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What is the heart and what is it responsible for?
The heart is a muscular pump. It is responsible for the circulation of the blood
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At what rate does the heart pump blood?
About a gallon of blood per minute
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How many times a day does the heart beat?
Slightly over 100,000 times per day
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How does the heart lie?
Obliquely (45 degree angle)
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Where does the heart lie?
within the mediastinum (the space between the lungs)
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The heart extends from the ________to the ____________ ______________.
sternum to the vertebral column
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Where is the apex of the heart?
The apex is at the bottom of the heart.
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The apex is the pointed end of the heart. It is directed....
anteriorly, inferiorly, and to the left
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Where is the base of the heart?
At the top of the heart
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Where do the great vessels enter and leave the heart?
at the base
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What vessels can be seen on the external surface of the heart?
the coronary arteries
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What vessels nourish the heart muscle itself?
the coronary arteries
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What veins follow the coronary arteries and how are they named?
- the coronary veins
- they are named according to the corresponding arteries
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What is the double layered sac called that contains the heart?
the pericardium
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What is the tough outer layer of the pericardium?
the fibrous pericardium
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What is the inner layer of the pericardium?
serous (parietal) pericardium
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What fluid does the serous pericardium secrete and what is the function of this fluid?
- pericardial fluid
- it acts as a lubricant to reduce friction as the heart beats
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Inflammation within the space between the heart and the pericardium is called...
pericarditis
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What is the condition called if bleeding occurs within the space between the pericardium and the heart and the heart is compressed?
cardiac tamponade
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How many layers is the heart wall divided into?
3
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what are the 3 layers of the heart wall?
- epicardium
- myocardium
- endocardium
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What is the outer layer of the heart wall called?
epicardium
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What is the epicardium made out of and what is capable of producing?
The epicardium is very thin transparent layer of serous tissue. It can produce serous fluid.
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What is the inflammation of the epicardium?
epicarditis
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middle layer of the heart wall
myocardium
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fibers myocardium made up of?
What does the myocardium do?
- thick bundles of muscle fibers
- cause the heart to contract
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inflammation of the myocardium
myocarditis
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thin inner lining of the heart wall?
endocardium
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endocardium is composed of?
simple squamous epithelium
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endocardium is continuous with?
the endothelium (inner lining) of the blood vessels
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inflammation of the endocardium
endocarditis
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How many circulatory routes does the heart have? What are those routes?
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How is the heart divided in order to deliver blood via its 2 routes (pulmonic and systemic)?
it is separated into right and left halves
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A low-pressure system involving the right half of the heart
pulmonic circulation
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The right half of the heart pumps blood where?
to the lungs
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What color is deoxygenated blood?
dark red
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Vascular illustrations depict deoxygenated blood as...
blue
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The right half of the heart pumps blood to the _________ for ___________.
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What is systemic circulation?
A high-pressure system involving the left half of the heart that pumps oxygenated blood throughout the body (except the lungs).
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What color is blood in the left side of the heart? why is it that color?
bright red, because it is oxygenated
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what color is oxygenated blood?
bright red
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Vascular illustrations depict oxygenated blood as...
red
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How many chamber is the heart divided into?
4
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What are the upper chambers of the heart called?
atria
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what are the lower chambers of the heart called?
ventricles
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Where is gas exchanged?
the tissues of the lungs
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What might cause cardiac tamponade?
pericarditis
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What causes myocarditis?
usually a viral infection, rheumatic fever, or exposure to radiation, chemicals, or medications
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What usually causes endocarditis?
bacterial infection (dirty needles)
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What does the latin word atrium mean?
room
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What chamber received the deoxygenated systemic blood?
Right atrium
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Returning blood enters the right atrium through what structures?
- superior vena cava
- inferior vena cava
- coronary sinus
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What helps to increase the volume of the atriums?
auricles
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What does auricle mean in Latin?
Ear
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What type of blood enters the left atrium?
oxygenated pulmonic blood (from the lungs)
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Where does the blood come from that enters the left atrium?
the lungs
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How may openings enter into the left atrium?
