9. N & NC Practice Questions Flashcards
Which of the following statements describing the primitive streak is not correct?
A. It initially develops in the cephalic portion of the bilaminar disk.
B. It identifies the site where the formation of embryonic mesoderm is initiated. C. It is the site where the formation of the notochord takes place.
D. It determines the body axis of the embryo.
E. It is a location where cells of the embryonic ectoderm invaginate.
A. It initially develops in the cephalic portion of the bilaminar disk.
Which of the following statements is correct about the cloacal membrane?
A. It is located between the notochord and primitive streak.
B. It is immediately caudal to the primitive knot.
C. It is composed of ectoderm, mesoderm, and endoderm.
D. It is formed prior to the formation of the primitive streak.
D. It is formed prior to the formation of the primitive streak.
Which of the following structures is not derived from ectoderm?
A. Spinal cord
B. Brain
C. Dermis of skin
D. Hair follicles
C. Dermis of skin
Which of the following structures is not derived from mesoderm?
A. Liver B. Skeletal muscle C. Cardiac muscle D. Smooth muscle E. Kidneys
A. Liver
Which of the following structures is not derived from endoderm?
A. Urethra
B. Pancreas
C. Epithelial lining of the urinary bladder
D. Vertebrae
D. Vertebrae
Which of the following population of mesodermal masses contributes to the body wall?
A. Paraxial mesoderm
B. Intermediate mesoderm
C. Axial mesoderm
D. Somatic layer of lateral plate mesoderm
E. Splanchnic layer of lateral plate mesoderm
D. Somatic layer of lateral plate mesoderm
Failure to fuse by which of the following structures leads to spinal bifida occulta?
A. Neural folds
B. Neural arch processes
C. Vertebral bodies
D. Neural plates
B. Neural arch processes
Which of the following statements about meningomyelocele is correct?
A. It leads to immediate death.
B. It is usually found in the cervical region of the vertebral column.
C. It usually produces no clinical symptoms.
D. It involves the vertebral arch, meninges, and nerve tissue.
D. It involves the vertebral arch, meninges, and nerve tissue.
Which of the following statements about neurulation is not correct?
A. Neural crest cells migrate from the neuroectoderm before neural tube closes.
B. Neural plate tissue invaginates to form a neural groove.
C. The notochord induces neural plate formation.
D. Neural crest cells induce the formation of brain.
D. Neural crest cells induce the formation of brain.
Which of the following statements about neurulation is not correct?
A. Failure of the neural groove to close can result in neural tube defects.
B. Neurulation precedes gastrulation.
C. The lumen of the neural tube persists as the ventricles of the brain.
D. The neural plate results from thickening of neuroectoderm.
B. Neurulation precedes gastrulation.
Which of the following statements is correct about the development of the neural tube?
A. It develops directly from cells of the primitive streak.
B. It develops from cells of the notochord.
C. It develops from ectoderm posterior (dorsal) to the primitive streak.
D. It develops from ectoderm posterior (dorsal) to the notochord.
D. It develops from ectoderm posterior (dorsal) to the notochord.
All of the following are neural crest derivatives except:
A. Neurons in the spinal ganglia
B. Neurons in the sympathetic ganglia
C. Astrocytes
D. Schwann cells
C. Astrocytes
The most likely developmental process causing anencephaly is:
A. Inadequate neural tube closure
B. Excessive production of cerebrospinal fluid
C. Excessive skull growth
D. Breakage of chromosomes
E. Defective osteoblasts (bone forming cells)
A. Inadequate neural tube closure
Transformation of the trilaminar embryonic plate into a tubular configuration is accomplished by the appearance of which of the following?
A. Primitive streak
B. Notochord
C. Body folds
D. Body stalk
C. Body folds
