1
Q
What are the boundaries of the middle mediastinum?
A
- Superior: transverse thoracic plane – disc between TV4 and TV5
- Inferior: diaphragm
- Lateral: mediastinal pleura
- Anterior: anterior surface of pericardium
- Posterior: posterior surface of pericardium
2
Q
Contents of the middle medistinum?
A
- Pericardium
- Heart
- Origin of great vessels: pulmonary trunk, ascending aorta, pulmonary veins.
- Phrenic nerve and pericardiophrenic vessels
3
Q
Describe the pericardium
A
A.A closed, fibroserous sac surrounding the heart and origins of great vessels.
- Fibrous pericardium
- serous pericardium
- pericardial sac
4
Q
Describe the fibrous pericardium
A
- Tough external layer composed of dense irregular connective tissue.
- Anchors heart and prevents overfilling.
- The fibrous pericardium is attached:
a. anteriorly to the sternum via superior and inferior sternopericardial ligaments.
b. posteriorly to the fascia of the esophagus.
c. Inferiorly to the central tendon of diaphragm via pericardiacophrenic ligaments.
d. Superiorly with the adventitia (outer connective tissue layer) of the great vessels.
5
Q
Describe the serous pericardium
A
- Thin serosal membranes (visceral and parietal layers)
- A closed sac that provides smooth, nearly frictionless surfaces for the heart to move in during contraction.
- Parietal pericardium
a. Composed of simple squamous epithelial cells + thin layer of loose connective tissue
b. Adherant to inner surface of fibrous pericardium - Visceral Pericardium
a. Composed of simple squamous epithelial cells + thin layer of loose connective tissue
b. Lines heart surfaces; continuous with parietal pericardium at great vessels.
c. Forms outer layer of the heart and is called the epicardium.
6
Q
Describe the two clinical correlations of the pericardial sac
A
- Potential space between parietal and visceral pericardium; contains only a minimal amount of lubricating serous fluid.
- CLINICAL CORRELATION – Cardiac tamponade: If the pericardial sac is filled with fluid (due to trauma, inflammation, malignant effusion) the heart cannot fill to capacity due to the surrounding fluid and the inflexibility of the fibrous pericardium. This condition can be lethal as filling of the heart (preload) is reduced. The maximum capacity of pericardial sac is approximately 300 cc.
- CLINICAL CORRELATION – Pericardiocentesis is a procedure which removes excess pericardial fluid. Typically, a big needle is inserted through the bare area of the heart (left of sternum; 5th or 6th intercostal space) to avoid pleural cavity.
7
Q
What are the pericardial sinuses?
A
Transverse pericardial sinus
oblique pericardial sinus
8
Q
Describe the transverse pericardial sinus
what is the clinical correlation associated with this structure?
A
- Anterior border: aorta and pulmonary trunk.
- Posterior border: SVC and pulmonary veins.
- CLINICAL CORRELATION – Clinically important sinus because it allows surgeons to pass a surgical clamp around the major arteries and veins and insert tubes allowing blood to be diverted to a cardiac bypass pump during coronary artery bypass grafting and other cardiac procedures.
9
Q
Describe the oblique pericarial sinus
A
- Pocket-like, cul-de-sac posterior to the heart.
- Bounded by the pulmonary veins and IVC.
10
Q
What are the sternopericardial attachments?
A
Superior sternopericardial ligament
Inferior sternopericardial ligament
phrenopericardial ligaments
11
Q
Describe the pericardial vascular supply
A
- Pericardiacophrenic arteries from internal thoracic artery
- Pericardiacophrenic veins → internal thoracic veins.
12
Q
Describe the pericardial innervation
A
- Phrenic nerve provides sensory innervation to fibrous and parietal pericardium.
- Visceral pericardium is supplied by the cardiac plexus (see below).
- CLINICAL CORRELATION: Pain from the pericardium is typically referred to the shoulder/neck region (dermatomes supplied by the phrenic nerves; C3,4,5).
13
Q
What happens if the serous pericardial membranes become inflamed?
A
If the serous pericardial membranes become inflamed (pericarditis), they become rough and no longer slide easily over one another. Pericarditis can be very painful due to the presence of pain fibers in the fibrous and parietal pericardium (There are no pain fibers in visceral pericardium).
