Ch. 29, Human Development

Spanking a newborn is required to initiate the infant's first breaths.

false

The rate of senescence of different organ systems is relatively the same.

false

the sperm penetrates the egg

fertilization

the _____________ trimester extends from fertilization through 12 weeks gestation

first

Unstable molecules destroy cells and normal molecules to satisfy their own valence shells.

free radical theory

name the process that results in the formation of the primary germ layers

gastrulation

embryonic tissue layers

germ layers

blastocoel

hollow internal cavity

the granulosa cells surrounding an egg bound together by hyaluronic acid. name the enzyme released by the sperm that digests this compund

hyaluronidase

will be replaced with endoderm

hypoblast

the process by which a blastocyst attaches to the lining of the uterus is called ________________

implantation

explain why an infant loses heat easily

it has larger surface area to volume ratio than an adult

name the condition that involves a yellowing of the skin, corneas, mucous membranes, and body fluids due to an excessive concentration of bilirubin

jaundice

at the placenta, __________ blood s found within placental sinuses and _____________ blood is found within chorionic villi

maternal; fetal

at about 72 hours after conception, the conceptus is called a ________________, consisting of 16 or more cells and resembling a mulberry

morula

the failure of homologous chromosomes to separate during meiosis is known as _____________________

nondisjunction

the process of ______________________ is the differentiation of the primary germ layers into organ and organ systems

organogenesis

stiffness and joint pain are symptoms of the most common joint disease of older people. the disease is known as __________________

osteoarthritis

the loss of bone caused by reduced activity of osteoblasts is called ___________

osteopenia

source of nutrition for most of the prenatal period

placenta

name the condition involving the loss of flexibilty of lens of the eye

presbyopia

during the _________ trimester, the organs complete most of their development

second

newly ovulated cell

secondary oocyte

The degeneration that occurs in an organ system following a certain age is called __________.

senescence

the ____________ are blocks of mesoderm tissue that will give rise to vertebral column, dermis of the skin, and trunk muscles

somites

carries the father's DNA

sperm pronucleus

substances that cause birth defects are known as

teratogens

describe a telomere

the end cap on each chromosome

during which trimester does the fetus grow rapidly, becoming self sufficient outside the womb?

third

the ___________ period is the first six to eight hours after delivery

transitional

name the disorder associated with the presence of 3 X chromosomes

triplo X syndrome

The presence of one extra chromosome producing a triplet set is called ____________

trisomy

After implantation, the conceptus resorts to ____________ nutrition.

trophoblastic

describe the blood vessels found in the umbilical cord

two umbilical arteries, one umbilical vein

the internal iliac arteries of the fetus gives rise to the _____________ ______________

umbilical arteries

a common adage is that it "only takes one sperm" to fertilize an egg. As an anatomy student, describe your response

while only one sperm head enters the egg, thousands are needed to break through the egg's defenses

name the segment of the female reproductive system in which the sperm will encounter an egg that is viable (able to survive) and can be fertilized

within the distal one-third of uterine tube

embryonic membrane that surrounds the yolk

yolk sac

slow block

- calcium ions stimulate exocytosis - cortical granules - sperm are pushed away from the egg - fertilization membrane

Which of the following is a benefit of regular exercise that may help slow the rate of senescence?

- cells lose their capacity for mitosis - proteins fold differently in older tissues - the body's immune system begins to attack normal body cells - free radicals destroy healthy body tissues

mesoderm

- dermis - muscle - bones

indicate circulatory changes that occur just after birth

- ductus arteriosus collapses - foramen ovale is closed by flaps in the left atrium

list some structures that arise from the ectoderm

- epidermis - CNS - salivary glands

list some effects of the senescence on the integumentary system

- graying hair - loss of skin elasticity

list changes in the body as a result of an aging female reproductive system

- increased loss of bone mass - increased cardiovascular risk - decrease in estrogen production

list some reasons that muscles weaken with age

- reduced myoglobin content - reduced mitochondiral number - sacromere disorganization

list some causes of reduced nervous system function with aging

- thinning of cerebral cortex - less neurotransmitter produced - loss of receptors

why is it difficult for premature infants to ingest milk?

