CONCEPT REVIEW (The heart) Flashcards
Where is the heart located?
The heart is located in the mediastinum and has a muscular wall covered by pericardium.
The heart is surrounded by a protective membrane, ___________________, consisting of a tough superficial fibrous pericardium and a deeper more delicate _________________that forms a double layer around the heart, an outer parietal layer and an inner visceral layer. A thin, slippery, lubricating pericardial fluid is found in the pericardial cavity between the parietal and visceral layers of the serous pericardium.
the pericardium
serous pericardium
What are the three layers of the heart?
The three layers of the heart wall from superficial to deep are the
1. Epicardium (visceral layer of serous pericardium)
- Myocardium (cardiac muscle tissue)
- Endocardium (endothelium overlying connective tissue). The endocardium also covers the valves of the heart.
The ____________________ encircles the heart between the superior atria and inferior ventricles.
coronary sulcus
The _____________________ marks the anterior boundary between the ventricles
anterior interventricular sulcus
The posterior boundary between the ventricles?
posterior interventricular sulcus
What chamber receives blood from the superior vena cava, inferior vena cava, and coronary sinus.
Right Atrium
The right Atrium is separated internally from the left atrium by the ______________, which contains the fossa ovalis. Blood exits the right atrium through the____________valve.
interatrial septum
tricuspid
The right ventricle receives blood from the ___________. It is separated internally from the left ventricle by the ______________and pumps blood through the __________________ into the pulmonary trunk that carries blood to the lungs.
right atrium
interventricular septum
pulmonary valve
The cusps of the tricuspid valve connect to ?
chordae tendineae
What does the papillary muscle do?
They connect to Chordae tendinae & help the valves to open and close
The left atrium receives blood from the ___________ through pulmonary veins. Blood from the left atrium passes through the _______________as it flows into the left ventricle.
lungs
bicuspid (mitral) valve
The left ventricle contains _____________ that anchor the cusps of the bicuspid valve to papillary muscles. Blood exiting the left ventricle passes through the ______________and into the ascending aorta, which carries blood to the heart wall and to the rest of the body.
chordae tendineae
aortic valve
Blood flows through the heart from areas of __________pressure to areas of _____________pressure. Contraction of the walls of a chamber increases pressure of the blood within the chambers.
high
low
The location of the bicuspid and tricuspid valves between the atria and ventricles has given them
the name___________________.
atrioventricular (AV) valves
The ___________________ are the aortic valve, at the entrance to the aorta, and the pulmonary
valve, at the entrance to the pulmonary trunk.
semilunar (SL) valves
The right side of the heart is the pump for?
pulmonary circulation
the circulation of deoxygenated blood through the lungs where blood unloads CO2 and picks up O2.
The left side of the heart is the pump for ?
systemic circulation
the circulation of oxygenated blood throughout the body except for the air sacs of the lungs
Blood enters the right atrium through three veins
- The superior vena cava,
- Inferior vena cava,
- Coronary sinus
The wall of the heart has its own blood vessels called the _____________________ that delivers blood to and from the myocardium.
coronary (cardiac) circulation
The main arteries of the coronary circulation are the?
left and right coronary arteries; the main veins are the cardiac veins and the coronary sinus.
The principal coronary vessels are the left and right _________________, which arise from the ascending aorta.
coronary arteries
The left coronary artery divides into the ___________________________serving both ventricles, and the _____________________serving the left atrium and ventricle.
anterior interventricular branch
circumflex branch
The right coronary artery branches to supply the?
right atrium
Branches of the right coronary artery form the posterior interventricular branch serving walls of ______________
both ventricles
Arteries of the coronary circulation have many ___________________________that allow detours
for arterial blood if a main route becomes obstructed.
anastomoses (connections)
Cardiac muscle fibers are connected end to end via ? Desmosomes in the discs provide strength, and gap junctions allow muscle action potentials to conduct from one muscle fiber to its neighbors.
intercalated discs.
