Heart
Which of the following is the correct conduction pathway through the heart? a. SA node-ventricular muscel-AV node-His bundle-bundle branches-Purkinje fibers-atrial muscle b. SA node-atrial muscle-AV node-bundle branches-His bundle-purkinje fibers-vetricular muscle c. SA node-atrial muscle-AV node-His bundle-bundle branches-Purkinje fibers-ventricular muscle d. SA node-purkinje fibers-AV node- His bundle- bundle branches-atrial muscle-ventricular muscle
C.
Middle mediastinum
Contains the pericardium and the heart and the immediately adjacent parts of the great arteries, phrenic nerves, main bronchi, and other structures in the root of the lungs GREATEST CLINICAL IMPORTANCE
Posterior interventricular branch
Is another branch of the right coronary artery It supplies blood to both ventricles, and then anastomoses with the circumflex artery from the left coronary artery
what is the oblique vein a remnant of
The embryonic left superior vena cava
Right marginal vein
ascends along the right margin of the heart and joins the small cardiac vein in the coronary sinus, or opens directly into the right atrium
Which of the following does NOT empty directly into the right atrium? a. azygous vein b. inferior vena cava c. superior vena cava d. coronary sinus
azygous vein
The left atrium and left ventricle receive their major arterial supply from which artery a. anterior interventricular branch of the left coronary artery b. circumflex branch of the left coronary artery c. marginal branch of the right coronary artery d. posterior interventricular branch of the right coronary artery
b. circumflex branch of the left coronary artery
A patient with a with a "heart valve problem" comes into the the dental clinic for periodontal therapy. She says that her old periodontist always gave her antibiotics before treatment, and insisting that the dentist hear the problem, she places the stethoscope in the left fifth intercostal space medial to the nipple line. Which heart valve is best heard over the apex of the heart a. Tricuspid valve b. mitral valve c. pulmonary valve d. aortic valve
b. mitral valve (bicuspid valve)
What does small cardiac vein receive
blood from the back of the right atrium and ventricle
How does electrical impulse reach AV node
by way of three internodal bundles. The AV node then initiates a signal that is conducted through the ventricular myocardium by way of the atrioventricular bundle (bundle of HIS) and purkinje fibers
The conducting system of the heart is all _________ fibers and NOT _________
cardiac muscle NERVES
What happens if there is resistance to pulmonary blood flow in the lungs
causes a strain on the right ventricle and results in ventricular hypertrophy
Anterior cardiac veins
comprise three or four small vessels which collect blood from the front of the right ventricle and open into the right atrium
Smallest cardiac veins (thesbian veins)
consist of a number of minute veins which arise in the muscular wall of the heart; the majority open into the atria but a few end in the ventricles
When viewed from the back (posterior view) the most obvious structure lying in the coronary sulcus is the
coronary sinus
When do coronary arteries receive most of their blood flow
during diastole or ventricular relaxation when the left ventricle is filing with blood
Sinus rhythm
every P wave is followed by a QRS complex, the R-R interval is regular, and the P-R interval is less than 0.2 seconds
Fast sinus rhythm
faster than 100 beats a minute also called SINUS TACHYCARDIA
The apex of the heart is located at the level of a. third left intercostal space b. fourth left intercostal space c. Fifth left intercostal space d. Sixth left intercostal space
fifth left intercostal space
What allows blood to pass from the right atrium to the left atrium, bypassing the nonfunctional fetal lungs while the fetus obtains oxygen from the placenta
foramen ovale
what is the permanently closed formaen ovale in adults called
fossa ovalis
Where do the coronary arteries arise
from the ascending aorta immediately above the aortic valve. Their major branches are distributed over the surface of the heart lying within subepicardial connective tissue
Where does the ductus arteriosus shunt blood
from the left pulmonary artery to the aorta just beyond the origin of the artery to the left subclavian artery
where does the right atrium receive blood, and what type of blood is it receiving
from the systemic circuit via the superior and inferior venae cavae as well as the coronary sinus deoxygenated blood
Internal or endocardium layer
homologous with the tunica intima of blood vessels. Lines the surface of the heart chambers with SIMPLE SQUAMOUS ENDOTHELIUM and underlying loose connective tissue containing small blood vessels
Myocardium layer
homologous with the tunica media of blood vessels. Forms the bulk of the heart mass and consists predominantly of cardiac muscle cells arranged in a spiral configuration. This spiral arrangement allows the heart to "wring" the blood from the ventricles toward the aortic and pulmonary semilunar valves
The oblique vein ends
in the coronary sinus near its left extremity; this vein is continuous above with the ligament of the left vena cava
Middle cardiac vein ends
in the coronary sinus near its right extremity
Where does the coronary sinus lie and open
