Chapter 23 Flashcards
What is the first to develop in a fetus
Morula
the morula is the early ball of cells that will become the blastocyst
Name a fact about blastomeres
Blastomere is an early cell type that divides by cleavage
Three facts about implantation
Involves a blastocyst the preembryo which implants
Has cells that produce HCG
Occurs by the sixth day
In the process of in vitro fertilization, the woman is given ? To induce follicle development
Human menopausal gonadotropin
HMG or related compounds will stimulate the ovary to produce follicles; HCG is then used to induce ovulation
The main factor that may NOT allow a 24 week fetus to survive independently is the
Surfactant
Surfactant is the lipid in the lungs that prevents collapse and allows the fetus to breathe; premature infants often lack this ability and must be sustained artificially until their surfactant is sufficient
The ductus venosus transports blood to the ?
Vena cava
The umbilical vein becomes the ductus venosus
The foramen ovale allows blood from the right atrium to enter the
Left atrium
Large amounts of blood do NOT enter r fetal lungs because their
Resistance is high
The resistance to blood flow in the fetal lungs is higher than the right ventricle blood flow pressure which cannot overcome the resistance to any great extent
The ductus arteriosclerosis allows blood to flow from the pulmonary trunk to the
Aorta
The ductus arteriosus is a shunt lung bypass between the pulmonary trunk and the aorta
What vessel transports blood rich in oxygen and nutrients to the fetus
Umbilical vein
The umbilical vain travels toward the heart of the fetus and is thus a vein; however it is coming from the placenta where it picked up oxygen and nutrients.
With in the fetus, much of the circulating blood bypasses the lungs and flow through the
Ductus arteriosus
The arteriosus shunts blood from the pulmonary trunk to the aorta
The period immediately after birth to four weeks of age is called the ? Period
Neonatal
The first month of extrauterine life in the neonatal period
Many changes occur in the newborn infant as it adapts to a life apart from its mother. What happens to the umbilical vein?
It closes off to become the ligamentum teres.
The umbilical vein remains as a ligament attached to the liver
What is the biological definition of human adulthood
Adolescence to old age
An adolescent is reproductively mature, and therefore is considered an adult
In which process do the cells become progressively smaller
Cleavage
Cell division takes place so rapidly during cleavage that the cells do not grow between divisions
When is a developing individual most susceptible to genetic birth defects from smoking
First trimester
The first trimester is the most critical time period in all of development
When is it possible to distinguish the sex of the fetus
Third month
The sex of the fetus begins differentiation around week 8 or 9
When does bone start to replace cartilage
Third month
Endochondral ossification and intramembranous ossification begin around week 10
The embryonic period lasts from the second week through ? Week
Eighth
The embryonic period begins when two distinct cell layers form and proceeds until around the eighth week when differentiation ends
Name 3 things that arise from the mesoderm
Muscle
Kidney
Blood
What prevents the maternal and embryonic blood cells from mixing
Placental membrane
The placental membrane is a layer of epithelial cells that separate the villi from the maternal endometrium
When will the embryo take on a human appearance
Eighth week
Human structures become evident and differentiated by the eighth week, prior to this time the embryo passes through. Stages that seem to resemble other mammals
Name 3 fetal component
Chlorion
Amnion
Umbilical cord
Of every 100 secondary oocytes that are exposed to sperm, how many infants are actually born alive
About 31
When does the amnion first appear
Second week
The rudimentary amnion appears in the second week and becomes fluid filled
What is the origin of fetal blood cells
Yolk sac
The yolk sac appears in the second week and is the origin of the fetal blood cells and gametes that will migrate into the fetus
What is the major cell process in the fetus
Mitosis
Differentiation has ended with the onset of the fetus and all growth processes are mitotic in nature
When can the male and female organs be distinguished first
Twelfth week
By the twelfth week the external genitalia are distinguishable
Name 3 things true at full term
Fingernail are present
Vertex position is evident
Fetus is 50 cm long
The testes begin to descend around the eight month but may not be completed until after birth
The umbilical arteries are branches of the
Internal iliac arteries
What has the greatest oxygen content in a fetus
Umbilical vein
Umbilical Arteries are traveling to the placenta to gain oxygen from the mother
What system function is most critical in the neonate
Respiratory
During the first month of life, the exchange of gasses is critical, the liver is one of the last organs to mature
