Exam #2 Flashcards
(130 cards)
1
Q
The cardinal anastomotic shunt becomes what mature structure? At what week does this shunt appear?
A
LEFT BRACHIOCEPHALIC VEIN- caudal part of left cardinal degenerates.
- 8th week
p. 191 Moore
2
Q
What forms the SVC (2)?
A
Right anterior and right common cardinal
3
Q
What are the adult derivatives of the posterior cardinal veins (2)?
A
root of the azygos vein and the common iliac veins.
4
Q
What are the adult derivatives of the subcardinal vein (4)?
A
- ) stem of the left renal vein
- ) the suprarenal veins
- ) the gonadal veins (testicular and ovarian)
- ) a segment of the inferior vena cava
p. 192
5
Q
What are the adult derivatives of the supracardinal veins (cranial (2) and caudal (2) to the kidneys – caudal left and right)?
A
Cranial: azygos and the hemiazygos veins.
Caudal: the left supracardinal vein degenerates, but the RIGHT supracardinal vein becomes the inferior part of the IVC.
p.192
6
Q
What are the four main IVC segments and where did they come from?
A
- ) Hepatic: Proximal part of right vitelline vein.
- ) Prerenal: Subcardinal vein.
- ) Renal: Subcardinal-supracardinal anastomoses.
- ) Postrenal: Right supracardinal vein
7
Q
Pharyngeal arches form during the ____–____ weeks
A
4th–5th weeks.
8
Q
What is the fate of the caudal dorsal aortas?
A
Fuse to form a single lower thoracic and abdominal aorta.
9
Q
What is the fate of the cranial pair of dorsal aortas?
A
Right disappears, left becomes the PRIMATIVE AORTA.
10
Q
What is the fate of the six aortic arch/pharyngeal arch arteries? (3 has proximal and distal, 4 and 6 have left and right).
A
1.) Maxillary and external carotid arteries.
2.) Dorsal aspects –Stapedial artery
3.) Proximal aspects –common carotids
Distal aspects – Internal carotids
4.) Left – Part of aortic arch. Right – right subclavian (proximal segment).
5.) Nothing
6.) Left –Proximal: proximal left pulmonary artery. Distal: Pre-natal shunt, ductus arteriosus.
Right –Proximal: Proximal right pulmonary artery.
Distal: Nothing.
11
Q
What is the precursor to the common iliac arteries?
A
Fifth lumbar pair of intersegmental arteries.
12
Q
What is the fate of the intersegmental arteries of the neck?
A
Join together to form the vertebral artery.
13
Q
What is the fate of the intersegmental arteries of the thorax?
A
Intercostal arteries
14
Q
The vitelline arteries supply the _______ and, later, the primordial _________, which forms from the incorporated part of the _______.
A
- umbilical vesicle
- primordial gut
- umbilical vesicle
p. 194
15
Q
What is the fate of the three vitelline arteries that persist and what do they supply?
A
- ) Celiac arterial trunk to foregut
- ) Superior mesenteric to the midgut
- ) Inferior mesenteric to the hindgut
16
Q
What is the fate of the umbilical arteries that persist and what do they supply?
A
- Proximal portions as the INTERNAL ILIAC and VESICAL ARTERIES.
- Distal part as the MEDIAL UMBILICAL LIGAMENTS.
17
Q
What early tissues form the heart primordium? From which layer?
A
Cardiogenic LATERAL PLATE mesoderm –SPLANCHNOPLEURIC LAYER at the cranial end of the embryonic disc.
18
Q
- ) The heart primordium comes from cardiogenic _______ at the ______ end of the embryonic disc.
- ) Most is ______ mesoderm from the ________.
- ) Mesoderm outflow portions of the heart is cranial mesoderm from the _______ and _______.
A
- ) Cardiogenic mesoderm at the cranial end of the embryonic disc.
- ) Most is splanchnic mesoderm from the primitive streak.
- ) Mesoderm outflow portions of the heart is cranial mesoderm from the NEURAL CREST and PARAXIAL COLUMNS.
p. 83 Netter
19
Q
Blood vessels first appear in what three places?
A
- ) next to the intraembryonic coelom in the lateral plate
- ) cardiogenic mesoderm (cranial end of embryonic disc)
- ) extraembryonic mesoderm of the yolk sac and connecting stalk.
