8.1 part too Flashcards
as the atria contract the signal reaches another node called the?
atrioventricular node (AV node)
The AV node transmits the electrical signal through a bundle of specialized fibres called the
bundle of His
After reaching the bundle of His the signal is relayed through two bundle branches that dived into fast conducting what?
purkinje fibres. These initatiate the almost simultaneous contraction of all cells of the ventricles
what can be used to measure the change in voltage produced by the heart?
an electocardiogram (ECG)
How many spikes are there on an electrocardiogram?
three. A small voltage increase is the electrical activity before atrial contraction, a large spike just before venctricular contraction and then another small spike as the ventricles recover from their contraction
What is the pressure called that blood exerts>?
Blood pressure (duh)
What do changes in blood pressure correspond to?
phases of the heartbeat
When the ventricles contract and force blood into the pulmonary arteries and the aorta the pressure increases in these vessels.
just know it
The maximum pressure during the ventricular contraction is called the?
systolic pressure
The lowest presssure before the ventricles contract again is called the?
diastolic pressure
Blood pressure is normally measured in?
millimeters of mercury. (Fancy unit of measurement the corresponds to vacuums and stuff. seriously look it up sometime it’s kinda interesting) also btw the symbol is mmHg
What device measures blood pressure?
sphygmomanometer. Yup it’s a massive word. Yup you need to know it. It’s common name is the blood pressure cuff
The blood pressure of a normal human is?
120 mmHg over 80 mmHg or 120/80.
Does the heart rate increase during exercise?
yup it do it
Why does heart rate increase during exercise?
Cause your muscles are working hard and need more oxygen and need more C02 removed
Blood pressure in a ventricle can drop as low as?
0 mmHg but it never gets this low in an artery
Which comes first the lub or the dub sound when measuring heart beats?
lub the dub
Two factors can affect cardiac output. What are they?
heart rate and stroke volume
what is heart rate
the number of beats per minute
what is stroke volume
The ammount of blood forced out of the heart with each heartbeat
The average person has a stroke volumeof
70ml
the average person has a resting heart rate of
70 beats per minute
How much blood does the average person have in their body?
5 L
What is Maximum heart rate
The highest heart rate attained during an all out physical effort