14
Q
Describe a cardiac tamponade
A
Surgeons and ER docs call this:
Beck’s Triad
- Distended neck veins
- Hypotension
- Muffled heart sounds
Mnemonic - 3 D’s:
- Distended jugular veins
- Decreased arterial pressure
- Distant heart sounds
15
Q
What is Dressler’s syndrome?
A
Post MI pericarditis
16
Q
Detail the flow of blood through the heart beginning with deoxygenated blood.
A
- Deoxygenated blood enters the right atrium through the SVC and IVC.
- Blood passes through the tricuspid valve to enter right ventricle.
- Blood exits right ventricle via pulmonary valve and pulmonary trunk – to lungs. (i.e. pulmonary circulation)
- Oxygenated blood enters left atrium through pulmonary veins (two on left, two on right).
- Blood passes through the bicuspid (mitral) valve to enter left ventricle.
Blood is pumped from the left ventricle to the systemic circulation through the aorta.
17
Q
What are the external sulci of the heart?
A
- Atrioventricular sulcus (coronary sulcus)
- Interventricular sulci (anterior and posterior)
18
Q
Describe the surfaces and borders of the heart
(3 borders, 4 surfaces)
A
- Surfaces
a. Anterior (sternocostal); 2/3 right ventricle, 1/3 left ventricle.
b. Right; right atrium.
c. Left; left ventricle + auricular appendage
d. Diaphragmatic (in the anatomical position, the heart rests on its diaphragmatic surface); 2/3 left ventricle, 1/3 right ventricle. - Borders
a. Right ; right atrium
b. Inferior ; 2/3 right ventricle, 1/3 left ventricle
c. Left ; left ventricle + auricular appendage
19
Q
What forms the base and apex of the heart?
A
- Apex
a. Directed inferiorly and to the left.
b. Composed entirely of left ventricle.
c. Lies posterior to the left fifth intercostal space (MCL). - Base
a. Formed by left atrium
b. Directed posteriorly
20
Q
Identify the tagged structures!
A
21
Q
Describe the function of the fibrous skeleton of the heart
A
a. Provide structural support for heart valves; maintaining patency and preventing distention during heart contraction.
b. Provide attachment sites for the cardiac muscle and for the valve leaflets.
c. Insulates against impulse conduction from atria to ventricles; prevents aberrant spread of impulses.
d. Provides tunnel for passage of the A/V Bundle (of His)
22
Q
Describe the structure of the fibrous skeleton of the heart
A
- Fibrous rings a) anulus fibrosis – around each orifice of the 2 atrioventricular valves.
b) fibrous coronets – around the aortic and pulmonary semilunar valves - Fibrous trigones - connections between the fibrous rings.
a. Left fibrous trigone forms a link between aortic and mitral valves.
b. Right fibrous trigone forms a link between aortic, mitral, and tricuspid valves. - Membranous portions of interventricular and atrioventricular septa
23
Q
Describe the ratio of the atrial wall to the right ventricular wall to the left ventricular wall.
A
1:3:9
24
Q
What are the noteable features of the right atrium?
A
- Sinus venarum
- auricle
- crista terminalis
- interartrial and atrioventricular septa
- fossa ovalis right atrioventricular orifice
- sinuatrial and atrioventricular nodes
25
Describe the sinus vernarum
a. Smooth and thin-walled; derived embrologically from the sinus venosus.
b. Forms the entrances of the IVC, SVC, and coronary veins.
26
Describe the auricle off the right atrium
a. Small, ear-like pouch extending anteriorly over the root of the aorta.
b. Represents the embryonic atrium.
c. Wall is lined with pectinate muscles.
27
Describe the crista terminaleis of the right atrium
a. Dividing line between sinus venarum and embryonic atrium (auricle).
b. The crista terminalis is demarcated externally by the sulcus terminalis.
28
Describe the fossa ovalis of the right atrium
a. Oval depression in interatrial septa representing the embryonic foramen ovale.
b. Embryologically, the foramen ovale allowed blood returning from the body to be shunted directly to the left atrium thus bypassing the fetal lungs.
29
Describe the Right atrioventricular orifice
a. Opening between right atrium and right ventricle with tricuspid valve.
b. Surrounded by a fibrous ring (anulus fibrosis) to maintain shape and patency.
30
Describe the Sinuatrial (SA) and atrioventricular (AV) nodes
a. SA node is located in the sub-epicardium of the right atrium near the junction of the sulcus terminalis and the SVC.
b. AV node is located in the sub-endocardium of the right atrium, near the opening of coronary sinus.
31
What are the structures of the right ventricle?
