Moduel 3.2 Flashcards
(41 cards)
Do you know what is meant by these principles of growth differentiation?
EXPAND
Simple to complex
Homogeneous to heterogeneous
General to specific
3 Growth Directions:
Cephalocaudal: Growth occurs from “head to tail”: the upper end of an organism develops faster and before the lower portion (maturation from head to hands and feet)
Proximodistal: Growth occurs from the middle (central axis) to extremities (near to far)
Bilateral: Growth occurs on both sides at the same time: growth is symmetrical
Define:
Karyotype
gestation
conceptus
Karyotype: a visual depiction of chromosome number and shape
Gestation: The prenatal period is that period of development from conception (fertilization] until birth
Conceptus: The product of fertilization is termed a zygote
The Placenta
- Placenta is disk-shaped and about 9 inches long, weighing about 1 lb.
- It usually delivers about ½ hour following birth (this represents the final stage of delivery).
- It enables passage of substances without directly exposing fetus to maternal blood.
- While also serving as a filter or protective barrier against some infective agents, the placenta is permeable to others, including alcohol.
Gestational period
40 weeks (280 days) (38 - 42 weeks is full term baby)
2 ways of describing prenatal developmental sequence
- by dividing gestational period into 3 equal trimesters
- by physiological stages (germinal, embryonic, fetal)
Developmental Sequence P
Gestational Period: FIRST TRIMESTER most basic body structures formed SECOND TRIMESTER growth and refinement THIRD TRIMESTER weight increases by about 6 lbs & length by about 8 inches
Physiological Stages: GERMINAL zygote implants, rapid cell division occurs EMBRYONIC 90% of 4500 body organs & structures FETAL growth in size & weight refinement of tissues & organs
What Starts Labour
The exact trigger of labour is not completely known, but a prominent view is that oxytocin receptor sites increase in smooth muscle of uterus throughout pregnancy, and at a critical point where growth and pressure is sufficient enough, oxytocin (hormone) is released by the hypothalamus and the sensitized uterus begins to contract.
The amniotic sac (bag of waters) may burst just before or during labour or during birth.
3 stages of labour
- Early Labour & Active Labour (Active Labour occurs at 4 cm dilation of cervix)
- Baby is Born (usually within 2 hours following 10 cm dilation)
- Delivery of Placenta (about ½ hour after birth of baby)
Braxton-Hicks
= False Labour. Tends to occur in the weeks before due date (most often during first pregnancy). May function to thin and soften the cervix (more pliable for dilation and delivery).
What happens during actual labour
the cervix begins to dilate and the mucus plug is lost. At 4 cm. mother is said to be in “active labour” (there are 3 stages of labour and delivery).
At 10 cm. most babies deliver within 2 hours [as short as 20 mins. and as long as a few hours] (average labour & delivery period for 1st time mothers is 12 hours). “Crowning” is when the head of the baby shows.
An Episiotomy may be needed to ease delivery (small cut to enlarge vaginal opening to assist birth: not used as much over recent decades).
Epidural Anesthesia
may be requested to help mother deal with pain and discomfort of labour & delivery. Other forms of anesthesia also exist.
Anesthesia given in the epidural space of lower back (above dura mater [outermost layer of 3 layers of meninges or membranes that cover spinal column]).
Helpful in easing pain and discomfort of childbirth. It can slow down the process a bit (contractions are typically not felt as strongly, and the urge to push is not as prominent.
Folic acid
If contemplating pregnancy, 0.4 mg (400 mcg) of folic acid per day is recommended:
Folic acid (folate) is a B-Complex vitamin found in leafy green vegetables, liver, eggs, orange juice, peanuts, beans, broccoli, asparagus, peas, lentils, enriched grain products, fortified breakfast cereals, and most multivitamins.
Folic acid is taken prior to getting pregnant in order to maximize effectiveness.
Among other things, folic acid is required for healthy neurological development of the fetus. Adequate folic acid intake is associated with reduced incidence of spina bifida.
Spina bifida types
Spina bifida occulta
Bony abnormality seen by x-ray Relatively common (5-10% of general population)
Open spina bifida
Or “spina bifida manifesta”
The diagnosis of open spina bifida is usually made at birth or during prenatal ultrasound screening.
Teratogens
a substance that interferes with normal growth and development and causes malformations
The effect of a teratogenic agent depends on:
- The strength of the teratogen
- The timing of the teratogen (While strength and duration are important considerations, as a general rule, exposure during the first trimester has the potential to be more traumatic than exposure during other trimesters. This is because it’s during the first trimester that most structures and organs are developing).