4
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Blood enters the left atrium through what vessels?
the 4 pulmonary veins
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What is the origin of the 4 pulmonary veins?
the lungs
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What structure separates the 2 atria of the heart?
interatrial septum
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Depression found on the 2 surfaces of the interatrial septum?
fossa ovalis
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What did the fossa ovalis originate from?
foramen ovale
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What is the foramen ovale and what does it become?
embryonic opening in the interatrial septum between the 2 atria which closes at birth
it forms the fossa ovalis
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Where does the right ventricle receive blood from?
from the right atrium
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what separates the right ventricle from the right atrium?
tricuspid valve (right atrioventricular (AV) valve
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another name for the tricuspid valve?
right atrioventricular (AV) valve
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What is the structure of the tricuspid valve?
3 downward opening flaps or cusps
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What is the meaning of cusp?
flap
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What type of valve does blood pass through when it leaves the right ventricle?
3 cusped semilunar valve
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the name of the valve in the pulmonary trunk that blood passes through when it leaves the right ventricle on the way to the lungs?
pulmonic semilunar valve
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How many cusps does the pulmonic semilunar valve have?
3
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What does semilunar mean?
half moon
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Where does the blood go when it passes through the semilunar valve of the right ventricle?
into the pulmonary trunk (pulmonary artery) then to the lungs
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what is another name for the pulmonary trunk?
pulmonary artery
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Is the blood in the pulmonary trunk oxygenated or deoxygenated?
deoxygenated
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What is the next major structure(s) that the blood would enter after leaving the pulmonary trunk?
the lungs
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Where does the blood come from that enters the left atrium?
from the lungs
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What valve separates the left atrium from the from the left ventricle?
bicuspid or mitral valve (left atrioventricular (AV) valve)
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The left ventricle receives oxygenated blood from the...
left atrium
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What are 2 other names for the bicuspid valve?
mitral valve or left atrioventricular (AV)valve
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Through what type of valve does blood leave the left ventricle ?
3 cusped semilunar valve of the aorta
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What separates the 2 ventricles of the heart from each other?
interventricular septum
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What is the interventricular septum?
A thick muscular wall that separates the 2 ventricles of the heart from each other
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What 2 chambers of the heart contain oxygenated blood?
the left atrium and the left ventricle
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What attaches both the tricuspid and the bicuspid valves underneath?
papillary muscles and chordae tendineae
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What are the tough fibers that attach the tricuspid and bicuspid valves underneath?
chordae tendineae
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What are the muscles that attach the tricuspid and bicuspid valves underneath?
papillary muscles
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What do the chordae tendineae and papillary muscles prevent?
prolapsing of the tricuspid and bicuspid valves, which prevents reflux of blood back into the atrium
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What does prolapse mean?
collapsing backward
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If the mitral valve prolapses what does it cause?
reflux of blood back into the atrium
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What are the primary heart sounds? What produces them?
lubb-dupp
the closing of the heart valves
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What is the first heart sound (S1)? What does it result from?
lubb
the near-simultaneous closing of the tricuspid and mitral valves
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What is the second heart sound (S2)? What does it result from?
dupp
the near-simultaneous closing of the pulmonary and aortic semilunar valves
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Listening to heart sounds with a stethoscope is...
auscultation
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What causes the primary heart sounds?
closing of the heart valves
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Are the closure sounds for each valve best auscultated directly over the valves?
no, the best locations for ausculation are slightly different from the actual valve locations
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an extra heart sound that consists of a flow noise heard before or after the primary heart sounds
heart murmur
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What are murmurs caused by?
turbulent blood flow around valves due to abnormal anatomy or increased blood volume
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What is the blood supply to the heart itself called?
coronary circulation
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How many arteries are in the coronary circulation system?
5
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What are the 5 main arteries of the coronary circulation system?
- left coronary artery
- right coronary artery
- anterior descending (interventricular)artery
- circumflex artery
- posterior descending (interventricular) artery
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What does coronary mean?
crown
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What 2 arteries initially lead into the coronary circulation system?