- underdeveloped sucking and swallowing reflexes - small stomach volume

outermost membrane enclosing all the embryonic membranes

chorion

fingerlike outgrowths of the chorion are called

chorionic villi

choose the term that means present at birth. Examples include an anatomical defect, a syphilis infection, or a hereditary disease

congenital

in some neonates the foramen ovale does not close to form the fossa ovalis. this is an example of

congenital anomaly

the _____________ and _____________ are two features of the fetal circulation that allow blood to bypass the non- \functional lungs

ductus arteriosus foramen ovale

carries the mother's DNA

egg pronucleus

the _______________ system degenerates less with aging than any other organ system

endocrine

replaces the hypoblast, gives rise to the most mucosal epithelium

endoderm

tissue that replaces the original hypoblast

endoderm

will eventually become ectoderm

epiblast

indicate the 3 major processes that occur during the preembryonic stage of gestation

- embryogenesis - implantation - cleavage

aging, but not senescence

- endochondral ossification - differentiation of stem cells - appearance of secondary sec characteristics - getting taller

endoderm

- epithelium of the GI tract - thyroid - thymus - urinary bladder

occurs by end of week 8

- eyes form - digital rays form - major blood vessels form - bone calcification begins - brain waves are detectable - nostrils are evident

aging and senescence

- heart disease - decreased insulin sensitivity - visibility of blood vessels through the skin of the cheeks and nose - replacement of muscle tissue with adipose tissue - presbyopia - decrease in the number of nephrons

Which of the following is true regarding sperm migration?

- less than 1 % of ejaculated sperm cells reach the egg - vaginal acids destroy many sperm cells

occurs by the end of week 4

- neural plate appears - limb buds form - heart beat - vertebral column begins to form

functions of the amniotic fluid

- protect fetus from temperature fluctuations - allow development of the lungs - protect fetus from trauma

Which of the following can cause birth defects?

- radiation exposure - drinking one alcoholic beverage per day while pregnant - cigarette smoking - infectious disease - prescription meds

sign of fetal alcohol syndrome

- small head - malformed facial features - hyperactivity

Which of the following statements is true regarding the fetal circulation?

- the foramen ovale allows blood to bypass the lungs - the ductus venosus allows the blood to bypass the liver - the umbilical vein carries blood from the placenta to the fetal circulation

Which of the following adaptations of the circulatory system occurs shortly after birth?

- the foramen ovale closes and seals, blocking blood between the atria from mixing - the ductus arteriosus collapses and stops pulmonary trunk blood from mixing with aortic arch blood - several vessels close off and form fibrous cords or ligaments

buried in the endometrium

implanted blastocyst

in the egg, ______________ begins before ovulation, but will only complete if fertilization occurs

meiosis II

gives rise to muscle tissue

mesoderm

third layer of embryonic tissue made of migrating epiblast cells

mesoderm

The lack of a chromosome, leaving one without a match, is called ____________

monosomy

the condition of having only one member of a homologous pair of chromosomes is known as ______________

monosomy

16 or more cells within the zona pellucida

morula

an infant up to 6 weeks old is classified as a

neonate

In ____________ , a pair of chromosomes fails to separate.

nondisjunction

Disruptions occur with the way polypeptides are folding and/or binding to carbohydrates.

other protein abnormalities

throphoblast

outer layer of cells

Trophoblastic nutrition wanes as ____________ nutrition takes over and ceases entirely by week ____________ .

placental; 12

The egg can utilize a rapid depolarization of the membrane or the secretion of an impenetrable fertilization membrane to prevent __________.

polyspermy

describe the primary cause of infant respiratory distress syndrome

prematurity and the lack of sufficient surfactant

midline structure making the embryo bilaterally symetrical

primative streak

midline structure making the embryo bilaterally symetrical

primitive groove

following fertilization, the genetic material of each gamete, prior to them combining, is contained within the

pronuclei

Cells lose their capacity for division and begin to die out.

replicative senescence

fast block

- Na ion channels open - membrane depolarization

Which of the following is a result of senescence?

- The loss of pigment in the hair due to dying out of melanocytes - The degeneration of the hyaline cartilage that lines the femoral head - The stiffening of the hyaline cartilage that connects the ribs to the sternum

Which of the following signs and/or symptoms in a premature infant is/are due to a poorly developed liver?

- a hypotonic enviroment in the blood plasma causing a net filtration pressure resulting in systemic tissue edema - a difficulty inhaling due to lack of surfactant - a yellowing of the skin and sclera - an inability to properly dispose of bilirubin

ectoderm

- anterior pituitary - outer ear - sensory neurons

name the stages of developing organism that occur during the preembryonic stage

1) zygote 2) cleavage 3) morula 4) blastocyst

When this occurs, one cell will receive ____________ chromosomes and the other will receive 22.

