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Heart , trachea, and lung
I.
Landmarks - know projection of heart on thoracic wall
A. apex - about 8 cm (range 5.5 - 12.5 cm) from the median plane in left fifth
intercostal space
B. base - the posterior aspect of the heart; mainly formed by the left atrium and a small
part of the right atrium.
1. pulmonary veins, the superior vena cava, and inferior vena cava connect with
the base
C. inferior border - marked by a line slopping caudally and to the left through the
xiphosternal border
D. right border (margin) - about 3 cm to the right of the sternal border
E. left border (margin) - angles superiorly from the apex to the second intercostal
space, 3 cm from the sternal margin
F. beginning of the ascending aorta - at level of the third intercostal space and marks
the superior border
G. pericardium - same as heart except superiorly where it goes beyond the base to end
on the great vessels under the second costal cartilage
H. heart valves
1. pulmonary valve
a. located near the left side of the sternum at the level of the 3rd costal cartilage
b. listen in the second intercostal space on the left
2. aortic valve
a. located near the left side of the sternum at the level of the 3rd intercostal space
b. listen in second intercostal space on the right
3. mitral valve
a. located near the left side of the sternum at the level of the 4th costal cartilage
b. listen in the 5th intercostal space about 3½ inches to the left of the midline
4. tricuspid valve
a. located behind the sternum at the level of the 4th intercostal space
b. listen over the lower left border of sternum
II.
Arteries of the heart
A. right coronary artery
1. marginal branch runs along the acute margin
2. sinoatrial nodal artery (60% from the proximal portion of the right coronary
artery, 40% from the beginning of the left circumflex artery
3. posterior interventricular branch runs in the interventricular sulcus
4. right posterolateral branches supply the posterior inferior wall of
ventricle
5. atrioventricular nodal branch - in 80% of population
B. left coronary artery
1. anterior interventricular branch sends off the anterior perforating branches
and the diagonal branch
2. circumflex branch
a. marginal branch
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3. posterior left ventricular branch (not constant)
III. Veins of the heart - terminate principally in the coronary sinus
A. great cardiac vein - begins in the anterior interventricular sulcus and travels with
the anterior interventricular artery, then the circumflex artery
B. middle cardiac vein - begins in the posterior interventricular sulcus and travels
with the posterior interventricular artery
C. small cardiac vein - in the posterior right coronary sulcus with the right coronary
artery
D. posterior vein of the left ventricle
E. oblique vein of the left atrium runs over posterior wall of left atrium
F. anterior cardiac veins - drain blood from the anterior wall of the right ventricle
and open directly into the right atrium
G. smallest veins - are in the walls of the right heart
IV.
Chambers of the heart - the heart is divided into two receiving chambers, atria, and
two pumping chambers, ventricles
A. right atrium receives deoxygenated blood from the body (via the superior and
inferior vena cava) and the heart (via the coronary sinus, mostly); its interior has
1. sinus venarum smooth part between the two vena cava
2. crista terminalis - internal to the sulcus terminalis
3. pectinate muscles (musculi pectinati) - bundled muscle fibers in the auricle
4. opening of the superior vena cava
5. opening of the inferior vena cava and its valve
6. ostium for the coronary sinus and its valve
7. fossa ovale and limbus of the fossa ovale
8. sinoatrial node and atrioventricular node
B. right ventricle - receives blood from the right atrium and pumps it to the lungs via
the pulmonary artery
1. right atrioventricular (tricuspid) valve
2. trabecula carnae - thick muscle bundles giving the ventricle its rugged texture
3. septomarginal trabecula (septal limb and moderator band) - goes from the
interventricular septum to the root of the anterior papillary muscle and carries
the right bundle branch
4. papillary muscles - conical projections of ventricular muscle related to the
cusps (anterior, posterior, and septal)
5. chorda tendinae - fibrous cords attaching papillary muscles to the valve cusps
6. infundibulum (conus arteriosus, outflow tract)
a. smooth portion of the right ventricle just inferior to the pulmonary valve
b. separated from the rough, trabecular portion (inflow tract) by the
supraventricular crest
7. pulmonary orifice - guarded by the pulmonary valve
C. left atrium - receives oxygenated blood from the lungs via the pulmonary veins
1. The smooth-walled portion receives oxygenated blood from the four pulmonary
veins
2. auricle - has pectinate muscles
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3. valve of the foramen ovale
D. left ventricle receives blood from the left atrium and pumps it throughout the
body via the aorta
1. left atrioventricular valve (mitral or bicuspid valve)
2. trabecula carnae
3. papillary muscles (anterior and posterior) and chorda tendinae
4. aortic vestibule (outflow tract) - smooth (non-trabecular) portion just inferior to
the aortic valve. The anterior mitral cusp separates the aortic vestibule from the
inflow tract.
5. membranous part of the interventricular septum is right below the right and
posterior cusps of the aortic valve.
V.