- left coronary artery
- right coronary artery
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What does the coronary circulation system do?
supplies blood to the heart
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Where do the left and right coronary arteries originate?
the aortic arch
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What does the left coronary artery bifurcate into?
- anterior descending (interventricular) artery
- circumflex artery
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anterior descending artery also known as...
anterior interventricular artery
-
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what branches of the right coronary artery?
posterior descending artery
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another name for the posterior descending artery
posterior interventricular artery
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The coronary veins carry deoxygenated blood into what large vein?
coronary sinus
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where does the coronary sinus empty?
right atrium
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nerve center that innervates the heart
cardiovascular center of the autonomic nervous system
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What nervous system is the cardiovascular system part of?
autonomic
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What influence does the cardiovascular center have over the heart?
it can slow or speed up the rate of contractions
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where is the cardiovascular center located?
brain stem
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sympathetic nervous system can...
increase heart rate
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parasympathetic nervous system can...
decrease heart rate
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what hormone acts with sympathetic nervous system to increase heart rate?
epinephrine
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what cranial nerve is involved in the heart parasympathetic distribution?
Vagus nerve (CNX)
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kind of system that cause the heart to contract?
intrinsic
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what does intrinsic imply?
that it's situated within or belongs solely to the body part on which it acts
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specialized muscle tissues that initiate and conduct electrical impulses in the the heart
Purkinje fibers
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Purkinje center that signals the contraction of the atria?
sinoatrial node (SA node)
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Where is the SA node located? What does it do?
upper wall of right atrium
initiates both atria to contract for each heart beat
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What is the SA node also referred to?
the pacemaker
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How many times per minute do the atria contract?
70
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What center signals the ventricles to contract?
atrioventricular node (AV node)
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AV node is located...
in the floor of the right atrium
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What simulates the AV node to contract?
SA node impulse
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After the AV node receives the pacemaker (SA node) impulse it...
delays it a fraction of a second, then excites the ventricles to contract
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where does the impulse go from the AV node?
it enters the atrioventricular (AV) bundle (Bundle of His)
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What is the atrioventricular (AV) bundle also known as?
bundle of His
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AV bundle (bundle of His) bifurcates to form...
- right bundle branch
- left bundle branch
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the right bundle branch goes to...
the right ventricle
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the left bundle branch goes to...
the left ventricle
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Where does excitation of the ventricular walls begin and how does it travel?
begins at the apex of the heart and radiates upward towards the base
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What mechanical device is used to regulate heart beats when there is a problem with the Purkinje system?
artificial pacemaker
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What function do intercalated discs perform?
rapid conduction of impulses within the heart
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What monitors blood pressure at points throughout the body?
baroreceptors
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How do baroreceptors work?
If blood pressure drops, nerve impulses are sent to increase the heart pumping action
they monitor the stretching of major arteries and veins caused by the pressure of the blood flowing through them
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If the blood pressure drops the heart rate will...
increase
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what baroreceptor is activated when suddenly arising form a prone sleeping position?
carotid sinus
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mechanical device used to measure the electrical activity of the cardiac conduction system
electrocardiograph
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record of electrical changes that occur during each cardiac cycle
electrocardiogram (ECG or EKG)
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3 waves represented in EKGs
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What does the P wave on an EKG represent?
Spread impulse from the SA node over the atria (known as depolarization)
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What is the term that describes P wave activity?
depolarization
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Electrical charge in the cardiac conduction system during depolarization?
positive
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QRS wave on EKG represents...
spread of the impulse from the AV Node through the ventricles
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what term describes QRS wave activity?
sequence
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What does T wave represent on an EKG?
ventricular repolarization
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What happens during ventricular repolarization?
muscles of the ventricles return to their resting state (relaxation)
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Why is atrial repolarization not seen on an EKG?
it is masked by the QRS sequence
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What other than the waves are important in interpreting an EKG?
