
MAP=CO x TPR
What happens if MAP is too low?
Fainting
What happens if too high?
hypertension
Where are baroreceptors located?
Two in carotid
aortic arch
What is the normal resting arterial pressure?
60mmHg
What nerve do carotid sinus baroreceptors send in formation about pressure to the brain via?
Glossopharyngeal
What nerve do the aortic baroreceptors connect to?
Vagus nerve
What corrective measures come from signals from the barroreceptors?
Sympathetic nerves will release noradrenaline to left vent increases contractility and therefore stoke volume
Constriction of alpha 1 receptors in veins increases preload– CO
What are the additional inputs to the medullary cardiovascular centres?
- Cardiopulmonary baroreceptors
- Central chemorecptors
- Chemoreceptors
- Joint Receptors
- Higher centres
What are higher centres responsible for?
The feed forward control
how does standing effect blood pressure?
-Increased hydrostatic pressure causes pooling of blood in veins/Venules of feet/legs
-Decrease venous return
-Decrease in EDV-MAP
Decreases baroreceptor firing rate
How does the reflex response effect blood pressure?
Decreases Vagal tone
Decreases sympathetic tone
What is the valsalva manoeurve?
Forced expiration against a closed glottis
What happens during the valsalva manoeuvre ?
- Rapid increase in thoracic pressure transmitted to aorta
- Veins are compressed so decrease in EDV and therefore MAP
- Decrease is detected by baroreceptors which initiate reflex Increase CO and increase TPR
- Decrease in thoracic pressure is transmitted through to the aorta
- VR is restored to SV increases -Reflex does no wear off immediately
- Normal
