Exam Three Flashcards
(202 cards)
1
Q
Name the 4 functions of the thoracic wall
A
- protection of thoracic and abdominal viscera 2. respiration, resists internal pressures of inspiratory movements 3. attachment and support of upper limb 4. musculature attachments of upper limbs, neck, abdomen and back
2
Q
Describe the 3 parts of the thoracic inlet and its other name
A
Superior Thoracic Aperture
- Body of T1
- First pair ribs and cartilages
- Superior end of Manubrium
3
Q
Describe the 3 parts of the thoracic outlet and its other name
A
Inferior Thoracic Aperture
- Xiphisternal joint
- 12th ribs and costochondral junction
- closed by thoracic diaphragm
4
Q
Describe the Median Anterior Wall of the thoracic wall and another way you can refer to it
A
Sternal region
- sternum (manubrium, body, xiphoid)
- clavicular and chondral attachments to sternum
5
Q
Name the 4 lines of orientation for the thorax
A
midclavicular, axillary (3), scapular, midsternal
6
Q
Name and describe the 3 axillary lines of orientation
A
- anterior - vertical line dropped at lateral border of pec major
- mid-axillary - vertical line through middle of axillary fossa
- posterior - vertical line dropped at lateral border of the Lats
7
Q
Name and describe the levels of the 5 anatomical landmarks of the thoracic wall
A
- jugular notch (T2-3)
- sternal angle (T4-5), manubriosternal joint, costal cartilage of 2nd rib
- xiphoid process (T9-10), which ossifies at 40 yoa
- root of spine of the scapula (T4, spine of T3)
- inferior angle of scapula (T8, spine T7, over rib 7, points to rib 8)
8
Q
name the 3 parts of the sternum and the vertebral levels of each part
A
manubrium (T3-4), body (T5-9), xiphoid process (T9-10)
9
Q
name and describe the type of the 3 sternal joints
A
- sternoclavicular - synovial, saddle type joint (see upper limb)
- manubriosternal - secondary cartilagenous joint
- xiphisternal - primary cartilagenous joint
10
Q
describe and name the two types of the general rib joints
A
costochondral - no movement, sternocostal - 1st rib is primary cartilaginous joint, the rest are synovial plane-type joints
11
Q
Name the three general types of ribs and tell me which pairs are each type
A
true (1st-7th pairs), false (8th-12th), floating (11th and 12th)
12
Q
name and describe the 4 parts of a rib
A
- head - vertebral end, has two facets for articulation with vertebral body of thoracic vertebrae
- tubercle
- body (shaft) - angle is the point of greatest curvature
- costal groove - houses the intercostal neurovascular bundle
13
Q
name and describe the two types of thoracic vertebrae joints that associate with the thoracic wall
A
- costovertebral - head of rib and vertebral body at and above its level
- costotransverse - tubercle of rib and transverse process of vertebra at the same level
14
Q
Describe the general features of the breast and its very general location
A
located in the superficial fascia, is a modified sweat gland, has an areola, nipple, and 20 glands with lactiferous ducts which open onto the nipple
15
Q
describe the location of the breast tissue in males
A
4th intercostal space
16
Q
describe the location of the breast tissue in females
A
- vertically from 2nd-6th ribs
- transversely from lateral border of sternum to mid axillar line
- 2/3 on deep fascia of pec major
- 1/3 on deep fascia of serratus anterior
17
Q
pec major
A
- proximal: lateral border sternum and upper 6 costal cartilages, clavicle
- distal: lateral lip of intertubercular groove
- innervation: medial and lateral pectoral nerves on deep surface
- blood: pectoral branches of thoracoacromial trunk
18
Q
pec minor
A
- proximal - 3-5th ribs
- distal - coracoid process of scapula
- innervation - medial pectoral nerve
- blood - pectoral branches of thoracoacromial trunk
19
Q
serratus anterior
A
- proximal: lateral wall of thoracic wall, upper 8-9 ribs
- distal: medial border of scapula
- nerve: long thoracic on its superficial surface
- blood: lateral thoracic A on its superficial surface
20
Q
what is the retromammary space and what is it’s purpose?
A
between glands and the deep fascia of the breast, allows for movement of the breast
21
Q
What is the suspensory (Cooper’s) ligament?