Name 3 factors that causes the first breath of life
Blood pH
Carbon dioxide
Low blood oxygen
The initiation of breathing occurs from stimulation of the brain stem, epinephrine is produced and rises because of the stress of delivery and is important for increasing the ability of the lungs to expand
In the first days of life, what is the primary source of energy
Lipid
The superior vesical arteries are remnants of the
Umbilical arteries
A portion of the umbilical arteries persist in the neonate as the superior vesical arteries that supply blood to the bladder
The ligament teres is the remnant of the
Umbilical vein
The ligamentum teres Is the fibrotic degeneration of the umbilical vein from the umbilicus to the liver
The ligamentum venosum is the remnant of the
Ductus venosus
The ductus venosus in the liver atrophies into the closed ligamentum venosum
The reason why blood no longer passes through the foremen ovale is initially explained by the
Increase in left atrial pressure
The increase in left atrial pressure during inspiration causes the septum primum valve to close the foremen ovale
The constriction of the ductus arteriosus is related most likely to
Bradykinin
At what age is most hemoglobin of the adult type
At four months
After age 30, the adult loses about ? % of their functional capacity each year
.8
It is estimated that degeneration occurs after age 30 when about .8% of their functional capabilities is lost each successive year
The chemical theory of aging involves the formation of
Free radicals
The premature separation of the placenta is
Abruptio placentae
Perinatology is a branch of medicine that studies the
Fetus and neonate
The domain of perinatology is the 24 week fetus through first four weeks after birth
Name 3 things that freely cross the placental membrane
Leukocytes
Glucose
NaCl
NOT erythrocytes. Leukocytes wander anywhere by diapedesis and chemotaxis
Epithelial lining of the digestive tract , respiratory tract and urethra all form from the ? Layer of the gastrula
Endoderm
Lining of passageways with an external connection come from endoderm
The portion of the placenta contributed by the embryo is the
Chorion
Within which embryonic membrane are blood cells formed in the early stages of development
Yolk sac
First blood cells come from yolk sac
At what age do age related degenerative changes begin in most adults
Age 30
“Aging” begins around 30
Name 3 things that aging appears to result from
Genetics
Apoptosis
Accumulation of free-radicals
What is the major cause of death in less-developed countries
Infections
In which menstrual cycle phase does implantation occur
Secretory
Implantation occurs after ovulation which means the uterus is inits secretory stage
What normally prevents the expulsion of an embryo by a menstrual flow
HCG
HCG causes the corpus luteum to remain, which in turn secretes progesterone thus preventing menses
The structure which implants in the endometrium is correctly termed a
Blastocyst
When can the term fetus be correctly used
When body systems have been established
What extra embryonic membrane encloses the embryo in a fluid filled cavity
Amnion
What membrane plays the greatest role in nutrient and waste exchanges
Chorion
Chorion is part of the placenta
What hormone prevents a second pregnancy during gestation
Progesterone
A sudden increase. In uterine size could indicate the development of a hydatid mole
T or F
True
A hydatid mole or cyst is an abnormal growth of chorionic tissue that might be extensive enough to replace the fetus and even mimic pregnancy
The ossification of the skull is completed by full term
T or F
False
Although much of the skull is ossified, it will not become complete until several months after birth
Fetal hemoglobin is different from the adult and has a higher oxygen capacity
T or F
True
The hemoglobin of the fetus has a 50% greater oxygen affinity than the maternal blood which favors fetal uptake
All the fetal veins contain deoxygenated blood
T or F
False
The ductus venosus contains highly oxygenated blood from the placenta
Because of the ductus arteriosus, greater amounts of oxygenated blood can travel to the brain
T or F
False
The ductus arteriosus is connected is connected to the descending portion of the aortic arch past the branching of the arteries that convey blood to the brain
The number of umbilical arteries is directly related to the structure of the fetal internal circulatory system
T or F
True
There is a strong correlation between umbilical arteries and fetal circulation, many heart and vessel defects are associated with having only one artery, which is why the umbilical vessels are counted at birth
Infant respiratory distress syndrome is less common if the mother had normal labor and delivery
T or F
True
The contractions of the uterus seem to increase the fetal ability to secrete surfactant, babies taken by cesarean delivery may have a higher incidence of respiratory distress syndrome
The kidneys of a neonate are immature and therefore do not excrete large amounts of water
T or F
