Lesson 10: Blood Pressure and Heartbeat Flashcards
how long do these heartbeats take under normal conditions?
0.8s
what is a cardiac cycle? what does it involve?
the process of a complete heartbeat; this involves a full contraction and relaxation of each chamber of the heart
how many phases is the cardiac cycle divided into? what are these phases?
2 phases
- diastole phase (when the heart is relaxed and filling with blood)
- systole phase (when the heart contracts and is emptying)
what is the heart’s sound caused by? what is happening in each part of the sound (lub and dub)?
caused by the opening and closing of heart valves; sounds like “lub-dub”
- the first part (lub) occurs when the atrioventricular valves closed and the ventricles begin to contract
- the second part (dub) occurs when the ventricles relax and the semilunar valves snap shut
stethoscope
- helps you hear your heartbeat
- if the heartbeat sounds are not normal, this may be a sign of a leaking valve, also known as a heart murmur
what is the myogenic muscle? what is its ability?
the heart muscle; it has to ability to contract and relax on its own without stimulation from nerves
how come an organism’s heart can still beat even though they have a damaged nervous system?
due to the mygenic muscle
what is the sinoatrial node (SA)?
the contraction that initiates the heartbeat, and is from a cluster or group of cells in the right atrium
what does the SA do (sinoatrial node)? what does it act as?
the cluster of cells sends an electrical signal which causes the atria to contract; it acts as a pacemaker (its responsible for setting a normal rhythm of the heartbeat, and determines heart rate)
what is the atrioventricular node (AV)?
it is located on the other side of the right atrium meartructure where the electrical signal then propagates or spreads to a group of cells in between of the right atrium and ventricle
what does the atrioventricular node (AV) do? what happens after this happens?
this cluster of cells sends an electrical signal through special conductive fibers called purkinje fibers; it serves as an electrical gateway to the ventricles, and delays the passage of electrical impulses to the ventricles (delay happens to ensure that the atria ejected all the blood into the ventricles before the ventricles contract)
- the AV node receives signals from the SA node, and passes them onto the atrioventricular bundle
what is the atrioventricular bundle? what happens next?
it is a bundle divided into right and left bundle branches, which conduct the impulses towards the apex of the heart- the signals are then passed to Purkinje fibers, turning upward and spreading throughout the ventricular myocardium
what is electrocardiogram? what are they used for?
where electrical activities of the heart is recorded (called ECG or EKG); they are used to observe the heart by measuring length and strength of the electrical signals
what can you do if theres an abnormality in the heart?
ECG (electrocardiogram) can provide doctors with information
what is blood pressure? how is it measured? why is blood always under pressure?
Blood pressure is the pressure your blood exerts on the walls of the circulatory system
- Blood is always under pressure in the blood vessels because of the contractions from your heart
- Pressure increases when your heart is contracting and decreases when your heart relaxes