24

Over the course of gestation, the conceptus is nourished in ____________ different ways

3

after ejaculation and during sperm migration, changes occur in the sperm that allow it to penetrate the egg.

capacitation

embryoblast

cell mass within blastocyst

Klinefelter syndrome results from what genotype?

XXY

___________ causes more birth defects than any other drug

alcohol

the term __________ refers to an abnormal number of chromosomes

aneuploidy

the stage of ______________ is complete when the blastomeres form 3 primary germ layers

embryogenesis

Collagen is disrupted by disulfide bridges and becomes stiff and less soluble.

cross linking theory

Which of the following is an existing scientific theory regarding the mechanism of senescence?

cross linking theory

Which of the following is a legitimate reason why a neonate's first few breaths are relatively difficult?

- upon birth, the alveoli are collapsed and the initial inflating requires a relatively large amount of force to generate the required pressure

Which of the following is a function of the placenta?

-The placenta allows the building blocks of proteins to diffuse from maternal to fetal blood. -The placenta helps the fetus dispose of metabolic waste that would normally be excreted by its own kidneys. -The placenta allows for gas exchange.

chronological regarding the development of the placenta

1)At implantation, extensions of the syncytiotrophoblast penetrate deep into the nourishing endometrium. These extensions are known as the chorionic villi. 2)The placenta begins to develop approximately 11 days after conception. 3)The placenta becomes a dominant mode of nutrition at the begninning of week 9. 4)By the end of week 12 the placenta is the sole mode of nutrition until birth. 5)Blood flows between the fetus and the mother by way of umbilical arteries and veins, attached to the placenta.

accurate explanation of fertilization

1)The sperm encounters the egg and undergoes an acrosomal reaction. 2)This reaction releases enzymes from the acrosome of the sperm cell, which then digest a path through the granulosa cells and the zona pellucida. 3)After the sperm contacts the egg, the sperm head and midpiece enter the egg. 4)At this point, the haploid set of chromosomes from each gamete combine to produce a full diploid set. 5)Finally, the egg blocks all other sperm from entering, in order to prevent a triploid cell.

sperm remain viable for ________ days after ejaculation

6

Trophoblastic nutrition remains the dominant mode of nutrition until the end of week ____________ .

9

A premature infant has an accelerated respiratory and heart rate, fatigue, and blood shows low oxygen levels. From which of the following conditions might the infant be suffering?

Patent Ductus Arteriosus: The ductus arteriosus failed to close Patent Foramen Ovale: The foramen ovale failed to seal.

becomes part of the urinary bladder

allantois

begins as an outpocketing of the yolk sac and forms the foundation of the umbilical cord

allantois

eventually encloses the embryo and is penetrated only by the umbilical cord

amnion

transparent sac that develops from cells of the epiblast

amnion

name the narrow space between embryoblast (inner cell mass) and the trophoblst during early embryogenesis

amniotic cavity

narrow space between the embryoblast and trophoblast

amniotic cavity

helps regulate fetal temperature

amniotic fluid in amniotic cavity

Lymphocytes begin to attack the body's own tissues.

autoimmune theory

dividing cells

blastomeres

outpocketing of the outermost membrane

chorionic villus

dividing of blastomeres

cleavage

Both chromosomes will then be passed to the ____________ cell.

daughter

In trophoblastic nutrition, the conceptus consumes ____________ of the endometrium

decidual cells

name the transport process by which oxygen, CO2, and nutrients cross the placenta

diffusion

the remaing epiblast after the first two layers have formed

ectoderm

the implanting of the blastocyst somewhere other than the uterus is known as a _____________ pregnancy

ectopic

blood flows into the fetus via these vessels

umbilical arteries

attaches the placenta to the uterus

umbilical cord

blood returns to the fetus via this vessel

umbilical vein

contains vessels used for gas exchange between mother and embryo

umbillical cord

hollow sphere with outer layer of squamous cells

unimplanted blastocyst

Shortly after conception, the conceptus absorbs ____________ while in the uterine tube and free floating in the uterus.

uterine milk

the ____________ ______________ arises from cells of the hypoblast. it contributes to the formation of the digestive tract and is the site of production of the first blood cells

yolk sac

susceptible to the acrosome's digestive enzymes

zona pellucida

a single-celled, fertilized egg is known as a

zygote

the fertilized egg cell

zygote