Cardiovascular System Flashcards
What major factors affect the rate of blood flow
Pressure differential between two points (directly) and the resistance to flow (inversely)
How does radius of the vessel affect the rate of flow
The flow is proportional to the radius to the power of 4
What are the systolic pressures of the heart
15-30 mmHg in right vent. 100-140 mmHg in left vent.
How do elastic arteries maintain pressure
Elastic recoil during diastole will cause the blood to be forced forward again keeping pressure high
In which artery is blood pressure taken
Brachial artery in the upper arm
What is pulse pressure
The systolic pressure minus diastolic pressure
What is the P wave
The first wave on the ECG graph which represents atrial depolarisation and then contraction
What is the QRS complex
Ventricular depolaristion and therefore contraction (and atrial repolarisation although not seen)
What is the T wave
Repolarisation of the ventricular myocardium the last section of an ECG
What is preload
The amount at which myocardium is stretched in diastole to allow for blood into ventricle
What is Contractability
The amount of force the muscle contracts with in the heart during systole
What is afterload
The force required to open the semi lunar valve and allow blood to be ejected from the ventricle
What is auto regulation of local blood flow
The ability to change the flow of blood in specific local regions as demand changes for blood. This is in response to certain stimuli and is supported by vasodilatory metabolites
Why are the capillary sphincters important
They control the amount of blood allowed into the capillary bed
How does baroreceptor inhibition increase heart rate and blood pressure
Cardioacceleratory centre activated, Cardioinhibitory centre inhibition, Vasomotor centre activation supported by endocrine response from endocrine glands (adrenaline)