Lecture 4 - Thoracic Cavity: Heart (GA) Flashcards
1
Q
12 components of the superior mediastinum?
A
- SVC
- L/R brachiocephalic veins
- Aortic arch + 3 branches
- Thoracic duct
- Trachea
- Esophagus
- Thymus
- L/R Vagus nerve
- L recurrent laryngeal nerves
- L/R phrenic nerves
- L/R pulmonary arteries
- Ligamentum arteriosum
2
Q
3 components of anterior inferior mediastinum?
A
- Thymus
- Lymph nodes
- Connective tissue
3
Q
5 components of middle inferior mediastinum?
A
- Pericardium
- Heart
- Roots of great vessels
- Arch of the azygos vein
- Main bronchii
4
Q
8 components of posterior inferior mediastinum?
A
- Esophagus
- Thoracic aorta
- Azygos system of veins
- Hemiazygos
- Vagus nerve
- Symphathetic trunks
- Thoracic splanchnic nerves
- Thoracic duct
5
Q
What are the 11 physiological systems?
A
- Integumentary
- Skeletal
- Muscular
- Nervous
- Endocrine
- CV
- Lymphatic
- Respiratory
- Digestive
- Urinary
- Reproductive
6
Q
Are all 11 physiological systems found in the mediastinum?
A
YUP
7
Q
Anterior border of mediastinum?
A
Sternum
8
Q
Posterior border of mediastinum?
A
Vertebral column
9
Q
Superior border of mediastinum?
A
Thoracic aperture
10
Q
Inferior border of mediastinum?
A
Diaphragm
11
Q
Lateral borders of mediastinum?
A
Lungs
12
Q
In which parts of the mediastinum do we find the same structures?
A
ALL
13
Q
Incidence of CVD?
A
1:5 males and females
14
Q
What is the leading cause of morbidity and mortality in the US and other developed countries? For how long has this been going on?
A
Congenital and acquired heart diseases
Since 1900 (except 1918)
15
Q
How many deaths per year in the US due to some sort of heart disease?
A
1 million
16
Q
What % of sudden deaths are due to heart disease?
A
90%
17
Q
What % of sudden cardiac deaths occur in men?
A
75%
18
Q
Who are the main victims of cardiac deaths?
A
Males between 45 and 64 (90%)
19
Q
Do women die more of breast cancer or heart disease?
A
Heart disease: 1:4 vs 1:9 (develop it)
20
Q
How many Americans have 1 or more types of CVD?
A
Over 60 million
21
Q
Does CVD claim more lives each year than the next 6 leading causes of death combined?
A
YUP (almost 10,500 more)
22
Q
What 5 things did the Greeks think they knew about the heart in 280 B.C.?
A
- 4 main vessels: arteries and veins
- Heart has 2 sides
- Right side was the only one to hold blood and did not pump
- Left side contained intelligence
- Valves were present at the root of great vessels
23
Q
When was the heart recognized as a pump?
A
270 B.C.
24
Q
What 3 variables contribute to the development of heart disease?
A
- Aging
- Disease
- Lifestyle
25
What can red wine reduce the risk of?
1. CVD
2. Alzheimer's
3. Cancer
26
How often does the heart beat in an average adult?
70 times/min at rest
27
Does the heart beat faster or slower in marathon runners?
Slower: 50 times/min at rest
28
What quantity of blood does the heart pump every day?
1800 gallons
29
Is the heart heavier in men or women? By how much?
Heavier in men: 300 g vs 250-275 g
30
What are the 4 components of the CV system?
1. Heart
2. Vascular system
3. Volemia
4. Pulmonary microcirculation
31
Is the vascular system open or closed?
CLOSED
32
What is the volemia portion of the CV system?
The blood volume that fills up the vascular system at a given pressure
33
What is the pulmonary microcirculation of the CV system?
A gas-exchange system between the blood and the surround environment
34
What are the 2 layers of the pericardial sac?
1. Fibrous pericardium
| 2. Serous pericardium
35
What is the fibrous pericardium?
