Question

Being as precise as possible, identify and explain 3 ways that cardiac output and total peripheral resistance are altered to affect blood pressure.

Answer 1

Cardiac output = Heart rate x stroke volume

Also cardiac output = Mean arterial pressure / Total peripheral resistance

Cardiac output decide the systolic blood pressure

Total peripheral resistance decide DIASTOLIC blood pressure .

Regulation of blood pressure

1) Short term control of BP - Baroreceptor mechanism Neural and is most sensitive .

Whenever there is low bP baroreceptors which are stretch receptors are activated and impulses travel via carotid sinus nerve brach of glossopharyngeal nerve and Depressor nerve branch of vagus nerve and they are integrated in Nucleus tractus solitarius in Medulla and response is increased sympathetic vasoconstrictor tone to vessels and increasing sympathetic discharge to heart and increase the cardiac output and increasing the Blood pressure.

2) Chemoreceptor -- Central and peripheral

Peripheral Chemoreceptor consist of carotid and aortic bodies which contain chemosensitive glomus cells .They detect the changes in blood po2 ,PCo2 and PH .

Stimulus is Hypoxia decreased po2 and increased PCo2 integartion occur in Vasomotor centre and response is Hyerventilation and vasoconstriction .Vasoconstriction cause increase in Diastolic Bp.

.3) Long term control of Bp - Renin angiotensin aldosterone axis .Aldosterone by sodium and water retention increase plasma volume and increase blood pressure .