Exam 1 Flashcards
What is a secondary tumor?
A tumor that formed from cells that have spread.
What kind of head and face abnormalities do down syndrome patients have?
Hypodontia, protrude tongue, brachycephaly, epicanthal folds, short hard palate, enlarged tongue, flat facial profile, hypoplasia of midface, high incidence of class III occlusion and open bites because of it.
What is the name of the layer that replaces the degenerating zona pellucida?
Cytotrophoblast, which is the layer (along with the syncytiotrophoblast) that helps implants into the endometrium. Happens about 5 days after fertilization.
What is the name of the epiblast layer once the ingressing of the epiblast cells is complete?
Ectoderm, and this is now when the bilaminar disc is called Trilaminar
What is the gene associated with Turner syndrome?
SHOX - Short Stature Homeobox gene, which provides instructions for making a protein that regulates the activity of other genes, and especially important for making skeleton.
What is the name of the daughter cells that they zygote is divided up into during cleavage? And what is the name of the 32-cell stage?
Blastomeres. Morula.
What is the name of the membrane that the hypoblast produces that helps form the definitive yolk sac?
It is called the endodermal lining of the definitive yolk sac. And remember that the hypoblast also helps form the extraembryonic endoderm, that turns into Heuser’s membrane, which then surrounds the newly formed primary yolk sac.
What are some bodily physical abnormalities in down syndrome patients?
Small stature, dysplasia of pelvis, dysplasia of midphalanx of fifth finger, short metcarpals and phalanges, simian crease, cardiac anomalies (often needed to consult with cardiologist for antibiotic prophylasix, wide gap between first and second toe.
What is the Bolton discrepancy?
It is when the tooth size ratio of the maxillary and mandibular teeth will not accommodate a proper occlusal relationship. Common with Kinefelter syndrome.
What will the neural plate give rise to?
Its broad cranial portion will give rise to the brain, and a narrow caudal portion will give rise to the spinal cord.
What is the centrosome?
It is an organelle located near the nucleus in the cytoplasm that divides and migrates to opposite poles of the cell during mitosis. It consists of two centrioles, oriented at right angles and embedded in a mass of amorphous material containing more than 100 different proteins. Just before mitosis, the two centrosomes move apart until they are on opposite sides of the nucleus.
Between what two cavities does the bilaminar disc lay?
Between the amniotic cavity and the blastocyst cavity (blastocoel)
What is PGD?
Preimplantation genetic diagnosis, and it is is a screening test used to determine if genetic or chromosomal disorders are present in embryos produced through in vitro fertilization (IVF). Blastomeres are used for this. This is usually performed on patients with increased age, and or when there is a high risk of transmitting a disease-causing mutation.
With TNM staging, what is T2?
Tumor is larger than 2 cm across, but smaller than 4 cm
When do most gene mutations occur?
After you’re born, and they are not inherited. Smoking, radiation, viruses, carcinogens, obesity, hormones, and a lack of exercise can all cause gene mutations. And these gene mutations combine and can make us more likely than others to develop a specific type of cancer.
What are the three main types of Spina Bifida?
- Myelomeningocele 2. Meningocele 3. Spina Bifida Occulta
What does the developing thyroid gland travel through?
The thyroglossal duct, and it keeps going and reaches its position just inferior to the cricoid cartilage by the seventh week, so it takes about 2-3 weeks.
On what day does the amniotic cavity appear usually?
On day 8. Fluid then begins to collect between the cells of the epiblast and the overlying trophoblast (or cytotrophoblast).
What is the name for a trisomy of sex chromosomes?
Klinefelter syndrome. Males that have an extra X chromosome in most of their cells. They can have one extra X or even multiple. It occurs in about 1 out of 500-1000 baby boys.
What causes anencephaly?
It happens if the upper part of the neural tube does not close all the way, and babies are born without front part of brain, cerebrum, or remaining parts are not covered by bone or skin.
What is the name of the mass of cytoplasm which helps begin the implantation of the blastocyst into the uterine wall?
Syncytiotrophoblast. It is formed when the blastocyst contacts the uterine endometrium and the trophoblasts are induced at the embryonic pole to proliferate, and they lose their cell membranes, and become this.
What is it called when an encephalocele emerges along with the meninges? Along with ventricular system (CSF)?
Meningoencephalocele, Meningohydroencephalocele
What does the somatic mesoderm of the first pharyngeal arch give rise to?
Muscles of mastication (masseter, temporalis, pterygoids) tensor tympani, mylohyoid, tensor palatini, and anterior belly of digastric.
What causes Down Syndrome?
Embryos formed by fusion of a gamete with two copies of chromosome 21 and with a normal gamete results in trisomy 21. 95% of all Down Syndrome cases are caused this way.
What is aneuploidy?
When a cell contains an incorrect number of chromosomes. Usually happens because of failure to line up at metaphase plate.
What is the name of the small plug of acellular material that seals the small hole where the blastocyst implanted?
The coagulation plug
What causes encephaloceles?
It happens early in a woman’s pregnancy when part of the developing skull doesn’t close completely. It can cause part of baby’s brain to stick out of skull. It can be located in base of skull, are of nose sinus and forehead, or around the back of skull. They are rare, 1 in 5000.