20
Q
During the ______ week (approximately ______ days), the primordial atrium and the sinus venosus, as well as the veins draining into them, are evident.
A
During the fourth week (approximately 24 days)
p.194
21
Q
What embryonic tissue layer(s) forms the epicardium (visceral pericardium)?
A
Epithelial cells from the cardiac mesoderm on the sinus venosus migrate over the myocardium to form the epicardium (visceral pericardium).
p.95 Netter
22
Q
The primordial heart initially appears ______ to the oropharyngeal membrane, but later becomes ______ to the oropharyngeal membrane and ______ to the foregut.
A
The primordial heart initially appears cranial to the oropharyngeal membrane, but later becomes caudal to the oropharyngeal membrane and ventral to the foregut
23
Q
What promotes fusing of the heart tubes into a single tube?
In what direction does the fusing take place?
A
- Lateral folding
- Cranial to caudal
p. 195
24
Q
The primordial myocardium is formed from the __________ surrounding the __________.
A
splanchnic mesoderm surrounding the pericardial coelom
p.195
25
The heart and the pericardial cavity appear ventral to the _______ and caudal to the __________.
ventral to the foregut and caudal to the oropharyngeal membrane.
p.196
26
What is the bulbus cordis composed of?
```
bulbus cordis (composed of the truncus arteriosus, the conus arteriosus, and the conus cordis)
p.195
```
27
Why does the heart bend on itself and form a U-shaped bulboventricular loop?
Because the bulbus cordis and the ventricle grow faster than the other regions
p.197
28
What primordial structure(s) forms the transverse pericardial sinus?
The degeneration of the central portion of the dorsal mesocardium (a mesentery that suspends the heart from the dorsal wall).
29
Blood enters the sinus venosum from which three sites and through which vessels?
1. ) The embryo through the common cardinal veins
2. ) The placenta through the umbilical veins
3. ) The umbilical vesicle through the vitelline veins
p. 198
30
The sinus venosus enters the _____ aspect of the primordial ______.
Dorsal aspect of the primordial atria.
31
Why do the sinus horns enlarge? (2)
Due to...
1. ) Changes in the umbilical and vitelline veins
2. ) Anastomoses of the left and right anterior cardinal veins (brachiocephalic veins and SVC).
32
What are the two main embryonic tissue sources for the heart?
Paraxial mesoderm and neural crest cells
33
Partitioning of the atrioventricular (AV) canal, the primordial atrium, and the ventricle begins at approximately the middle of the _____ week and is essentially completed by the end of the ______ week.
begins at approximately the middle of the fourth week and is essentially completed by the end of the eighth week.
p.199
34
1. ) What is the purpose of the foramen primum? Where does it occur?
2. ) What does it become?
1. ) Allows shunting of oxygenated blood from the right to the left atrium – Occurs between the developing right and left atrium.
2. ) It closes and becomes the primordial AV septum.
p. 199
35
After birth, the oval foramen functionally closes due to ___________, and the valve of the oval foramen fuses with the _________, forming the oval fossa.
- higher pressure in the left atrium
- septum secundum
p. 202
36
By the end of the fourth week of development, the _____ sinual hom becomes larger than the ____ sinual horn.
right sinual hom becomes larger than the left sinual horn
| p.202
37
What becomes of the right and lift sinual horns?
Right: Becomes incorporated into the wall of the right atrium.
Left: Becomes the coronary sinus.
p.202
38
Which parts of the atrium are derived from the primordial atrium?
The trabeculated portions (auricle and anterior internal surface that is not the sinus venarum).
p.202
39
Most of the wall of the left atrium is smooth because why?
| What about the left auricle?
It is formed by the incorporation of the primordial pulmonary vein.
- The small left auricle is derived from primordial atrium and, thus, has a trabeculated appearance.
p. 202
40
The IV foramen usually closes by the end of the ______ week as the _____ fuse with the ______.
- by the end of the seventh week
| - bulbar ridges fuse with the endocardial cushion.
41
Closure of the IV foramen results from fusion of tissue from which three sources?
