How does angiotensin II increase blood pressure by increasing peripheral resistance?

Angiotensin II increases blood pressure primarily by causing vasoconstriction, which narrows blood vessels and increases peripheral resistance. It achieves this by binding to specific receptors on smooth muscle cells, leading to their contraction. Additionally, angiotensin II stimulates the release of aldosterone, promoting sodium and water retention, which further elevates blood volume and pressure. This combined effect results in a significant increase in systemic vascular resistance and overall blood pressure.