Cardiopulmonary Anatomy Flashcards
1
Q
Describe the mediastinum
A
- Central compartment of thoracic cavity b/w 2 pulmonary cavities
- Superior part is above T4-T5
- Inferior part is divided into anterior, middle, & posterior
- Pericardium & its contents constitute the middle mediastinum
2
Q
Describe the pericardium
A
- Closed sac with two layers
- Fibrous layer: tough external layer that protects the heart against sudden overfilling
- Serous layer: parietal and visceral layer
- Pericardial cavity: b/w the serous layers that contains a thin film of fluid that enables the heart to move/beat in a frictionless environment
3
Q
Describe a cardiac tamponade (heart compression)
A
- Extensive pericardial effusion doesn’t allow full expansion of the heart limiting the amount of blood the heart can receive which reduces cardiac output
- Potentially lethal condition bc heart volume is increasingly compromised by the fluid outside the heart but inside the pericardial cavity
4
Q
If the increase in fluid is rapid as little as _______ml of fluid can result in tamponade
A
- 200ml
5
Q
Describe the role/importance of the fibrous skeletal of the heart
A
- Used as an anchor for cardiac muscle fibers
- Provides attachment for leaflets and cusps of valves
- Forms electrical “insulator” separating conduction of impulses in atria from ventricles
6
Q
What are the nerve supply of the pericardium
A
- Phrenic nerve (C3-C5): primary sources of sensory/pain fibers with pain referring to C3-C5 dermatomes of the ipsilateral supraclavicular region
- Vagus nerve
- Sympathetic trunks of vasomotor
7
Q
List the order of circulation through the heart from right to left
A
- Venous systemic circulation (less O2)
- Vena Cavae (less O2)
- R Atrium (less O2)
- R ventricle (less O2)
- Pulmonary circulation (both/reoxygenation)
- L Atrium (O2)
- L ventricle (O2)
- Arterial systemic circulation (O2)
8
Q
Describe the role/importance of the R Atrium
A
- Receives venous blood from SVC (enters at 3rd costal cartilage), IVC (enters at 5th costal cartilage), & coronary sinus
- Sinus centrum: smooth, thinned wall
- Pectinate muscles: rough, muscular anterior wall
- Interatrial septum separates the atria and has the oval fossa which is a remnant of the oval foramen & its valve in the fetus
9
Q
Describe the R ventricle role/importance
A
- Conus arteriosus: superior, leads to pulmonary trunk
- Trabecular carneae: irregular muscular elevations
- Tricuspid valve: guards R AV Orifice
10
Q
where do the anterior, posterior, and septal cusps of the tricuspid valve attach to
A
- Fibrous ring of orifice
11
Q
Describe the role/importance of the tricuspid valve
A
- Attached to corresponding papillary muscles via chordae tendinae
- Prevents regurgitation of blood from the R ventricle back into the R atrium during ventricular systole
12
Q
Describe the pulmonary valve role/importance
A
- Semilunar valve with 3 cusps: no tendinous cords for support
- Situated at the apex of the conus arterioles at the level of the L 3rd costal cartilage
13
Q
What 2 valves are semilunar valves
A
- Pulmonary
- Aortic
14
Q
How to semilunar valves work/role
A
- After relaxation of the ventricle the elastic recoil of the wall of the pulmonary trunk or aorta forces the blood back toward the heart
- Cusps snap closed like an umbrella caught in the wind as they catch the reversed blood flow
15
Q
Describe the blood flow/relationship between the R atrium and R ventricle
A
- Inflow of blood into R ventricle enters posteriorly
- When the ventricle contracts the outflow of blood into the pulmonary trunk leaves superiorly and to the L
16
Q
Describe the structures of the interior of the L atrium
A
- 4 pulmonary veins (2 superior, 2 inferior) entering the smooth posterior wall (valveless entry)
- Slightly thicker wall than R atrium
- Interracial septum that slopes posteriorly to the R
17
Q
Describe L atrial appendage & atrial fibrillation
A
-
18
Q
Describe the structures of the interior of the L ventricle
A
- Walls are 2-3x thicker than R ventricle
- Walls mostly covered with mesh of trabeculae carneae more numerous/finer than R ventricle
- Conical cavity longer than R ventricle
- Double leaflet mitral valve that guards the L AV orifice
