Blood Pressure and Heart Rate KAAP 310 Lab

Autorhythmiticity The heart triggers its own contractions Due to permeability to Potassium ions Slow leakage of Sodium and Calcium

Cardiac Action Potential

Pacemakers Primary: Sinoatrial node (SA node) (60-100 BPM) Secondary: atrioventricular node (AV) (40-60 BPM) Tertiary: bundle of His (30-40 BPM) Last: Purkinje Fibers (under 30 BPM)

Nervous System Sympathetic: increases HR/BP Increases with inhalation Parasympathetic: decreases HR/BP Increases with exhalation

Measuring HR Pointer and middle finger together Use radial artery Count beats starting at 0 for 15 seconds and multiply by 4 Who knows why you wouldn’t use your thumb? It has its own heart beat

Heart rate ranges Normal 60-100 BPM (unless endurance athlete) Bradycardia: under 60 BPM Tachycardia: over 100 BPM Cardiac output= heart rate * stroke volume Why, then, can endurance athletes have a resting heart rate less than 60 BPM but still maintain the same cardiac output as somebody without training?

What is Blood Pressure? Force exerted by blood on arterial walls during cardiac cycle Systolic – force during contraction Diastolic – force during relaxation BP = Q x Total Peripheral Resistance (TPR) Amount of blood (Q) Resistance to flow (TPR) Typically measured through brachial artery 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 Antecubital region (elbow pit) Stethoscope with ear pieces ‘forward’ Drum turned ‘on’ Arm is resting on table and at heart level Inflate to pulse obliteration pressure Deflate at 2-4 mmHg/second Listen very carefully NOTE: show video!

Lab activity Get in groups Follow steps and make sure each person gets a chance to take HR and BP Homework BP questions due next week by start of lab (1 per group) Study Lesson 5 Introduction of Biopac (EKG) Short quiz to start class Bring Lesson 5 with you next week