1. Activity 4.3.5: Smoking Can Cost You an Arm and a Leg!
Par II – Blood Pressure

2. Blood Pressure
In Part I, you learned that John may be at risk for peripheral vascular disease (PVD), specifically peripheral artery disease (PAD). One simple test for diagnosing PAD is called the ankle brachial index (ABI).
Before we can any testing, we have to learn about blood pressure.

3. Blood Pressure
Blood pressure (BP) is the pressure exerted by circulating blood upon the walls of blood vessels
The blood pressure in the circulation is principally due to the pumping action of the heart.
Mean blood pressure decreases as the circulating blood moves away from the heart through arteries, capillaries and veins due to losses of energy

4. Blood Pressure
The measurement of blood pressure usually refers to the systemic arterial pressure measured at a person's upper arm and is a measure of the pressure in the brachial artery.

5. Regulation of Blood Pressure
The renin-angiotensin system (RAS) is a hormone system that regulates blood pressure and water (fluid) balance.

6. When blood volume is low, renin is released from kidneys into the blood.
Converts angiotensinogen (from liver) released by the liver to angiotensin I.
Angiotensin I
Angiotensin I is converted to angiotensin II in the lungs. Angiotensin II causes blood vessels to constrict causing increased Blood Pressure.
Angiotensin II
Angiotensin II also stimulates the secretion of the hormone aldosterone from the adrenal cortex.
Aldosterone causes the tubules of the kidneys to increase the reabsorption of sodium and water into the blood.
This increases the volume of fluid in the body, which also increases blood pressure.

7. When blood pressure is too high….
Renin is not secreted so there is no increase in blood pressure.
But, salt volume can still be high
Kidneys secrete salt into urine.
Salt can still be too high due to diet
When the body cannot regulate the blood pressure, you will ultimately have high blood pressure and medication is needed.

8. Meds Renin inhibitors – prevent renin from binding to angiotensinogen
ACE inhibitors inhibit angiotensin-converting enzyme (found in the lungs) thereby decreasing the tension of blood vessels and blood volume, lowering blood pressure.

9. Diet and Exercise Decrease salt intake and exercise
A stronger heart can pump more blood with less effort. If your heart can work less to pump, the force on your arteries decreases, lowering your blood pressure.

10. Ankle Brachial Index (ABI)
It is the ratio of the blood pressure in the legs to the blood pressure in the arms. 
To calculate, divide the systolic pressure of the ankle and foot by the systolic pressure in the arm.  
 Systolic blood pressure is a measure of blood pressure while the heart is beating.
Diastolic pressure is a measure of blood pressure while the heart is relaxed.
120/80 = Normal Blood Pressure
120 = Systolic pressure, 80 = Diastolic pressure