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level: Level 1

Questions and Answers List

level questions: Level 1

QuestionAnswer
From what structure does the Embryo Proper develop?Embryonal Disc (central part)
What structure connects the fetal membranes to the surrounding fetal membranes and placenta?Umbilical chord
Name the 10 steps of the Development of the Body Form1) Cylindrical Body Formation; 2) Formation of the Chorion & Amnion; 3) Futher Development of the Nervous System; 4) Initial Development of the Cardio-Vascular System; 5) Further Development of the Digestive System; 6) Initial Development of the Urogenital System; 7) Further Development of the Trunk; 8) Further Development of the Head; 9) Formation of the Tail; 10) Formation of the Limbs
Embryonic FoldingEmbryo changes shape from a flat trilaminar disc to a cylinder
Embryonic Folding Occurs in the _____ and _____ Planes.Horizontal; Median
Two Lateral Body Folds is the result of _____ folding.Horizontal
Embryonic folding in the median plane leads to the development of the _____ and _____ foldsCranial; Caudal
What germ layer is responsible for the development of the GIT?Endoderm
What structure ruptures at the end of the fourth week of development to form the mouth?Oropharyngeal Membrane
What structure is formed at the connection between the Midgut and the Yolk Sac?Vitelline Duct (Narrow Tube)
What structure temporarily closes the hindgut at the caudal end?Cloacal Membrane
The Cloacal membrane ruptures to form the _____ and _____ openings.Urogenital; Anal
During embryonic folding what part of the embryo is the first to become cylindricalHead
What body folds are involved in the formation of the head?Ventral merging of the head Folds with the most cranial sections of the Lateral Folds
Cephalic FlexureVentral deflection of the head process Caused by the the dorsal aspect of the head growing more rapidly than the ventral aspect
What body folds are involved in the formation of the tail bud?Ventral merging of the Tail Folds with the most caudal sections of the Lateral Folds
Pre-enteronForegut
MetenteronHindgut
MesenteronMidgut
The _____ _____ assists in the advancement of the tail fold.Sacral Flexure
The _____ _____ assists in the advancement of the head fold.Cephalic Flexure
Name the 2 structures involved in the formation of the Foregut (Pre-enteron)?Head Fold; Cephalic Flexure
Name the 2 structures involved in the formation of the Hindgut (Metenteron)?Tail fold; Sacral Flexure
Where does the lateral body folds develop?In the Somatopleure, on either side of the embryo
Name the 2 structures that are involved in the formation of the Midgut (Mesenteron)?Lateral Body Folds Dorsal portion of the Yolk Sac.
The _____ mesoderm of the four body folds (head, tail, 2x lateral) fuses with the _____ mesoderm to form the _____ _____.Somatic Splanchnic Umbilical Chord
What structure separates the endo- and exocoelom?Umbilical Chord
Somatic Mesoderm of the Umbilical Chord is surrounded by a layer of ectoderm that continues proximally with the _____ of the embryo, and distally with the _____.Ectoderm Trophoblast
Name the 4 structures that the early umbilical chord consists of.Vitelline Duct Blood Vessels Splanchnic Mesoderm Somatic Mesoderm
Describe formation of the Ventral Body Wall Cranial to the Umbilical Chord.Merging of the head fold and two lateral body folds ventral to the primitive gut. After fusion the ventral body wall consists of ectodermal and somatic mesodermal layers.
Describe formation of the Ventral Body Wall caudal to the Umbilical Chord.Merging of the tail fold and two lateral body folds ventral to the primitive gut. After fusion the ventral body wall consists of ectodermal and somatic mesodermal layers.
From what structure does the chorioamniotic folds develop?Somatopleure
Name the structure that runs continuously with the outer lamina of the chorioamniotic folds?Trophoblast
Name the structure that runs continuously with the inner lamina of the chorioamniotic folds?Somatopleure surrounding the umbilical chord
The prosencephalon develops to form the two cerebral hemispheres of the _____, and the centrally placed diencephalonTelencephalon; Diencephalon
Name the ventricles of the ProsencephalonLateral ventricles of the Cerebral Hemispheres and the Third Ventricle of the DIencephalon
Name the structure that connects the third ventricle to the fourth ventricleMesencephalic Aqueduct
Name the structures that make up the Rhombencephalon (including their substructures)Metencephalon (Cerebellum and Pons) Myelencephalon (Medulla Oblongata)
Name the Ventricle of the RhombencephalonFourth Ventricle
When does the embryo obtain its C-shape?When the four flexures are maximally developed. Approximately day 20
Name the 4 flexures.Cephalic Cervical Dorsal Sacral
From what coelom does the Pleural and Pericardial cavaties develop?Pleuropericardial Coelom
Describe the formation of the pleuropericardial coelom.Internal delamination of the mesoderm peripheral to the developing head region.
