Final Exam Flashcards
1
Q
When does the skeletal system of the embryo begin to form?
A
At the end of the 4th week of development
2
Q
Somites divide into what two parts?
A
Dermomyotome (dermatome and myotome) and Slcerotome
3
Q
The skeletal system begins development with what part of the somites?
A
The ventral medial somite.
4
Q
Somites develop specifically from what embryonic layer?
A
Paraxial mesoderm
5
Q
In general, what embryonic layer gives rise to the skeletal system?
A
Mesoderm
6
Q
The dividing somite is made up of mesodermal cells, which give rise to what?
A
Mesenchyme
7
Q
This structure is a meshwork of loosely organized embryonic connective tissue. Bone and cartilage develop from it.
A
Mesenchyme
8
Q
What are the two types of cartilage bone development?
A
Intercartilagenous and endochondral ossification
9
Q
The cartilage stage in bones can grow rapidly to match what?
A
The growth of the fetus
10
Q
When does cartilage begin to form?
A
The middle of the 5th week
11
Q
These are mesenchymal cells that proliferate, enlarge, and become round. They also produce collagenous fibers and matrix.
A
Chondroblasts
12
Q
Chondroblasts form what type of centers?
A
Chondrification centers
13
Q
What does internal growth of cartilage result from?
A
Division of cartilage cells and from the production of matrix
14
Q
The growth of cartilage follows the growth of what other type of tissue?
A
Bone tissue
15
Q
During what week of development do mesenchyme cells condense to form chondrification centers?
A
8th week
16
Q
What type of cells lay down new bone tissue?
A
Osteoblasts
17
Q
When osteoblasts become trapped within bone tissue what type of cells do they develop into?
A
Osteocytes
18
Q
Condensation of mesenchyme will give rise to what?
A
The formation of bone models
19
Q
Describe intramembranous ossification?
A
- Mesenchyme condenses and vascularizes
- Cells differentiate into-osteoblasts, which deposit osteoid tissue to form ossification centers
- Bone matrix is deposited to form lamellae, which develop around blood vessels to form osteons
- The lamellae then grows and thickens to become trabeculae
20
Q
What are the two types of development for the skull?
A
Neurocranium and splanchinocranium
21
Q
Where does the neurocranium develop from?
A
The mesenchyme surrounding the brain
22
Q
What are the two types of neurocranium development?
A
Neurochondrocranium and neuromembranocranium
23
Q
This type of neurocranium development involves the cartilaginous base of the neurocranium and the skull and is followed by endochondral ossification, which begins around 8 weeks.
A
Neurochondrocranium
24
Q
This type of neurocranium development involves the sides and the roof of the neurocranium and is formed by intramembranous ossification.
A
Neuromembranocranium
25
During fetal life, bones are separated by connective tissue membranes known as what?
Sutures
26
At the angle of bones within the skull of the developing fetus, large fibrous areas are formed. The membranes covering these spaces are known as what?
Fontanelles
27
What are the names of the fontanelles of a developing child?
Anterior, posterior, anterolateral, and posterolateral fontanelles
28
When does the anterior fontanelle close?
It closes by the end of the second year.
29
What is the largest fontanelle in a developing child?
Anterior fontanelle
30
When does the anterolateral fontanelle close?
At two to three months
31
When does the posterolateral fontanelle close?
At the end of the first year
32
Due to the softness, fontanelles and sutures of the fetal skull what can undergo changes during the birth process?
Calvaria or skull cap
33
This type of splanchnocranium undergoes endochondral ossification and is composed of replacing bone.
Splanchnochondrocranium
34
The cartilaginous skeleton develops from what?
Visceral, pharyngeal, or branchial arches
35
How many visceral, pharyngeal, or branchial arches do humans have?
We start with 6 but the 5th disappears in 1.5 days.
36
What does the first visceral arch form?