A
attaches to the dermis of the skin to suspend the breast; well developed superiorly
22
Q
describe the vasculature of the breast
A
internal thoracic A, lateral thoracic A, pectoral branches of the thoracoacromial trunk
23
Q
describe the lymphatic drainage of the breast
A
75% through axillary nodes, 25% through clavicular and parasternal nodes
24
Q
serratus posterior superior
A
elevates thorax
25
serratus posterior inferior
depresses thorax
26
levator costarum
transverse processes C7-T11 to costal tubercle and costal angle, 12 pairs of fan shaped muscles
27
Name the thoracic muscles from superficial to deep
intercostals (external, internal, innermost), subcostal, transversus thoracis
28
name the 3 muscles that make up the upper limb musculature of the thoracic wall
pec major and minor, serratus anterior
29
describe the thoracic diaphragm
sternal, costochondral and lumbar attachments
| 80% quiet breathing (other 20% is intercostals)
30
general innervation to intercostal muscles
local intercostal nerves (ventral primary ramus of spinal nerve)
31
external intercostal
1. elevates
2. fibers run anteroinferiorly from upper rib to lower rib
3. muscle starts at costal tubercle, runs to costochondral junction - stops at front
4. extends to sternum as external (anterior) intercostal membrane
32
internal intercostal (intermediate layer of intercostals)
1. costal (bony ribs) portion - depresses, chondral (costal cartilage) portion- elevates
2. fibers run posteroinferiorly from upper to lower rib
3. muscle starts at lateral border of sternum, runs to costal angle - stops at back
4. extends to vertebrae as internal (posterior) intercostal membrane
33
innermost intercostal
1. elevate or depress
2. located in third muscular layer of intercostal space
3. found internally on posterolateral thoracic walls
34
subcostal muscle
1. located internally on posterior thoracic wall
2. elevates
3. located in third muscular layer of intercostal space posteriorly
4. runs over more than one space
35
transversus thoracis
1. anterior chest wall
2. depresses ribs
3. lower sternum to internal surface of 2nd-6th costal cartilage
4. located in third muscular layer of intercostal space anteriorly
36
how many intercostal spaces are there?
11
37
what 3 muscles are located in the intercostal spaces and how are they attached to the parietal plerua?
intercostals, subcostals, transversus thoracis - all via endothoracic fascia
38
name the 3 general structures in the intercostal spaces
muscles, parietal pleura, neurovascular bundle
39
describe the location of the neurovascular bundle in general terms
housed in the costal groove between the second and third muscular layers of the intercostal spaces
40
name the two divisions of intecostal nerves and their locations
thoracic (T1-11), thoracoabdominal (T7-11)
41
name the vein and vein system that both supply the intercostal spaces
azygos system of veins and internal thoracic vein
42
name the two divisions of the intercostal arteries (in general) and describe their anastomoses location
anterior and posterior divisions - meet in the intercostal space
43
describe the anterior intercostal artery and name its divisions
anterior internal thoracic artery terminates 6th IC space
1. musculophrenic supplies 7-9th spaces
2. superior epigastric
3. no anterior intercostals in 10th and 11th spaces
44
describe the posterior intercostal arteries and their branches
supreme (superior) intercostal- costocervical trunk assist in supplying the 1st and 2nd spaces
1. thoracic aorta - supplies all 11 intercostal spaces
45
describe the thoracic aorta
supplies all 11 i.c. spaces - first two intercostal spaces reinforces blood supply of the supreme intercostal a. from the costocervical trunk and sup. thoracic a. from 1st part of axillary artery
46
Describe subcostal nerve, artery, and vein
located under 12th rib, T12 nerve
47
describe the location of the trachea and what it's made out of
begins at C6, C shaped cartilages that open posteriorly, ends at sternal angle T4/5 (bottom of manubrium), deep to aortic arch in mediastinum
48
describe the right primary bronchus
wider, shorter and more vertical than the left one, 2.5 cm long
49
describe the left primary bronchus
passes inferolaterally, inferior to the aortic arch, anterior to the esophagus and descending aorta, 5 cm long
50
describe the carina
heavily innervated for cough reflex, a "keel like" ridge located between the orifices of the primary bronchi internally
51
describe the right lung and information about its lobes and fissures
3 lobes (upper, middle, lower), oblique and horizontal fissures
52
describe the left lung and information about its lobes and fissures
2 lobes (upper and lower), oblique fissure
53
what is the lingula?
projection of the upper lobe of the left lung
54
describe the 4 surfaces of the lungs and name them
1. cervical
2. costal - on the ribs
3. mediastinal - faces the heart and mediastinal structures
4. diaphragmatic - bases of lungs
55
name the 3 borders of the lungs
anterior, posterior, inferior
56
what is the hilum of the lung?
depression or pit at the the part of the lung where the vessels and nerves enter
57
what major ligament is found at the root of the lungs?
pulmonary ligament - formed by the reflection of parietal pleura as it becomes visceral pleura
58
Name the 5 general structures that make up the root of the lung
1. pulmonary arteries/veins
2. bronchus
3. bronchial arteries/veins on back on bronchus
4. nerves
5. lymphatics
59
Name the 7 components of the respiratory tree
1. primary bronchus
2. secondary (lobar) bronchus
3. segmental bronchi
4. terminal bronchioles
5. respiratory bronchioles
6. alveolar ducts
7. alveolar sacs
60
describe the bronchopulmonary segment and where it is
surgical unit of the lung that is pyramidal in shape, is separated by avascular septa, has its own segmental artery/bronchus/vein, and is part of the segmental bronchi
base - peripheral, apex - hilum
61
what is pleura of the lungs?
double layered serous membrane with a capillary layer of serous fluid
62
what is the purpose of pleural fluid and where is it found?
reduces friction between pleural layers (found in between them)
63
describe the visceral pleura of the lungs
inner layer of membrane that remains closely attached to the lung and moves with the lung as the lung expands and relaxes (Cannot be separated) - innervated by splanchnic and visceral nerves
64
describe the parietal pleura of the lungs
outer layer of membrane that stays attached to the internal surface of the thoracic wall by the endothoracic fascia.
innervated by somatic nerves b/c it's part of the wall. named as it relates to the surface which it contacts
65
name and describe the four surfaces of parietal pleura on the lung
1. cervical surface - emerges through the thoracic inlet
2. costal - contacts the ribs
3. mediastinal - in contact with mediastinal structures
4. diaphragmatic surface - in contact with the domes of the diaphragm
66
what is the pleural cavity?
space between the two pleural membranes
67
what are pleural reflections? Name two.