- intervals between peaks
- amplitudes and widths of waves
- regularity or rhythms of wave sequences
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a graphic outline of functioning heart structures compiled from ultrasound vibrations that are echoed into a receiving monitor
echocardiogram
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what is used to obtain the outlines of the heart in a echocardiogram?
ultrasound
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in a normal cardiac cycle what happens?
- the 2 atria contact almost simultaneously while the two ventricles are relaxed
- then the ventricles contract while the atria relax
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contraction phase of the ventricles
systole
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stroke pressure of systole
- 120mm of mercury in left ventricle
- 20mm in the right ventricle
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ventricular relaxation phase
diastole
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diastolic (resting) pressure
- 80mm of mercury in left ventricle
- 10mm in right ventricle
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the amount of blood ejected by the left venricle
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amount of blood remaining in the left ventricle after systole
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Why are the walls of the atria relatively weak?
their only function is to receive blood from the great veins and pump it into the ventricles
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Why is the left ventricular myocardium thicker than the right?
because of the greater stroke pressure needed to drive blood throughout the body
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anatomical flaws in the heart structures that are present from birth
congenital heart defects
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term used for babies born with congenital heart defects
blue babies
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why are blue babies described as blue?
cyanosis (blue discoloration of the skin and mucus membranes) caused by the mixing of oxygenated blood with de-oxygenated blood in babies with congenital heart defects
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name 5 types of congenital heart defects
- coarctation of the aorta
- patent ductus arteriosus
- interatrial septal defect
- interventricular septal defect
- Tetralogy of Fallot
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a portion of the aorta is narrowed which reduces blood flow of systemic blood and causes hypertrophy of the left ventricle
congenital heart defect - coarctation of the aorta
-
ductus arteriosus (fetal blood vessel between the aortic arch and pulmonary trunk) doesn't close at birth to form the ligamentum arteriosum
Patent ductus arteriosus - congenital defect
-
ligamentum arteriosum
the remnant of the ductus arteriosus (fetal blood vessel between aortic arch and pulmonary trunk) which closes at birth
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mixture of atrial blood caused by a failure of the foramen ovale to close at birth
interatrial septal defect
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what is the most common congenital heart defect?
interatrial septal defect
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a mixture of the blood between the two ventricles as a result of an opening in the interventricular septum
interventricular septal defect - congenital heart defect
-
a combination of 4 heart defects common in Down Syndrome children
Tetralogy of Fallot
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What 4 defects does Tetralogy of Fallot include?
- stenosed pulmonary semilunar valve
- interventricular septal defect
- enlarged right ventricle
- an aorta emerges from both ventricles
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What does blockage of the coronary arteries cause?
ischemia (decreased blood flow) to the heart muscles
-
What does ischemia caused by partial blockage of the coronary arteries result in?
angina pectoris
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What is angina pectoris?
- chest pain
- ischemia caused by partial blockage of the coronary arteries
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Complete blockage of coronary arteries leads to...
myocardial infaction
-
partial blockage of the coronary arteries causes...
angina pectoris
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myocardial infarction results in...
tissue death
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Americans who will have had a myocardial infarction (MI) by the age of 60
1 in 5
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Risk factors for MI
- Tobacco
- Obesity
- lack of regular exercise
- overuse of alcohol
- high BP
- gender (males vs females)
- genetics
- high blood cholesterol
- age - risk increases with age
- stress
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Heart condition often associated with old age
congestive heart failure
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Chronic condition where heart becomes inefficient and weak, blood doesn't circulate well
congestive heart failure
-
sign of congestive heart failure
peripheral edema, especially in ankles
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objectives of medical treatment for congestive heart failure (CHF)
what treatments are used?
- increase the contractile ability of the myocardium, digitalis
- remove fluid from the body, lasix (diuretic)
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arteries take blood
away from the heart
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veins take blood
to the heart
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what are the only veins that carry oxygenated blood?
pulmonary veins
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what are the only arteries that carry deoxygenated blood?
pulmonary arteries
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