Palate, maxilla, meckel's cartilage, incus, and malleus. Muscles of mastication
37
What does the second visceral arch form?
Stapes, cranial half of the hyoid, and lesser horn. Facial muscles
38
What does the third visceral arch form?
The caudal half of the hyoid and the greater horn. Stylo-pharyngeal muscle
39
What do the 4th and 6th visceral arches form?
Cartilages of the larynx. No ossification occurs here. Laryngeal muscles, pharyngeal muscles, palate muscles, part of the SCM, and part of the trapezius
40
The vertebral column develops from what?
Somite mesenchyme sclerotome
41
When does chondrification of the vertebrae occur?
7th week in the cranial vertebrae and follows to lower levels
42
Vertebral arches do not unite to form spinous processes until what time?
The 3rd month after birth
43
When does ossification of the vertebrae occur?
Begins at 9 weeks
44
How many ossification centers are there in the vertebrae? Where are they located?
There are three. One in the centrum and one in each half of the vertebral arch
45
How many ossification centers are present on the vertebrae during puberty? Where are they located?
There are 5. One at the tip of the spinous process, one at each tip of the transverse process, and two on the rim of the epiphyseal center
46
Where do the ribs develop from?
The mesenchyme and cartilage of the costal processes
47
How many ossification centers does each rib have? When does ossification occur?
One. Occurs in the 9th week
48
This bone begins as intramembranous bone, develops growth cartilages at both ends, and ossifies before any other bone.
Clavicle
49
This condition is more commonly known as dwarfism, autosomal dominant, and is characterized by slow growth of cartilage and bone ossification resulting in a small stature, megalocephaly (large face, head), and skeletal issues.
Achondroplasia syndrome
50
This is a mild form of achondroplasia characterized by small stature and short bowed limbs/lumbar lordosis.
Hypochondroplasia syndrome
51
This condition is characterized by the storage of lipids in the nervous system and an accumulation of mucopolysaccharides in the mesenchyme.
Mucopolysaccaridosis (Hurlers and Hunters)
52
This condition is characterized by clavicle agenesis, skull disorders, and jaw disorders.
Cleidocranial dysostosis
53
This type of spina bifida is limited to the skeletal components.
Occulta
54
This type of spina bifida occurs in the meninges (meningocoele) and the meninges and spinal cord (meningomyelocoele).
Cystica
55
This condition is characterized by abnormal curvature of the spine (numerical variations, morphological variations, or both)
Congenital scoliosis
56
This condition is characterized by the lack of ossification of the skull at the time of birth.
Cranial dysostosis
57
This is characterized by a premature closure of the sutures of the skull.
Craniostenosis
58
This condition is characterized by all of the sutures closing prematurely and symmetrically.
Oxycephaly
59
This condition is characterized by all of the sutures closing asymmetrically.
Plagiocephaly
60
This condition is characterized by the sagittal sutures closing prematurely.
Scaphocephaly
61
This condition is characterized by the coronal suture closing prematurely.
Acrocephaly (brachycephaly)
62
This condition is characterized by acrocephaly (premature closure of the coronal sutures) and syndactyly (fusion of the digits).
Aperts
63
This condition characterized by scaphocephaly (premature closure of the sagittal sutures) and no syndactyly (fusion of the digits)
Crouson's
64
This condition is characterized by a complete absence of limbs and is most often caused by environmental factors
Amelia
65
This condition is characterized by an absence or reduction of the proximal part of the limbs and is most often caused by environmental factors.
Phocomelia
66
This condition is characterized by an absence or reduction of the distal part of the limbs and is most often caused by environmental factors.
Meromelia
67
This condition is characterized by hypoplasia and fusion of the lower limbs and occurs spontaneously.
Sympodia (monopodia)
68
This condition is characterized by a duplication of the distal parts of the limbs and is autosomal dominant.
Dichiria
69
This condition is characterized by the presence of extra digits and is autosomal dominant.
