OB unit 1 Flashcards
III. OOGENESIS
A. The process of female gamete production
B. The female gonad is the ovary
C. The female gamete is called the ovum or egg
Spermatogenesis
A. The process of male gamete production
B. The male gonad is the testis
C. The male gamete is called spermatozoa
XII. FUNCTION OF PROGESTERONE
A. Called the hormone of pregnancy
B. Causes the endometrium to increase in vascularity
C. Increases glycogen stores in endometrium
D. Supports endometrial lining
E. Causes cervical mucus to become “thick and sticky”
F. Relaxes smooth muscles
Progesterone
- increase causes maturation of mammary gland tissue
- hCG continues the supply of estrogen and progesterone needed to maintain pregnancy.
- miscarriage occurs if the corpus luteium stops functioning b4 the placenta is producing sufficient estrogen and progesterone.
- The placenta eventually produces more of the steroid hormone progesterone than the corpus luteium does during the first months of pregnancy.
- Progesterone maintains the endometrium, decreases the contractility of the uterus, and stimulates maternal metabolism and development of breast alveoli.
XI. FUNCTION OF ESTROGEN
A. Causes the endometrium lining to thicken in preparation for implantation
B. Controls the development of secondary sexual characteristics
C. Aids in maturation of the ovum
D. Causes changes in cervical mucus
1. Becomes more thin and watery – “spinnbarkheit”
E. Increase contractibility of tubes
1. Propel large ovum thru tube
-stimulates growth of breasts by inducing fat deposition in the breasts.
- estrogen also increases the vascular its of Breast tissue
Estrogen
- Women over 50 experience menopause associated with decreased estrogen.
- Decrease causes numerous cytologic and structural changes of the vagina, vulva, and lower urinary tract.
- Deficiency leads to narrowing and shortening of the vagina and thinning of the vaginal walls, resulting in vaginal dryness, itching, burning, and dyspareunia.
- Loss causes reduced smooth muscle relaxation, decreased vaginal secretions.
- It plays a role in formation of bone matrix, and a decrease mY lead to osteoporosis.
- Declining estrogen can increase the risk for heart disease.
- Decrease can cause a relaxation of ligaments and connective tissue, which effects the support of the bladder and uterus.
- Decrease affects the hypothalamus, causing hot flashes.
estrogen
- miscarriage occurs if the corpus luteium stops functioning before the placenta is producing sufficient estrogen and progesterone.
- By 7 weeks after fertilization the placenta is producing most of the maternal estrogens.
- The major estrogen secreted by the placenta is estriol, whereas the ovaries produce mostly estradiol.
- estriol levels may be measured to determine placental functioning.
- It stimulates uterine growth and uteroplacental blood flow.
- Causes a proliferation of the breast glandular tissue and stimulates myometrial contractility.
- Placental estrogen production increases greatly toward the end of pregnancy.
- lactation delays the production of cervical and other estrogen-influenced mucus and mucosal characteristics.
- Postpartum estrogen deprivation is responsible for the thinness of the vaginal mucosa and absence of rugged
I. Implantation
A. The trophoblasts attaches itself to surface of endometrium
1. Most frequent site of attachment is fundus
B. 6-10 days after conception, burrows into uterine lining
C. Cells of trophoblast grow down into the endometrium forming fingerlike projections called
“chorionic villi” which allow early exchange of oxygen and carbon dioxide
II. CELLULAR DIFFERENTIATION
A. 10 - 14 days after fertilization, blastocyst cells differentiate into primary germ layers
B. All tissues, organs and structures will develop from one of these three layers
III. DEVELOPMENT OF EMBRYONIC MEMBRANES
A. Chorion-outermost
1. Encloses amnion and embryo
2. Chorionic villi on the surface
3. Villi grow into endometrium & form fetal part of placenta
4. Rest of chorion lose villi except where attached to uterine wall
B. Amnion-inner
1. Thin, protective membrane
2. Contains amniotic fluid
3. As baby grows, comes in contact with chorion
**Eventually the chorion and the amnion “fuse” to form the “bag of waters”
IV. AMNIOTIC FLUID
A. Functions as cushion to protect FETUS & CORD against injury
B. Helps control embryo’s temperature
C. Allows symmetrical external growth of embryo
D. Prevents adherence of amnion to embryo
E. Allows freedom of movement
F. Can analyze to determine fetal health and maturity
G. Amount of amniotic fluid
—10 weeks ~ 30 ml
—20 weeks ~ 350ml
—After 20 weeks ~ 800 - 1200 ml
H. Amniotic Fluid index
1. Method to evaluate the ‘wellness’ of the baby
a. Oligohydramnios-deficiency of amniotic fluid.
