Blood Pressure & Pulse (LAB PRACTICAL) Flashcards
Cardiac cycle
Cycle of contraction & relaxation of both atria and ventricles
Systole
-Contraction of atria or the ventricles
-Blood is pumped out of a chamber
Diastole
-Relaxation of the atria or the ventricle
-Blood is filling a chamber
Atrial diastole
-Blood delivered into atria via veins
-80% of blood flows passively into the ventricles
Ventricular systole
-Begins shortly after atrial systole
-Ventricular contraction begins, pressure rises, closing the AV valves
-Ejection phase: As pressure begins to rise in ventricles, blood is pumped into the great arteries
Atrial systole
Last 20% of blood left in atria delivered to the ventricles via systole
Ventricular diastole
Repetition of cardiac cycle
First heart sound
Lub: Closure of atrioventricular valves
Second heart sound
Dub: Closure of semilunar valves
Heart murmur
Abnormal heart sounds
Pulse
-Surges of pressure in arteries
-Equivalent to heart rate
Heart rate
Number of beats per minute
Normal range for resting heart rate
60-100 BPM
Average resting heart rate
70-76 bpm
Length of average heart beat
0.8 seconds
Calculating heart rate from heart beat length
(60 Seconds/Heart beat Duration)=HR
Blood pressure
Pressure exerted against walls of arteries
Systolic Blood Pressure
Pressure exerted against the walls of the arteries during ventricular systole
Diastolic Blood Pressure
Pressure exerted against the arterial wall during ventricular diastole
Tool to measure BP
Sphygmomanometer
Units for BP
mmHg
Normal blood pressure
-Systolic: Less than 120
-Diastolic: Less than 80
Elevated blood pressure
-Systolic: 120-129
-Diastolic: Less than 80
High Blood Pressure (Hypertension) Stage I
-Systolic: 130-139
-Diastolic: 80-89
High Blood Pressure (Hypertension) Stage II
-Systolic: 140 or Higher
-Diastolic: 90 or Higher
Hypertensive Crisis
-Systolic: Higher than 180
-Diastolic: Higher than 120
How to measure systolic and diastolic BP
- Place BP cuff on upper left arm
- Place stethoscope on brachial artery
- Inflate cuff until circulation is cut off
- Use valve to slowly release pressure by ~2mmHg/sec
- First sound heard = systolic pressure
- When sound disappears = diastolic pressure
Sounds of Korotkoff
Sound heard in stethoscope at the start of systole
Total peripheral resistance (TPR)
Amount of force exerted on circulating blood by the vasculature
Stroke volume
Amount of blood pumped by the left ventricle during one contraction
Average stroke volume
70 mL
Cardiac output
-Amount of blood pumped by the heart in 1 minute
-CO= SV x HR
Formula for blood pressure
BP = CO x TPR
Pulse pressure
-Difference between systolic and diastolic pressure
-Pulse pressure = SBP - DBP
Mean arterial pressure
-Average pressure in a patients arteries during one cardiac cycle
-Represents force generated by the heart during contraction
-Considered a better indicator of perfusion to viral organs than systolic BP
Formula for mean arterial pressure
MAP = DBP + (Pulse Pressure/3)