The outermost layer of the pericardium made of tough connective tissue
36
What attaches to the fibrous pericardium superiorly, inferiorly, and anteriorly?
1. Superiorly: tunica adventitia of SVC
2. Inferiorly: central tendon of diaphragm
3. Anteriorly: posterior surface of the sternum
37
What is the main function of the fibrous pericardium?
Protect the heart from sudden over filling
38
What are the 2 layers of the serous pericardium? Describe each.
1. Parietal: outer layer lining the inner surface of the fibrous pericardium
2. Visceral: inner layer covering the external surface of the heart
39
Which other organs have a 2 layers membrane (visceral and parietal)?
Lungs (pleura)
40
What is another name for the visceral serous pericardium?
Epicardium
41
Is there a space between the 2 layers of the serous pericardium?
Yes, but it's a potential space with a tiny amount of fluid to lubricate it (secreted by the serous membrane) and does not become a true space unless there is a pathology
42
Why are we asked to hold our breath during X-rays?
Because the fibrous pericardium is bound to the diaphragm and the heart will not be accurately depicted if we are breathing (aka the diaphragm is moving)
43
Which is more common: AP or PA?
PA
44
What is the potential space between the 2 serous pericardial layers called?
Pericardial cavity
45
What are 5 possible causes of pericardial pathological conditions?
1. Pericarditis
2. Pericardial effusion
3. Cardiac tamponade
4. Cardiomegaly
5. Hemopericardium
46
What is pericarditis? 2 possible causes?
Inflammation of the pericardium
1. Virus
2. Bacteria
47
What is pericardial effusion?
Pericardial cavity becomes a real space with fluid build-up
48
What is cardiac tamponade?
Heart compression due to pericardial effusion or hemopericardium
49
What is hemopericardium? Treatment?
Blood fills up pericardial cavity
Treatment: pericardiocentesis (draining)
50
What does the suffix "-itis" mean?
Inflammation
51
How do bacteria or viruses reach the pericardial space?
Piece of fascia extends from base of the skull to the thorax
52
What is a common cause of bacterial pericarditis? How can this be avoided?
Oral surgery
Prophylactic antibiotics
53
What are 3 potential causes of cardiac tamponade?
1. Ruptured aortic aneurism
2. Ruptured myocardial infarct
3. Penetrating injury
54
Can any blood born pathogen have potential access to the pericardial sac?
YUP
55
What are the 5 signs of cardiac tamponade?
1. Elevated venous pressure
2. Distended neck veins
3. Distant heart sounds
4. Patient in variable degrees of shock
5. Decreased arterial and pulse pressures
56
What does pathognomic mean?
Characteristic for a particular disease
57
Is the elevated venous pressure a pathognomic sign of cardiac tamponade?
YUP
58
Is the decrease arterial and pulse pressures a pathognomic sign of cardiac tamponade? What does this mean?
NOPE
Unreliable for diagnosis
59
What is pulse pressure?
The difference between the systolic and diastolic pressure readings
60
Where exactly is pericardiocentesis performed? Why? Other name for this area?
Bare area of the pericardium = Larrey's area => just inferior to the 5th rib (5th intercostal space) about 1 inch to the left of the sternum
No lung overlying this area
61
What is an aneurysm? Vessels in which this is most commonly found? Long-term consequence?
Excessive sac-like localized enlargement of a vessel due to vessel weakening
Most commonly found in abdominal aorta and carotid arteries
LT consequence: bursting due to gradual worsening of the weakening of the wall
62
What is a ruptured myocardial infarct?
TBD
63
What does "in extremis" mean?
In extreme circumstances; especially: at the point of death
64
How does venous pressure increase during cardiac tamponade?
Linearly
65
What is jugular venous distention called? When is this observed?
Kussmaul's sign
During inspiration, when the venous pressure in the jugulars is supposed to decline
66
What are the 4 signs of pericarditis?
1. Atypical chest pain
2. High-pitched friction rub
3. Effusion (mimics cardiac tamponade)
4. Exudate associated with acute disease
67
To where can the fluid in the pericardial space drain to?
