Chapter 14 Flashcards
What is the purpose of the pulmonary circuit pump?
To pump venous blood from the heart to the lungs
What is the purpose of the system circuit pump?
To pump arterial blood to the body from the heart
Where is blood coming from and going to in the system circuit pump?
From the left side of the heart (left ventricle) and goes to the arteries and sends the blood to the rest of the body
Where is blood coming from and going to in the pulmonary circuit pump?
From the right side of the body (right ventricle) to the lungs to get oxygen then it goes back to the heart
What type of blood is in the pulmonary circuit pump and the system circuit pump? Which circuit has blood with more CO2 and O2 and vice versa?
Pulmonary: Venous blood rich in CO2 and poor in O2. (deoxygenated)
System circuit pump: Arterial blood rich in O2 but poor in CO2 (oxygenated)
What is the difference between the pulmonary circuit pump and the system circuit pump?
pulmonary circuit pump: Has deoxygenated blood, comes from the right side of the heart, sends blood to lungs
system circuit pump: Has oxygenated blood, comes from the left side of the heart, sends blood to the body
What chambers/vessels does the tricuspid valve separate?
The right atrium and the right ventricle
What chambers/vessels does the bicuspid (mitral) valve seperate?
The left atrium and left ventricle
What chambers/vessels does the pulmonary valve seperate?
The right ventricle and pulmonary trunk
What chambers/vessels does the Aortic valve seperate?
Left ventricle and Aorta
Identify each valve in picture #3 in the notes
1 Aortic Valve
#2 Tricuspid valve
#3 Bicuspid valve
#4 Pulmonary valve
How does the tricuspid valve prevent backflow of blood?
Pre contraction the papillary muscles are contracting and holding onto the Chordae tendineae. When the big contraction happens in the right ventricle the force of blood will go under the cusps of the Chordae Tendineae and close. The papillary muscles contract and allow the cusps of the Chordae tendineae to close and not invert so the blood doesn’t back flow.
How does the bicuspid (mitral) valve prevent backflow of blood?
Pre contraction the papillary muscles are contracting and holding onto the Chordae tendineae. When the big contraction happens in the left ventricle the force of blood will go under the cusps of the Chordae Tendineae and close. The papillary muscles contract and allow the cusps of the Chordae tendineae to close and not invert so the blood doesn’t back flow.
How does the pulmonary valve prevent backflow of blood?
When the right ventricle contracts it forces blood up into the pulmonary artery. Which makes the cusps open and allows blood through. When the contraction is done gravity pushes the blood left over to flow back to the heart. The backflow of blood causes the cusps to fill up. Which helps keep the cusps closed and sealing the valve so no backflow of blood can come back into the heart
How does the Aortic valve prevent backflow of blood?
When the left ventricle contracts it forces blood up into the aorta. Which makes the cusps open and allows blood through. When the contraction is done gravity pushes the blood left over to flow back to the heart. The backflow of blood causes the cusps to fill up. Which helps keep the cusps closed and sealing the valve so no backflow of blood can come back into the heart.
Which way does blood usually flow in the heart?
AWAY FROM THE HEART
What arteries contain unoxygenated blood? (2)
Pulmonary trunk, and pulmonary arteries
What way do veins usually flow in the heart?
Carry blood toward the heart
What is the function of papillary muscles and chordae tendineae?
It is to prevent the inversion of the cusps in the tricuspid and bicuspid valves. The papillary muscles contract and pull on the chordae tendineae to prevent the inversion. They also ensure that the valves are closed tightly and no backflow happens.
What veins carry oxygenated blood? (1)
The pulmonary veins
What is the pacemaker in the body? What makes it the pacemaker?
The SA NODES, It is where the heart patterns of each heart beat start
What type of receptors are in the SA nodes of the heart? Why?
The baroreceptors because it gets stimulated by pressure
What is the cardiac pathway? (6 steps)
- SA node is triggered by blood pressure and depolarizes
- Action potentials spread via intercalated discs (gap junctions) between right and left atria to the AV node
- depolarization pathway from the SA node to AV node funnels the electrical pathway and the only electrical connection between the atria and ventricles depolarization slows down to allow the atria to contract before the ventricular stimulation occurs
- AV node is at the base of the right atrium and AV bundle conduct toward the ventricles
- In the interventricular septum the bundle of AV bundles divide into right and left bundle branches
- Branch bundles become purkinje fibers, which depolarize up through the ventricular walls to push blood out.
What is autorhythmicity?
The heart’s ability to generate its own heartbeat
What part of the heart is the electrical connection between the atria and the ventricles?
The AV nodes
What would happen if any part of the conduction pathway was blocked?
Essentially your heart would beat at a lower rate. And you would have irregular heart beats and contractions.
How does the heart contract in such a regular rhythm (consider cells structure and movement of conduction pathway through cells)
By the SA node (pacemaker) which automatically sends electrical signals. the myocardium also helps by spontaneously contracting sending the signal down. And if the SA node is broken then the AV node and Purkinje fibers will work as secondary pacemakers (ectopic pacemakers) and send electrical stimulus just at a slower rate.
What parts of the heart conduction pathway can be a “pacemaker”?
ALL OF THEM just you will have a slower heart rate compared to if the SA node was working
Label the parts on PIC #4 on the ECG
- P wave
- P-Q interval
- QRS Wave
- S-T segment
- T Wave
1 P-Q interval
#2 QRS Wave
#3 S-T segment
#4 T wave
#5 P wave
What do these mean/represent?
