Anatomy and Physiology of the Heart Flashcards
Describe the structures and cellular interactions within the Heart
Where is the heart located in the chest?
The heart sits above the diaphragm, posterior, and slightly left of the sternum.
Define:
Epicardium
A thin membrane surrounding the outside of the heart.
Define:
Myocardium
A muscular layer found between the endocardium and epicardium.
Define:
Endocardium
A thin membrane that lines the inside of the heart.
Define:
Pericardium
A tough, fibrous sac that envelops the entirety of the heart.
How does the heart receive oxygen?
Through the coronary arteries.
Where do the coronary arteries branch off?
aorta
Name the two main coronary arteries.
- Left Main Coronary Artery
- Right Coronary Artery
What are the two branches of the LMCA?
- Left Anterior Descending
- Left Circumflex
Fill in the blank.
The Right Coronary Artery travels between the ___ ___ and ___ ___.
right ventricle; right atrium
Define:
collateral circulation
These are additional blood vessels that form due to poor circulation.
Name the four chambers of the Heart.
- Right Atrium
- Right Ventricle
- Left Atrium
- Left Ventricle
Name the four valves of the Heart.
- Tricuspid
- Mitral
- Pulmonary
- Aortic
What valve separates the RA from the RV?
Tricuspid valve
What valve separates the LA from the LV?
Mitral valve
What are the anchors of each heart valve leaflet?
Chordae Tendineae
What valve feeds blood from the LV to the aorta?
Aortic valve
Define:
Diastole
It’s a period when the ventricles and atria are resting.
Define:
Systole
It’s a period of time when the ventricles or atriums are contracting.
True or false.
Both atriums typically contract at the same time.
True
What is the muscle that separates the left and right side of the heart?
Interventricular septum
Describe the step-by-step procedure of how blood flows through the heart.
The blood:
- Enters the RA from superior/inferior vena cava.
- Passes through the tricuspid valve into the RV.
- Pumped through the pulmonary valve into the pulmonary artery, where blood flows through the lungs for oxygenation.
- Oxygenated blood returns via the pulmonary veins into the LA.
- Exits the LA through the mitral valve and empties into the LV.
- Goes through the aortic valve and enters the aorta, where it is distributed throughout the body.
Define:
preload
It refers to the initial stretching of the left side of the heart.
Define:
afterload
It refers to the resistance of systemic arteries.
What are the three structures of a blood vessel?
- Tuncia Adventitia
- Tunica Media
- Tunica Intima
Define:
blood pressure
The pressure exerted by blood on the arterial walls.
What is the main purpose of capillaries?
It exchange gases and nutrients.
Define:
cardiac output
The blood that is pumped out by either ventricle.
HR x SV = CO
What is the normal cardiac output?
5-6 L/min
This value can vary depending on factors such as age, physical condition, and metabolic demands.
Define:
stroke volume
The blood pumped out in a single contraction.
What is the normal stroke volume?
60-100 ml
Define:
Ejection Fraction
The percentage of blood that leaves the heart during each contraction.
Normal EF: 55-70%
What is the Frank-Starling mechanism?
It limits how much the cardiac muscle can stretch.
What is the Inotropic effect?
These are factors that affects the contractility of the heart.
What is the Chronotropic effect?
These are factors that affects the heart rate.
Fill in the blank.
Heart muscle conducts without the nervous system, which is called __________.
automaticity
What is the dominant pacemaker of the heart?
SA node
What is the normal path of electrical activity through the heart.
- SA node
- AV node
- Bundle of His
- Left and right bundle branch
- Purkinje fibers
What is the gatekeeper of electrical impulses in the heart?
AV node
Define:
depolarization
It is when the muscle fibers are stimulated to contract.
What happens during absolute refractory period?
The heart is completely depolarized.
What happens during relative refractory period?
The heart is partially repolarized and able to respond to stimulus.
What is the intrinsic rate of SA node?
60-100 bpm
What is the intrinsic rate of AV node?
40-60 bpm
What is the intrinsic rate of Purkinje fibers?
20-40 bpm
What indicates a P Wave in an ECG?
atrial depolarization
What indicates a QRS complex in an ECG?
ventricular depolarization
Define:
PR interval
The distance from the beginning of P wave to the beginning of R wave.
What indicates a T wave in an ECG?
ventricular repolarization
What is an ST Segment?
The period between ventricular depolarization and beginning of ventricular repolarization.
What is an R-R interval?
The duration between two ventricular depolarizations.
What is the function of the parasympathetic nervous system?
“rest and digest”
What is the function of the sympathetic nervous system?
“fight-or-flight”
What effect does the alpha-1 have on the body?
vasoconstriction
What effect does the beta-1 have on the heart?
- increases HR
- force
- automaticity
What is the formula to find blood pressure?
CO x peripheral vascular resistance