- Aortic orifice on the R posterosuperior aspect where the ascending aorta begins
19
Q
Describe the role/relationship b/w the L atrium and L ventricle
A
- L AV orifice: Orifice which the L atrium discharges O2 blood it receives from the pulmonary veins into the left
- L ventricle outflow tract: aortic vestibule = smooth, nonvascular, superoanterior outflow part; leads from ventricular cavity to aortic orifice & aortic valve
20
Q
Describe the role/importance of the mitral valve
A
- L AV valve
- Posterior to sternum at level of 4th costal cartilage
- Each cusps receives tendinous cords from more than one papillary muscle
- Cords become taut just before/during systole to prevent cusps from being forced into L atrium
21
Q
Describe the aortic valve
A
- Semilunar (3 cusps)
- Posterior to L aspect of sternum at level of 3rd intercostal space (obliquely oriented)
22
Q
Which valves are open versus closed during diastole
A
- Mitral & tricuspid valves are OPEN allowing ventricular filling
- Pulmonary & aortic valves are CLOSED (“Dub”)
23
Q
Which valves are open versus closed during systole
A
- Mitral & tricuspid valves are CLOSED (“Lub”)
- Pulmonary & aortic valves are OPEN allowing pulmonary & systemic circulation
24
Q
What structures does the R coronary artery supply
A
- R atrium
- most of R ventricle
- part of the L ventricle (the diaphragmatic surface)
- part of the IV septum, usually the posterior third
- SA node (in approximately 60% of people)
- AV node (in approximately 80% of people)
25
Q
What structures does the L coronary artery supply
A
- L atrium
- most of the left ventricle
- part of the right ventricle
- most of the IVS (usually its anterior two thirds), including the AV bundle of the conducting system of the heart, through its perforating IV septal branches
- SA node (in approximately 40% of people)
26
Q
What are the branches of the R coronary artery
A
- Sino-Atrial (SA) Nodal Branch
- Atrioventricular (AV) Nodal Branch
- Right Marginal Branch
- Posterior Interventricular Branch (Posterior Descending Artery)
27
Q
What are the branches of the L coronary artery
A
- Circumflex Branch
- Anterior Interventricular Branch (Left Anterior Descending (LAD) AKA “Widow Maker”
- Left Marginal Branch
- Posterior Interventricular Branch
28
Q
How is the heart primarily drained
A
- Mainly by veins that empty into the coronary sinus and partly by small veins that empty into the right atrium
29
Q
Describe the coronary sinus
A
- It’s the main vein of the heart, is a wide venous channel that runs from left to right in the posterior part of the coronary sulcus
30
Q
What is the correct order of conduction through the heart
A
- SA node: pacemaker (~70 bpm)
- AV node: secondary pacemaker (40-60 bpm)
- Atrioventricular bundle of His: bridge b/w atrial & ventricular myocardium
- R bundle
- L bundle
- Subendocardial branches (AKA Purkinje fibers): penetrate the myocardium & stimulate muscle contraction form the apex upward toward the base of the heart in a “wringing” action
31
Q
What is the normal pacing ability of the SA node at rest
A
- 60-100 bpm
32
Q
What is the main function of the AV node during each cardiac cycle
A
- To slow down the cardiac impulse to mechanically allow time for the ventricles to fill
33
Q
Describe the P-wave on EKG/ECG
A
- Represent atrial depolarization and mechanical atrial contraction
- In sinus rhythm a p-wave precedes each QRS complex
34
Q
Describe the PR interval on EKG/ECG
A
- From the start of the P-wave to the start of the Q-wave
- Represents the time taken for electrical activity to move b/w the atria & ventricles
- AV node delays conduction of impulse from atria shown as the isoelectric line following the P-wave before the QRS complex
35
Q
Describe the QRS complex on EKG/ECG
A
- Represents depolarization of the ventricles caused by the R/L bundle branches
- Seen as three closely related waves on the ECG
36
Q
Describe the ST segment on EKG/ECG
A
- Starts at the end of the S-wave and ends at the start of the T-wave
- An isoelectric line that represents the time b/w depolarization & repolarization of the ventricles (i.e. contraction)
37
Q
Describe the T-wave on ELG/ECG
A
