Why is High Blood Pressure a Concern?

Jul 24, 2024

Why is High Blood Pressure a Concern?

Introduction

  • High blood pressure, or hypertension, is a major health risk.
  • Cardiovascular diseases are the leading cause of death related to high blood pressure.

What is Blood Pressure?

  • Blood pressure ensures that blood flows through the circulatory system, delivering oxygen and nutrients to tissues.
  • Chronic high blood pressure damages the heart and blood vessels.

The Impact of Hypertension

  • Stiffening, leaking, or rupturing of arterial walls.
  • Extra work on the heart can lead to heart failure.
  • Statistic: 1 in 3 adults in the U.S. has high blood pressure.

Causes of High Blood Pressure

  • Emotional stress
  • Physical exertion
  • Dehydration
  • High salt intake
  • High fat intake (e.g., butter on bacon)

Blood Flow and Resistance

  • Blood Flow: Volume of blood flowing through vessels per minute.
  • Cardiac Output: Determined by blood volume per beat and beats per minute.
  • Resistance: Anything hindering flow or creating friction (e.g., blood viscosity, vessel length, vessel diameter).

Factors Affecting Resistance

  • Temporary: Vasoconstriction or vasodilation (diameter changes).
  • Permanent: Fatty plaque build-up (LDL cholesterol) in arteries affecting vessel diameter.
  • Blood pressure, flow, and resistance relationship can be expressed mathematically.

Body's Response to Blood Pressure Changes

Short-Term Fixes

  • Neural Controls:
    • Baroreceptors in carotid arteries, aorta, and larger arteries.
    • Brain alters blood flow distribution and vessel diameter.
    • Mechanisms like dilating arterioles or reducing heart rate.
  • Hormonal Controls:
    • Hormones like epinephrine and norepinephrine increase heart rate, blood volume, and resistance.
  • These controls are temporary; baroreceptors reprogram themselves to new normal.

Long-Term Control

  • Kidneys:
    • Regulate sodium and fluid levels using hormones like renin and angiotensin.
    • Reduce blood volume by excreting extra water (urination).
    • Excess sodium retains water, increasing blood volume and pressure.

Consequences of Sustained High Blood Pressure

Heart Issues

  • Increased workload leads to muscle growth in the left ventricle.
  • Increased muscle requires more oxygen without additional blood vessels.
  • Term: Heart failure happens when heart muscles die from lack of nutrients.
  • Heart Attack: Blockage in coronary arteries.

Blood Vessel Issues

  • Arteriosclerosis: Hardening and loss of flexibility in arteries.
  • Aneurysm: Bulging of weak spots in arteries may burst.
  • Organ damage if smaller arterioles leak or burst.

Conclusion

  • Balance in blood pressure is crucial for health.
  • Chronic high BP can lead to serious health issues.
  • Avoid high sodium and fat intake to manage blood pressure.

Brought to you by Crash Course. Support at patreon.com/crashcourse.

Credits: Written by Kathleen Yale, consultant Dr. Brandon Jackson, various roles directed or edited by Nicole Sweeney, Michael Aranda, and Thought Cafe.