A&p Chapter 29 Development And Inheritance

The umbilical cord is the connection between the placenta and the embryo. It contains blood vessels that transport oxygen and nutrients from the placenta to the developing embryo, and also remove waste products from the embryo. The umbilical cord is responsible for supplying the embryo with everything it needs for growth and development during pregnancy.

Fertilization normally occurs within the fallopian tubes. The fallopian tubes are responsible for transporting the egg from the ovary to the uterus. During ovulation, the egg is released from the ovary and enters the fallopian tube. If sperm is present in the fallopian tube, it can fertilize the egg, resulting in pregnancy. The fallopian tubes provide the ideal environment for fertilization to occur, with their ciliated lining and muscular contractions helping to move the egg and sperm towards each other. Once fertilization occurs, the resulting embryo will continue its journey towards the uterus for implantation.

The fusion of the secondary oocyte and the sperm results in the formation of a zygote. The zygote is the initial stage of development after fertilization, where the genetic material from both the mother (contained in the female pronucleus) and the father (contained in the male pronucleus) combine to form a single cell with a complete set of chromosomes. The zygote will then undergo further cell divisions and development to form an embryo.

The chorionic villi of the placenta serve as the primary structure for the exchange of material between the mother and the fetus. These finger-like projections extend from the chorion (part of the fetal membrane) into the uterine wall, allowing for the transfer of nutrients, oxygen, and waste products between the maternal and fetal bloodstreams. This exchange is essential for the development and nourishment of the fetus throughout pregnancy. The chorionic villi increase the surface area available for this exchange, facilitating the efficient transfer of substances between the mother and the developing fetus.

The trophoblast is the part of the blastocyst that promotes implantation and produces hCG. Implantation is the process by which the blastocyst attaches to the uterine wall, allowing for the development of the embryo. The trophoblast plays a crucial role in this process by secreting enzymes that allow it to penetrate the uterine lining. Additionally, the trophoblast is responsible for producing human chorionic gonadotropin (hCG), which is a hormone that helps to maintain pregnancy. Therefore, the trophoblast is the correct answer as it fulfills both criteria mentioned in the question.

If a child has B blood and the mother has B blood, the possible genotypes of the father could be B, O, or AB. This is because the child can only inherit the B blood type from either the mother or the father. The father could have the B blood type (genotype BB), the O blood type (genotype OO), or the AB blood type (genotype AB).

The correct answer is "STAGE OF DILATION". This refers to the time from the onset of labor to the complete dilation of the cervix. During this stage, the cervix gradually opens up or dilates to allow the baby to pass through the birth canal. It is an important stage in the process of childbirth and marks the beginning of active labor.

A mutation refers to a permanent change in an allele, which can occur due to various factors such as errors during DNA replication or exposure to mutagens. This change can alter the genetic code, leading to a different sequence of nucleotides in the DNA. As a result, the mutation can cause changes in the phenotype (observable characteristics) of an organism. Therefore, the given correct answer is "MUTATION".

The correct answer is AMNION. The amnion is a membrane that develops from the epiblast and surrounds the embryo, forming a protective fluid-filled sac called the amniotic sac. This sac provides a cushioning effect and helps to protect the developing embryo from mechanical shocks, temperature fluctuations, and infections. It also allows for the free movement of the embryo, facilitating proper development.

If one parent has type A blood and the other parent has type B blood, their child can have any blood type - AB, A, B, or O. This is because when it comes to blood type inheritance, both type A and type B are dominant over type O. Therefore, the child can inherit either type A or type B from one parent, or both types from each parent, resulting in blood types AB, A, B, or O.

Murray Llewellyn Barr is credited with the discovery of the Barr body. This is a condensed, inactive X chromosome that is present in the cells of females. Barr's discovery of the Barr body in 1949 was significant in the field of genetics as it provided evidence for X-chromosome inactivation in female mammals. This phenomenon ensures that females do not have double the dosage of X-linked genes compared to males. Barr's discovery laid the foundation for further research on X-chromosome inactivation and its role in genetic expression.

Progesterone is a hormone that plays a crucial role in preparing the uterus for pregnancy and maintaining pregnancy. It helps to thicken the lining of the uterus, making it ready for implantation of a fertilized egg. If progesterone levels are high, it inhibits the contraction of the uterine muscles, preventing labor from occurring. Therefore, labor cannot take place until all of progesterone's effects are diminished.