(6)
1. Trabeculae carnae
2. conus arteriosus
3. right atrioventricular (tricuspid) valve
4. Membranous interventricular septum
5. muscular interventricular septum
6. pulmonary (semilunar) valve
7.
32
Describe the trabeculae carnae
a. Muscular ridges of the ventricular wall.
b. Moderator band (septomarginal) – a specialized trabecular muscle passing from the interventricular septum to the anterior papillary muscle.
33
Describe the conus arteriosus
smooth-walled portion of chamber leading to pulmonary artery
34
Describe the 1.Right atrioventricular (tricuspid) valve
a. Located posterior to the sternum at the 4th or 5th intercostal space.
b. 3 cusps (anterior, posterior and septal) attach to fibrous ring.
c. Chordae tendineae connect the valve cusps to the papillary muscles.
d. Papillary muscles attach valve cusps to ventricle wall. When papillary muscle contract they pull the valve leaflets centrally and close the AV orifice. This also prevents the valves from everting into right atrium during ventricular contraction.
35
Describe the pulmonary (semilunar) valve
a. Located posterior to the sternum at the level of the 3rd costal cartilage.
b. 3 cusps (anterior, left and right) attach to fibrous ring.
c. Free edge of the cusp is thickened to form the nodule and lunule.
d. Pulmonary trunk surrounding each cusp is dilated, forming pulmonary sinuses.
e. When ventricle relaxes, blood in pulmonary trunk reverses its flow. The sinuses fill with blood and the cusps close.
36
Describe the left atrium
1. Receives the 2 superior and 2 inferior pulmonary veins.
2. The auricle represents the embryonic atrium and is lined with pectinate muscles.
3. Interatrial and atrioventricular septa.
4. The valve of the foramen ovale is located in interatrial septa opposite fossa ovalis.
5. Left AV orifice
a. Opening between left atrium and left ventricle with bicuspid (mitral) valve.
b. Surrounded by a fibrous ring (anulus fibrosis) .
37
Describe the left atrium during development
1.During development, the proximal portion of the pulmonary vein becomes incorporated into the adult left atrium, forming the larger, smooth-walled posterior portion of the chamber.
38
Describe the left ventricle
1. Trabeculae carneae muscles are finer but more abundant than in the right ventricle.
2. Aortic vestibule: smooth-walled portion of the left ventricle leading to the aorta.
3. Left atrioventricular (bicuspid, mitral) valve
a. Located posterior to the sternum at the 4th costal cartilage.
b. 2 cusps (anterior, posterior) attach to fibrous ring.
c. Chordae tendineae, papillary muscles (see tricuspid valve for action)
4. Aortic (semilunar) valve
a. Located posterior to the sternum at the level of the 3rd intercostal space.
b. 3 cusps (posterior, left, right) attach to fibrous ring.
Within the left and right cusps are openings for left and right coronary arteries
39
systoli or diastoli?
Systoli
40
Systoli or diastoli?
Diastoli
41
What sites do we need to know for ausculation of the heart?
Pulmonary 2nd ICS; left of sternum
Aortic 2nd ICS; right of the sternum
Tricuspid 4th ICS left of the sternum
Bicuspid(mitral) 4th or 5th ICS; left MCL
42
What is valve insufficiency (regurgitation)?
How do we detect this?
1. the failure of any of the heart valves to close completely.Valve stenosis is narrowing of the valvular orifice.
2. These anomalies can be detected upon auscultation as a heart murmur.
43
What is the origin of the Right coronary artery (RCA)? Where do the vessels of the heart travel in the epicardium?
a. The right coronary artery originates from the right aortic sinus within the right cusp of aortic valve.
b. The vessels of the heart travel within the loose connective tissue of the epicardium.
44
What are the branches of the RCA?
a. Sinuatrial node branch to SA node (60% from RCA; 40% from LCA)
b. Right marginal branch which travels along the inferior border of heart to apex.
c. Posterior interventricular artery (posterior descending artery-PDA) which courses along the posterior interventricular sulcus to the apex of the heart. Gives rise to the atrioventricular node branch (80% from RCA; 20% from LCA).
45
What does the RCA typically supply?
1. Typically supplies:
a. Right atrium including the SA and AV nodes.
b. Most of the right ventricle.
c. Some of the diaphragmatic portion of the left ventricle.
d. Posterior 1/3 of the interventricular septum.
46
What is the origin of the left aortic sinus?
