The Developing Human Clinically Oriented Embryology 9th Edition By Moore – Test Bank

9. ________ Source of nephrons
A. Renal agenesis
B. Nephrogenic cord
C. Metanephric diverticulum
D. Kidney lobes
E. Polycystic kidney

ANS: B
The metanephric mesenchyme in the nephrogenic cords gives rise to nephrons. When stimulated by a substance produced by the metanephric diverticulum, the metanephric mesenchyme begins to differentiate into nephrons.

10. ________ Caused by dilations of the nephron loops
A. Renal agenesis
B. Nephrogenic cord
C. Metanephric diverticulum
D. Kidney lobes
E. Polycystic kidney

ANS: E
Congenital polycystic disease of the kidneys is transmitted on an autosomal basis (ARPKD). The cysts may result from failure of the first formed rudimentary nephrons to degenerate; later, these remnants may accumulate fluid and form cysts. Cysts may also develop from detached parts of metanephric tissue, which gives rise to rudimentary renal vesicles. It is now widely believed that these cysts are dilations of the nephrons, particularly of the nephron loops.

11. ________ Oligohydramnios
A. Renal agenesis
B. Nephrogenic cord
C. Metanephric diverticulum
D. Kidney lobes
E. Polycystic kidney

ANS: A
Oligohydramnios (an abnormally small volume of amniotic fluid) may be associated with renal agenesis (absence of kidneys). In the neonate, renal agenesis is suggested by large, low-set ears. This type of auricle also suggests numerical chromosomal abnormalities (e.g., trisomy 18). The fetal kidneys normally produce large amounts of urine, which is excreted into the amniotic fluid. When one or both kidneys fail to form or there is urethral obstruction, the volume of amniotic fluid is small because urine production fails to occur or the urine cannot pass into the amniotic fluid.

12. ________ Mesonephric duct
A. Renal agenesis
B. Nephrogenic cord
C. Metanephric diverticulum
D. Kidney lobes
E. Polycystic kidney

ANS: C
The metanephric diverticulum develops as an outgrowth of the mesonephric duct near its opening into the urogenital sinus. This diverticulum gives rise to the ureter, renal pelvis, calices, and collecting tubules.

13. ________ Intermediate mesoderm
A. Renal agenesis
B. Nephrogenic cord
C. Metanephric diverticulum
D. Kidney lobes
E. Polycystic kidney

ANS: B
The intermediate mesoderm in the early embryo forms a longitudinal mass on each side called the nephrogenic cord. These cords give rise to nephrons, which connect with the collecting tubules formed from the metanephric diverticula.

14. ________ External evidence of them disappears during infancy
A. Renal agenesis
B. Nephrogenic cord
C. Metanephric diverticulum
D. Kidney lobes
E. Polycystic kidney

ANS: D
The external evidence of the kidney lobes disappears during infancy, usually by the end of the first year. Thereafter, lobes are observed only in sections of the kidney and are defined as a medullary pyramid with its cap of cortical tissue.

29. ________ Suprarenal medulla
A. Adrenal hyperplasia
B. Penile hypospadias
C. Zona reticularis
D. Neuroectoderm
E. Coelomic epithelium

ANS: D
The medulla of the suprarenal gland is derived from neuroectoderm. Neural crest cells, comparable to those that form sympathetic ganglia, invade the mesodermal suprarenal cortex on its medial side and soon become surrounded by it.

30. ________ Gives rise to the suprarenal cortex
A. Adrenal hyperplasia
B. Penile hypospadias
C. Zona reticularis
D. Neuroectoderm
E. Coelomic epithelium

ANS: E
The fetal suprarenal cortex is derived from mesenchymal cells that arise from the coelomic epithelium. These large cells make up most of the suprarenal cortex before birth, forming the massive fetal cortex. The fetal cortex gradually involutes after birth and usually is not recognizable after the first year.

31. ________ Differentiates after birth
A. Adrenal hyperplasia
B. Penile hypospadias
C. Zona reticularis
D. Neuroectoderm
E. Coelomic epithelium

ANS: C
At birth, the suprarenal gland consists mainly of fetal cortex. The zona reticularis of the adrenal cortex forms after birth. It usually is recognizable by the end of the third year. The other two layers of the permanent cortex (zona glomerulosa and zona fasciculata) are present at birth but are not fully differentiated.

32. ________ Unfused urogenital folds
A. Adrenal hyperplasia
B. Penile hypospadias
C. Zona reticularis
D. Neuroectoderm
E. Coelomic epithelium

ANS: B
Failure of the urogenital folds to fuse in males results in hypospadias. In most cases, the urethra opens on the ventral surface near the junction of the glans and the body of the penis.

33. ________ Ambiguous external genitalia
A. Adrenal hyperplasia
B. Penile hypospadias
C. Zona reticularis
D. Neuroectoderm
E. Coelomic epithelium

ANS: A
Ambiguous external genitalia often indicate virilization of a female, resulting from congenital virilizing adrenal hyperplasia. Excessive production of adrenal androgens by the hyperplastic fetal cortices of the suprarenal glands causes masculinization of the external genitalia. A neonate with ambiguous genitalia, a palpable uterus, but no palpable gonads usually is a female pseudohermaphrodite whose condition is caused by adrenocortical hyperplasia.

34. ________ Associated with chordee
A. Adrenal hyperplasia
B. Penile hypospadias
C. Zona reticularis
D. Neuroectoderm
E. Coelomic epithelium

ANS: B
Chordee, a curving downward of the penis, often is associated with hypospadias, especially with the more severe types (e.g., penoscrotal hypospadias).