1. ) Right bulbar ridge
2. ) Left bulbar ridge
3. ) Endocardial cushion
p. 202
42
Where is the smooth part of the right atrial wall (_____) derived from?
(Sinus venarium) – Derived from the RIGHT SINUAL HORN.
| p.203
43
Where are the crista terminales, valves of IVC and coronary sinus derived from?
RIGHT SINUATRIAL VALVE.
| p.203
44
The primordial right atrium becomes the ______.
Right auricle.
| p.203
45
Active proliferation of which type of cells form the bulbar ridges? When?
Mesenchymal cells in the walls of the bulbus cordis.
- During the 5th week.
p. 203
46
The bulbar and truncal ridges are derived mainly from the _________________.
neural crest mesenchyme
| p.203
47
The spiral orientation of the bulbar and truncal ridges, possibly caused in part by__________________, results in the formation of a spiral ____________ when the ridges fuse.
- the streaming of blood from the ventricles
- aorticopulmonary septum.
p. 203
48
What is the function of the aorticopulmonary septum?
It divides the bulbus cordis and the truncus arteriosus into two arterial channels: the aorta and the pulmonary trunk.
p.204
49
Because of the ______________, the pulmonary trunk twists around the ascending aorta.
spiraling of the aorticopulmonary septum
| p.204
50
In the right ventricle, the bulbus cordis is represented
| by the _______, which gives origin to the ________.
- conus arteriosus (infundibulum)
- pulmonary trunk
p. 204
51
In the left ventricle, the bulbus cordis forms _________________. Describe what this structure is.
- the walls of the aortic vestibule.
- It is the part of the ventricular cavity just inferior to the aortic valve.
p. 204
52
The initial contractions of the heart originate in _______ during week ______.
muscle – During WEEK 4
| p.198
53
Of the two septa in the primordial atrium, which contains the foramen ovale?
Septum secondum
| p.99 Netter
54
Valve development is completed by _____ weeks.
8 weeks
| p.101 Netter
55
Which three structures fuse to complete ventricular separation?
1. ) Endocardial cushions
2. ) Interventricular septum
3. ) Spiral septum
p. 102 Netter
56
Give the adult derivatives of the following primordial structures:
1. ) Truncus arteriosus (2)
2. ) Bulbus cordis (2)
3. ) Ventricle (1)
4. ) Atrium (1)
5. ) Sinus venosus (2)
1. ) Ascending aorta, pulmonary trunk.
2. ) Aortic vestibule of left ventricle, Conus arteriosus of right ventricle.
3. ) Trabecular walls of left and right ventricles.
4. ) Auricles/pectinate muscle walls of left and right atria (smooth wall of left atrium from pulmonary veins).
5. ) Coronary sinus, smooth wall of right atrium.
p. 103 Netter
57
1. ) What is the most common type of ASD?
2. ) What are the possible causes? (2)
3. ) and what are symptoms?
1. ) Ostium secundum ASD: Occur in the oval fossa and blood is shunted through oval foramen into left atrium. Mixes oxy- with deoxygenated blood.
2. ) Includes both the septum primum (excessive resorption – cannot close oval foramen) and secondum (abnormal resorption of = Large oval foramen that septum primum cannot close).
3. ) Produces cyanosis.
* Most prevalent in females and can be any combination of the two*
p. 207
58
1. ) What is the most common type of CHD?
2. ) What does it involve?
3. ) What is the physiological consequences (2)?
1. ) VSDs.
2. ) Most VSDs involve the membranous part of the IV septum.
3. ) Most people with a large VSD have massive LEFT TO RIGHT shunting of blood.
* Pansystolic/ Holosystolic murmur*
p.210
59
1. ) Persistent truncus arteriosus results from what?
2. ) What is the physiological consequence?
3. ) What is always present with PTA?
1. ) Failure of the truncal ridges and the aorticopulmonary septum to develop normally and to divide the truncus arteriosus into the aorta and the pulmonary trunk.
2. ) Single arterial trunk, the truncus arteriosus, arises from the heart and supplies the systemic, pulmonary, and coronary circulations.
