Flashcards in Week 1 Deck (33):
Process of male gametogenesis
Type A spermatogonia (stem cells) through mitosis to Type A spermatogonia (progenitor cells) through mitosis to Type B spermatogonia. Type B spermatogonia through mitosis to primary spermatocyte through meosis to secondary spermatocyte through meosis to spermatid. Spermatid will go through spermiogenesis (differentiation) until they reach mature spermatozoa
Process of female gametogenesis
Oogonium through mitosis to primary oocyte (arrested in prophase I); primary oocyte through meiosis to secondary oocyte (arrested in metaphase II); if fertilized secondary oocyte to ovum through meosis II
-number of times female has been pregnant; regardless of pregnancy outcome
-twin pregnancy counts as one
-number of pregnancies reaching viable gestational age (including live births and stillbirths).
-number of fetuses does not determine the parity;Twin pregnancy carried to viable gestational age is counted as 1.
the process of carrying or being carried in the womb between conception and birth.
Relate advanced maternal age to occurrence of chromosomal abnormalities and miscarriages
-cohesin and securin are proteins present that help keep chromosomes together at their centers. Lower levels of these proteins cause the chromosome pairs or sister strands to be more loosely connected and further apart.
-Researchers found that older female mice had lower amounts of these proteins in their eggs, suggesting that as the eggs age, the levels of these proteins fall.
- leads to instability in the chromosome pairs and a higher likelihood that chromosome division will happen unevenly. The result could lead to an increased chance of older mice having offspring with an abnormal number of chromosomes.
mechanisms that cause chromosomal abnormalities
-aneuploidy due to non-disjunction
-aneuploidy due to anaphase lag
aneuploidy due to non-disjunction
non-disjuction occurs during first meotic split
aneuploidy due to anaphase lag
non-disjuction occurs during second meotic split
Down Syndrome (trisomy 21)
- light or severe degree of intellectual disability and a number of physical features. -develop less quickly, both physically and mentally.
-Many babies with Down syndrome die during pregnancy.
-50% are born with cardiac abnormality and/or other abnormalities. Cardiac abnormality can be treated surgically depending on the nature and severity of the abnormality.
Edwards syndrome (trisomy 18)
- Most die during pregnancy or shortly after birth.
-Most children die in the first year of their lives.
-have severe mental retardation.
-9 out of 10 children have a serious congenital heart defect.
Patau Syndrome (trisomy 13)
-most die during pregnancy or shortly after birth.
-Most children die in the first year of their lives.
-severely mentally retarded; brains and the heart fail to develop properly; Kidney defects and abnormal gastrointestinal tracts may also occur.
-may develop more fingers or toes.
-cleft lip and palate.
Noninvasive Prenatal Testing (NIPT
new, optional non-invasive evaluation that combines a maternal blood screening test with an ultrasound evaluation of the fetus to identify risk for specific chromosomal abnormalities, including Down Syndrome Trisomy-21 and Trisomy-18.
Quad screening test
-AFP: alpha-fetoprotein is a protein that is produced by the fetus
-hCG: human chorionic gonadotropin is a hormone produced within the placenta
-Estriol: estriol is an estrogen produced by both the fetus and the placenta
-Inhibin-A: inhibin-A is a protein produced by the placenta and ovaries
- test to examine chromosomes in a sample of cells. This test can help identify genetic problems as the cause of a disorder or disease.
- can use amniotic fluid, blood, bone marrow, or placenta to extract cells
-cells are grown and then stained, microscope used to examine the size, shape, and number of chromosomes in the cell sample, sample is photographed to show the arrangement of the chromosomes.
Ultrasound for birth defects
-level 2 ultrasound; images are much clearer and more detailed t
-baby measured from crown to rump, around the middle, and around the head; his or her weight will be estimated.
-Will look at four chambers of the heart, kidneys, bladder, stomach, brain, spine and sex organs, amniotic fluid levels, location of the placenta and fetal heart rate.
-can also tell you the sex of your baby with less than 100 percent reliability and depending on baby's cooperation.
-positive results from a prenatal screening test; chromosomal condition or a neural tube defect in a previous pregnancy; If a previous pregnancy was affected by conditions such as Down syndrome or a neural tube defect; You're 35 or older; family history of a specific genetic condition, or you or your partner is a known carrier of a genetic condition.
-Leaking amniotic fluid; Miscarriage; Needle injury to baby; Infection to mom; Infection transmission from mom to baby
- can use amniotic fluid to test for karyotype, fetal lung testing, fetal infection , paternity; can be used as treatment if mother has too much fluid (polyhydramnios)
Types of Down Syndrome
- Trisomy 21: 95 percent of the time;
-Mosaic Down syndrome: rare form; a person has only some cells with an extra copy of chromosome 21; caused by abnormal cell division after fertilization.
-Translocation Down syndrome: portion of chromosome 21 becomes attached (translocated) onto another chromosome, before or at conception. These children have the usual two copies of chromosome 21, but they also have additional genetic material from chromosome 21 attached to another chromosome.
Common features of down syndrome
-Flattened face;Small head; Short neck; Protruding tongue; Upward slanting eye lids (palpebral fissures); Unusually shaped or small ears; Poor muscle tone; Broad, short hands with a single crease in the palm; Relatively short fingers and small hands and feet; Excessive flexibility; Tiny white spots on the colored part (iris) of the eye called Brushfield's spots; Short height
Complications of Down Syndrome
-Heart defects: 50% born with congenital heart defect; can be life-threatening and may require surgery in early infancy.