The correct answer is "CLEAVAGE OF ZYGOTE". Cleavage refers to the process of cell division in the early stages of embryonic development. The zygote is the fertilized egg formed by the fusion of sperm and egg, and cleavage of the zygote refers to the division of cells that occurs after fertilization. This division leads to the formation of a solid ball of cells called a morula, which eventually develops into an embryo. Therefore, the correct answer is the cleavage of the zygote.

Sickle cell disease is an example of incomplete dominance because it occurs when an individual inherits one normal hemoglobin gene and one sickle hemoglobin gene. Incomplete dominance is a genetic inheritance pattern where neither allele is completely dominant over the other, resulting in a phenotype that is a blend of both alleles. In the case of sickle cell disease, individuals with two normal hemoglobin genes have normal red blood cells, while individuals with two sickle hemoglobin genes have sickle-shaped red blood cells. However, individuals with one normal and one sickle hemoglobin gene have some sickle-shaped red blood cells, but not enough to cause the full symptoms of the disease.

Capacitation is the correct answer because it is a series of functional changes that sperm go through when they are in the female reproductive tract. During capacitation, the sperm undergoes changes in its membrane and acrosome, which enable it to penetrate and fertilize the egg. This process prepares the sperm for fertilization by enhancing its motility and allowing it to recognize and bind to the egg. Therefore, capacitation is an essential step in the reproductive process.

Amniocentesis is a prenatal test that is typically performed between 14-16 weeks of gestation. It involves the removal of a small amount of amniotic fluid from the sac surrounding the fetus. This fluid contains fetal cells that can be analyzed for genetic abnormalities such as Down syndrome, cystic fibrosis, and spina bifida. Amniocentesis is considered a more invasive procedure compared to other prenatal tests like sonogram, chorionic villus sampling (CVS), and AFP test, but it provides more accurate and detailed information about the genetic health of the fetus.

Involution is the process by which the uterus returns to its pre-pregnancy size and shape after childbirth. During pregnancy, the uterus expands to accommodate the growing fetus, and after delivery, it gradually contracts and decreases in size. This process is essential for the uterus to heal and resume its normal functions. The expulsion of the placenta, cutting of the umbilical cord, and dilation of the cervix are all separate processes that occur during childbirth but are not directly related to involution.

The correct answer is DECIDUA BASALIS. The decidua basalis is the portion of the endometrium that lies between the embryo and the stratum basalis. It is the layer of the endometrium that undergoes changes during pregnancy to support the implantation and development of the embryo. It is responsible for forming the maternal part of the placenta and providing nutrients and oxygen to the developing fetus.

The correct answer is DUCTUS VENOSUS. In infants, the ductus venosus is a blood vessel that connects the umbilical vein to the inferior vena cava. This allows oxygenated blood from the placenta to bypass the liver and be delivered directly to the heart. After birth, the ductus venosus typically closes and becomes a ligament.

During pregnancy, the body undergoes various physiological changes to support the growing fetus. One of these changes is an increase in blood volume. This increase in blood volume leads to an increase in stroke volume, which is the amount of blood pumped out of the heart with each contraction. The correct answer, 30%, suggests that during pregnancy, the stroke volume can increase by 30% compared to the non-pregnant state. This increase in stroke volume helps meet the increased demands of the mother and the developing fetus for oxygen and nutrients.

The correct answer is CHORION. The chorion is a membrane that surrounds the fetus and forms the outer layer of the placenta. CVS (chorionic villus sampling) is a prenatal test that involves taking a small sample of cells from the chorion to test for genetic abnormalities or other conditions. The cells are collected through a needle inserted into the uterus, usually guided by ultrasound. This procedure is typically done between 10 and 13 weeks of pregnancy.

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Each somite may differentiate into a dermatome. A somite is a segment of the embryo that gives rise to various structures in the body, including muscle, bone, and connective tissue. The dermatome is a specific region of the skin that is innervated by a single spinal nerve. Therefore, the differentiation of a somite into a dermatome allows for the formation of the skin in a specific region of the body.

Genomic imprinting refers to the phenomenon where certain genes are expressed differently depending on whether they are inherited from the mother or the father. This can result in a drastic difference in the phenotype of an individual depending on the parental origin of the gene. Therefore, the correct answer is genomic imprinting.

Oxytocin is the correct answer because it is the hormone responsible for releasing milk into the mammary ducts. It is produced by the pituitary gland and released during breastfeeding. Oxytocin stimulates the contraction of the muscles surrounding the mammary glands, allowing milk to be released and flow into the ducts for the baby to consume.