- made when a specific pleural surface becomes another pleural surface. These reflections form recesses that are potential spaces, within the pleural cavity which can fill with fluid.
- these potential spaces are termed recesses
- Costodiaphragmatic and costomediastinal recesses are examples
68
Describe the nerve supply to the lungs
- pulmonary plexus: anterior and posterior plexi, related to the carina
- sympathetics
- parasympathetics
69
describe the sympathetic and parasympathetic innervation to the lungs
1. sympathetic - vasoconstrictors and bronchodilators
2. parasympathetic - vasodilators, bronchoconstrictors, secretomotor and afferents
- cough reflex located aroudn carina, irritant receptor
- respiratory control via stretch receptors located in bronchial tree
- touch and pain located in respiratory epithelium
70
Describe the innervation of the 3 divisions of the parietal pleura
1. costal and cervical - local intercostal nerves
2. mediastinal - phrenic
3. central diaphragmatic - phrenic, peripheral - local intercostal nerves
71
describe the innervation to the visceral pleura
insensitive to pain and pressure
72
Name the two divisions of the lung lymphatics
superficial plexus and deep plexus
73
describe the superficial lymphatic plexus of the lung
lies deep to visceral pleura, draining lung and visceral pleura, vessels drain into superior and inferior tracheobronchial lymph nodes
74
describe the deep lymphatic plexus of the lung
lymph vessels within the lamina propria of the bronchi
75
are there lymph vessels in the alveoli?
NO!
76
describe the lymphatic pathway of the lungs
deep plexus -> pulmonary lymph nodes along large branches of main bronchi -> bronchopulmonary lymph nodes -> superior and inferior tracheobronchial lymph nodes -> bronchomediastinal lymph trunks made by vessels from parasternal, tracheobronchial, and ant. mediastinal lymph nodes -> thoracic duct (left) or right lymphatic duct
77
when does the respiratory primordium develop?
28 days
78
laryngotracheal groove
outgrowth from the caudal end of the ventral wall of the primordial pharynx, caudal to the 4th pair of pharyngeal pouches
79
laryngotracheal diverticulum (5)
1. end of 4th week
2. ventral to caudal part of the foregut
3. elongates and is invested with splanchnic mesenchyme
4. distal end enlarges to form the globular respiratory bud - responsible for the trachea and bronchial buds
5. maintains communication with pharynx through primordial laryngeal inlet
80
tracheoesophogeal folds (2)
1. develop in the posteroinferior aspect of the laryngotracheal diverticulum
2. approach each other and fuse to become the tracheoesophageal septum
81
tracheoesophageal septum
1. divides ventrally into the laryngotracheal tube and dorsally into the oropharynx and esophagus
82
primordial laryngeal inlet
opening of the laryngotracheal tube into the pharynx
83
trachea (laryngotracheal tube) - 3
1. the distal end, tracheal portion, differentiates into the trachea, starts at approx 4th week. The position of this tube gives the bud a new name, respiratory (tracheal) bud.
2. endodermal lining - epithelium and glands of the trachea
3. overlying splanchnic mesenchyme - cartilage, connective tissue, muscles of the trachea
84
describe the development of the bronchi (8 key steps)
1. as the tracheal bud continues to grow inferiorly, it forms two outpouchings - primary bronchial (lung buds)
2. bronchial buds, from endoderm grow laterally into the mesenchyme surrounding the pleuroperitoneal canals, primordia of the pleural cavities
3. endodermal lining - epithelium and glands of the bronchial branches
4. overlying splanchnic mesenchyme - cartilage, connective tissue, muscles of the bronchi, and visceral pleura
5. early 5th week the mainstem bronchi form (Right main bronchus larger & oriented more vertically than left)
6. main bronchi develop into secondary lobar bronchi
7. 7th week, segmental (tertiary) bronchi develop with surrounding mesencyme from the bronchopulmonary segments
8. 24 weeks, 17 orders of branches, respiratory bronchioles have developed
85
Name the 4 stages of lung maturation and the weeks at which they occur
1. pseudoglandular period (6-16 weeks)
2. canalicular period (16-26 weeks)
3. terminal sac period (26 weeks to birth)
4. alveolar period (32 weeks to 8 years)
86
Key developments during canalicular period of lung maturation (3)
respiratory bronchioles, alveolar ducts, terminal saccules (primordial alveoli)
87
key developments of terminal sac period of lung maturation (3)
1. development of blood/air barrier
2. Type I alveolar cells - pneumocytes, air exchange occurs
3. Type II alveolar cells - surfactant producing cells - surfactant production begins by 20 weeks but only in small amounts, the production then greatly increases the last two weeks of pregnancy
88
key developments during alveolar period of lung maturation
1. development of alveoli is mainly complete by 3 years of age but new alveoli may be added until 8 years of age
- primordial alveoli appear as bulges on the walls of respiratory bronchioles
- after birth the primordial alveoli increase in size forming the mature alveoli
2. 150 million primordial alveoli present in newborn infant
3. between years 3 8, 300 million mature alveoli is achieved
89
Describe the "pericardium"
- double-walled fibroserous sac which encloses the heart and roots of the great vessels
- attached to sternum via sternopericardial ligaments
90
what are the two layers of the pericardium?