-Gastrointestinal (GI) defects: occur in some children; may include abnormalities of the intestines, esophagus, trachea and anus. The risk of developing digestive problems, such as GI blockage, heartburn (gastroesophageal reflux) or celiac disease, may be increased.
- Immune disorders: increased risk of developing autoimmune disorders, some forms of cancer, and infectious diseases, such as pneumonia.
- Sleep apnea: Because of soft tissue and skeletal changes that lead to the obstruction of their airways
-Obesity: greater tendency to be obese compared with the general population.
- Spinal problems: Some have a misalignment of the top two vertebrae in the neck (atlantoaxial instability). This condition puts them at risk of serious injury to the spinal cord from over extension of the neck.
- Leukemia: Young children with Down syndrome have an increased risk of leukemia.
-Dementia: greatly increased risk of dementia — signs and symptoms may begin around age 50; also increases the risk of developing Alzheimer's disease.
-Other problems: endocrine problems, dental problems, seizures, ear infections, and hearing and vision problems.
-Chiari type II malformation
-Lethargy; Poor feeding; Irritability; Stridor; Ocular motor incoordination; Development delay
-Cognitive or behavioral changes, Decreased strength,Increased spasticity, Changes in bowel or bladder function, Lower cranial nerve dysfunction, Back pain, Worsening spinal or lower extremity orthopedic deformities
-Laryngeal and pharyngeal paralysis,Apnea, Swallowing difficulty, Respiratory stridor, Nystagmus, Upper extremity weakness
Complications of sinabifida
-closure of the back defect; may cause hydrocephaluc (hind brain herniation)
- Chiari type II malformation: is seen in 80-90%; caudal displacement of the cerebellum, pons, and medulla and elongation of the fourth ventricle. This can impede cerebrospinal fluid flow and is involved in the development of hydrocephalus
- ortho: scoliosis, lordosis, and kyphosis; development of scoliosis associated with the neurologic level (thoracic defects have an 80-100% risk, sacral very low risk)
-Abnormalities of foot : 90% of children and adolescents. goal of treatment is to achieve a plantar grade foot for weight bearing and allow shoe wear. Clubfoot and rockerbottom feet common
-neurogenic bladder and bowel: use caths
-neuropsychologic promblems: nonverbal learning
-provides a standard method to assess the physical condition of newborns immediately after birth & can be used to assess an infant's response to resuscitation.
-The heart rate, respiratory effort, muscle tone, response to stimuli, and color are assessed at 1 and 5 minutes.
-Zero to two points are awarded in each category. A score of 7 to 10 is considered normal.
-A score of less than 7 should be repeated at 5-minute intervals up to 20 minutes.
Indications for c-section
indications for cesarean delivery (85%) are previous cesarean delivery, breech presentation, dystocia, and fetal distress
-Drugs: Category A: no risk to fetus in human studies; Category B: no risk to fetus in other studies;Category C: risk cannot be ruled out; Category D: positive evidence of risk; Category X: contraindicated in pregnancy
-Alcohol: causes cell death, failure of cell migration
-Smoking: impairs oxygen delivery to fetus; decreases placenta blood flow and decreases oxyhemoglobin
Drugs known to be teratogenic in animals and humans
-Seizure Drugs: Valproic acid à these drugs are assoc. with decreased folic acid in the mother and baby, which leads to neural tube defects
-Chemotherapy: targets rapidly dividing cells and can kill these rapidly dividing cells in baby
-Methotrexate (Anti-inflammatory): inhibits folate metabolism
-Antibiotics: may disrupt folate metabolism in fetus
importance and functions of folate (folic acid) in early development.
-relate to its ability to transfer one-carbon groups.
-It is essential in the de novo synthesis of nucleotides and in the metabolism of several amino acids
- adequate levels of dietary folate are important for fetal and placental development and are needed to support rapid cell growth, replication, cell division, and nucleotide synthesis.
-critical that pregnant women consume adequate folate before and during the first 4 weeks of embryologic development
Anatomy of the abnormality of spinabifida
-contains protruding sac that can contain meninges, spinal cord, or both
location of a neural tube defect affects a patient’s symptomatology and clinical complications
-T12: totally paralyzed lower limbs
-L1-2: Hip flexors
-L5: Hamstrings, anterior tibial muscles
-S1: Lat hamstring and peroneal muscles
-S2-3: mild loss of intrinsic foot muscles
pathogenesis of hydrocephalus
- excess cerebrospinal fluid (CSF) accumulation in the head caused by a disturbance of formation, flow, or absorption.
Spina bifida occulta
-midline defect of the vertebral bodies without protrusion of the spinal cord or meninges.
- asymptomatic and lack neurologic signs,
-condition is usually of no consequence.
-meninges herniate through a defect in the posterior vertebral arches or the anterior sacrum.
-spinal cord is usually normal and assumes a normal position in the spinal canal, although there may be tethering of the cord,
-most are well covered with skin and pose no immediate threat to the patient.
-asymptomatic children with normal neurologic findings and full-thickness skin covering the meningocele, surgery may be delayed or sometimes not performed.