Blood Pressure and Heart Rate (4) Flashcards Preview

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Flashcards in Blood Pressure and Heart Rate (4) Deck (19):

What is systole?

Maximum pressure when heart pumps, occurs after contraction of ventricle


What is diastole?

The bottom level of pressure, occurs after contraction of atria


How do you measure heart rate (beats/time seconds)?

Systolic Pressure- Diastolic Pressure


How do you measure flow in terms of Darcy's Law?

Flow (volume/time)= Pressure 1- Pressure 2/ Resistance
Pressure- mmHg
Resistance- mmHg time/volume


What is another term for flow?

Cardiac Output (CO)


What is the equation to calculate Cardiac Output?

CO (volume/time)= (Arterial Pressure- Venous Pressure)/ Resistance


How do you calculate Arterial blood pressure?

Arterial blood pressure= CO x TPR (total peripheral resistance)
Arterial blood pressure= heart rate x stroke volume x TPR


What are the pacemakers in the parasympathetic nerve system?

Sino atrial (SA) node- iniates contraction
Atrioventricular (AV) node- drives system is SA node fails


What is Bradycardia?

Slowing down of heart rate


What is tachycardia?

Speeding up of heart rate


Where does each electrical signal in the heart begin?

SA node


What does an Electrocardiogram record?

Strength and timing of electrical signals as they pass through the heart


From the SA node where does the electrical signal move to?

Through the left and right atria
Causes atria to contract, helps move blood into lower chambers of the heart


What is the electrical signals recorded as that pass through the atria?

P wave


What does the electrical signal between the atria and ventricle pass through?

Atrioventricular node (AV)


What is the pathway of a electrical signal in the heart?

SA node-> Atria-> AV node (P wave)-> Ventricle-> Bundle of His->Contraction of heart (QRS wave)


What are the phases of action potential in heart cells?

1. Early repolarization- brings the potential down to a plateau level over 2 to 3 milliseconds
2. Plateau- accounts for most of the action potential duration
3. Repolarization- brings the potential back to resting level
4. Period between action potential- stable except in cells that have the property of autorhythmicity


What do baroreceptors do?

Pressure-sensitive neurones that monitor stretch in the aorta (prevent build up of pressure)


Where does blood flow from and to?

Areas of high pressure to areas of low pressure
The greater the gradient the greater the flow