- Represents ventricular repolarization
- Seen as a small wave after the QRS complex
38
Q
Describe the RR interval on EKG/ECG
A
- Starts at the peak of one R wave and ends at the peak of the next R wave
- Represents the time b/w 2 QRS complexes
39
Q
Describe the QT interval on EKG/ECG
A
- Starts at the beginning of the QRS complex & finishes at the end of the T-wave
- Represents the time taken for the ventricles to depolarize & then repolarise
40
Q
At what points during a normal EKG does the atria and ventricles activate
A
- Just before the P-wave the ventricles fill passively
- ~the end of the P-wave the atria contracts to eject up to 20% of the end diastolic ventricular volume (atrial kick)
- Shortly after onset of the QRS complex a period of isovolumic ventricular contraction begins
- Ventricular ejection coincides with the early portion of the ST segment
41
Q
What are the 5 areas that heart auscultations are best heard from
A
- Aortic area: second intercostal space close to the sternum on the right of the sternum
- Pulmonary area: second intercostal space to the left of the sternum
- 3rd L intercostal space: murmurs of both aortic and pulmonary origin are best heard here
- Tricuspid area: located at the lower-left sternal border, approximately the fourth to fifth intercostal space
- Mitral area (apex of heart): located in the fifth left intercostal space, medial to the midclavicular line
42
Q
Describe the cardiac plexus
A
- Formed by both sympathetic & parasympathetic fibers going towards the heart & visceral afferent fibers conveying reflexive/nocioceptiive fibers from the heart
- Located on posterior aspect of ascending aorta & pulmonary trunk
- Fibers extend from the plexus to the coronary vessels & to the SA node
43
Q
What does sympathetic stimulation influence in the heart
A
- C2-T4 ganglia
- Triggers release of catecholamines (epinephrine & norepinephrine)
- Increased heart rate
- Increased impulse conduction
- Increased force of contraction
- Increased blood flow through the coronary vessels to support the increased activity
44
Q
What does parasympathetic stimulation influence in the heart
A
- Vagus nerve (CN X)
- Triggers release of acetylcholine
- Slows the heart rate
- Reduces the force of the contraction
- Constricts the coronary arteries, saving energy between periods of increased demand
45
Q
List the great vessels that connect to the cardiopulmonary system
A
- Brachiocephalic veins (R & L): L is 2x as long as R
- Superior vena cava
- Inferior vena cava
- Pulmonary trunk: pulmonary arteries (less O2)
- Pulmonary veins (O2 rich)
- Ascending aorta: coronary arteries
- Arch of aorta: brachiocephalic trunk (R common carotid artery & R subclavian artery), L common carotid artery, & L subclavian
46
Q
What is the role/purpose of the thoracic wall
A
- Protect vital organs from external forces
- Resist neg. internal pressures generated by elastic recoil from the lungs/inspiratory movements
- Provide attachment/support for the upper limbs
- Provide anchoring attachment of many muscles that move/maintain position of the upper limbs
47
Q
Describe the 3 different types of ribs
A
- True (vertebrosternal) ribs: 1-7 ribs, attach directly to the sternum through thrown costal cartilages
- False (vertebrochondrral) ribs: 8-10 ribs, cartilages are connected to the cartilage of the rib above them
- Floating (vertebral, free) ribs: 11-12 ribs, rudimentary cartilages of these ribs do not connect even indirectly to the sternum but instead end in the posterior abdominal musculature
48
Q
What is the purpose of the costal cartilage
A
- Contributes to the elasticity of the thoracic wall
- For ribs 1-10 they anchor the anterior end of the rib to the sternum
49
Q
Describe the main landmarks/anatomy of the strenum
A
- Jugular Notch: at the level of the inferior border of the body of T2 vertebra
- Manubrium: lies at the level of the bodies of T3 and T4 vertebrae
- Sternal Angle (Angle of Lous): lies at the level of the T4–T5 IV disc
marks the level of the 2nd pair of costal cartilages - Body of the Sternum: lies anterior to the right border of the heart and vertebrae T5–T9
- Xiphisternal Joint: the level of the inferior border of T9 vertebra