Polydactyly
70
This condition is characterized by the fusion of digits and is autosomal dominant.
Syndactyly
71
What embryonic layer does the muscular system develop from?
Mesoderm
72
What are the divisions of skeletal muscle?
Epimere/epiaxial (small dorsal division) and hypomere/hypaxial (large ventral division
73
These form the extensor muscles of the vertebral column and the dorsal primay rami.
Epimers
74
These give rise to the muscles of the limbs and body wall, as well as the ventral primary rami.
Hypomers
75
What is the normal direction that muscles develop in?
Craniocaudal direction
76
What are some examples of changes in muscle direction?
- Migration of a muscle (latissimus dorsi)
- Fusion of successive myotomes (rectus abdominus)
- Longitudinal splitting of the myotome (sternohyoid)
- Tangential splitting of the myotomes (oblique and transverse muscles of the abdomen)
- Degeneration of myotomes- forms ligaments (tensor fascia lata)
77
What is the innervation of the 1st visceral arch?
Trigeminal nerve (V)
78
What is the innervation of the 2nd visceral arch?
Facial nerve (VII)
79
What is the innervation of the 3rd visceral arch?
Glossopharyngeal (IX)
80
What is the innervation of the 4th and 6th visceral arches?
Vagus (X) and hypoglossal (XII)
81
What are limb buds made from?
Muscular mesenchyme
82
Where is cardiac muscle derived from?
Splanchnic mesoderm
83
Do most muscle defects affect one or both sides?
Most muscle defects are unilateral
84
What is the most common muscle defect?
Pectoralis
85
What muscle defect is always bilateral?
Abdominal muscles
86
This condition is characterized by a distended abdomen from aplasia of the abdominal musculature.
Prune belly
87
Below umbilicus what is the abdominal muscle that is most frequently and bilaterally absent?
Transverse abominus is the most frequent followed by rectus abdominus
88
Above umbilicus what is the abdominal muscle that is most frequently and bilaterally absent?
Internal oblique is the most frequent followed by external oblique and rectus abdominus
89
This is a condition resulting from damage to the sternocleidomastoid (SCM) during development (position in the uterus or muscle development). It affects both sides, is autosomal dominant, and in the congenital form the SCM becomes fibrous.
Torticollis
90
What body system does the urinary system develop from?
Reproductive system
91
The urinary and genital system both develop from what specific embryonic layer?
Intermediate mesoderm
92
During development of the urogenital system a longitudinal ridge develops from the intermediate mass along the 7th to 28th somite level and extends along the dorsal body wall of the embryo. The longitudinal elevation of the mesoderm is known as what?
Urogenital ridge
93
During development of the urogenital system, along the 7th to 14th level of somites there are groups of segments sitting beside them. These segments are known as what?
Nephrotomes
94
What are the three distinct types of kidneys?
Pronephroi (1st), mesonephroi (2nd), and metanephroi (3rd)
95
When does development of the kidneys begin?
3rd week
96
Out of the three kidneys, which becomes the permanent set?
The third set or metanephroi
97
This is the first set of kidneys, are rudimentary, and have very little function. It develops from the 7th to 10th somite level and is referred to as the head of the kidney and degenerates around the 4th week.
Pronephroi
98
This is the second set of kidneys, are well developed, and function briefly. They are located at the 10-26th somite level, have 38 pairs of tubules, and have closed tubules.
Mesonephroi
99
Some of the mesonephric tubules and duct remain in the male to form what? What happens in females?
Genital duct system. In females none of these tubules are retained
100
This is the third set of kidneys and eventually become our permanent kidneys. They develop in the 5th week, located lateral to the mesonephric duct (26-28th somite), and has a duct system.
Metanephroi
101
What is the flat end of the bud of the metanephroi called?
Renal pelvis
102
What develops from the renal pelvis?
Major or minor calyces. Branching of the minor calyces produce the collecting duct system of the kidneys
103
Each kidney has approximately how many nephrons?