Origin - left aortic sinus; within the left cusp of the aortic valve
47
What are the branches of the left coronary artery (LCA)?
1. Branches
a. Anterior interventricular branch (left anterior descending artery-LAD) courses within anterior interventricular sulcus.
b. Circumflex artery courses within coronary sulcus; gives off a left marginal artery.
48
What does the LCA supply?
a. The left atrium
b. Most of the left ventricle
c. Some of the anterior portion of the right ventricle
d. The anterior 2/3 of the interventricular septum
49
What is the most likely location of a heart attack?
LAD
50
What are common variations in arterial supply?
1. Dominance is determined by which artery provides posterior interventricular branch (PDA).
a. Right dominance (67%)
b. Left dominance (15%)
c. Codominance (18%)
2. Some people have only 1 coronary artery; others have accessory artery (4%).
51
What are the consequences of coronary artery disease?
1.Coronary artery disease (atherosclerosis) results in reduced blood flow to the heart, which can lead to a myocardial infarction (MI). If blood flow is suddenly occluded (for example, by an embolus), damage or death of the heart muscle occurs. If the occlusion occurs slowly (as in the case of the atherosclerotic process), collateral circulation within the heart may develop and may prevent a MI.
52
Describe the cardiac anastamosis!!!!
There really isn't one. The LCA and RCA are functional end arteries.
53
what does ischemia to the heart below the MI threshold produce?
What are the symptoms?
Angina
## Footnote
1.Angina results in chest pain, tightness of the chest and pain which radiates to the shoulder and inner arm region (mainly the left inner arm).
54
Describe the venous drainage of the heart
A.The coronary sinus receives most of the venous drainage of the heart; this vein travels within the posterior left coronary sulcus and opens into the right atrium.
55
What are the three tributaries of the coronary sinus?
1. Great cardiac vein (parallels the anterior interventricular artery (LAD)).
2. Middle cardiac vein (parallels the posterior interventricular artery (RCA)).
3. Small cardiac vein (parallels the right marginal artery).
56
Some of the smaller veins enter the heart directly, what are these? (2)
1. Anterior cardiac veins; drain the anterior surface of the right ventricle.
2. Venae cordis minimae; small veins originating in the myocardium drain directly into each chamber.
57
What is arterial dominance determined by?
Dominance is determined by which artery provides
posterior interventricular branch (Posterior Descending Artery)
Right dominance (67%)
Left dominance (15%)
Co-dominance (18%)
58
What are the sites of coronary artery occlusion in order of frequency?
59
Describe the lymphatic drainage of the heart
A.Most lymph drains to the subepicardial lymphatic plexus.
B.Lymphatic vessels following right coronary artery terminate in anterior mediastinal lymph nodes → left bronchomediastinal trunk.
C.Lymphatic vessels following left coronary artery terminate in inferior tracheobronchial nodes → right bronchomediastinal trunk.
60
Describe the location and function of the sinuatrial (SA) node. Where do impulses travel from here?
1. Located in right atrium near the SVC orifice (at sulcus terminalis).
2. Pacemaker – sets the heart rate between 60-100 beats/minute.
3. From SA node, impulses spread rapidly throughout left and right atrium to AV node.
61
Describe the location and function of the atrioventricular (AV) node. Where do impulses travel from here?
1. Located in inferior portion of atrial septum; near the opening of the coronary sinus.
2. Once impulses reach AV node, there is a slight pause (on the order of milliseconds) before the impulses spread to the ventricles. This pause, which is maintained by the fibrous skeleton, allows time for atria to fully empty before the ventricles contract.
62
What is the AV conducting bundle?
Bundle of His
## Footnote
1.Continuation of the AV node through the membranous interventricular septum.
63
Describe the path and desinty of fibers from the bundle of His
1. After passing through the membranous portion of the interventricular septum, the AV bundle splits into left and right bundle branches.
2. Right bundle branch sends fibers through septomarginal band to anterior papillary muscle.
64
Where does the bundle of His begin the contraction of ventricles?
1.Contraction of ventricles begins at the apex and spreads superiorly.
65
Describe the order and location of auscultation of the heart valves
PATM
66
Where does one hear murmurs of the valves?
67
Describe the cardiac autonomic plexus
1. Postganglionic sympathetic and preganglionic parasympathetic nerve cell processes to the muscles and nodal tissues of the heart.