Valves of the heart
A. atrioventricular valves
1. separate the atria from the ventricles and insure that blood flows only from the
atria to the ventricles
2. valves have rings, cusps, chorda tendinae, and papillary muscles
a. papillary muscles are the only active part
3. right atrioventricular or tricuspid valve (three cusps)
4. left atrioventricular valve or mitral or bicuspid valve (two cusps)
B. semilunar valves -each has three cusps with nodules
1. pulmonary valve - has anterior, right, and left cusps
2. aortic valve - has posterior, right, and left cusps. Openings for the right and left
coronary arteries are in the aortic sinuses.
VII. conduction system of the heart - specialized cardiac muscle cells form nodes and
bundles which initiate and conduct the impulses through the heart
A. sinoatrial node (pacemaker) - at the junction of the superior vena cava and right
atrium, near the end of the sulcus terminalis just deep to the epicardium
B. atrioventricular node - at the right side of the interatrial septum above and in front
of the opening for the coronary sinus
C. atrioventricular bundle (Bundle of His)
1. runs below the membranous part of the interventricular septum
2. divides into the right and left bundle branches
a. right bundle branch
(1) cord-like and runs on the moderator band
(2) connects with the Purkinje fiber network of the right ventricle
b. left bundle branch
(1) wider than the right bundle branch
(2) divides into anterior and posterior fascicles on left surface of the
interventricular septum
(3) connects with the Purkinje fiber network
VIII. nerves of the heart - these modify the hearts intrinsic rhythmicity
A. cardiac nerves -from the vagus and sympathetic chain
B. cardiac plexus
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C. coronary plexus
IX. Trachea and primary bronchi
A. trachea
1. inside diameter of 3 mm at birth and about 12 mm in adults
2. 10 - 12 cm long in adults, beginning at C6, ending at upper T5
3. has 16 - 20 C-shaped cartilages deficient in back part, next to the esophagus
a. the last cartilage is the carina
4. angle of transition from the trachea to primary bronchus
a. subcarinal angle is 62 degrees
b. 25 degrees from vertical center for the right bronchus (more vertical)
c. 37 degrees from vertical center for the left bronchus (more horizontal)
B. right primary bronchus
1. is wider, shorter (2.5 cm) and more vertical than the left bronchus
2. enters the right lung opposite T5
C. left primary bronchus
1. is narrower, longer (5 cm), and less vertical than the right bronchus
2. enters the left lung opposite T6
X.
Lungs
A. each lung has an apex, which projects above the clavicle but not above the neck of
the first rib
B. costal surface is separated
1. anteriorly from the mediastinal surface by the anterior margin
2. inferiorly from the diaphragmatic surface by the inferior margin
C. are free in the pleural cavities, except at the hilus, which contains the root of each
lung and the pulmonary ligament
D. mediastinal surface is marked by the structures to which it is related
E. right lung - two fissures separate the lung into three lobes
1. three lobes
a. upper lobe -served by three segments: apical, posterior, and anterior
b. middle lobe -served by two segments: lateral and medial
c. lower lobe - served by five segments: superior, medial basal, anterior
basal, lateral basal, and posterior basal
2. two fissures
a. oblique fissure
(1) separates the upper and middle lobes from the lower lobe
(2) starts at the fifth rib or higher posteriorly, follows the sixth rib to reach
the diaphragmatic border anteriorly
b. horizontal fissure
(1) separates the middle from the upper lobe, beginning at the sixth rib in the
mid-axillary line and ending at the fourth rib behind the sternum
F. left lung - an oblique fissure separates the lung into two lobes
1. upper lobe - served by four segments: apico-posterior, anterior , superior
lingular, and inferior lingular
2. lower lobe - served by five segments (named the same as the right lung)
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XI.
a bronchopulmonary segment is a part of a lung served by one segmental bronchus
and its accompanying segmental artery
A. can be separated from the rest of the lung by blunt dissection in normal living lung
B. veins tend to be intersegmental
XII. Blood supply
A. right pulmonary artery
1. at the root of the lung it is inferior to the primary (epiarterial) bronchus
B. left pulmonary artery
1. at the root of the lung it is anterior and superior to the primary bronchus
C. bronchial arteries
1. 2 left branches and 1 right branch
2. the left branches cone directly off the aorta
3. right branch comes off an intercostal artery or one of the left bronchial arteries
4. supply blood to bronchi, areolar tissue, bronchial lymph nodes, and esophagus
a. nutrition is its most important duty for the alveoli since they already have air
D. two pulmonary veins
1. superior and inferior, serve each lung
2. lie anterior and inferior to other structures (bronchi, pulmonary arteries) at the
hilus of the lungs
E. lymphatics
1. superficial plexus lies in or near the visceral pleura
a. has no nodes of its own , so it empties into the hilar nodes
2. a deep plexus follows the conducting system
a. pulmonary (intrapulmonary) nodes - at bronchopulmonary segments
b. bronchopulmonary (hilar) nodes - at primary / secondary bronchial
segment junctions
c. tracheobronchial nodes - at trachea and primary bronchial junctions
(1) superior - at tracheal bifurcation, above primary bronchi
(2) inferior or carinal - below tracheal bifurcation