Desmosomes in the discs provide strength, and __________________ allow muscle action potentials to conduct from one muscle fiber to its neighbors.
gap junctions
Cardiac conduction system action potentials occur as follows: Excitation is initiated at the heart’s pacemaker, the sinoatrial (SA) node then what?
An action potential propagates throughout both atria,
The atrioventricular (AV) node, the atrioventricular (AV) bundle, the right and left bundle branches, and finally, the Purkinje fibers.
The Purkinje fibers conduct the action potential from the apex upward to the remainder of the ventricular myocardium.
Phases of an action potential in a ventricular contractile fiber ?
Phases of an action potential in a ventricular contractile fiber include depolarization, plateau, and repolarization.
Cardiac muscle tissue has a _____________lrefractory period, which allows chambers to refill with blood.
long
What are the stages of a NORMAL ECG?
A normal ECG consists of a
- P wave (atrial depolarization),
- QRS complex (onset of ventricular depolarization),
- T wave (ventricular repolarization).
A cardiac cycle consists of the (contraction)? what is it called?
systole
Using a stethoscope, the first two of the four heart sounds of a cardiac cycle are loud enough to be heard. S1, the first heart sound (lubb), is caused by blood turbulence associated with the ?
closing of the atrioventricular valves.
S2, the second sound (dupp) of the heart, is caused by blood turbulence associated with the ?
closing of semilunar valves.
There are 10 events during a cardiac cycle what are the first 2?
(1) atrial depolarization and P wave occur;
(2) atrial systole forces blood across open AV valves into relaxed ventricles
There are 10 events during a cardiac cycle what are the 3rd & 4th?
(3) ventricular filling occurs;
(4) QRS complex signals the onset of ventricular depolarization
There are 10 events during a cardiac cycle what are the 5th & 6th?
(5) atrial diastole and ventricular systole close the AV valves;
(6) increasing pressure inside the ventricles opens the SL valves, resulting in ventricular ejection
There are 10 events during a cardiac cycle what are the 7th & 8th?
(7) at rest, 70 mL of blood is ejected from each ventricle;
(8) T wave indicates ventricular repolarization
There are 10 events during a cardiac cycle what are the 9th & 10th?
(9) ventricular diastole decreases ventricular pressure, causing SL valves to close;
(10) as ventricular pressure continues to drop, AV valves open, and ventricular filling begins.
What is Cardiac output ?
Cardiac output is the blood volume ejected by a ventricle each minute.
What is stroke volume?
Stroke volume is the volume of blood ejected by the ventricle with each contraction (beat).
Stroke volume is related to ___________(stretch on the heart before it contracts), contractility (forcefulness of contraction), and _____________ (pressure that must be exceeded before the SL valves open and ventricular ejection begins). According to the______________ law of the heart, greater stretch of ventricular muscle fibers during diastole leads to____________ of contraction during systole.
preload
after load
Frank Starling
greater force
The cardiovascular center is in the ?
in the medulla oblongata
What is the role of the medulla oblongata ?
This region receives input from proprioceptors, chemoreceptors, and baroreceptors, and from the limbic system and cerebral cortex.
How is heart rate increased?
Sympathetic neurons arising from the cardiovascular center release norepinephrine to increase heart rate and force of contraction.
How is heart rate decreased ?
Parasympathetic neurons from the cardiovascular center release acetylcholine to decrease heart rate.
What hormones increase heart rate?
Epinephrine, norepinephrine, and thyroid hormones increase heart rate and contractility.
What effect does Elevated Na+ or K+ have on heart rate and contractility?
Elevated Na+ or K+ decreases heart rate and contractility
What effect does elevated Ca2+ have on heart rate and
c o n t r a c t ilit y .
elevated Ca2+ increases heart rate and
c o n t r a c t ilit y .
Factors that influence heart rate?
factors that influence heart rate include age, gender, physical fitness, and body temperature.