fibrous pericardium, serous pericardium
91
describe the fibrous pericardium
- most superficial layer of pericardium
- fused to central tendon of diaphragm
- inelastic and protects against overfilling of the heart chambers
92
describe the serous pericardium
- three parts
1. parietal - fused to internal surface of the fibrous pericardium
2. visceral - epicardium
3. pericardial cavity with sinuses
- oblique: walling off of great vessels
- transverse: result of heart embryologically bending; keeps inflow in back of heart (Atria) ad outflow in front of heart (ventricles)
93
name the location of the base of the heart
apex (left vent) at the location of the left 5th i.c. space, mid-clavicular line (where you listen to mitral valve)
94
name and describe the 3 surfaces of the heart
1. sternocostal (anterior) - right ventricle (most anterior chamber of the heart)
2. diaphragmatic (inferior) - both ventricles, primarily the left
3. pulmonary (left) - left ventricle, occupies the cardiac notch
95
Name and describe the 4 borders of the heart
1. right: right atrium, right 3rd costal cartilage to right 6th costal cartilage
2. inferior: right vent (mostly) and apex of left vent, right 6th costal cartilage to left 5th i.c. space
3. left: left vent and left auricle, left 5th i.c. space to left 2nd costal cartilage
4. superior: right and left auricles, conus arteriosus, left 2nd costal cartilage to right 3rd costal cartilage
96
Name the 2 cardiac grooves
anterior interventricular and posterior interventricular (back)
97
Name and describe the prominent sulcus found on the heart
coronary sulcus (atrioventricular) - coronary arteries found in this groove, which encircles the heart like a crown between the ventricles and atria
98
Describe the general make up of the cardiac skeleton and its 3 main functions
- fibrocartilagenous tissue
- divides atria from ventricles
- provides barrier between atria and ventricles for conductive system
- provides attachment for heart valves and myocardium
99
Name and describe the 4 components of the cardiac skeleton
1. tendon of conus arteriosus - aortic to pulmonary semilunar valves
2. left fibrous trigone - mitral valve to aortic semilunar valves
3. right fibrous trigone - atrioventricular valves to aortic semilunar valves
4. membranous portions of the interventricular and interatrial septa
100
Describe the right coronary artery
- marginal and posterior interventricular branches, anastomoses with circumflex
- 60% supplies SA node, supplies AV node
101
Describe the left coronary artery
- circumflex and anterior interventricular branches
| - 40% supplies SA node
102
Name the 4 main veins that drain the heart
coronary sinus, great cardiac vein, middle cardiac vein, small cardiac vein
103
What is the purpose of the heart's conducting system?
cardiac muscle cells and conducting fibers specialized for initiating and conducting impulses
104
Name the 3 major components of the heart's conducting system
sinuatrial (SA) node, atrioventricular (AV) node, atricoventricular bundle (Purkinje fibers)
105
Describe the location of the SA node and its function
- initiates impulse for contraction, 70-80/minute
| - located at the junction of SVC and right atrium
106
Describe the functions and location of the AV node
- if required to initiate impulses, 40-60/minute
- collects impulses from atria and distributes to ventricles
- located in the posteroinferior region of interatrial septum, near coronary sinus
107
Describe the functions and location of the AV bundle (Purkinje fibers)
- if required to initiate impulses, 20-40/minute
- divides into right and left bundle branches
- located within IV septum to ventricular myocardium
108
The surface anatomy of heart consists of what 2 general things?
heart borders, heart valves
109
name the 4 heart valves (located in an oblique line from left 3rd costal cartilage to the right 6th costal cartilage)
1. aortic semilunar (in aorta)
2. pulmonary semilunar (in pulmonary artery)
3. tricuspid valve (between right atria and vent)
4. mitral (bicuspid) valve (between left atria and vent)
110
Name the 4 ausculatory areas and describe where they are
normal heart sounds are a result of blood turbulence upon closure of the heart valves
1. aortic semilunar valve - right 2nd ic space
2. pulmonary semilunar valve- left 2nd ic space
3. tricuspid - lower left body of sternum
4. mitral - left 5th ic space
111
What is the intraembryonic coelom? When does it develop?
- primordium of embryonic body cavities
- develops during the 4th week
- horseshoe shaped cavity develops in the lateral mesoderm via apoptosis
112
What are the two main components of the intraembryonic coelom?
cranial end, caudal limbs
113
Describe the cranial end of the intraembryonic coelom
- future pericardial cavity
- embryo undergoes the head-fold which brings the pericardium and heart ventrocaudally to take its position anterior to the foregut
114
Describe the caudal limbs that develop from the intraembryonic coelom (6)
- future pleural and peritoneal cavities
- opens to the extraembryonic coelom
- accommodates the growth and movement of the developing organs
- loses connection with the extraembryonic coelom during 10th week of development as the developing intestines return to the body cavity
- embryo folds in the horizontal plane brings the two caudal limbs together ventrally, which then fuse to form the peritoneal cavity
- results in a gut tube suspended between two layers of membrane (mesentery) suspended from the body wall of the embryo
115
What is a mesentery?
double layer of peritoneum that extends from the abdominal wall to convey blood vessels, nerves, and lymphatics to organs and divides the peritoneal cavity into right and left halves
116
What are the 2 divisions of peritoneum?
visceral and parietal
117
What are the 2 divisions of the mesentery? Describe them.