Two cardiac sinuses = spaces created by the reflections of the serous pericardium
68
Where are the borders of the 2 cardiac sinuses?
Where the visceral pericardium extends off the surface of the heart to become continuous with the parietal pericardium
69
What are the 2 cardiac sinuses? Where is each located?
1. Oblique pericardial sinus: formed by reflections onto the pulmonary veins: inferior to the level of the pulmonary veins, posterior to the heart
2. Transverse pericardial sinus: separates arteries from veins, superior to the level of the pulmonary veins, posterior to the pulmonary trunk/ascending aorta between them and the SVC
70
Are the 2 cardiac sinuses connected?
NOPE
71
How is one of the cardiac sinuses exploited during bypass surgery?
The location of the transverse one is exploited as a surgical clamp is introduced into the space and blood flow of the aorta/pulmonary trunk is stopped momentarily before great vessels are connected to the bypass machine
72
Describe the heart borders in the anatomical position.
1. Right border: right atrium
2. Anterior border: right ventricle
3. Left border: left ventricle
73
Can one see the left atrium from the anterior view of the heart in anatomical position?
NOPE (very very small portion)
74
Why does the heart need its own blood supply instead of just using the blood inside of it?
Because its walls are so thick that the blood does not have time to diffuse across the heart tissue
75
Are the roots of the great vessels inside the pericardium?
YUP
76
Where do the coronary arteries reside?
Grooves, or sulci, on the surface of the heart
77
How were the sulci on the surface of the heart produced?
By tissue folding during embryonic development
78
What are the 2 sulci of the surface of the heart? Describe the position of each.
1. Coronary sulcus: between the atria and the ventricles circumscribing the entire heart
2. Interventricular sulcus: between the ventricles on both the anterior and posterior surfaces of the heart
79
What is another name for the coronary sulcus?
Atrioventricular sulcus
80
What are the 2 coronary arteries?
Right and left
81
What arteries does the left coronary artery give rise to? Describe their location.
1. Left anterior descending (LAD) artery: in the interventricular sulcus traveling inferiorly
2. Circumflex branch artery: in the atrioventricular sulcus, traveling posteriorly
82
Where is the right coronary artery located? What branches does it give rise to?
Located in the atrioventricular sulcus and gives rise to:
1. Sinoatrial node branch: traveling superior to SA node near the origin of the right artery
2. Right marginal branch: traveling anteriorly and inferiorly along the surface of the right ventricle
3. Posterior interventricular branch (PIB) traveling inferiorly in the posterior interventricular sulcus and supplying the AV node
83
Which coronary artery is called the widow maker?
LAD
84
What does heart dominance refer to?
Refers to which side of the heart is responsible for giving rise to the posterior interventricular artery
Most people (85%) are right heart dominant
85
What are the 4 major branches of the coronary veins? Describe their location and size.
1. Great cardiac vein: LARGE, in the anterior interventricular sulcus
2. Middle cardiac vein: MEDIUM, in the posterior interventricular sulcus
3. Small cardiac vein: SMALL, along the inferior margin of the heart
4. Anterior cardiac veins: SMALL, on anterior border of RA and RV
86
Which are more superficial: coronary arteries or veins?
Veins
87
Where do all of the cardiac veins drain?
All in the coronary sinus of the RA, except for the anterior cardiac veins which drain directly into the RA
88
Where is the coronary sinus located?
Runs along the posterior atrioventricular sulcus, medial to the IVC
89
What is another name for the left anterior descending (LAD) artery
Anterior interventricular artery
90
Where are marginal branches of the coronary arteries located?
Run towards the apex of the heart
91
From which branch does the posterior interventricular branch arise in left heart dominant patients?
The circumflex artery
92
Can people be heart co-dominant?
YUP, but very rare
93
How to assess whether there is a circulatory issue in the coronary vessels?
Angiogram
94
What is angiogram?
Imaging technique used to assess the blood flow through any vessel by injecting a contrasting dye into the vessels, which will spread if there is no blockage or clot
95
How are the coronary arteries accessed in an angiogram?