The given correct answer is "NONE OF THE ABOVE". This means that none of the options provided (carcinogen, toxin, nicotine) are the correct explanation for the given statement. The question is asking for an agent or influence that causes developmental defects in an embryo, and none of the options listed fit this description. Therefore, the correct answer is none of the above.

The correct answer is C. The morula stage is an early stage in embryonic development where the fertilized egg undergoes several rounds of cell division, resulting in a solid ball of cells. In this stage, the embryo is made up of about 16 to 32 cells and has not yet formed a central cavity. Option C represents this stage because it shows a cluster of cells without a central cavity, indicating the morula stage of embryonic development.

The blastocyst stage is an early stage of embryonic development in mammals. It occurs after the morula stage and is characterized by the formation of a hollow ball of cells with an inner cell mass and an outer layer of cells called the trophoblast. In the given options, option D is the only one that represents a hollow ball of cells with an inner cell mass, resembling the blastocyst stage.

The stage that occurs 3-4 days after fertilization is the blastocyst stage. During this stage, the fertilized egg undergoes multiple cell divisions and forms a hollow ball of cells with an inner cell mass. The blastocyst is the stage at which the embryo implants into the uterine lining.

The correct answer is E. The amnion is a membrane that surrounds and protects the developing embryo in mammals, including humans. It is filled with amniotic fluid, which provides cushioning and protection for the developing fetus. The amnion is located within the amniotic sac, which is part of the gestational sac.

The question asks what line G is pointing to, and the given options are chorion, sinusoid, chorionic villi, and none of the above. However, since the question does not provide any context or visual representation of line G, it is impossible to determine what it is pointing to. Therefore, the correct answer is none of the above.

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Line G is pointing to the chorionic villi. Chorionic villi are finger-like projections that extend from the chorion, which is the outermost fetal membrane. These villi play a crucial role in the exchange of nutrients, oxygen, and waste products between the mother and the fetus. They contain a network of blood vessels that allow for the transfer of these substances. The chorionic villi also help in the production of hormones that support the pregnancy.

Line F is pointing to the maternal endometrial layer. The endometrial layer is the innermost lining of the uterus, which undergoes changes during the menstrual cycle to prepare for implantation of a fertilized egg. In the context of fetal blood vessels, the maternal endometrial layer plays a crucial role in providing nutrients and oxygen to the developing fetus through the placenta. Therefore, line F is indicating the maternal endometrial layer, which is involved in supporting fetal development during pregnancy.

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The cells that are derived from the yolk sac and form a connective tissue layer are most likely mesenchymal cells. Mesenchymal cells are multipotent stem cells that can differentiate into various cell types, including connective tissue cells such as fibroblasts, adipocytes, and chondrocytes. These cells play a crucial role in embryonic development and tissue repair. Therefore, option B is the correct answer.

CRH, or corticotropin-releasing hormone, is secreted by nonpregnant women from secretory cells in the hypothalamus. This hormone plays a crucial role in the regulation of the body's response to stress. It stimulates the release of adrenocorticotropic hormone (ACTH) from the pituitary gland, which in turn triggers the release of cortisol from the adrenal glands. This cascade of events helps the body adapt to stress by increasing energy production and suppressing non-essential functions.

The correct answer is C. The statement suggests that the composition being referred to is made up of the syncytiotrophoblast and the cytotrophoblast.

Chromosome #15 is considered a linked gene. Linked genes are genes that are located close to each other on the same chromosome and tend to be inherited together. The term "linked gene" does not refer to a specific type of chromosome or gene, but rather describes the physical proximity of genes on a chromosome and their tendency to be inherited as a unit.

The pharyngeal arches are a series of structures that form during embryonic development and give rise to various structures in the head and neck region. In humans, there are a total of six pairs of pharyngeal arches. These arches play a crucial role in the development of structures such as the jaws, face, and neck. Each arch has its own set of specific structures that develop from it, and any abnormalities in their development can lead to various congenital defects.

The line "A" is pointing to the blastocyst. A blastocyst is an early stage of development in mammals, including humans, where the embryo has formed a hollow ball of cells. It is formed after the embryo undergoes several cell divisions and differentiates into two main cell types: the inner cell mass (embryoblast) and the outer layer of cells (trophoblast). The blastocyst is responsible for implanting into the uterine wall and eventually developing into a fetus.