1. dorsal - permanent structure
2. ventral - remains attached to caudal part of the foregut (suspends primordial liver, primordial stomach and proximal part of duodenum - i.e. becomes falciform ligament and lesser omentum)
118
What are the 4 main divisions of the embryonic body cavity?
1. pericardioperitoneal canals
2. pleuropericardial membranes
3. pleuroperitoneal membranes
4. diaphragm
119
Describe the development and make up of the pericardioperitoneal canals in the developing embryo body cavity
- term for intraembryonic coelom after embryonic folding
- lies lateral to the foregut (future esophagus)
- dorsal to the septum transversum (Future central tendon of the diaphragm)
- partitions form in each canal due to developing bronchial buds
120
Name and describe the two ridges that develop in the pericardioperitoneal canals due to developing bronchial buds
1. cranial ridges (pleuropericardial folds) - located superior to developing lungs, separate pleural from pericardial cavities
2. caudal ridges (pleuroperitoneal folds) - located inferior to developing lungs, separate pleural from peritoneal cavities
121
What is a congential diaphragmatic hernia?
- posterolateral defect associated with embryonic development of body cavities
- associated with congenital hiatal hernia (herniated abdominal contents in thoracic cavity)
122
Describe the development of the pleuropericardial membranes (5)
1. enlargement of the pleuropericardial folds becomes the partition that separates the pleural from the pericardial cavities
2. contain the common cardinal veins
3. contains the phrenic nerve
4. pleural cavities
5. 7th week the pleurocardial membranes have fused with the ventral mesenchyme, forms the primordial mediastinum - contains all organs of the thoracic cavity except the lung and pleura
123
What is the purpose of the common cardinal veins in the developing embryo?
drain the primordial venous system into the sinus venosus of the primordial heart
124
Describe the development of the pleural cavities in the embryo
1. as the bronchial buds mature into the lungs, they grow into the pleural cavity
2. pleural cavities expand ventrally around the heart which splits the mesenchyme into: outer layer (thoracic wall) and inner layer (fibrous pericardium/ pleuropericardial membrane) that contains the phrenic nerve
125
Describe the development of the pleuroperitoneal membranes (3)
1. enlargement of the pleuroperitoneal folds becomes the partition that separates the pleural from the peritoneal cavities
2. during the 6th week, these membranes extend ventromedially and fuse with the dorsal mesentary of the esophagus and the septum transversum, which separates the pleural cavity from the peritoneal cavity (the closure is assisted by the migration of myoblasts into the pleuroperitoneal membrane)
3. left pleuroperitoneal membrane is last to close
126
the Thoracic diaphragm develops from what 4 things?
1. septum transversum
2. pleuroperitoneal membranes
3. dorsal mesentary of the esophagus
4. muscular ingrowth from the lateral body walls
127
Describe the innervation (development of) the thoracic diaphragm
1. myoblasts migrate into pleuroperitoneal membranes from 3-5 cervical myotomes carrying their nerves with them
2. these nerves pierce the pleuropericardial membranes (in the adult, located on the fibrous pericardium)
3. motor: C3,4,5 keeps the diaphragm alive - phrenic
128
Definitions of "mediastinum"
- thick partition of tissue in and on each side of the median plane
- the space between the two pleural sacs which contains all the structures in the thorax except the lungs and pleurae
129
Name/describe the 4 borders of the mediastinum
1. superior - thoracic inlet
2. inferior - thoracic diaphragm
3. anterior - sternum and costal cartilages
4. posterior - thoracic vertebrae
130
What are the two primary divisions of the mediastinum?
