Blood Pressure and
Heart Rate
KAAP 310 Lab
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Autorhythmiticity
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The heart triggers its own contractions
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Due to permeability to Potassium ions
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Slow leakage of Sodium and Calcium
Cardiac Action Potential
Pacemakers
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Primary: Sinoatrial node (SA node) (60-100 BPM)
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Secondary: atrioventricular node (AV) (40-60 BPM)
Tertiary: bundle of His (30-40 BPM)
Last: Purkinje Fibers (under 30 BPM)
Nervous System
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Sympathetic: increases HR/BP
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Increases with inhalation
Parasympathetic: decreases HR/BP
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Increases with exhalation
Measuring HR
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Pointer and middle finger together
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Use radial artery
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Count beats starting at 0 for 15 seconds and multiply
by 4
Heart rate ranges
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Normal 60-100 BPM (unless endurance athlete)
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Bradycardia: under 60 BPM
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Tachycardia: over 100 BPM
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Cardiac output= heart rate * stroke volume
What is Blood Pressure?
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Force exerted by blood on arterial walls during cardiac
cycle
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Systolic – force during contraction
Diastolic – force during relaxation
BP = Q x Total Peripheral Resistance (TPR)
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Amount of blood (Q)
Resistance to flow (TPR)
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Typically measured through brachial artery
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Unit of measure is mmHg
Blood Pressure Normative Values
Category
Systolic (mmHg)
Diastolic (mmHg)
Normotensive
< 120
< 80
Pre-Hypertensive
120-139
80-89
Hypertension
(Stage 1)
140-159
90-99
Hypertension
(Stage 2)
> 160
> 100
*According to American Heart Association (AHA)
Measuring Blood Pressure
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Antecubital region (elbow pit)
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Stethoscope with ear pieces ‘forward’
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Drum turned ‘on’
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Arm is resting on table and at heart level
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Inflate to pulse obliteration pressure
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Deflate at 2-4 mmHg/second
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Listen very carefully
Lab activity
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Get in groups
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Follow steps and make sure each person gets a chance
to take HR and BP
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Homework
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BP questions due next week by start of lab (1 per group)
Study Lesson 5 Introduction of Biopac (EKG)
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Short quiz to start class
Bring Lesson 5 with you next week