3. ) A VSD is always present with truncus arteriosus, and the truncus arteriosus straddles the VSD.
p. 210
60
What does a Teratology of Fallot consist of?
| *What is the main outcome?*
The classic group of four cardiac defects known as tetralogy of Fallot consists of the following:
1. ) Pulmonary stenosis (obstructed right ventricular outflow)
2. ) Ventricular septal defect
3. ) Dextroposition of the aorta (straddling or overriding the aorta)
4. ) Right ventricular hypertrophy
* The pulmonary trunk is usually small, and there may be varying degrees of pulmonary artery stenosis as well*
* Malalignment of the subpulmonary infundibulum (aka conus arteriosus)*
p. 213
61
1. ) What are endocardial cushion defects with patent foramen primum (ECD)?
2. ) What does it lead to (2)?
3. ) Usually seen in what patients?
1. ) Septum primum does not fuse with the endocardial cushions.
2. ) Leads to patent foramen primum and defects in mitral valve.
3. ) Trisomy 21 patients.
62
What is a Sinus Venosus ASD?
Sinus venosus not incorporated into the wall of right atrium – septum secundum develops abnormally.
63
1. ) What are the clinical findings of ASDs (3)?
| 2. ) Symptoms?
1. ) Murmur, abnormal EKG, enlarged heart.
| 2. ) Fatigue, cyanosis, difficulty breathing, failure to thrive, trouble breathing while eating.
64
1. ) What is the nature of transposition of the great arteries? What is the physiological consequence?
2. ) What causes it?
1. ) Aorta and pulmonary arteries change places – Blood returning from body bypasses lungs and is pumped back out.
2. ) Failure of incorporation of the bulbus cordis into the ventricles and incorrect neural crest cell migration.
65
What is dextrocardia? What is it the result of?
Heart displaced to the right side (transposition of the vessels). Caused by abnormal folding of the heart tube to the left side.
66
1. ) What is coarctation of the aorta?
2. ) In whom is it most common? Presentation?
3. ) X-ray finding?
1. ) Coarctation = constriction
2. ) 2x more common in males than females – Most are asymptomatic – but may be HTN at exam and can cause CHF is dx is late.
3. ) Notching of the ribs
67
By the end of week ______, somites develop from _______.
Week 3, paraxial mesoderm.
68
What are the two parts that somites develop into, from which part, and what do they become?
1. ) Dermomyotome (dorsolateral): Myotome region forms myoblasts (primordial muscle cells). Dermotome region becomes the dermis (fibroblasts).
2. ) Sclerotome (ventromedial): Becomes vertebrae and ribs.
pp. 226-227
69
_______ condenses to form chondrification centers; during what week?
Mesenchyme – Week 5
70
What are the three places of origin for chondrocytes and what structures do they give rise to? (two structures for each origin)
1. ) Paraxial mesoderm: Axial skeleton and base of skull.
2. ) Lateral mesoderm: Limbs and sternum.
3. ) Neural crest: Face and neck.
71
What is the main difference between endochondral and intramembranous ossification? What type of bones?
No cartilage ever involved with intramembranous –Mesenchyme straight to bone.
-Flat bones
72
The process of endochondral ossification is complete by what age?
Age 20
73
1. ) When do chondrification centers first appear?
| 2. ) When does the process of endochondral ossification begin?
1. ) Week 6
| 2. ) Week 8
74
Sclerotome cells from which primordial region form the following bones:
1. ) Vertebral body
2. ) Neural arch
3. ) Ribs
1.) Around notocord
2.) Around neural tube
3.) Body wall
#12
75
1. ) Where are the chondrification centers of vertebrae (3)?
| 2. ) Ossification centers?
1.) On the lamina near at the beginning of the arch, at the base (medial) of the TPs/costal processes, and around the periphery of where the nucleus pulposus would be on the vertebral body.
2.) Totally surrounding the periphery of where the nucleus pulposus would be on the vertebral body, near the center of the pedicle.
#13
76
Cells from adjacent ______ combine to form a primordial vertebral body, also called a _______.
-From adjacent SCLEROTOMES.
-Centrum.
#14
77
Between the vertebrae, the ______ expands to form the gelatinous center of the IV disc, the nucleus pulposus.
notochord
78
The sternum arises from mesenchymal ________ in the body wall which fuse _________ at the midline.
-mesenchymal sternal bars in the body wall.
-Fuse craniocaudally.