50
Q
Describe the sternocostal joints
A
- Synchondrosis of 1st rib: costal cartilages articulate with the manubrium by means of a thin dense layer of tightly adherent fibrocartilage interposed b/w the cartilage & manubrium
- 2-7th ribs articulate with the sternum at synovial joints with fibrocartilaginous articular surfaces on both the chondral & sternal aspects allowing movement during respiration
51
Q
The head of the rib articulates with
A
- Superior costal facet of the corresponding vertebra (ex: 7th rib and T7)
- Inferior costal facet of the vertebra superior to it (ex: 7th rib and T6)
- Adjacent intervertebral (IV) disc uniting the 2 vertebrae
52
Q
Where do the 3 main costotransverse ligaments pass through
A
- Costotransverse lig: passes from the neck of the rib to the transverse process
- Lateral costotransverse lig: passes from the tubercle of the rib to the tip of the transverse process; strengthening the anterior & posterior aspects of the joint
- Superior costotransverse lig: a broad band that joins the crest of the neck of the rib to the transfers process superior to it
53
Q
How does the thoracic wall move during inspiration/expiration
A
- Inspiration: increases in intrathoracic volume/diameter -> decreased intrathoracic pressure -> air is drawn into lungs
- Expiration: decreased intrathoracic volume -> increased intrathoracic pressure with concurrent decrease in intra-abdominal pressure -> elastic recoil of lungs -> expelling air
54
Q
How do the ribs move during inspiration/expiration
A
- Pump handle: elevation/depression of the sternal ends of the ribs/sternum in the sagittal plane; increases A-P dimensions of thorax
- Bucket handle: elevation/depresion of the lateral most portions of the ribs in the transverse plane; increases transverse dimensions of thorax
55
Q
Describe the muscles used for respiration
A
- External/internal intercostal activation is primarily isometric; their role is mostly for forced respiration and to support the intercostal space
- Diaphragm is the primary muscle of inspiration
- Expiration is passive unless exhaling against resistance
- Elastic recoil of the lungs & decompression of abdominal viscera expel previously inhaled air
56
Q
What is flail chest
A
- Multiple rib fxs that allow the anterior/lateral thoracic wall to move freely
- Loose segment of wall moves paradoxically (inward on inspiration & outward on expiration)
- Extremely painful & impairs ventilation therefor affecting oxygenation of the blood
- During tx the loose segment may be internally fixed w/plates or wires to prevent movement
57
Q
What does a chest tube remove
A
- Removes air, blood, serous fluid, and/or pus from the pleural cavity
58
Q
Describe how a chest tube is placed
A
- Short incision at 5th or 6th intercostal space in midaxillary line
- Tube can be directed superiorly or inferiorly for fluid drainage
- Extracorporeal end of tube is connected to an underwater drainage system with controlled suction to prevent air from being sucked back into the pleural cavity
59
Q
What muscles are used during inspiiration
A
- Serratus posterior superior to elevate the superior 4 ribs
- Serratus posterior superior to depress the inferior ribs
- These muscles may have more of a proprioceptive function during inspiration
60
Q
What muscles are used during forced expiration
A
- Transverse thoracis
- Transverse abdominis
- Intercostales interni (interosseous fibers)
- Obliquus externus abdominis
- Rectus abdominis
61
Q
What is tripod breathing
A
- Hands on knees breathing
62
Q
Describe the structure of the diaphragm
A
- Double domed musculotensinous partition separating the thoracic and abdominal coavities
- R dome is higher than L due to presence of the liver
- Chief muscle of inspiration
- Pericardium lies on the central part of the diaphragm depressing it slightly
63
Q
Describe the important ligaments of the diaphragm
A
- Central tendon
- Median arcuate ligament: units them as it arches over the anterior aspect of the aorta forming the aortic hiatus; fascia covering the posts major
- Lateral arcuate ligament: covers the quadrates lumborum
- Caval opening: inferior vena cava & branches of R phrenic nerve
