30 Questions
Which of the following structures will develop into the epiblast of the bilaminar disk?
embryoblast (inner cell mass)
How many germ layers are found in a gastrula?
Three
Choose the TRUE statement re: cleavage in the early embryo:
Cleavage tends to cause blastomere cells to become smaller and smaller with each cell division.
Which of the following is a function of the notochord?
It induces the overlying ectoderm to become the primordium of the central nervous system
Choose the TRUE statement about the connecting stalk in the early embryo.
The connecting stalk develops later into the umbilical cord and is formed from extraembryonic mesoderm
Lateral folding of the embryo causes the endoderm layer to be incorporated into what will become:
The midgut
Choose the TRUE statement regarding the brain vesicles
The myelencephalon later becomes the medulla
Which of the following structures develops from the intraembryonic coelom?
The pericardial cavity
Choose the TRUE statement regarding tail folding in the development of the embryo.
It brings the connecting stalk towards the ventral surface of the embryo.
Choose the TRUE statement about spinal cord development:
The basal plate forms the ventral and lateral gray horns and has a predominantly motor function
Where do red blood cells first develop in the embryo?
From the vessel primordia in the extravesical a-embryonic mesoderm of the umbilical vesicle and allantois
Choose the TRUE statement regarding the umbilical vein:
The umbilical vein carries oxygenated, nutrient-rich blood
The perimysium is a connective tissue sheath that surrounds:
One fascicle
Which of the following components of the sarcomere will shorten (get smaller) during muscle contraction?
The I-band
Choose the TRUE statement regarding calcium release in the skeletal muscle cell.
The L-type calcium channel is a voltage-gated channel that is activated by the action potential
Choose the TRUE statement about the umbilical artery:
The umbilical artery carries deoxygenated, nutrient-poor blood to the placenta
In the spinal cord, the cells of the alar plate later become:
the dorsal gray horns
Choose the TRUE statement regarding the brain vesicles
The myelencephalon later becomes the medulla
Which of the following structures is an important organizer of the head and mouth regions?
pre-chordal plate
During gastrulation, the cells that remained within the epiblast become which germ cell type?
Ectoderm
Which of the following is a function of the zona pellucida?
It helps ensure that only one sperm fertilizes the ovum.
Choose the TRUE statement regarding the primitive streak.
The primitive streak develops at the caudal end of the embryo within the epiblast - it is the area that gives rise to mesodermal and endodermal cells.
Which of the following is NOT a role of the notochord?
It induces the formation of the prechordal plate.
The neural crest cells eventually give rise to:
The dorsal root ganglia
Choose the TRUE statement regarding notochord development.
The notochordal process develops a lumen (canal), but later becomes a solid "rod" when it matures to become the notochord
The ____________________ bring(s) the heart tube ventrally, close to the future site of the mediastinum.
Head fold
You would find capillaries in:
Tertiary chorionic villi
Choose the TRUE statement regarding hCG (human chorionic gonadotropin).
hCG is secreted by the syncytiotrophoblast - it prevents the shedding of the endometrium.
When calcium binds to ________________, then ___________________ reveals the myosin-binding site on actin.
troponin; tropomyosin
Choose the TRUE statement about tetany in skeletal muscle fibres:
During tetany, calcium clearance into the SR (sarcoplasmic reticulum) is inadequate to drop cytosolic calcium levels low enough to result in sarcomere relaxation.
Study Notes
Embryonic Development
- The epiblast of the bilaminar disk develops from the inner cell mass.
- A gastrula has three primary germ layers: ectoderm, mesoderm, and endoderm.
- True statement about cleavage: It is a process of rapid cell division without significant growth, resulting in a cluster of cells.
Notochord and Germ Layers
- The notochord provides a flexible, rod-like structure that provides support and gives rise to the spinal cord.
- True statement about the connecting stalk: It forms the umbilical cord and attaches the embryo to the trophoblast.
- Lateral folding of the embryo causes the endoderm layer to be incorporated into the foregut and hindgut.
- The notochord does not give rise to the neural crest cells.
Brain and Spinal Cord Development
- True statement about the brain vesicles: They eventually develop into different brain regions, including the forebrain, midbrain, and hindbrain.
- The spinal cord develops from the neural tube, which is derived from the ectoderm.
- True statement about spinal cord development: The alar plate cells give rise to the sensory neurons.
- Red blood cells first develop in the embryo's yolk sac.
Umbilical Structures and Blood Vessels
- True statement about the umbilical vein: It carries oxygenated blood from the placenta to the embryo.
- The umbilical artery carries deoxygenated blood from the embryo to the placenta.
- True statement about the umbilical artery: It branches off into the vitelline arteries.
Muscle Development and Function
- The perimysium is a connective tissue sheath that surrounds a group of muscle fibers.
- During muscle contraction, the sarcomere's actin and myosin filaments shorten.
- True statement regarding calcium release: It is released from the sarcoplasmic reticulum, allowing muscle contraction to occur.
- True statement about tetany: It is a state of muscle contraction caused by low calcium levels.
Organizer and Germ Cell Types
- The notochord is an important organizer of the head and mouth regions.
- During gastrulation, the cells that remained within the epiblast become the endoderm.
- The zona pellucida helps prevent polyspermy during fertilization.
- True statement regarding the primitive streak: It forms the site of gastrulation and gives rise to the mesoderm and endoderm.
Miscellaneous
- The neural crest cells eventually give rise to the peripheral nervous system, cranial nerves, and sensory neurons.
- True statement about hCG: It is produced by the syncytiotrophoblast and maintains the corpus luteum during pregnancy.
- Capillaries are found in the villi of the placenta.
- When calcium binds to troponin, tropomyosin reveals the myosin-binding site on actin.
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