2 million
104
Are the kidneys in the fetus lobulated or smooth?
Lobulated, but smooth later on in development
105
Where are developing kidneys initially located? Where do they migrate to as a result of growth?
They are initially located in the pelvic area and then migrate to the abdomen as a result of body growth
106
When does the urinary bladder develop?
7th week of development
107
What structure is continuous with the bladder?
Allantosis
108
What is the allantosis known as in the fetus? In an adult?
In the fetus it is known as the urachus, but in the adult it becomes vestigial and is known as the median umbilical ligament.
109
This congenital malformation of the kidneys can be both bilateral or unilateral. It is characterized by the absence of a kidney.
Renal Agenesis. Potter Syndrome is another name for the bilateral condition
110
This congenital malformation of the kidneys is characterized by an incomplete development of the kidneys. Can be both unilateral or bilateral.
Renal hypoplasia
111
This type of condition is characterized by symmetrically enlarged kidneys.
Congenital cystic kidneys
112
How many types of congential cystic kidney are there?
5 types
113
This type of congenital cystic kidney is found in infants.
Type 1
114
This type of congenital cystic kidney is unilateral, the kidneys are variable in size and shape, and the cysts grow larger with age.
Type 2
115
This type of congenital cystic kidney contains normal and abnormal tissue. Both kidneys are involved and it is often found in trisomy individuals.
Type 3
116
This type of congenital cystic kidney can result in urethral obstruction due to the accumulation of cysts in the collecting tubules. Requires mild surgery to repair.
Type 4
117
This type of congenital cystic kidney manifests itself in adults and can cause low back pain and kidney infections. Can result in death in the 50s if not treated.
Type 5
118
Horseshoe and donut kidneys are common in individuals with what conditions?
Trisomies or turner's
119
This condition is characterized by renal tumors in children that originate from the mesoderm. Symptoms include abnormal facial features and vision/urinary/ambulatory problems.
Wilm's tumor
120
The reproductive system develops at what time?
5th-6th week (indifferent stage: sex cannot be determined)
121
When can sex identification occur?
8th week
122
What types of tissue do the gonads develop from?
Coelomic epithelium, inner mesenchyme tissue, and primordial germ cells
123
This is the precursor to the gonads.
Genital ridge
124
What is the genital ridge covered by?
Coelom epithelium
125
These structures are created from cells within the genital ridge and grow into the underlying mesenchyme.
Primary sex cords
126
The indifferent gonad has what two components?
Cortex (outer layer) and medulla (inner layer)
127
In the indifferent gonad, what happens to the cortex in males and females?
Males: cortex regresses
Females: cortex develops
128
In the indifferent gonad, what happens to the medulla in males and females?
Males: medulla regresses
Female: medulla develops
129
What develops from the testes cords?
Seminiferous tubules, tubuli recti, and rete testis
130
What does each follicle contain?
Ooblasts (derives from primordial germ cells and follicular cells (derived from the cortical cords)
131
The epididymis, ductus deferens, ejaculatory duct, cranial part-efferent ducts are formed from what?
Genital ducts
132
The genitalia pass through what type of stage?
An indifferent stage
133
What accessory glands are found in the male? Female?
Male: seminal vesicles, prostrate, bulbourethral glands
Female: there are none
134
This congenital malformation is characterized by ovaries that are small in size, poor breast development, and a small uterus. it can be unilateral or bilateral.
Ovarian hypoplasia (turner's syndrome)
135
This congenital malformation is a result of the germ cells not migrating from the yolk sac.
Pure gonadal dysgenesis
136
This condition is characterized by an individual appearing as a female despite the presence of testes. Genetically they are male, but raised as female.
Androgen Insensitivity or testicular feminization syndrome.
137
A female would test positive in a chromatin test due to the presence of what?
Barr bodies
138
A male would test negative in a chromatin test due to the absence of what?