Catheter is inserted into the femoral artery and passed in a retrograde manner through the aorta into the coronary arteries (VERY invasive)
96
What is an angiogram of arteries called?
Arteriogram
97
What area will be oxygen deprived by a blood clot or plaque that occludes a vessel?
The area DISTAL to the blood clot
98
What is it called when a blood clot or plaque blocks coronary artery circulation?
Myocardial ischemia
99
What is a major risk factor for myocardial ischemia?
High blood cholesterol
100
Who performed the first angiogram of the heart?
Werner Theodor Otto Forssman (later became a Nazi)
101
What are the 6 sites of coronary occlusion in order of frequency?
1. Anterior interventricular branch of the left coronary artery (or LAD) (40-50%)
2. Right coronary artery (30-40%)
3. Circumflex branch of the left coronary artery (15-20%)
4. Left coronary artery
5. Posterior interventricular branch of the right coronary artery
6. Marginal artery branch of the right coronary artery
102
What is a common complication of coronary ischemia? How fast does this occur?
Ischemic necrosis of the heart (tissue death)
Within 20-30 min after occlusion
+ cardiac tamponade
103
What is the clinical presentation of myocardial ischemia?
1. Angina pectoris = pressure, discomfort, or feeling of choking in the left chest that radiates to the left shoulder and arm as well as the neck, jaw/teeth, abdomen, and back (referred pain)
2. Shortness of breath
3. Nausea/vomiting
4. Perspiration
5. Weakness, collapse, coma
104
Where does MI usually begin? Why?
In the subendorcardium because most poorly perfused region of the ventricular wall
105
What is the patency of vein grafts?
7 to 9 years
106
What are the 3 treatments for myocardial ischemia?
1. Coronary artery by-pass surgery
2. Percutaneous transluminal angioplasty
3. Stents
107
What is another name for coronary artery by-pass surgery?
Cabbage
108
Describe coronary artery by-pass surgery.
The internal thoracic artery (right or left) or the great saphenous vein (right or left) are used as graft to create an alternate path for blood to flow around the occluded coronary artery.
109
What needs to be done if the great saphenous vein is used during coronary artery by-pass surgery?
Reverse the direction of the vein since it has valves OR turn it inside out
110
Where is the great saphenous vein found?
The thigh
111
Which has better long-term results: coronary artery by-pass surgery using the great saphenous vein or the internal thoracic artery? Why?
Internal thoracic artery, because:
1. Arterial grafts so do not have valves
2. Better match size
3. Easy to harvest
4. Low vasoconstrictor sensitivity and high vasodilator sensitivity
112
Describe percutaneous transluminal angioplasty.
Method in which a deflated balloon catheter is placed in the vessel blockage and inflated to crush the blockage to re-establish circulation
113
What is saphenous vein graft disease? Treatment?
Complication after coronary artery by-pass surgery where the vein presents a diffuse and friable plaque and often a thrombus
Treatment: stents
114
Describe how stents are used in the coronary arteries. When is this often done?
Stent often coated with anticoagulants is inserted using a catheter in the femoral artery and placed at the site of blockage to help the vessel stay patent (usually during the angioplasty intervention)
115
What is a major complication of stents? Who does this often happen to?
If the patient has an accident he will bleed very quickly (usually to death) because of the anticoagulants on the stent
Elderly who fall a lot or have another type of surgery
116
How are the heart chambers arranged in the anatomical position?
Like a cross (counter clockwise starting at 12): LA - LV - RV - RA
117
What is the anterior chamber of the heart?
RV
118
What is the posterior chamber of the heart?
LA
119
Which heart chamber is most often contused in car accidents?
RV
120
What is a contusion?
A region of injured tissue or skin in which blood capillaries have been ruptured
121
Diastole?
Ventricular relaxation and filling with atrial contraction at the end
122
Systole?
Ventricular contraction and emptying
123
When are the atria directly above the ventricles?
Oblique cut of the heart
124
What are the 4 components of the RA?