- Esophageal hiatus: esophagus & vagus nerve trunks
- Aortic hiatus: aorta & thoracic duct
64
Q
Describe the motor and sensory innervation of the diaphragm
A
- Entire motor supply is from R/L phrenic nerves
- Pain and proprioception to the diaphragm is mostly from the phrenic nerves
- Peripheral parts of the diaphragm receive sensory supply from the intercostal nerves & subcostal nerves
65
Q
What is the role of sympathetic fibers on the lungs versus parasympathetic
A
- Sympathetic: inhibitory to the bronchial muscle (bronchodilator) and inhibitory to the alveolar glands of the bronchial tree
- Parasympathetic: motor to the smooth muscle of the bronchial tree (bronchoconstrictor); secretory tot eh glands of the bronchial tree (secretomotor)
66
Q
What is pleura
A
- Each pulmonary cavity(right and left) is lined by apleural membrane(pleura) that also reflects onto and covers the external surface of the lungs occupying the cavities
67
Q
Describe the two pleural that surround the lungs
A
- Visceral: invests all surfaces of the lungs; provides the lung with a smooth slippery surface, enabling it to move freely on the parietal pleura
- Parietal: lines the pulmonary cavities; consists of 3 parts -> costal, mediastinal, & diaphragmatic and the cervical pleura
68
Q
What is the main function of the lungs
A
- To oxygenate the blood by bringing inspired air into close relation with the venous blood in the pulmonary capillaries
- Lungs are elastic & recoil to ~1/3 their size when the thoracic cavity is opened
69
Q
What are the features of the right lung
A
- 3 lobes: superior, middle, inferior
- Larger and heavier than L lung but is shorter and wider bc the diaphragm sits higher
70
Q
What are the features of the left lung
A
- 2 lobes: superior and inferior
- Anterior border has a deep cardiac notch consequent to the deviation of the apex of the heart to the L side
71
Q
What is the hilum of the lung
A
- It’s a hedge-shaped area on the mediastinal surface of each lung through which the structures forming the root of the lung pass to enter or exit the lung
- Pulmonary arteries, pulmonary veins, bronchial vessels, & bronchi
72
Q
Describe the trunk and branches of the tracheobronchial tree
A
- Trachea is the trunk and bifurcates at the level of the sternal angle into main bronchi (one for each lung)
- R main bronchus: wider & shorter and runs more vertically then the L as it passes directly to the hilum of the lung
- L main bronchus: passes inferolaterally inferior to the arch of the aorta & anterior to the esophagus & thoracic aorta to reach the helium of the lung
73
Q
Each main (primary) bronchus divides into secondary lobar bronchi which are
A
- 2 on L and 3 on R, each of which supplies a lobe of the lung
- Each lobar bronchus divides into several tertiary segmental bronchi that supply the bronchopulmonary segments
74
Q
Describe the structure/importance of the bronchioles
A
- 20-25 generations that eventually end as terminal bronchioles (smallest conducting bronchioles)
- Lack cartilage in their walls
- Conducting bronchioles transport air. but lack glands or alveoli
- Each terminal bronchiole gives rise to several generations of respiratory bronchioles with scattered, thin walled outpocketings (alveoli) that extend from their lumens
- Each respiratory bronchiole gives rise to 2–11alveolar ducts, each of which gives rise to 5–6 alveolar sacs
- Alveolar ductsare elongated airways densely lined with alveoli, leading to thealveolar sacs,into which clusters of alveoli open.
75
Q
What is the basic structural unit of gas exchange in the lung
A
- Pulmonary alveolus
76
Q
What is the correct order of the pulmonary circulation
A
- R/L pulmonary arteries carry low-O2 blood to the lungs for O2
- Lobar arteries (less O2)
- Segmental arteries (less O2)
- Pulmonary capillary beds within alveolar walls (mixed blood)
- Segmental veins (O2 rich)
- Lobar veins (O2 rich)
- Superior & inferior pulmonary veins on each side carry O2 rich blood from corresponding lobes of each lung to the L atrium of the heart
77
Q
What does elevation versus depression of the ST segment on an EKG/ECG indicate
A
- ST elevation = MI
- ST depression = heart ischemia
