Hypertension?

Question

It is said that increased cardiac output may be an early feature, followed by increased peripheral resistance and normalisation of cardiac output.
The increased peripheral resistance is developed in a compensatory manner to prevent the raised pressure being transmitted to the capillary bed where it would substantially affect homeostasis.
What i don't understand is why is peripheral resistance developed when cardiac output increased? How does this mechanism work?
And does this only apply to essential hypertension?
Thanks.

Answer 1

Blood vessels more so arteries and arterioles have elastic vessel walls. They can constrict and dilate. When cardiac output increases ie more bloodflows into system, vessels constrict reflexly first and structurally next to regulate blood flow. This increases peripheral resistance. This change occurs even if the hypertension is secondary . However in secondary hypertension like hyperthyroidism as the cause is curable, no permanent changes occur in vessel walls. Cardiac output and peripheral resistance come back to normal.