superior and inferior
131
Describe the borders of the superior mediastinum
superior to the sternal angle (manubriosternal plane) at vertebral level of T4-5
132
Name the 11 structures found within the superior mediastinum
1. thymus
2. braciocephalic veins (right and left)
3. superior vena cava
4. aortic arch & its branches
5. vagus nerves
6. left recurrent laryngeal nerve
7. phrenic nerves
8. trachea
9. thoracic duct
10. esophagus
11. sympathetic chain
133
Describe 2 traits of the thymus regarding its development and location in the superior mediastinum
- infancy and childhood lies posterior to the manubrium
| - adulthood is composed largely of adipose tissue, 10% functioning thymus tissue
134
describe the two brachiocephalic veins found in the superior mediastinum
- form from the union of the internal jugular veins with the subclavian veins
- left brachiocephalic vein is twice as long as the right brachiocephalic vein (because it has to go to the right of the heart)
135
Name the 3 branches of the aortic arch that are found in the superior mediastinum
brachiocephalic, left common carotid, left subclavian
136
Name the 3 divisions of the inferior mediastinum and where it is generally located
- anterior, middle, posterior
| - inferior to sternal angle (T4-5) through T12 vertebrae
137
Name/describe the 2 borders of the anterior mediastinum
- anteriorly - sternum and transversus thoracis muscle
| - posteriorly - pericardium
138
Name the 7 structures found within the anterior (inferior) mediastinum
1. remains of thymus (below sternal angle)
2. loose CT
3. fat
4. lymph nodes
5. vessels
6. branches of internal thoracic artery
7. sternopericardial (xiphoid to pericardium) ligament
139
Describe the borders/relations of the middle (inferior) mediastinum
- anteriorly: body of sternum, 2nd-6th costal cartilages
| - posteriorly: 5th-8th thoracic vertebrae
140
Name the 8 structures found in the middle (inferior) mediastinum
1. heart
2. pericardium (pericardial sac)
3. phrenic nerves
4. primary bronchii
5. origins of the great vessels (svc, ascending aorta, pulmonary arteries and veins)
6. ligamentum arteriosum
7. nerves
8. lymphatics (subpericardial lymph plexus, lymph vessels, drain into inferior tracheobronchial lymph nodes)
141
Describe the ligamentum arteriosum
- remnant of aortic arch, from ductus arteriosus
- found on pulmonary trunk
- serves as attachment to aorta
142
Name/describe the two borders of the posterior (inferior) mediastinum
anteriorly - pericardium and diaphragm
posteriorly - T5-12 vertebrae
143
Name the 6 structures found within the posterior (inferior) mediastinum
1. thoracic (Descending) aorta
2. thoracic duct
3. azygos system of veins
4. esophagus
5. nerves
6. lymphatics
144
Name/describe the 7 branchings of the descending (thoracic) aorta
1. bronchial - 1 right, 2 left
2. esophageal - usually 2 branches
3. mediastinal - to lymph nodes and other tissues
4. pericardial
5. posterior intercostals (3-11th spaces)
6. subcostal - under 12th rib
7. superior phrenic - last branch, superior surface of diaphragm
145
7 things to know about the thoracic duct, including location and function
1. drains 3/4 of the body
2. cisterna chyli - expanded end of duct at T12 vertebrae
3. passes through aortic haitus at inferior end of duct near diaphragm
4. duck between two gooses (esophagus and azygos)
5. ascends on right side, crosses over between T4-6
6. empties into union of left internal jugular vein and left subclavian vein
7. travels from right obliquely and superiorly up to left side to drain into left internal jugular vein in the neck
146
What is the purpose of the azygos system of veins? Name the 4 main components
- connects IVC to SVC
| - azygos vein, hemiazyos vein, accessory hemiazygos vein, right and left superior intercostal veins
147
Describe the azygos vein (4) - how it's made, what it does, where it's at
1. drains right side of thoracic and abdominal wall (everything there)
2. union of right subcostal and right ascending lumbar vein
3. ascends posterior thoracic wall within posterior mediastinum
4. arches over the root of the right lung into svc
148
Describe the hemiazygos vein (3) - what it does, where it's at, how it's made
- union of left subcostal and left ascending lumbar vein
- drains left 9th-11th i.c. spaces
- ascends to cross over to azygos at vertebral level T9
149
Describe the accessory hemiazygos vein (3) - what it does, where it's at, how it's made
- descends the left side of the thoracic vertebral column
- drains left 4th-8th i.c. spaces
- cross over to azygos at vertebral level T7 or T8
150
Describe the drainage of the right and left superior intercostal veins
- right drains into azygos
| - left drains into left brachiocephalic vein
151
Name the 3 constrictions of the esophagus and where it passes through the diaphragm
- passes through its own hiatus
| - aortic, bronchial, diaphragmatic constrictions
152
Describe the innervation of the posterior (inferior) mediastinum (3)
1. esophageal plexus - vagus nerves
2. aortic plexus - autonomic nerves
3. throacic splanchnic nerves - greater, lesser, least
153
Describe the make-up of the thoracic splanchnic nerves found in the posterior mediastinum (3) and their purpose, as well as how they attach to spinal nerve
- main source of sympathetics to the abdomen, preganglionic sympathetic fibers, synapse at pre-aortic ganglion
1. greater - via sympathetic chain ganglia T5-9 (go to midline)
2. lesser - via sympathetic chain ganglia T10-11
3. least - via sympathetic chain ganglia T12
- rami communicantes connects to costal nerve to connect these nerves to the spinal nerve
154
Describe the lymphatics of the posterior (inferior) mediastinum
1. posterior mediastinal lymph nodes
2. intercostal lymph nodes - in intercostal space
3. diaphragmatic lymph nodes - on the diaphragm
* either drain directly into the thoracic duct or the bronchomediastinal lymph trunks
155
Name the derivatives of the 1st aortic arch (pharyngeal arch artery)
right - maxillary artery, most of arch regresses
left - maxillary artery, most of arch regresses
156
Name the derivatives of the 2nd aortic arch (pharyngeal arch artery)
right - hyoid and stapedial arteries, most of arch regresses
left - hyoid and stapedial arteries, most of arch regresses
157
Name the derivatives of the 3rd aortic arch (pharyngeal arch artery)
right- proximal region is common carotid artery, distal region is internal carotid artery
left - proximal region is common carotid artery, distal region is internal carotid artery
158
Name the derivatives of the 4th aortic arch (pharyngeal arch artery)
right - proximal region is right subclavian artery
left - portion of the aortic arch
159
Name the derivatives of the 5th aortic arch (pharyngeal arch artery)
NONE!
