Chapter 29-Human Development
Terms
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When a conceptus arrives in the uterus, it is at what stage of development?
a. zygote
b. morula
c. blastomere
d. blastocyst
e. embryo - morula
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The entry of a sperm nucleus into an egg must be preceded by
a. the cortical reaction
b. the acrosomal reaction
c. the fast block
d. implantation
e. cleavage - the acrosomal reaction
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The stage of the conceptus that implants in the uterine wall is
a. a blastomere
b. a morula
c. a blastocyst
d. an embryo
e. a zygote - a blastocyst
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Chorionic villi develop from
a. the zona pellucida
b. the endometrium
c. the syncytiotrophoblast
d. the embryoblast
e. the corona radiata - the syncytiotrophoblast
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Which of these results from aneuploidy?
a. turner syndrome
b. fetal alcohol syndrome
c. nondisjunction
d. progeria
e. rubella - turner syndrome
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Fetal urine accumulates in the_____and contributes to the fluid there.
a. placental sinus
b. yolk sac
c. allantois
d. chorion
e. amnion - amnion
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One theory of senescence is that it results from a lifetime of damage by
a. teratogens
b. aneuploidy
c. free radicals
d. cytomegalovirus
e. nondisjunction - free radicals
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Photoaging is a major factor in the senescence of
a. the integumentary system
b. the eyes
c. the nervous system
d. the skeletal system
e. the cardiovascular system - the integumentary system
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Which of these is not a common effect of senescence?
a. reduced synthesis of vitamin D
b. atrophy of the kidneys
c. atrophy of the cerebral gyri
d. increased herniation of the intervertebral discs
e. reduced pulmonary vital capac - increased herination of intervertebral discs
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For the first 8 weeks of gestation, a conceptus is nourished mainly by
a. the placenta
b. amniotic fluid
c. colostrum
d. decidual cells
e. yolk cytoplasm - decidual cells
- Viruses and chemicals that cause congenital anatomical deformities are called_______.
- teratogens
- Aneuploidy is caused by________, the failure of two homologous chromosomes to separate in meiosis.
- nondisjunction
- The maximum age attainable by a member of the human species is called the______.
- life span
- The average age attained by humans in a given population is called the________.
- life expectancy
- Fetal blood flows through growths called________which project into the placental sinus.
- chorionic villi
- The enzymes with which a sperm penetrates an egg are contained in an organelle called the________.
- acrosome
- Stiffening of the arteries, joints, and lenses in old age may be a result of cross-linking between_______molecules.
- collagen
- An enlarged tounge, epicanthal folds of the eyes, and mental retardation are characteristics of a genetic anomaly called________.
- down syndrome
- The fossa ovalis is a remnant of a fetal shunt called the_______.
- foramen ovale
- A developing individual is first classified as a/an______when the three primary germ layers have formed.
- embryo
- T/F Freshly ejaculated sperm are more capable of fertilizing an egg then are sperm several days old.
- False, sperm require about 10 hours to become capacitated and able to fertilize an egg.
- T/F Fertilization normally occurs in the lumen of the uterus.
- False, fertilization normaly occurs in the uterine tube.
- T/F An egg is usually fertilized by the first sperm that contacts it.
- False, Several early-arriving sperm clear a path for the one that fertilizes the egg.
- T/F By the time a conceptus reaches the uterus, it has already undergone several cell divisions and consists of 16 cells or more.
- True
- T/F The conceptus is first considered a fetus when all of the organ systems are present.
- True
- T/F The placenta becomes increasingly permeable as it develops.
- True
- T/F The endocrine system shows less senescence in old age than most other organ systems.
- True
- T/F Fetal blood bypasses the nonfunctional liver by passing through the foramen ovale.
- False, bypasses the lungs
- T/F Blood in the umbilical vein has a higher PO2 than blood in the umbilical arteries.
- True
- T/F It is well established that people who exercise regularly live longer than those who do not.
- False, exercise has proven to improve quality of live in old age, but hasn't shown to increase life expectancy significantly.