1. Pectinate muscles
2. Fossa ovalis
3. Cristae terminalis
4. Vessels that drain into the RA
125
What are the 4 vessels that drain in the RA? Where are they located?
1. SVC
2. IVC
3. Coronary sinus
4. Anterior cardiac veins
Posterior wall
126
Where are the pectinate muscles located in the RA? Function?
Horizontal rough inner surface of the anterior wall
Allow for atrial contraction
127
What is the thinnest portion between the RA and LA?
Fossa ovalis
128
What are the cristae terminalis?
Longitudinal smooth raised ridge running superior to inferior on the lateral border of the RA and separates the anterior and posterior walls
129
Other name for pectinate muscles?
Musculi pectinati
130
Where is the fossa ovalis located in the RA?
Posterior wall
131
What % of coronary circulation returns to the heart via the coronary sinus?
95%
132
What are the 4 components of the RV?
1. Tricuspid valve
2. Papillary muscles/chorda tendinae
3. Septomarginal trabecula
4. Trabeculae carneae
133
What are the different cusps of the tricuspid valve?
1. Anterior
2. Posterior
3. Septal
134
By what are the 3 cusps of the tricuspid valve connected to the papillary muscles?
Via cordae tendinae
135
What is another name for the septomarginal trabecula?
Moderator band
136
Function of septomarginal trabecula?
Connects the interventricular septum to the base of the anterior papillary muscles
137
What does the septomarginal trabecula contain? Function?
The right bundle of the conducting system of the heart => carries signals for muscle contraction to the papillary muscles
138
What are the trabeculae carneae? Function?
Muscular ridges roughening the inner surfaces of the RV wall to help support the walls of the ventricles
139
How do the papillary muscles work?
Contract to prevent cusps from prolapsing back into the RA during ventricular contraction => aka they hold the cusps shut (but do not actively close them) to prevent them from leaking when the heart contracts
140
What does failure of the papillary muscles lead to?
Valve prolapse, which we hear as a heart murmur
141
What are the 4 components of the LV?
1. Mitral valve
2. Papillary muscles/chorda tendinae
3. Septomarginal trabecula
4. Trabeculae carneae
142
Other name for mitral valve?
Bicuspid valve
143
What are the different cusps of the mitral valve?
1. Anterior
| 2. Posterior
144
Difference between papillary muscles in RV and LV? Explain why.
Not as prominent in LV because the left ventricle wall is thicker, so the papillary muscles are located closer to the mitral valve
145
Difference between muscular wall in RV and LV?
Much thicker in LV
146
What is unique about the LA compared to the other heart chambers?
1. It does not sit on the diaphragm (large gap between the 2)
2. It rests directly on the esophagus posteriorly (soft vertical bump on LA if you remove the heart) - both are perpendicular to each other
147
What is a common cause of LA enlargement? Explain.
How to diagnose? Common symptom?
Mitral valve stenosis: blood backs up in LA and causes it to grow larger
Diagnosis using PA chest X-ray which will show double shadow of the LA
Symptom: trouble swallowing (drink fluids to help)
148
What is the only organ that receives the ENTIRE cardiac output?
Lungs
149
Are the 2 pumps of the heart arranged in series or parallel? Implication?
Series: the LV must receive the same amount of blood per beat as the RV
150
Only veins in body to carry oxygenated blood?
Pulmonary veins
151
What does vein mean?
Carries blood to the heart
152
What does artery mean?
Carries blood away from the heart
153
Which AV valve is stronger: tricuspid or mitral? Why? Implication?
Mitral because it only has 2 cusps and needs to withstand so much more pressure
Increase in pressure from LA to LV is 10x higher
154
What are the 2 semilunar valve?
1. Pulmonary valve
| 2. Aortic valve
155
What does the SVC drain?
Body above diaphragm, excluding the heart, lumbar azygos, and hemiazygos veins
156
What does the IVC drain?
Body below diaphragm
157
What 2 factors propel blood from atria to ventricles?
1. Gravity
| 2. Contraction
158
How do heart valves open and close
Respond to differences in BPs on either side of the valves
159
How do the semilunar valves work?