in the posterior part of the coronary sulcus (ATRIOVENTRICULAR GROOVE) and opens in the right atrium between the opening of the inferior vena cava and the right atrioventriucluar orfice, it's opening is guarded by a semilunar valve (THEBESIAN VALVE)
Sympathetic stimulation will have which direct effect on the heart a. decreased automaticity b. AV block c. Increased vagal response d. bradycardia e. increased stroke volume
increased stroke volume
What effect does sympathetic nerves at SA node have
increases heart rate. The effect on the muscle is an increase in rise of pressure within the ventricle, thus increasing stroke volume
What is larger the inferior or superior vena cava
inferior
Where does the great cardiac vein open
into the left extremity of the coronary sinus
where does the small cardiac vein open
into the right extremity of the coronary sinus
Anterior interventriucalar artery (left anterior or descending artery)
is a branch of the left coronary artery and accompanies the great cardiac vein
Fossa ovalis
is a depression in the right atrium of the heart, the remnant of a thin fibrous sheet that covered the foramen ovale during fetal development
AV node
is an area of specialized tissue between the atria and the ventricles of the heart, specifically in the posterioinferior region of the interatrial septum near the opening of the coronary sinus Conducts the normal electrical impulse from the atria to the ventricles
Left ventricle
is larger and thicker than right ventricle and pumps blood through all other vessels of the body
Myocarditis
is the inflammation of the muscular layer of the heart (myocardium)
What is a remnatn of the ductus arteriosus in the fetus
ligamentum arteriosum
Sinuatrial node location and function
located at the junction of the superior vena cava and the right auricle it is the most rapidly depolarizing cardiac muscle tissue of the heart (this is way its refereed to as the "pacemaker"
What does the left coronary artery supply
major part of the heart including the left atrium, left ventricle, and ventricular septum
Myocardium
muscle tissue of the heart it forms the middle layer between the outer epicardium and inner endocardium striated muscle
A worker in the meat-processing industry comes down with an illness presenting with symptoms of fever, headache, and sore throat. A few days later, he feels chest pain and has pink, frothy sputum. His physician states that the worker has a viral infection caused by coxsackie B. This patient has inflammation of which layer of the heart a. epicardium b. myocardium c. endocardium d. pericardium
myocardium
Where does the AV bundle of HIS leave
near the lower part of the interatrial septum and splits over the upper part of the interventriuclar septum into a left and right bundle branch
Does the heart require external influences in order to beat
no the conduction system stimulates the heart to beat independently
Where does the inferior vena cava open and where is it returning blood
opens into the lower part of the right atrium and it returns blood from the lower half of the body
What is the effect of the vagus nerve on the SA node
opposite of sympathetics!!!! It decreases heart rate The vagus nerve also decreases the excitability of the junctional tissue around the AV node, and this results in slower transmission Note: strong vagal stimulation here may produce an AV block
Where do sympathetic fibers go
pass into the cardiac plexus and from there to the SA node and the cardiac muscle
Right ventricle
pumps blood to the lungs
Coronary Sinus
receives most of the venous blood from the heart and empties into the right atrium
Where does the left atrium receive blood and what type of blood is it
receives oxygenated blood from the lungs
What vein frequently opens inot the right atrium and is therefore sometimes regarded as belonging to the anterior cardiac veins
right marginal vein
Where do the sympathetic fibers arise from
segements T2-T4 of the spinal cord and are distributed through the middle cervical and cervico-thoracic (or stellate ganglia) and first four ganglia of the thoracic sympathetic chain
What artery supplies the SA node
sinoatrial nodal artery
Slow sinus rhythm
slower than 60 beats per minute SINUS BRADYCARDIA
Coronary Sinus tributaries
small cardiac vein middle cardiac vein great cardiac vein
Right coronary artery arises from
the anterior aortic sinus of the ascending aorta and runs forward between the pulmonary trunk and the right auricle.
Where do ventricles receive blood from
the atria
Where does the left coronary artery arise from
the left posterior aortic sinus of the ascending aorta and passes forward between the pulmonary trunk and the left auricle
What is the small vein that arises along the left side of the left atrium just beneath the lower left pulmonary artery
the oblique vein
What does the rate of discharge of the SA node set
the rhythm of the entire heart
How many valves of the heart are there and what is there function
there are 4 valves of the heart that are designed to allow one-way flow only of blood. Their function is to PREVENT BACKFLOW into the releasing chamber
Where does the blood travel after entering the right atrium
to the right ventricle via the right AV valve. The right ventricle then pumps blood into the pulmonary circuit via the pulmonary semilunar valve, which allows blood to flow into the pulmonary arteries.
