Which of the following embryonic layers contribute to the formation of limbs?
ectoderm
endoderm
mesoderm
neural crest cells
By the ___th week of development, osteogenesis of the long bones begins.
4th
5th
6th
7th
Which of the following statements is true regarding limb development?
The upper and lower limbs develop along the same timeline
The upper limbs begin to develop before the lower limbs
The lower limbs begin to develop before the upper limbs
The positions of the limbs do not change as the embryo grows
Which of the following chromosomal aneuploidy syndromes is associated with polydactyly?
Monosomy X
Trisomy 13
Trisomy 18
Trisomy 21
All of the following are true regarding Rickets except?
It can be due to vitamin D deficiency and hypophosphatemia
Affected individuals have dental anomalies including hypomineralization of enamel
Affected individuals have abnormal appearing bones/limbs aside from just short stature
The only mode of inheritance is autosomal recessive
The limb defect known as ________, also called lobster-claw deformity or forked hand is associated with a type of congenital ectodermal dysplasia.
Meromelia
Phocomelia
Ectrodactyly
Adactyly
All of the following mechanisms are necessary for normal limb development except:
Apoptosis
Inductive interactions and secretions of SHH
HOX gene expression
Cellular migration of sclerotome from somites
The most critical period of limb development is between _____ to _____ days; certain teratogen exposures during this time greatly increases the risk for limb defects.
24 to 36 (beginning of embryonic period)
38 to 50 (middle of embryonic period)
52 to 63 (end of embryonic period)
Most visible changes occur during what period of development?
10 to 14 weeks
20 to 28 weeks
3 to 8 weeks
15 to 20 weeks
Each of the following conditions can result in death during the neonatal period except:
Congenital heart defects
Hypertrichosis
Ichthyosis
Renal agenesis
All of the following are congenital heart defects that will result in cyanosis except:
Tetralogy of Fallot
Transposition of the Great Arteries
Patent Ductus Arteriosis
Truncus Arteriosus
All of the following syndromes involve abnormal tooth development. Which is autosomal dominant?
Treacher Collins syndrome
Rickets
Pierre Robin
Amelogenesis Imperfecta
Which of the following describes an abnormality of the digits commonly associated with skeletal dysplasias (especially achondroplasia)?
Brachydactyly
Polydactyly
Syndactyly
Which type of skeletal dysplasia is also known as "brittle bone disease"?
Camptomelic dysplasia
Chondrodysplasia punctata
Achondroplasia
Osteogenesis imperfecta
Which of the following is a risk factor for limb anomalies?
Uncontrolled maternal diabetes
Thalidomide exposure during embryonic period
Chromosomal aneuploidy
All of the above are risk factors for limb anomalies
Limb reduction defects range in severity depending on what embryonic age there was disruption of limb formation. Amelia is the most severe.
Most cases of syndactyly are osseous (involving bone) and include functional appendages/digits with bones, nerve and musculature.
The recurrence risk for congenital hip dislocation/developmental hip dysplasia is less than 1%.
Minor defects of limbs are relatively common and can be corrected surgically.
Your skin has both thick and thin components which both contain sweat glands, hair follicles, arrector muscles of hairs, and sebaceous glands.
The secretory parts of the eccrine and apocrine sweat glands open into the skin and begin to function shortly after birth.
Hair follicles and glands are derived from the epidermis and grow down into the dermis.
Males and females have lactiferous ducts as part of the mammary gland.
Delayed tooth eruption can be a sign of hypothyroidism.
Babies that are born very prematurely (i.e. before 26 weeks) are not at increased risk for neurological or developmental problems, however they may have fingernails that have not yet reached the tips of their digits and may have cardiovascular complications, such as patent ductus arteriosis.
Explain the concept of incomplete penetrance
The is superficial epithelial tissue derived from surface embryonic ectoderm and the is a deep layer of dense, irregularly arranged connective tissue derived from mesenchyme.
is a fetal adaptation made from exfoliated peridermal cells and secretions from sebaceous glands. is the fine hairs that cover the surface of fetal skin.
Occulocutaneous albinism is an autosomal condition. There is a lack of pigment due to an underlying defect in tyrosinase production. Two clinical features of this syndrome are and .
The hardest tissue in the human body is .
is a condition characterized by absence of the pectoralis major muscle that results in hypoplastic fused ribs, unilateral absence of breast, nipple, areola, hemivertebrae, syndactyly, brachydactyly, and in some cases dextrocardia.
Name 3 body cavities that make up the Intraembronic Coelom during the 2nd month:
Two "fruity" signs that are ultrasound findings which may be associated with underlying defects of the nervous system are the and signs. Their presence may be associated with other anomalies including congenital clubfoot and clenched fists.
A is a type of lymphatic angioma that may be associated with chromosomal aneuploidy and poor pregnancy outcome.
For each of the following teratogenic substances, list a potential consequence/fetal anomaly. Primary rubella infection tetracycline exposure high maternal blood sugar levels thalidomide primary zika infection carbamazepin
A type of lower limb defect known technically as congenital vertical talus is also a feature of trisomy 18❌
A type of upper limb defect caused by a defect of the digital rays to form a central digit or digits❌
The most common musculoskeletal deformation, also associated with some neural tube defects❌
A condition involving a hemifacial hemangioma (port-wine stain) and possibly an underlying angioma in the meninges of the brain that causes seizures❌
Enlargement of male breast tissue, often associated with Klinefelter syndrome❌
The karyotype for Klinefelter syndrome
The term that describes supernumerary nipples❌
This soft marker is characterized by a dilated renal pelvis easily detectable by prenatal ultrasound. It is seen in about 25% of fetuses that have Down syndrome❌