2. Distribute via coronary arteries,
3. Superficial plexus (located in the concavity of aortic arch).
4. Deep plexus (located posterior to arch of aorta; anterior to tracheal bifurcation).
68
What is the function of the cardiac sympathetic plexus?
a. Increase heart rate.
b. Dilate coronary vessels to increase blood flow to the heart.
c. Visceral afferents (acute pain fibers) piggyback sympatheic nerves to upper thoracic spinal segments. (nerve cell bodies are located in dorsal root ganglia)
69
Where are preganglionic sympathetic nerve cell bodies?
1. Preganglionic nerve cell bodies located in T1-T4 segments of spinal cord
2. (interomediolateral cell column of gray matter); their processes enter sympathetic chain.
70
Where are postganglionic nerve cell bodies located? What do their cell processes form?
1. Postganglionic nerve cell processes from the sympathetic ganglia form cardiac branches which are called cardiopulmonary splanchnic nerves. Note: these “splanchnic” nerves are POST ganglionic unlike nearly all other splanchnic nerves which are preganglionic
a. Superior cervical sympathetic cardiac nerve
b. Middle cervical sympathetic cardiac nerve
c. Inferior cervical sympathetic cardiac nerve
d. Thoracic (T1-4) sympathetic cardiac nerves
71
Because afferent pain nerves follow sympathetic nerves to the T1-T4/T5 spinal segments, pain from the heart is...
...referred to dermatomes supplied by these segments especially on the left side. Thus, pain from the heart often is referred to the chest and medial surface of the brachial area.
72
Where are preganglionic parasympathetic nerve cell bodies for the heart found?
1. Preganglionic nerve cell bodies located in the brain stem and processes travel with the vagus nerve.
2. In the neck, the vagus gives off cervical cardiac parasympathetic branches (superior and inferior) and in the thorax, thoracic cardiac parasympathetic branches.
73
Where are postganglionic parasympathetic nerve cell bodies found in the heart? What is the parasympathetic nervous system's function on the heart?
1. Postganglionic nerve cell bodies are found within the wall of the heart (especially around the SA and AV node).
2. Functions
a. Decrease heart rate
b. Constrict coronary vessels
c. Also may carry visceral afferents (stretch receptors; mainly in right atria)
74
What is unique about the cardiopulmonary splanchnic nerves?
They are postganglionic!
75
How many pairs of cardiopulmonary splanchnic nerves?
7
76
How many pairs of Vagal cardiopulmonary nerves?
6
77
The heart sits obliquely in the thoracic cavity with the...
... right atrium to the right, left ventricle to the left, right ventricle anterior, and left atrium posterior.
78
The sequence of blood flow through the heart is
1. venae cavae
2. right atrium
3. right ventricle
4. pulmonary trunk
5. lungs
6. pulmonary veins
7. left atrium
8. left ventricle
9. aorta.
79
The fossa ovalis and ligamentum arteriosum represent structures through which...
... blood bypassed the lungs in the fetus.
80
The sequence of impulse conduction to the heart is...
...cardiac plexus to S/A node to atrial musculature to A/V node to A/V bundle to bundle branches to apex(subendocardial plexus).
81
Thickened (fibrous) parietal pericardium is nondistensible. Therefore...
... pericardial effusion or bleeding into the pericardial cavity is life threatening, the fluid displaces the heart (cardiac tamponade) and may result in cardiac arrest.
82
In a high interventricular septal defect the back-flow of blood may pass from...
... the left ventricle into both the right ventricle and right atrium.
83
To visualize the left atrium on a radiograph it is necessary...
... to take a lateral x-ray of the chest.
Cardiovascular I
flashcards
Decks in class (18)
# Cards
-
Lung Presentation - Steve36
-
Heart Presentation - Steve83
-
Cardiovascular Histology - Steve97
-
Embryonic Clinical Correlations17
-
Cardiac Physiology: APs, RMP, and Conduction System24
-
DSA: Cardiac physiology and the electrocardiogram - Steve25
-
Clinical Correlations of RMPs, APs, and Conduction System9
-
Physiologic Basis for ECG - Steve88
-
Microcirculation5
-
EKG Interpretation Unrein Lecture18
-
Radiology21
-
Cardiac circulation!7
-
Embryonic Structures26
-
Cardiac Cycle, Pressures, Volume, Output & Blood Flow43
-
Introduction to the ANS32
-
Regulation of Cardiac Output46
-
Central Neural and Humoral Control of Blood pressure75
-
BSC: Physiology - Montemayor1