- The duration of exposure to the teratogen
Smoking & Pregnancy
When a mother smokes during pregnancy, the baby is more likely to be born pre-term and at a low birth weight
Low birth weight is correlated with several long-term health issues
For example, inhibited growth throughout life, and susceptibility to chronic diseases later in life
Alcohol & Pregnancy
-Alcohol passes through placental barrier & is not well broken down (metabolized) by immature infant
-The blood alcohol content of the fetus is therefore greater than that in the mother
-Similar to other teratogens, prenatal effects of exposure to alcohol depend on:
>Timing (which trimester[s]): though morphological effects generally occur in the first trimester, because the brain continues to develop and is sensitive throughout the pregnancy, neurological/developmental/cognitive effects can result during all trimesters.
>Amount consumed (and how often [duration])
>Genetic makeup of fetus
>Mother’s ability to metabolize (breakdown & excrete) alcohol
The most severe type of Fetal Alcohol Spectrum Disorder is Fetal Alcohol Syndrome [FAS].
- facial characteristics
- growth retardation
- neuro-developmental challenges
- maternal alcohol use
3 specific ways teratogens can impact fetus
mutagenetic (effect DNA composition, effects growth and development) environmental teratogens (how cells act or react or how they multiply) epimutagenetic teratogens (effect the epigenome, the molecular expression of DNA without changing the DNA itself)
Toxoplasmosis
A fetus may contract toxoplasmosis through the placental connection with its infected mother
The mother may be infected by: improper handling of cat litter, handling or ingesting contaminated meat
Rh Incompatibility
Occurs when Rh- mother carries and Rh+ fetus. If mixing of blood occurs, mother’s immune system becomes sensitized and develops antibodies against fetus’s Rh factor. If not detected, this can have serious consequences for fetus.
In most cases, the first child is not at risk. Mothers are usually not sufficiently sensitized until after the birth of their first baby. When this occurs, subsequent fetuses are placed at risk.
In most cases, Rh- mothers are identified, and if carrying an Rh+ fetus (determined through amniocentesis or umbilical cord blood sample), precautions are taken.
Throughout the pregnancy, the mother’s blood is monitored for the prevalence of antibodies (through the “Coombs Test”). If antibodies reach a threshold amount, then the fetus will likely receive a blood transfusion of Rh- blood. The transfusion occurs through the cord.
APGAR Test
-First assesment done on infant A = appearance P = pulse G = grimace A = activity R = respirations
A score is given for each sign at one minute and five minutes after the birth. If there are problems with the baby an additional score is given at 10 minutes. A score of 7-10 is considered normal, while 4-7 might require some resuscitative measures, and a baby with an APGAR score of 3 and below requires immediate resuscitation.
Newborns with a score of 3 or less are 3 X as likely to have neurological problems.
The results of assessments like the Apgar simply gather data. If the assessment reveals something concerning, the individual is usually sent for more advanced diagnostic testing.
metabolic disorders
metabolic disorders are passed along by recessive means and are the result of genetic mutations that cause the DNA code to be disrupted (missing base element), resulting in a missing enzyme and failure to metabolize certain substances.
Many of these disorders can be treated with dietary modifications.
Tandem Mass Spectrometry is used to assess for as many as 30 disorders with one drop of blood from the heel prick.
Involved in bodys ability to break down substances or create one the body needs
Important to test newborns because If body can’t break down the substances they can build up and become toxic. If the body cant create substances, it can have a toxic effect on the body which is cumalitive where the longer it goes the worst the effects can be.
What is a screening test?
Screening tests are laboratory tests that help to identify people with increased risk for a condition or disease before they have symptoms or even realize they may be at risk so that preventive measures can be taken. They are an important part of preventive health care.
Screening tests help detect disease in its earliest and most treatable stages. Therefore, they are most valuable when they are used to screen for diseases that are both serious and treatable, so that there is a benefit to detecting the disease before symptoms begin.
What are the characteristics of good screening instruments?
- Can be administered in short time
- Don’t require highly specialized and extensive training to administer
- Have clear Pass/Fail criteria
- High sensitivity and specificity
- Do what they’re supposed to do [are valid]
A good screening instrument must have sensitivity, which is the ability to correctly determine who does have the condition
A good screening tests must also have specificity, the ability to correctly determine who does not have the condition
Lanugo
A soft, downy covering of hair, mostly on shoulders, the back of extremities, the forehead and temples