At what week is closure of the vertebral arches completed?
Week 11
What is the name of the area formerly known as the blastocyst cavity once Heuser’s membrane has formed?
It is now called the primary yolk sac.
What is a homolog?
The 46 chromosomes in the nucleus of most human cells consist of 23 pairs of homologous chromosomes, or homologs, meaning that each of these pairs is alike, but not necessarily identical.
What does the somatic mesoderm from the third pharyngeal arch give rise to?
The stylopharyngeus muscle
What are the main phases of the cell cycle?
M - Mitosis G1 - Growth S - DNA replication G2 - Growth
Which bones are derived from neural crest mesenchyme from the first pharyngeal arch?
Maxilla, mandible, zyogamatic, and squamous portion of temporal bone
What does the first pharyngeal cleft develop into?
The external auditory canal
How many chromosomes are formed during Telophase II?
Four haploid nuclei (containing chromosomes with single chromatids) are formed in Telophase II. And these four cells are not identical because of the genetic diversity that took place in Meiosis I.
What happens during Metaphase of Mitosis?
The centrosomes are at opposite poles of the cell, and the chromosomes are highly coiled condensed and arranged at the metaphase plate. Each sister chromatid is attached to a kinetochore microtubule coming from the closest pole.
What ploidy are immature gametes like spermatogonia and oogonia?
Diploid 2N, and they are produced from the primordial germ cells. They undergo a process called meiosis where they are changed from diploid 2N to haploid 1N.
By the end of the second week, what should the developing embryo look like?
The definitive yolk sac and the bilaminar germ disc should be suspended in the chorionic cavity by a thick connecting stalk.
Which arteries does the six pharyngeal arch give rise to?
The ductus arterious and the definitive pulomonary arteries
What are the names of the two poles of the blastocyst called?
Embryonic pole by the inner cell mass, and the Abebmbryonic pole by the blastocoel.
What is the name of the central cartilages that arise from the maxillary swellings of the first arch?
Palatoperygoquadrate cartilages
What is the clinical appearance of Klinefelter?
Enlarged breasts Malocclusions Increased pulmonary disorders Increased autoimmune disorders Diabetes mellitus in 8% Cleft palate Bolton discrepancy Taurodontism
What does the second pharyngeal pouch develop into?
Crypts of the palatine tonsil, and later, lymphocytes from the bone marrow and thymus infiltrate the underlying lamina propria to establish the definitive palatine tonsil
What does the second arch cartilage, which originates from neural crest cells, give rise to?
Stapes, styloid process, styloid hyoid ligament, lesser horn of hyoid bone, upper rim of body of hyoid bone.
What is the bilaminar disc made up of?
An epiblast (primary ectoderm) and a hypoblast (primary endoderm)
What is the name glycoprotein layer that surround a zygote?
The zona pellucida, and it surrounds the zygotes plasma membrane. It plays a role in zygote development, protection, fertilization, and preventing premature implantation.
What happens during Telophase of Mitosis?
The chromosomes assemble in sets at the two poles, they begin to uncoil. A nuclear envelope reforms around each chromosome set, the spindle disappears, and the nucleolus reforms. Nuclear division by mitosis is complete at this point.
What is the name of the cells that detach as neurulation occurs? And what do they do?
Neural crest cells, and they undergo an epithelial to mesenchymal transformation and migrate to numerous locations in the body. The route they take and where they stop determines what they will be.
What is the name of the long arm of the chromosome?
Q arm
What are the two groups of cells that the cleaving embryo first divides into?
The trophoblast and the embryoblast
What is the name of an undifferentiated germ cell that gives rise to oocytes?
Oogonia
What layer do all three germ layers derive from during gastrulation?
Epiblast
What is translocation?
When a copy of chromosome 21 in a developing gamete becomes attached to the end of another chromosome, suchas chromosome 14, during the first or second division of meiosis. This can also cause Down Syndrome.
How many chromosomes do the nuclei of most human cells contain?
They contain 46 chromosomes
What structure is just cranial to the oropharyngeal membrane, and what will it give rise to?
The cardiogenic area (it is horseshoe shaped), the heart.
What artery does the first pharyngeal arch give rise to?
The terminal branch of the maxillary artery
What is the name of the foot like processes that the flattened epiblast cells around week 16 develop? And what is their function?
Pseudopodia, and they allow the epiblast cells to migrate through the primitive streak into the space between the epiblast and the hypoblast.
Is the thyroid gland ectodermal, mesodermal, or endodermal in origin?
It appears in the late fourth week as a small solid mass of endoderm proliferating at apex of foramen cecum. But remember that the thyroid gland is not derived from any of the pharyngeal arches. It arises from a midline thyroid diverticulum that forms from the endoderm in the floor of the pharynx just caudal to the first pharyngeal arch. And these endoderm cells differentiate into the follicular cells of the thyroid gland.
What are the main five factors known to increase the risk of cancer?
- Age 2. Habits 3. Family History 4. Health conditions (especially chronic conditions) 5. Environment
What is the N number and ploidy at the start and end of Mitosis?