What does the great cardiac vein receive
tributaries from the left atrium and both ventricles: one, the left marginal vein is of considerable size and ascends along the left margin of the heart
What wave represents ventricular repolarization
T wave
The order of blood flow through the heart
1. Entering the right atrium are the coronary sinus and the superior and inferior venae cavae carrying deoxygenated blood from the systemic circuit 2. Upon contraction of the right atrium, blood passes through the right AV valve to the right ventricle 3. Upon contraction of the right ventricle, blood leaves to pass to the right and left lungs via pulmonary arteries 4. Blood gases are exchanged in the lung, and oxygenated blood returns via pulmonary veins to the left atrium 5. Upon contraction of the left atrium, blood passes through the left AV valve to the left ventricle 6. Upon contraction of the left ventricle, oxygenated blood passes through the aortic valve to the systemic circuit via the aorta and its branches
The apex of the heart is formed by the tip of the left ventricle and is located at the level of the
5th left intercostal space
What is the spontaneous depolarization rate of SA node
60 to 100 times per minute, causing the atria to contract
Which of the following arteries accompanies the great cardiac vein a. circumflex artery b. anterior interventricular artery c. posterior interventricular artery d. right marginal artery
Anterior interventricular artery
What artery is most often involved in coronary occlusions and is often the one that is bypassed in bypass cardiac surgery
Anterior interventricular artery (typically provides the most blood to conducting tissue)
What is an important branch the right coronary artery gives off
Anterior right atrial branch (this then gives off the sinoatrial nodal artery)
What divides the two atriums of the heart
Atrial septum
Pressure of atriums before birth and after birth
Before Birth: R is high and L is low After Birth: R is low and L is high
Where does blood travel after it enters the left atrium
Blood flows through the left AV valve in to the left ventricle. From the left ventricle, blood passes through the aortic valve and enters the arch of the aorta, which will deliver blood to the body's systemic circuits
What parts of the autonomic nervous system are involved in the control of the heart
Both parasympathetic and sympathetic
What causes shortness of breath and pulmonary edema
If the pressure in the veins of the lungs increases causing fluid accumulation in the lung
Which of the following describes the function of the ductus arteriosus in the fetus? a. it shunts blood from the aorta to the pulmonary artery b. it shunts blood from the pulmonary artery to the aorta c. it shunts blood from the right atrium to the left atrium d. it shunts blood from the umbilical vein to the inferior vena cava
It shunts blood from the pulmonary artery to the aorta
What is larger the right or left coronary artery?
Left
What artery supplies the right ventricle
Marginal branch of the right coronary artery (located in the coronary sulcus)
What wave represents atrial deploraization
P wave
What wave represents impulse between SA and AV node (AV conduction)
PR
The major sensory nerve to the parietal pericardium is from branches of the
Phrenic nerve (C3-C5)
During VENTRICULAR SYSTOLE the ventricles of the heart contract and the _______ and _______ valves open to allow blood to be pumped into the pulmonary and general circulatory systems, respectively, while the other valves are closed
Pulmonary and Aortic
Most veins carry deoxygenated blood from the tissues back to the heart what are the only TWO EXCEPTIONS
Pulmonary and umbilical veins (both carry oxygenated blood)
What wave represents ventricular depolarization
QRS
What wave represents the ejection of blood
QT
The _____ node is in the wall of the ______ atrium, near the enterance of the superior vena cava
SA right
electrical impulse of the heart is initiated by the
Sinoatrial (SA) node (pacemaker) and spreads to the rest of the right atrial myocardium directly, to the left atrial myocardium by way of a bundle of interatrial conducting fibers
What provides parasympathetic control of the heart
Vagus nerve
What divides the two ventricles of the heart
Ventricular septum
What is fatigue caused by
When the left side of the heart is not able to pump as much blood forward causing less oxygen to be received by the remainder of the body
Posterior (descending artery) intervenricular artery
a branch of the right coronary artery, and accompanies the middle cardiac vein
What cardiac veins do not end in the coronary sinus
anterior cardiac veins smallest cardiac veins
What does the left coronary artery branch into once it enters the atrioventricular groove
anterior interventricular branch and the circumflex branch
Pericardium layer
is the set of membranes around the heart (its actually composed of three layers of membranes). The innermost is the visceral pericardium, the middle is the parietal pericardium, and the outer one is the extra one, called the fibrous pericardium. The visceral and pareital are rather thin and delicate. The outer one, the fibrous pericardium is tough
What happens to the foramen ovale after birth
it is intially closed by the septum primum (valve of the ovale) as pressure in the left atrium exceeds that in the right atrium. Eventually the foramen ovale becomes permanently closed with fibrous connective tissue and becomes the fossa ovalis in adults
Where does the superior vena cava open and where is it returning blood
it opens into the upper part of the right atrium and it returns blood from the upper half of the body
What has larger and thicker walls the atria or the ventricles
ventricles
Patent ductus arteriosus
when the ductus does not close (closes mostly after 24 hours after birth)