#16
79
With regards to the sternum, which part is the last to ossify? When?
Xiphoid process – childood.
80
List the five 2˚ ossification centers that appear on the vertebrae after puberty
1.) One at the tip of the SP
2.) One at the tip of each TP
3,4,5.) Two anular epiphyses, one on the superior rim, and one on the inferior rim of the vertebral body.
p.231
81
Which cranial bones constitute the membranous neurocranium (2)?
Frontal and parietal bones.
82
Which cranial bones constitute the membranous viscerocranium (4)?
Nasal, maxilla, mandible, and squama temporalis.
83
Which cranial bones constitute the cartilagenous viscerocranium (5)?
Incus, stapes, malleus, hyoid, and thyroid cartilage.
84
Which cranial bones constitute the cartilagenous neurocranium (3)?
```
Sphenoid, petrous part of temporal bone, occipital bone.
#19
```
85
Which muscles comprise the epaxial (4) and hypaxial (8) divisions of myotomes?
```
Epaxial: Segmental muscles of body axis, extensors of head, neck, and vertebral column.
Hypaxial: All limb muscles, muscles of anterior neck, lateral and ventral flexors of vertebral column, intercostals, abdominals, pelvic diaphragm, anus and sex muscles.
#22
```
86
From which myotome derivatives are the following derived from:
1. ) Tongue
2. ) Extrinsic eye muscles
3. ) Limbs
1.) Occipital myotomes (CN XII)
2.) Mesenchyme near prechordal plate
3.) Myoblasts from hypaxial division of myotome migrate to develop near bones.
#23
87
What structures are derived from mesoderm in pharyngeal arches? (4)
```
Muscles of facial expression, mastication, pharynx, larynx.
#23
```
88
Concerning muscle – ______ produce the peri- and epimysium, and ________ produces endomysium.
- Fibroblasts
| - External lamina of myofibers
89
What causes diameter growth in skeletal muscle?
Myofilament production.
90
What are the smooth muscle derivatives of the following:
1. ) Splanchnic mesoderm
2. ) Somatic mesoderm
3. ) Ectodermal mesenchyme
1.) Endoderm of primordial gut
2.) Blood and lymph vessels
3.) Muscles of iris, mammary and sweat glands.
#27
91
Smooth muscle formation is different from that of skeletal muscle in that....
New myoblasts differentiate from mesenchyme...NO FUSION.
92
How does cardiac muscle proliferate?
Single myoblast differentiation...NO FUSION
93
Mesenchyme around the developing heart is from what?
Splanchnic mesoderm.
94
When do limb buds appear?
End of week 4
95
What induces limb growth and development?
Apical ectodermal ridge (AER).
96
When do digital rays appear?
Week 6
97
When are digits fully separated?
Week 8
98
```
Describe what happens in limb development at the following intervals:
Week 5
Week6
Week 7-12
Age 1
```
Week 5: Mesenchyme aggregations and chondrification centers (lateral mesoderm).
Week 6: Cartilage model laid down.
Week 7-12: 1˚ ossification centers in all long bones.
Age 1: 1˚ ossification centers in carpals.
#35
99
Dermatomes are formed and partitioned along dividing lines called what?
```
Ventral axial lines
#38
```
100
What is amelia and when does it occur?
Amelia: Complete absence of a limb – Suppression of limb development *EARLY ON IN WEEK 4*
101
What is meromelia and when does it occur?
Meromelia: Partial absence of a limb – Disturbance of limb development *WEEK 5*
102
What is syndactyly and what are the two types?
Syndactyly: Fused digits.
1. ) Cutaneous: Webbing of digits.
2. ) Osseous: Bone fusion – *SYNOSTOSIS*
103
What is the precursor to pulmonary epithelium, larynx glands, trachea, and bronchi?
Endoderm
104
What is the primordium of the lower respiratory system?
Laryngotracheal groove
105
Where do lung buds first appear? When does this occur?
```
In the LARYNGOTRACHEAL TUBE – During the 4th-5th weeks.
#4
```
106
The epithelial lining of the larynx develops from the _______ of the cranial end of the _______.
endoderm of the cranial end of the laryngotracheal tube.
| p.131
107
What is SCAPHOCEPHALY? What characterizes is?