In mitosis, a diploid 2N cell replicates its DNA becoming a diploid 4N cell, and undergoes a single division to yield two diploid 2N daughter cells. For Big N, just count the number of chromosomes (or what I like to call chromatids). And the only haploid cells will be at the end of Meiosis I (secondary spermatocytes and secondary oocyts), and the end of Meiosis II (gametes).
What is nondisjunction?
When two copies of chromosome 21 fail to separate during the first or second meiotic division, which results in one cell having 24 chromosomes and the other having 22 chromosomes. More common in gametogenesis of older females.
What is the name of the structure that the thyroid gland originates from?
It is the foramen cecum, and it is found on the developing tongue
What are the two main possible reasons why there is such a large range and variability of symptoms and diseases with down syndrome people?
One possible reason for the variability is due to mosaicism and the difference in the genes that are triplicated. Another reason is because of gene penetrance.
What happens during Prophase of Mitosis?
Chromosomes thicken and coil and the nucleolus (the site in the nucleus where rNA transcription and processing/ribosome assembly occurred) shrinks and disappears. The mitotic spindle in the cytoplasm forms between the two pairs of centrioles. The nuclear envelope disappears at the end of prophase, which signals for a substage called prometaphase to take place.
What is the end result of Meiosis?
Produces four mature gametes (meiocytes) containing 23 chromosomes (one of each pair) in each cell and are said to be haploid 1N.
What is chromatin?
The combination of DNA, histone, and other proteins that make up chromosomes and is found inside the nuclear envelope of eukaryotic cells.
At what stage is the embryo called blastocyst?
When the morula has absorbed fluid and formed a blastocoel along with the inner cell mass.
What are the characteristics associated with meningoceles?
With this type, a sack of fluid comes through an opening in the baby’s back, but the spinal cord is not in this sac, and usually little or no nerve damage.
What is the process of compaction involving cleavage?
Compaction is when the blastomeres that are being cleaved, their outer surface become convex and their inner become concave, it changes their cytoskeleton. This segregates some of the blastomeres to the center of the morula and others to the outside.
What is a mitotic spindle fiber?
As mitosis proceeds, microtubules grow out from each centrosome with their + ends growing toward the metaphase plate. These clusters of microtubules are called mitotic spindle fibers. They all serve to pull and push the sister chromatids apart toward the opposite spindle poles.
What does the somatic mesoderm inside the pharyngeal pouches contribute to? And how about the neural crest mesenchyme inside the pharyngeal pouch?
The arch artery as well as skeletal muscle tissue. The neural crest mesenchyme develops into bone, cartilage, and connective tissue in each arch.
What are the four phases of Mitosis?
PMAT Prophase Metaphase Anaphase Telophase
Are girls or boy more likely to have encephaloceles in front or back of skull, respectively?
Girls = back Boys = front North America = back Southeast Asia = front
What does the definitive endoderm end up giving rise to?
The gut and gut derivatives
What structure appears at the beginning of the third week? And what three structures does it contain?
The primitive streak (faint midline structure), which contains the primitive groove, the primitive pit, and the primitive node.
What is the name of the structure that will give rise to the future mouth of the embryo, and where is it located?
The oropharyngeal membrane, and it is located at the thin area located cranial to the neural plate of the embryonic disc.
What are the two types of errors or mutations that occur when DNA is improperly copied or Mitosis screws up?
Silent mutations and Missense mutations. Silent have no impact on DNA sequence, while missense does and messes with the function.
What are all cancer types traced back to?
Harmful mutations multiplied by mitosis. Cancer occurs when normal “checkpoints” regulating mitosis are ignored or over-riden by a cancer cell, resulting in uncontrolled cell division.
What days do the cranial and caudal ends close by?
Cranial 24 and Caudal 26
Which artery does the second pharyngeal arch give rise to?
The stapedial artery
What innervates the third pharyngeal arch?
The glossopharyngeal nerve IX
What are the main oral differences to watch for with Down Syndrome patients?
High mouth breathing = decreased saliva, fluoride toothpaste to help with caries Fissured Tongue = Show them how to brush their tongue Angular Cheilitis = usually by candida Delayed tooth eruption Microdontia Class III occlusion Early orthodontic clinical and x-ray eval is important Occlusal sealants are recommended Decay in primary dentition should be treated (because of delayed and missing permanent Early severe periodontal disease (96% with adults)
Which arteries does the third pharyngeal arch give rise to?
The common carotid artery and internal carotid artery
What does the third pharyngeal pouch develop into?
Dorsal portion of third pharyngeal pouch develops into the inferior parathyroid gland, while ventral portion develops into the thymus
What is the difference between a germ cell and an oocyte?
The germ cells develop in the fetus and before birth begins mitosis, then DNA replication, and then freezes right at the start of the first meiotic prophase division. And when they are stopped, they are now called primary oocytes, at very start of Meiosis I. And only when signaled by hormones does one single primary oocyte pick up meiosis where it left off.
What is the name of the central cartilages that arise from the mandibular swellings of the first arch?
Meckel’s cartilages