- P wave
- P-Q interval
- QRS Wave
- S-T segment
- T Wave
- P wave: Change big the change is atrial depolarization
- P-Q interval: Atrial systole (contraction of atrium)
- QRS Wave: Ventricular depolarization
- S-T segment: Plateau phase, ventricular systole
- T Wave: Ventricular repolarization
What are the 4 things that the ECG can tell us?
- What the heart rate is
- If the rhythm is regular or irregular
- Are all waves present and recognizable
- Is the QRS complex present in each wave and if so is the P-R segment constant in length
In regards to the 4 things the ecg tells us, how can that be used to determine heart failure? (4)
- If the heart rate is abnormally slower or faster then that can be used to determine heart failure
- If you have an irregular heart beat then that can be used to determine heart failure
- if waves are not present or you might not be able to recognize them then that can be used to determine heart failure
- If the QRS complex is not present and the P-R segment is not a constant length then that can lead to heart block then that can be used to determine heart failure
What is Tachycardia and Bradycardia? in regards what the ECG tells us
Tachycardia: Irregular fast heart rate
Bradycardia: Irregular slow heart rate
What is Arrhythmia and atrial fibrillation in regards what the ECG tells us?
Arrhythmia: irregular heart rhythm
atrial fibrillation: SA node lost its ability to set the pace for the heart
what is heart block in regards what the ECG tells us
Heart Block: Failure to transfer electrical current from atria to ventricles
What is Depolarization Plateau of the cardiac muscle contraction?
It is where there is calcium influx in the cardiac muscles and it creates a longer refractory period so the heart doesn’t contract as often so the heart can rest. In the heart we do not want to contract super often like we want in skeletal muscles.
Why do we need the Depolarization Plateau of the cardiac muscle contraction in the heart? How long does it last?
It creates a longer refractory period so the heart has time to rest so we don’t over work it and pump blood effectively before contraction again. It lasts about 200 milliseconds
Why don’t we need the Depolarization Plateau of the cardiac muscle contraction in the skeletal muscles? How long does it last?
Because they need to contract and relax rapidly many times. They don’t need a time to relax like the heart does. Skeletal muscles want to sustain contractions. Lasts about 1-5 milliseconds
What happens when the heart is at rest in the cardiac cycle? (4)
- Atria fills with blood
- Atrioventricular valves open
- Ventricles fill up with blood to 80%
- semilunar valves are closed
What happens in the atrial systole step of the cardiac cycle? (4)
- pressure builds up in the right atrium
- the atrium contracts after depolarization
- The atria tops off the ventricles with blood (fills the remainder 20%)
- AV valves open Semilunar valves are closed
What happens in the atrial diastole step of the cardiac cycle? (1)
- The atrium just simply relaxes
What happens in the Ventricle systole step of the cardiac cycle? (2)
- Isovolumic ventricular contraction (the AV valves and semilunar valves are closed, No blood moves in or out during this step)
- ventricular ejection (semilunar valves are opened, blood moves out from the aortic and pulmonary trunks)
What happens in the ventricular diastole step of the cardiac cycle?
The ventricles relax and ALL 4 valves are CLOSED
What is Isovolumic ventricular contraction in the ventricular systole step in the cardiac cycle?
Where the initial pressure causes the left and right AV to close and no blood is ejected out. No blood is coming in or out NO CHANGE IN VOLUME
What is stroke volume? And what is the normal range for it?
The amount of blood pumped by one ventricle during a contraction
Normal Range: 60-80
What is ventricular ejection in the ventricular systole step in the cardiac cycle?
- where the pressure gets so high it ejects the blood to the aortic and pulmonary trunks
What is systole and diastole?
Systole: Contraction of the heart muscles
Diastole: Relaxation of the heart muscles
What is End diastolic volume (EDV)? And what is the normal range for it?
The total volume of blood in the ventricles at the end of ventricular diastole.
Normal Range: 125 -130mL
What is End systolic volume (ESV)? And what is the normal range for it?
The amount of blood left in the left ventricle after the ventricular systole (1/3 of EDV)
Normal Range: 35mL-100mL
What causes absent P wave, absent QRS wave, and Absent T wave out of these options?
- AV block
- Atrial fibrillation
- Absent ventricle repolarization
Absent P wave: Atrial fibrillation
Absent QRS wave: AV block
Absent T wave: Absent ventricle
How do you calculate the stroke volume?
End-diastolic volume (EDV) MINUS End-systolic volume (ESV)
End-diastolic volume (EDV) - End-systolic volume (ESV)
EDV - ESV
How do you calculate the Ejection fraction?
The stroke volume DIVIDED BY End-diastolic volume (EDV)
Stroke volume/End-diastolic volume (EDV)
What is the normal range for the ejection fraction?
50%-70% 60% is closer to normal
What is the normal range for a cardiac output?
5-6 liters per minute
How do you calculate a cardiac output?
Stroke volume TIMES heart rate
What is the starlings law of the heart?
It stretches the walls of the heart and causes them to contract more forcefully, more in = more out. GREATER THE MUSCLE STRETCH THE MORE FORCEFUL THE CONTRACTION
How is the starlings law of the heart associated with pre-load?
So when it stretches it contracts more forcefully and you can get more into the heart as well as push more out. Causes an increase in preload
How does starlings law of the heart affect stroke volume?
Well it causes the heart walls to stretch more which can get more into the heart. Which leads to pushing more blood out. SO IT INCREASES THE STROKE VOLUME