False
The kidneys are immature and do not excrete large amounts of electrolytes and thus produce a dilute urine increasing the chances for dehydration
The fossa ovalis is the depression in the heart that was the foramen ovale
T or F
True
The foramen ovale closes shortly after birth and becomes a solid depression called fossa ovalis
The ligamentum arteriosum forms in the neonate as a remnant of the ductus arteriosus
T or F
False
The process of scar formation in the replacement of the ductus arteriosus require several months to complete, the term ligamentum arteriosum is more appropriate in an adult heart
Heart failure is a common form of death in the first neonatal month
T or F
True
Failure of the ductus arteriosus to collapse will result in a deficiency of oxygen to the heart relative to a high demand
Childhood typically ends when the person is six years of age
T or F
False
Childhood is a period from one year to the time of puberty and is therefore variable, but usually falls between one year and around 11 years
The average female has a shorter adolescent period than males
T or F
True
The attainment do sexual and physical maturity occurs sooner in females, who usually attain puberty earlier
Females are taller and stronger than males when they are both in early adolescence
T or F
True
Females reach a peak earlier than males, but males develop a growth spurt in late adolescence that causes them to exceed females size and strength
Older persons require fewer calories and can survive well on smaller portions of food
T or F
False
Older persons require less calories but still require an adequate intake of vitamins, minerals and other essential nutrients which may not be present in a typical small portion of food
Older persons have a reduced capacity to prevent infection
T or F
True
The immune system slowly degenerates along with others causing a reduction in the ability to produce antibodies and phagocytic cells
Senescence usually ends in death because of neurological changes and degeneration
T or F
False
Death usually results from failures and degenerative changes in the cardiovascular system, a person may have brain death but still remain alive
The human life span and life expectancy have both increased in the last one thousand years
T or F
False
Although the life expectancy has generally increased for the total population because of technology and medical care, the theoretical point of death has not increased
Collagen synthesis decreases with age and the collagen molecules become soft and degenerated
T or F
False
The collagen fibers actually form cross- links and become stiffer and less flexible, contributing to the dysfunctions seen in the elderly
Exposure to sunlight and other forms of radiation may increase the rate of aging
T or F
True
The rate of aging is influenced by the speed of DNA mutation formation, radiation increases the probability of mistakes in DNA synthesis that lead to cancer or aging
Within 6 days following fertilization, the blastocyst contains cells that are fated to become the infant
T or F
True
Within six days, the process of differentiation has resulted in the inner cell mass which will develop into the human embryo
Dizygotic twins share same placenta and are indentical.
T or F
False
Dizygotic twins result from the separate fertilization of two oocytes and are not identical (fraternal twins) monozygotic twins resulted from a single egg and are identical.
The study of abnormal fetal development is teratology
T or F
True
Many factors could cause birth defects and deformities, the study of these is called teratology.
The umbilical cord contains maternal and fetal components
T or F
False
The umbilical cord is derived from the embryonic stalk, but the placenta has both maternal and fetal components
Amniocentesis is a technique for examining the genetics of fetal skin cells
T or F
True
In amniocentesis, a needle is inserted into the amniotic cavity and fluid withdrawn, the fluid generally contains cells that have been sloughed off and can be used for microscopic and genetic studies to screen for possible defects
Postpartum meconium refers to the discharge of fluid from the skin or lungs
T or F
False
Meconium is the first fecal discharge of a newborn before food or milk has been ingested
The amount of elastic fibers increases during the aging process causing the lung tissue to regress and constrict
T or F
False
In aging, the amount of elastic tissue in the lungs decreases making it more difficult to exhale, from loss of elastic recoil
The cardiovascular system increases the synthesis of some lipids during the aging process.
T or F
True
The coronary artery lumens are decreased by the addition and synthesis of cholesterol-laden plaques made by the artery
The placenta is comprised of maternal and fetal portions
T or F
True
The fetal chorion and the maternal endometrium combine to form the placenta
The inner cell mass of the blastocyst will become the extra embryonic membranes and part of placenta
T or F
False
The ICM becomes the embryo proper
