Blood Pressure and Hypertension

Blood Pressure

Your Blood Pressure Reflects:

1) How hard your heart is working

2) The condition of your arteries

Cardiac Output x Arterial Resistance

• Cardiac Output = Amount of blood your heart pumps per minute

• Arterial Resistance = Pressure the walls of the arteries exert on the flowing blood

What regulates your blood pressure?

• Complex interactions among your central nervous system (CNS), hormones, and substances your blood vessels produce from the endothelium

• Endothelium = layer of cells lining the inner wall of blood vessels; produce both vasodilators and vasoconstrictors

What happens when blood pressure gets too high?

• Nerve cells in your circulatory system tell your autonomic nervous system (ANS)

• ANS – manages involuntary activities of smooth muscles, including those in the intestines, sweat glands, airways, heart and blood vessels

Autonomic Nervous System

• The ANS is made of the sympathetic and parasympathetic nervous systems

The SYMPATHETIC nervous system:- Prepares body for action- Triggers release of neurotransmitters

epinephrine and norepinephrine- Raises blood pressure

Autonomic Nervous System

• The ANS is made of the sympathetic and parasympathetic nervous systems

The PARASYMPATHETIC nervous system helps the body recover from action

How is blood pressure measured?

• Sphygmomanometer – traditional blood pressure measuring device; measures in mm Hg (mercury)

Systolic pressure = top #, amount of pressure during the heart’s pumping phase (systole)

Diastolic pressure = bottom #, amount of pressure during resting phase between heartbeats (diastole)

Classifications of Hypertension

ESSENTIAL HYPERTENSION (Primary hypertension)

- 90-95% of cases

-condition has no identifiable cause

Classifications of Hypertension

SECONDARY HYPERTENSION – arises from other condition; often treatable

Common causes1) Renal artery stenosis – narrowing of artery that

supplies blood to the kidneys2) Hyperaldosteronism – too much aldosterone, a

hormone made by the adrenal glands that regulates potassium and sodium levels

Secondary Hypertension

3) Hyperthyroidism – overactive thyroid gland

How High is High Blood Pressure?

See your handout for information on:

-Prehypertension

-Stage 1 Hypertension

-Stage 2 Hypertension

Risk Factors for Hypertension

• Race

• Family history

• Age

• Sex

Risk Factors for Hypertension

• Cigarette smoking

• Heavy alcohol consumption

• Diet (too much salt, saturated fat, and calories; not enough fruits and vegetables)

• Obesity and overweight

• Inactivity

• Stress