- Ventricular contraction causes their cusps to flatten against great vessel walls
- Ventricular relaxation causes blood to backflow and shut them closed
160
Do both atrioventricular valves close at the same time?
NOPE, mitral closes slightly before and opens slightly after
161
Do both semilunar valves close at the same time?
NOPE, aortic closes slightly before and opens slight after
162
What allows the 4 heart valve closures to be distinctly heard with a stethoscope?
The difference in timing of their closing
163
What is the lub sound of the heart?
AV valves closing
164
What is the dub sound of the heart?
Semilunar valves closing
165
Describe the 5 steps of the cardiac cycle.
1. Beginning of diastole: closure of semilunar valves
2. Early diastole: opening of AV valves
3. Late diastole: atrial contraction
4. Early systole: closure of AV valves
5. Systole: ventricular contraction and opening of semilunar valves
166
What plane do ALL the heart valves lie on?
Plane of coronary sulcus
167
Are the heart valves heard at the skin level where they are located?
NOPE, downstream from the blood flow
168
Where to listen to aortic valve?
Right side of sternum below rib 2
169
Where to listen to tricuspid valve?
Left side of sternum below rib 5
170
Where to listen to mitral valve?
Bare area of the pericardium = just inferior to the 5th rib about 1 inch to the left of the sternum
171
Where to listen to pulmonary valve?
Left side of sternum below rib 2
172
Describe the conduction system of the heart.
Composed of series of specialized cardiac muscle cells that carry impulses throughout the heart muscle signaling heart chambers to close in proper sequence
173
What are the 6 components of the heart conduction system?
1. Sinoatrial node (SA)
2. Internode fibers
3. AV node
4. Atrioventricular bundle
5. R and L bundle branches
6. Subendocardial branches of Pujinke fibers
174
What component of the heart conduction system is the pacemaker?
SA node
175
Where is the SA node location?
RA wall, near SVC entry
176
How do heart cells beat at baseline?
At their own rate (with ventricle cells at a lower rate than atrial cells)
177
Describe the pathway of the heart conduction system.
Impulse signaling begins at SA node => impulses spread in a wave along cardiac muscle fibers of atria, signaling atria to contract => some impulses travel along the internodal pathway => AV node => impulse delay for fraction of a second => impulses pass through the AV bundle => impulses divide into R and L bundle branches => halfway through septum they become the subendocardial branches of Purjinke fibers => subendocardial branches approach heart apex and arc superiorly to ventricular walls => ventricular myocardial contraction begins at apex in endocardium and then epicardium
178
Other name for AV bundle?
Bundle of His
179
Other name for R and L bundle branches?
Crura
180
Purpose of impulse delay at AV node?
Allows ventricles to fill completely
181
Is the fibrous skeleton between atria and ventricle conducting? Implication?
NOPE, so only the impulses that follow the AV node can continue on the pathway
182
What is a heart block? Treatment?
Damage to either the AV node or AV bundle causing the ventricles to beat slower than the atria
Treatment: pacemaker
183
What would cause the AV node to die?
Occlusion of the posterior interventricular artery
184
How does an artificial pacemaker work?
2 leads:
- One activates the pacemaker
- One activates the AV node
185
What does pulmonary edema indicate?
Mitral valve stenosis
186
What is cardiopulmonary congestion? What is it a feature of? Symptom?
Blood fills up in the lungs
Feature of left heart failure
Symptom: trouble breathing, especially when they lay down and systemic hypoperfusion
187
What can it mean when a patient intuitively grabs onto something to support them while standing?
Left heart failure
188
Signs of right heart failure?
SYSTEMIC CONGESTION and PULMONARY HYPOPERFUSION:
1. Cyanotic patients = blue
2. Bilateral jugular vein distention
3. Enlarged liver
4. Ascites
5. Pitting edema on legs, ankles, and feet
189
Where does fluid go during systemic hyperperfusion?
Serosal cavities:
1. Pleura = pleural effusion
2. Pericardium = pericardial effusion
3. Peritoneal cavity = ascites