What structure prevents the pleuropericardial coelom of expanding?Solid wall of unsplit metoderm (connecting the soma- and splanchnopleure)
The pleuropericardial coelom communicates caudally with the _____.Endocoelom
Name the structure from which the heart develops.Cardiogenic Plate (delaminated mesoderm)
The unsplit mesodermal plate just in front of the cardiogenic plate will later form the _____ _____.Septum transversum
The transverse septum lies caudo-dorsal to the apex of the _____ _____, caudal to the developing _____ and ventral to the _____.Pleuropericardial coelom Heart Pre-enteron (Foregut)
The liver will be formed as an evagination of the _____ and will grow into the _____ _____.Duodenum Septum Transversum
The Septum Transversum will form part of the _____ to which the _____ will remain attached by ligamentsDiaphragm Liver
What structure is responsible for the "pot-belly" of the young embrio?Heart
The _____ is initially the most prominent organ, but later the _____ becomes the more prominent.Heart Liver
A shallow cleft between the heart and liver bulges indicates the position of the future _____.Diaphragm
What structure connects the primitive Mesenteron to the Yolk Sac?Vitelline Duct
What structure forms the rostro-ventral border of the pre-enteron?Oropharyngeal Membrane (Formerly the prechordal plate)
The stomodeum is formed ventral to the _____, it is bounded rostrally by the _____ _____, laterally by the _____ primordia, and caudally by the _____ bulge.Oropharyngeal Membrane Head Process Jaw Cardiac
The oropharyngeal membrane later ruptures and this establishes communication between the _____ cavity and _____.Oral Pharynx
The _____ ______ forms the caudo-ventral border of the metenteron.Cloacal Membrane
After the cloacal membrane ruptures, the cloacal opening is devided horizontally by the caudally directed _____ septum to form the _____ (dorsally) and the _____ opening (ventrally).urorectal anus urogenital
How is the proctodeum formed?Anal hillocks develop on either side of the anus forming the anal canal
Between what 2 structures does the Labio-scrotal swellings and Genital Tubercule (Phallus) develop?Urogenital Opening Umbilicus
The labio-scrotal swellings become the _____ (male) or _____ female.Scrotum Labia
The Phallus (Genital Tubercule) become the _____ (male) or _____ female.Penis Clitoris
The allantois (one of the fetal membranes) develops as a ventral outgrowth of the _____; it extends through the _____ _____(where it is surrounded by splanchnic mesoderm) and expands into the _____.Metenteron Umbilical Chord Exocoelom
Name the structure that connects the distal saccular portion of the allantois to the metenteron?Allantoic Duct
From what structure does the urinary bladder develop?Proximal portion of the allantoic duct (Urachus)
What structure connects the embryo to the fetal membranes?Umbilical Cord
Name the structures that the umbilical cord consists of.Vitelline Duct Paired Vitelline arteries and veins (for as long as the yolk sac persists) Allantoic Duct Paired Umbilical arteries and veins
The bones of the cranium and the surrounding connective tissues are formed from head _____.Mesoderm
The facial skeleton, which supports the rostral _____ and _____ _____, originates from _____ _____ _____ with contributions from the _____ _____.Pre-enteron Respiratory tract Paryngeal arch Mesoderm Neural Crests
What structure forms the future optic nerve?Optic Stalk
How long after birth does the eyes of carnivores remain closed?8-12 days
The eyes are initially directed _____; after formation of the face, they are directed more _____ in species with well-developed binocular vision (e.g. carnivores).Laterally Medially
What structure gives rise to the adenohypophysis?Rathke's Pouch
Where does Rathke's pouch develop?In the roof of the stomodeum, just rostral to the oropharyngeal membrane. It grows to-wards the mid-brain where it will give rise to the adenohypophysis.
