Zoology 142 Final-Ch 29: Fetal Development

Total Flash Cards » 49
 

1. 

Order of prenatal development

 

zygote, cleavage, morula, blastocyst, embryo, fetus

 
2. 

process that makes it possible for sperm to penetrate the egg is called

 

capacitation

 
3. 

In the slow block to polyspermy, sperm penetration releases an inflow of ___________, which in turn stimulates the ________.

 

Ca2+; cortical reaction

 
4. 

In the fast block to polyspermy, binding of sperm opens up _________ channels, which depolarizes the egg membrane and _________

 

Na+; prevents the entrance of any more sperm

 
5. 

The optimal "window of opportunity" to conceive a child is

 

a few days before ovulation to less than a day after

 
6. 

The spheroidal stage of early prenatal development with about 16 to 64 cells is called a/an

 

Morula

 
7. 

Twins produced when a single egg is fertilized are called _____________ twins, and twins produced from two eggs ovulated at the same time are called ___________ twins

 

monozygotic; dizygotic

 
8. 

In the blastocyst, the trophoblast will become ____________, whereas the embryoblast will become __________

 

part of the placenta; the embryo

 
9. 

Primary germ layers are formed during

 

gastrulation

 
10. 

Mesenchyme gives rise to

 

muscle, bone and blood

 
11. 

During implantation, the trophoblast divides into a deep layer, the _________, composed of individual cells, and a superficial layer, the ___________, composed of a multinucleate mass of cytoplasm

 

cytotrophoblast; syncytiotrophoblast

 
12. 

By the time the conceptus arrives in the uterus

 

it consists of 16 or more cells

 
13. 

Out of the 300 million ejaculated sperm, only about ____________ reach the vicinity of the egg

 

3,000

 
14. 

Prior to ejaculation, __________ in the sperm plasma membrane prevents premature release of ______________

 

cholesterol; acrosomal enzymes

 
15. 

These are derivatives of ectoderm except

 

the dermis

 
16. 

The first body cavity is called the

 

coelom

 
17. 

By the end of 8 weeks, the individual is considered a fetus because

 

all of the organ systems are present

 
18. 

The ___________ completely encloses the embryo and provides a stable environment for it.

 

amnion

 
19. 

The ___________ encloses all the rest of the membranes and the embryo

 

chorion

 
20. 

The embryonic membrane that forms the fetal portion of the placent

 

the villous chorion

 
21. 

As it implants, the conceptus is nourished by means of

 

trophoblastic nutrition

 
22. 

The vessel that provides oxygenated blood to the placenta is

 

a maternal artery

 
23. 

In fetal circulation, the __________ bypasses the liver and the _________ bypasses the lung

 

ductus venosus; ductus arteriosus

 
24. 

In fetal circulation, blood bypasses the lungs by flowing through

 

the foramen ovale and ductus arteriosus

 
25. 

Which of the following major events of prenatal development happens first? -eyes are fully open-body covered with lanugo-bone calcification begins-central nervous system begins to form-meconium accumulates in intestines

 

the central nervous system begins to form

 
26. 

Oxygenated blood reaches the fetus through the

 

umbilical vein

 
27. 

The embryonic membranes include all of the following except the

 

placenta

 
28. 

_______ pass(es) from the maternal blood to the fetal blood; while fetal _________ pass(es) the other way

 

Oxygen and nutrients; wastes

 
29. 

The digital rays of a fetus give rise to

 

fingers and toes

 
30. 

The first 6 weeks of postpartum life constitute

 

the neonatal period

 
31. 

The fossa ovalis is a remnant of the ___________ of the fetus

 

foramen ovale

 
32. 

During birth, an infant is normally stimulated to breathe by

 

CO2 accumulating in the baby's blood

 
33. 

Which organ system shows the greatest anatomical change in the transitional period after birth?

 

Circulatory

 
34. 

Infant respiratory distress syndrome (IRDS) is caused by

 

deficiency of pulmonary surfactant.

 
35. 

Which organ system faces the greatest physiological challenge in the transitional period after birth?

 

Respiratory

 
36. 

A teratogen is most likely to cause

 

a deformity of the limbs.

 
37. 

These are have potentially teratogenic effects except-smoking-alcohol-infectious diseases-sunlight-x-rays

 


sunlight.

 
38. 

Down syndrome (trisomy-21) results from

 

nondisjunction.

 
39. 

The most likely outcome of nondisjunction is the production of a gamete receiving

 

22 chromosomes.
 
40. 

Only autosomal trisomies involving chromosomes 13, 18, and 21 are survivable. why would this be?

 

These are relatively gene-poor chromosomes.

 
41. 

Urine retention is a greater problem for elderly men than for elderly women because men

 


usually develop benign prostatic hyperplasia.

 
42. 

Muscular weakness tends to develop in old age for all of the following reasons except:-aged muscle has less glycogen, myoglobin, and creatine phosphate.-there are fewer motor neurons in the spinal cord.-aged muscle fibers have fewer myofibrils.-there are fewer and smaller mitochondria.-myocytes do not synthesize myosin anymore.

 

myocytes do not synthesize myosin anymore.

 
43. 

Older people may require lower drug doses than younger people because

 

they have lower rates of renal clearance.

 
44. 

Telomeres

 

are DNA segments at each end of a chromosome.

 
45. 

The observation that there is a limit to how many times a cell can divide is the basis for the

 

replicative senescence theory.

 
46. 

Clinical death is widely defined as

 

brain death.

 
47. 

Which of the following systems shows the least overall senescence?

 

endocrine system

 
48. 

Senescence of the immune system makes older people more subject to cancer and infectious disease because of a decline in

 

antigen-presenting cells and helper T cells.

 
49. 

Congenital anomalies can result from all of the following except-an infectious disease in the mother during pregnancy.-genetic disorder-exposure to teratogens during pregnancy-smoking during lactation-smoking during pregnancy

 

smoking during lactation.