160
Name the derivatives of the 6th aortic arch (pharyngeal arch artery)
right- proximal region is a portion of the right pulmonary artery and distal region regresses
left - proximal region is portion of the left pulmonary artery and the distal region is the ductus arteriosus
161
Describe the relations of the adult aorta (the 3 main parts) to the derivatives of the pharyngeal arches
1. ascending aorta- truncus arteriosus and aortic sac
2. arch of aorta - aortic sac and left 4th aortic arch (pharyngeal arch artery)
3. descending aorta - dorsal aorta
162
7 key facts about the aortic arches (pharyngeal arch arteries)
1. develop during the 4th and 5th weeks
2. supply the pharyngeal arches
3. originate from the aortic sac
4. six pairs, one for each pharyngeal arch
5. arches are NOT ALL PRESENT AT THE SAME TIME
6. by the time the 6th pair developed, the first 2 pairs have taken their adult positions or have regressed
7. the 5th aortic arch disappears as does the 5th pharyngeal arch so there are no derivatives!!!
163
Name the 3 primary things derived from the aortic sac
- a portion of the ascending aorta
- the brachiocephalic artery (leads to right side circulation; the right subclavian and right common carotid)
- most of the aortic arch
164
where do the aortic arches terminate?
in the dorsal aortae; these will fuse caudal to the pharyngeal arches to from a single dorsal aorta
165
Which embryological system is the first to functionally develop? When does this happen?
cardiovascular! Develops during the middle of the 3rd week
166
when does blood start to circulate in the embryo?
beginning of the 4th week
167
Describe the steps involved in the early development of the heart in the embryo (7)
1. angioblastic cords in the cardiogenic area, cranial end of embryo canalize to form Endocardial Heart Tubes in late 3rd week
2. lateral folding (hug folds) of the embryo brings the endocardial heart tubes together and they fuse to form a single heart tube with three layers
3. heart begins to beat at 22-23 days
4. head-folding of the embryo brings the developing heart and pericardial cavity ventral to the foregut and caudal to the oropharyngeal membrane (future mouth)
5. elongation of the heart develops swellings
6. bulbus cordis and ventricle grow faster than the other regions of the developing heart causing the heart to bend upon itself.
7. blood flow through the primordial heart moves caudally to cranially in the embryo
168
Describe the flow of blood through the primordial heart (caudal to cranial)
sinus venosus -> primodrial atrium -> atrioventricular canal -> primordial ventricle -> bulbos cordis -> truncus arteriosus -> aortic sac -> aortic arches
169
when does partitioning of the heart primordium begin?
around middle of the 4th week, essentially completed by the end of the 5th week
170
describe the development of the semilunar valves
- develop from three swellings of subendocardial tissue
- swellings are restructured to form thin-walled cusps
- position of the cusps after rotation is the normal anatomical way of naming cusps
171
describe the development of AV valves
proliferation of endocardial cushions around the AV canals
172
name the two parts that make up partitions of the primordial atrium
septum primum, septum secundum
173
Describe the development of the Septum primum (2)
1. this is the first septum, as it grows inferiorly to the atrioventricular junction, it closes an opening between the primitive atrium called the Foramen Primum, this divides the primitive atrium into a right and left atria. This foramen will eventually close.
2. before closure of the foramen primum a second opening forms in the septum called the Foramen secondum
174
Describe the Development of the Septum secundum
1. on the right side of the septum primum, this membrane grows inferiorly. It will grow only as much as to overlap the newly formed foramen secundum.
2. this overlapping of the foramen secundum forms a flap-valve over the foramen called the Foramen Ovale
175
Describe the formation of the adult right atrium
- left horn of sinus venosus: coronary sinus
- right horn of sinus venosus: posterior wall of the right atruim, called the sinus venarum (smooth portion of adult right atrium)
- primitive atrium form the rough anterior wall of the adult right atrium (pectinate muscles) - only part that is maintained as a functional structure of adult tissue
176
describe the formation of the adult left atrium
- smooth walls formed from the incorporation of the primordial pulmonary vein into the left atrium
- primordial left atrium becomes the left auricle
177
What is the congenital defect, Total Anomalous Pulmonary Vein?
occurs when the primordial pulmonary vein is incorporated to the right side of the developing interatrial septum therefore draining into the right atrium instead of the left atrium
178
What are the two parts of the interventricular septum and what is its function as a whole?
muscular and membranous portions - partitioning of the primordial ventricle
179
describe the development of the muscular portion of the interventricular septum
infolding of primitive ventricle growing superiorly to meet the membranous portion; divides primitive ventricle into a right and left side
180
describe the development of the membranous portion of the interventricular septum
- forms from right side of fused endocardial cushions
| - fuses with aorticopulmonary septum and the muscular part of the interventricular septum
181
describe the 4 steps involved in the formation of the outflow tracts
1. partitioning of the bulbus cordis and truncus arteriosus
2. aorticopulmonary septum
3. bulbus cordis derivatives
4. truncus arteriosus derivatives
182
describe the partitioning of the bulbus cordis and truncus arteriosus (describe the process and the two ridges involved)
- starting with the bulbar ridges, these ridges approach each other to fuse; they undergo 180 degree spiraling, possibly due to the streaming of blood from the ventricles.