Barr bodies
139
This is a condition characterized by excessive androgen production from the adrenals. Occurs in genetic females and masculinization results.
Adrenogenital syndrome
140
When does the cardiovascular system develop?
3rd week
141
Angioblasts develop from what?
Splanchnic mesoderm, mesenchyme of the yolk sac, mesenchyme of the umbilical cord, and mesoderm of the chorion
142
What composes the primitive vascular system?
Vitelline veins, umbilical veins, and cardinal veins
143
These veins are part of the primitive vascular system and return blood from the yolk sac.
Vitelline veins
144
These veins are part of the primitive vascular system and bring blood from the chorion (placenta).
Umbilical veins
145
These veins are part of the primitive vascular system and return blood from the body.
Cardinal veins
146
How does the heart develop?
-Two thin walled endothelial tubes (endocardial heart tubes), which are the continuation of the first aortic arches form a single tube
147
This is the sickle shaped crest acting as the roof of the atrium.
Septum Primum (1st wall)
148
This is the opening between the septum primum and endocardial cushion.
Ostium Primum (1st opening)
149
This is the opening in the septum primum
Ostium secundum (2nd opening)
150
This septum is formed when the right atrium incorporates part of the sinus.
Septum secundum (2nd wall)
151
This is the opening in the septum secundum
Oval foramen
152
This is the opening in the wall separating the right and left heart atria. it is necessary for communication between right and left atria.
Foramen ovale
153
Before birth, blood enters the right atrium from inferior vena cava to the left atrium via what?
Interatrial shunt
154
During development, the interatrial shunt allows the blood of the fetus to bypass what organ?
Lungs
155
When does the septum primum, and septum secundum fuse and the oval foramen close?
After birth
156
This developmental defect of the heart is characterized by the septum primum and septum secundum failing to fuse.
Probe patency of the oval foramen
157
Simple ebb and flow type of circulation begins on what day of development?
22nd day
158
By what days does the heart have unidirectional blood flow and contractions of the heart tube.
28-30 days
159
Oxygenated blood enters the fetus from the placenta via what?
Veins
160
Deoxygenated blood leaves the fetal body via what?
Arteries
161
This structure is a shunt in the fetal pulmonary truck that diverts blood back to the aorta.
Ductus Arteriosus
162
This structure is a shunt in the fetal heart that causes oxygenated blood to bypass the fetus' developing liver to reach the vena cava.
Ductus Venosus
163
During the 5th week ridges form in the walls of the truncus and bulbus. Their course is spiraled and eventually fuse to form the what structure?
Spiral septum or aorticopulmonary septum
164
This congenital malformation is characterized by the absence of a heart.
Acardia
165
This congenital malformation is characterized by a heart that is located outside of the body through the sternal fissure either through the neck or a diaphragmatic heniation.
Ectopic cordis
166
This congenital malformation is characterized by a heart that is located in the right hemithorax. It can occur alone, but is usually associated with other anomalies, such as situs inversus.
Dextra cardia
167
This congenital malformation is characterized by a small patent foramen ovale or a complete absence of the interatrial septum. Individuals have a loud systolic murmur and exhibit cyanosis (bluing)
Atrial septal defect (ASD)
168
This congenital malformation is similar to atrial septal defect. Individuals have a harsh systolic murmur (Erb's point) and no cyanosis.
Ventricular septal defect (VSD)
169
This congenital malformation is characterized by pulmonary stenosis, ventricular septal defect, overriding aorta, and right ventricular hypertrophy. Symptoms include cyanosis (bluing) and paroxysmal dyspnea with exertion
Tetraology of Fallot
170
What is the life expectancy of an individul with fallot without surgery?
Approximately 12 years
171
What is the trilogy of fallot?
- Pulmonary stenosis
- Atrial septal defect
- Right ventricular hypertrophy
172
This is used to describe an individual whose organs are the mirror image of what they should be.
Situs inversus