Premature closing of SAGITTAL SUTURE.
| Characterized by a long, narrow head.
108
When does the primordium of the respiratory system appear?
28 DAY EMBRYO
109
From which arches does the laryngeal and tracheal cartilage arise?
Mesoderm (from arches 4 and 6)
110
_______ begins swelling to form the respiratory bud.
Laryngotracheal diverticulum
111
R bronchus branches into _____ 2˚ bronchi, L branches into _____.
R bronchus branches into THREE 2˚ bronchi, L branches into TWO.
112
When is the Pseudoglandular stage? What do the lungs resemble at this point? Can the fetus be born?
weeks 6-16: Resemble exocrine glands because all elements present EXCEPT THOSE FOR GAS EXCHANGE.
○ Respiration is NOT POSSIBLE.
○ Fetus non-viable at this point because it is not capable of self-respiration.
113
When is the earliest a fetus is viable? What is this stage called and defined by (2)?
```
Canalicular stage (weeks 16-26): Lumen of bronchi and bronchioles enlarge. Tissue becomes vascularized.
○ Respiration possible by the end of this period.
```
114
Primordial terminal (alveolar) sacs appear by ____ WEEKS
24 WEEKS
115
What are the survival rates from 24-26 weeks?
○ Survival rates 39-80% —> 24 Weeks
○ 50-60% by week 25
○ ≈ 80% by week 26
116
What determines respiratory viablility in the developing fetus?
Respiratory Viability: Prior to 24 weeks, not enough alveolar SA for gas exchange.
• Inadequate vascularization.
-Inadequate surfactant production.
117
What is atelectasis? What are the consequences?Treatment?
Lack of SURFACTANT leads to ATELECTASIS.
- Collapse of saccules during exhalation.
- Improving survival of premature infants – Antenatal corticosteroids stimulates surfactant production.
- Also, surfactant replacement therapy.
118
When does the transition from the placental dependence to gas exchange occur? What is this period called? Give two characteristics.
```
Alveolar Stage (weeks 32 – 8 years): Formation of alveolus, thinning of pulmonary epithelium (type 1 pneumocytes), establishment of blood-air-barrier.
*Transition from placental dependence to GAS EXCHANGE*
```
119
What is the cause of a trachealesophageal fistula (TEF) and when does it occur?
Symptoms (3)?
TEF: an abnormal passage between the trachea and the esophagus. R
-Results from incomplete division of the cranial part of the foregut into respiratory and esophageal parts during the FOURTH WEEK.
***The usual anomaly is a BLIND ENDING of the superior part of the esophagus (esophageal atresia)***
*Most common anomaly in lower respiratory tract*
Symptoms: Excess fluid in mouth, milk regurgitation (atresia), aspiration pneumonia/pneumonitis.
p.133
120
What signs on a prenatal US would indicate TEF?
Polyhydramnios, lack of air in fetal stomach, low fetal weight.
121
What is oligohydramnios? Why is this bad?
Low amniotic fluid volume – because it restricts fetal thorax size, and the fluid helps fetus work out lungs prior to birth.
122
What is the sinus venosus?
The sinus venosus is a large quadrangular cavity which precedes the atrium on the *venous side* of the chordate heart.
123
1. ) The valve which closes the oval foramen is derived from what primordial structure?
2. ) The oval foramen originates as what primordial structure?
1. ) Septum primum
2. ) Foramen secondum
p. 200
124
What is the area where cranial sutures meet called?
Fontanelles
| p.232
125
Which end of the heart tube is arterial and which is venous? When it begins looping, which way does each go? Cephalic end
Caudal end
Cephalic end –arterial end – Ventral & to the right
| Caudal end –Venous end – Dorsal & to the left
126
Which way does the bulboventricular loop bend? What about in dextrocardia?
Bulboventricular loop bent to the right – dextrocardia to the left.
127
What do the right and left horns of the sinus venosus become?
Right horn enlarges– sinus venarum of right atrium
| Left horn –coronary sinus
128
What causes a fixed wide split of S2?
Ostium secundum defect
129
Where does the membranous part of the IV septum arise from ?
Endocardial cushion
130
What can dailure of spiralling of Aorto-pulmonary septum lead to ?
Transposition of great vessels