- when the ridges fuse, they from the aorticopulmonary septum
1. trunchal ridges (mesenchymal cells): derived from neural crest, within the truncus arteriosus
2. bulbar ridges (mesenchymal cells): derived from neural crest, within the bulbus cordis
183
what are the 2 truncus arteriosus derivatives?
ascending aorta, pulmonary trunk
184
name the 2 derivatives of the bulbus cordis
1. conus arteriosus of the right ventricle
| 2. aortic vestibule of the left ventricle
185
what 2 things does the aorticopulmonary septum separate?
aorta and pulmonary trunk
186
name 4 atrial septal defects (ASDs)
1. secundum type
2. endocardial cushion defect with primum type
3. sinus venosus type
4. common atrium
187
Describe ventricular septal defects (VSDs)
- more severe than ASDs because they create problems with pumping blood out (cycle oxygenated blood back and forth through lungs not body)
- membranous, muscular septal defect, absence of interventricular septum - all blood mixes together
188
describe what can occur when the truncus arteriosus does not properly divide (6)
1. persistent truncus arteriosus - don't develop a full aorticopulmonary system (deoxygenated blood and oxygenated blood pumped into one vessel)
2. aorticopulmonary septal defect
3. transposition of the great vessels - caused by incorrect spiraling of deoxygenated blood being pumped back to the body where it came from and oxygenated blood being pumped back to lungs where it came from
4. unequal division of the truncus arteriosus
5. pulmonary atresia
6. aortic stenosis and atresia
189
Describe what could happen if the truncus arteriosus divided unequally
1. pulmonary stenosis - pulmonary artery is really small
2. tetralogy of Fallot (pulmonic valvular stenosis, VSD, overriding aorta, right ventricular hypertrophy and left side that gets smaller)
190
From where does the laryngotracheal diverticulum and tube originate and when does this occur?
from laryngotracheal groove at end of 4th week
191
as far as the embryology of respiratory system goes, from what does the endoderm become? How about the splanchnic mesoderm?
- pulmonary epithelium, glands of trachea, larynx and bronchi
- CT, cartilage, smooth muscle in larynx, trachea, bronchi and lungs
192
What divides the laryngotracheal tube? Into what segments is it divided?
- tracheoesophageal septum
| - ventral (larynx, trachea, bronchi, lungs) and dorsal (oropharynx, esophagus)
193
What is a tracheoesophageal fistula? How is it caused?
- abnormal passage between trachea and esophagus
| - incomplete division of laryngotracheal diverticulum and incomplete fusion of tracheoesophageal folds
194
Describe the development of the respiratory and bronchial buds
- respiratory bud develops at caudal end of laryngotracheal diverticulum
- divides into 2 primary bronchial buds
- primordia of main bronchi form connection of each bronchial bud with trachea in early 5th week
- main bronchi subdivide into secondary bronchi that form branches
195
Describe the development of the tracheal bud
- endodermal lining of laryngotracheal tube --> epithelium and glands of trachea
- splanchnic mesoderm around laryngotracheal tube --> cartilage, CT and muscles of trachea
196
What is the role of overlying mesenchyme in fetal CT? (4)
- splanchnic kind surrounding bronchi form cartilaginous plates, bronchial smooth muscle, bronchial and pulmonary CT, capillaries
- visceral pleura acquired cavities grow caudally into mesenchyme of body wall
- lungs & pleural cavity grow caudally into mesenchyme of body wall
- body wall becomes lined with parietal pleura from splanchnic mesoderm
197
What are the pericardioperitoneal canals?
-the space the body gives to allow the growth of the secondary bronchial buds
198
Name the 4 stages of lung maturation
1. pseudoglandular (5-17 wks)
2. canalicular (16-25 wks)
3. terminal saccular (24 wks- late fetal period)
4. alveolar (late fetal period - 8 yrs)
199
Describe the pseudoglandular period of lung maturation
- all major elements of lung except those involved with gas exchange form
- infants born during this stage die b/c respiration isn't possible
- 5 to 17 wks
200
Describe the canalicular period of lung maturation
- lumina of bronchi and terminal bronchioles become larger
- lung tissue becomes highly vascular
- terminal bronchioles give rise to respiratory bronchioles, which divide into primordial alveoli
- 16 to 25 weeks
201
Describe the terminal saccular period of lung maturation
- more terminal sacs (primordial alveoli) are made
- capillaries bulge into terminal sacs
- blood/air barrier set
- proliferation of capillary network around developing alveoli
- type 1 pneumocytes: terminal sacs lined by squamous epithelium
- type 2 pneumocytes: secretory epithelial cells that secrete surfactant
202
Describe the alveolar period of lung maturation
- bronchioles terminate into terminal sacs (Future alveolar ducts)
- 95% mature alveoli develop in postnatal period
- alveolar development complete by 3 years