Seessel's pouch develops in the roof of the _____, just caudal to the _____ _____.Pharynx Oropharyngeal membrane
Rupture of the oropharyngeal membrane establishes communication between the _____ _____ and _____.Oral cavity Pharynx
Name the structure responsible for the development of the pharyngeal pouches.Pre-enteron
The ectoderm overlying each pharyngeal pouch invaginates to form a (a). Each (a) is separated from its corresponding pouch by a (b), a thin sheet consisting of ectoderm and endoderm in contact with one another.a) Pharyngeal groove b) Pharyngeal membrane
Rostral to the first pharyngeal groove and between successive pharyngeal grooves, the mesoderm proliferates to form dorso-ventrally orientated, outward-bulging structures known as _____ _____.Pharyngeal arches
In theory, _____ pharyngeal arches are formed; however, only the first _____ are clearly distinguishable.6 3
Name the pharyngeal pouch that never reaches the ectoderm.Pharyngeal Pouch IV
Name the 3 tissues that are developed from each pharyngeal arch.Cartilage Blood vessel (aortic arch) Muscle
The aortic arches are also numbered from rostral to caudal; they connect the ventrally situated _____ _____ (cranially directed from the heart) to the two dorsal _____.Truncus arteriosus Aortae
Name the largest pharyngeal arch.Pharyngeal Arch I
Pharyngeal Arch I comprises a short _____ prominence (rostrally) and a longer _____ prominence (caudally). The groove between the two prominences will eventually form the _____ __ __ _____.maxillary mandibular angle of the mouth
Name the structure that separates the maxillary prominence from the from the frontonasal prominence.Nasolacrimal groove
The nasal _____, the future nostril, invaginates to form the nasal _____; continued development of the nasal pit will form the nasal _____.placode pit cavity
What structure allows the nostril to communicate with the stomodeum?Nasomaxillary groove
The nostril is bordered by _____ and _____ nasal prominences that develop from the rostral part of the frontonasal prominence.medial and lateral
The fusion of the medial nasal prominences also forms the median (central) portion of the upper lip and gum; in the dog and sheep, the line of fusion is clearly visible as a vertical groove, the _____, running between the nostrils and dividing the upper lip in half.philtrum
Defective fusion of the medial nasal prominences is seen as a central _____.harelip
The maxillary prominence gives rise to a medially directed (a). The left and right (a)s fuse with each other and with the (b).a) palatine process b) nasal septum
What structure separates the oral and nasal cavities?Palatine Process
Defective fusion of what structure leads to the formation of a cleft palate?Palatine Processes
Each maxillary prominence fuses with the medial nasal prominence and eliminates the _____ _____ and forms the _____ portion of the upper lip and gum.nasomaxillary groove lateral
Defective fusion of the maxillary prominence with the medial nassal prominence causes the development of a lateral _____; this condition sometimes occurs bilaterallyharelip
Each maxillary prominence fuses with the lateral nasal prominence and forms the ventro-lateral quadrant of the _____. Fusion causes invagination of the ectodermal cells forming the _____ _____.nostril nasolacrimal groove
Nasolacrimal groove becomes hollow and forms the _____ _____, which runs from the medial angle of the _____ to the ventral part of the _____ _____.nasolacrimal duct eye nasal cavity
The primordium of the inner ear, the _____ _____, develops from an ectodermal thickening dorso-caudal to the first _____ _____.otic placode pharyngeal groove
The otic placode invaginates to form the (a). The (a) separates from the ectoderm to form the (b) which later migrates deeper to assume its correct position opposite the (c).a) otic cup b) otic vesicle (or otocyst) c) middle ear
The auricle, the cartilaginous part of the external ear, is formed by parts of the first and second _____ _____.Pharyngeal arches
What structure forms the external auditory meatus?Pharyngeal groove I
What structure forms the middle ear?Pharyngeal pouch I
What structure forms the tympanic membrane?Pharyngeal membrane I
What structure forms the auditory ossicles?Cartilages of the first and second pharyngeal arches
What structure maintains the communication between the Pharyngeal Pouch I and the pharynx?Eustachian tube (auditory tube)
The end bud is formed by the retreating _____ _____ when it reaches the caudal end of the _____ _____.primitive node primitive streak
Name the structures that will differentiate to form the tissues of the tail.notochord paraxial mesoderm neural tube
The tail bud also contains the tail gut, a dorso-caudal evagination of the _____; however, this structure soon completely disappears.metenteron
Name the 2 structures from which the caudal vertebrae develop?notochord and mesodermal somites
From what structure does the somites develop?Paraxial Mesoderm
Besides the vertebrae, name the other tissues that the somites give rise to.Caudal muscles Fasciae Ligaments
The caudal neural tube diminishes in size and, in the adult animal, is seen only as the _____ _____.Filum terminale
The _____ aspect of the tail develops more rapidly than the _____ aspect and this causes ventral flexion of the tail; the distal end of the tail usually lies to the _____ of the body.dorsal ventral left
From what structure does the limbs develop?Wolffian ridges
The _____ limbs develop from the cranial portions of the Wolffian ridges, while the _____ limbs develop from the caudal portions; the ridges' _____ portions soon disappear.thoracic pelvic middle
The thoracic limb buds form just dorsal to the _____ and are visible at an early age (day 17-18 in the pig); the pelvic limb buds form in the region of the _____, but at a slightly later stage. The limb buds initially consist of dense mesoderm covered by ectoderm.heart sacrum
In man, all five digits develop fully; in the carnivores, digit _____ is reduced or absent.I
In man, all five digits develop fully; In the pig and ruminants, digits _____ and _____ are reduced and digit _____ is absent.II V I
In man, all five digits develop fully; while in the horse, only digit _____ develops fully.III
The heart develops in the _____.Pleuropericardial Coelom
True or False? The chrorioamniotic folds form a continuous groove around the embryo proper.False The body folds form a continuous groove around the embryo proper.
True or False? In the embryo the tail bud contains the tail gut.True
The mandibular arch is pharyngeal arch number:I
The lens develops from the:Ectoderm
The grey matter (cell bodies) originates from the:Mantle layer
True or False? Seesels’s pouch is the origin of the adenohypophysis.False Rathke's pouch is the origin of the adenohypophysis.