b. Polyhydramnios-excessive amniotic fluid
V. DEVELOPMENT OF PLACENTA
A. Means of O2, CO2 and nutrient exchange btw embryonic and maternal circulation
B. Begins to function about 3rd week after fertilization (5 weeks after LMP)
C. Two parts
1. Maternal portion - red & flesh-like
2. Fetal portion - shiny gray
D. Eventually form a single layer of cells called the “syncytium” where exchange takes place
1. Fetal blood and maternal blood should not mix!
E. Blood flow within the intervillous spaces of the placenta depends on maternal BP
1. Blood flows from area of high pressure to area of low pressure
2. Braxton - Hicks enhances circulation
3. Labor & High BP decreasecirculation
F. As placenta “ages”, circulation can decrease
G. Fetal RBCs can pass into maternal circulation thru breaks in placental membrane
1. RH sensitization
VI. FUNCTIONS OF PLACENTA
A. Fetal Respiration
B. Nutrition
C. Excretion
D. Protection
E. Endocrine
1. Produces HCG, progesterone, estrogen, human chorionic somatomammotropin
F. Immunity-passiveVII. UMBILICAL CORD DEVELOPMENT
A. Formed from amnion
B. 1st referred to as “body stalk”
C. Fuses with fetal portion of placenta to provide circulatory pathway
D. One VEIN AND Two ARTERIES
1. Vein carries oxygenated blood, arteries carry unoxygenated blood
E. Contains special connective tissue called Wharton’s Jelly
VIII. FETAL CIRCULATION
A. Most of fetal blood _____________ the ______________
B. Key to fetal circulation is right to left shunting Placenta OXYGEN RICH through umbilical vein Liver Ductus Venosus Inferior Vena Cava Right Atrium Foramen Ovale Left Atrium Mitral Valve to Left Ventricle Aorta Head & Neck
DEOXYGENATED Superior Vena Cava Right Atrium Tricuspid Valve to Right Ventricle Pulmonary Artery Ductus Arteriosus Aorta Trunk and Lower Extremities
MIXED blood throughout systemic circulation then back to placenta via umbilical arteries
IX. FETAL DEVELOPMENT
A. Embryonic stage - conception to 8 weeks
1. This period of development most vulnerable to teratogens
2. By end of the 3rd week (after conception), primitive heart is beating
3. At 8 weeks, resembles a human
4. Beginnings of all essential internal and external structures are present
B. Fetal stage - end of 8th week to term
1. Every organ system and external structure found in full-term infant is present
2. Heart tones can be heard between 8 & 12 weeks
a. Normal range 110-160 bpm
b. May be heard with Doppler at 8-12 weeks
c. Heard with “fetoscope” at 16-20 weeksl
3. 20 weeks - fetal movements can be felt by mom. Called “quickening”
4. At 24-25 weeks, fetus has sufficient lung & CNS development to potentially survive outside the uterus
5. Last 12 weeks, period of rapid weight gain
6. lung maturity occurs around 35 weeks gestation
1st Trimester
Heart beating Genitals distinguishable Kidneys urinating Liver Bladder Intestines Teeth Legs, Arms Hands, Feet Fingers/Toes/Nails Lungs Ears Spinal column/CSF circulates Bones Nervous System/Brain Waves detectable Eyes/Eyelids fuse at 8wks Nose Mouth Vocal Cords Sucking and Grasping
2nd Trimester
Taste Buds Bone Marrow REM Sleep Sweat Glands Alveoli/Bronchioles Nostrils open Vernix Caseosa Lanugo Scalp Hair Internal Ear Canal Meconium in Bowel/Anus open “Practices” Breathing
Third trimester
- eyelids reopen- open and close
- pupils react to light
- senses present-vision, hearing, taste, touch, smell
- Sleep & Wake Cycles
- SubQ Fat produced and stored
- Antibodies present
- Glycogen stores present
- Muscle tone increases
Teratogens
Any agent (drug, virus or radiation) that can cause development of abnormal structures
GREATEST RISK during embryonic period
- The woman may be exposed to teratogenic agents before knowing about being pregnant.
- Pre conception counseling can educate the woman about the effects of these agents and disease.
- pre conception counceling can help prevent harm to the fetus or allow the woman to make an informed decision about her willingness to accept potential hazards should a pregnancy occur.
Teratogens
- chemicals, cleaning agents, paints, sprays, herbicides, and pesticides are included and can be found in the yard, home, workplace, soil, and water.
- –read labels for ingredients and proper use of products
- –ensure adequate ventLation with clean air
- –wear gloves when handling chemicals
- –change job assignments or workplace if necessary
- –avoid travel to high-altitude regions, which could jeopardize oxygen intake.
teratogens control.
- During the embryo stage, from day 15 until aprox. 8 weeks after conception is the most critical stage in development of the embryo.
- —Because of these areas with rapid cell division they are most vulnerable to malformation caused by environmental teratogens.
- Congenital malformations ( meaning present at birth) can be a result of teratogens.
- disabilities caused by teratogens are theoretically totally preventable.
- Known teratogens are certain drugs and chemicals, infections, exposures to radiation, and certain maternal conditions such as diabetes and PKU.
- They have their greatest effects on organs and parts of an embryo during its periods of rapid growth and differentiation during the embryonic period specifically from day 15-60.
- During the first 2 weeks they either have no effect or have effects so severe that they cause miscarriage.
- brain growth and development continue during the fetal period and teratogens can severely effect mental development throughout gestation.
Teratogens
- Smoking impairs fertility in women and men.
- –during pregnancy it can cause a decrease in placental perfusion and is a cause of low birth weight.
- Alcohol can lead to fetal alcohol syndrome
- Prescription drugs, especially psychotherapeutic drugs, can have some effect on the fetus when taken during pregnancy and must be very carefully monitored.
- Illicit drugs cause many problems for the fetus and mother
Risk factors of Teratogens found on assessment can include
- Medications and medical treatments
- –prescription medications, especially those contraindicated during pregnancy, over the counter meds, radiation exposure
- Personal behaviors and exposures
- –smoaking, alcohol consumption, illicit drug use
- –environmental agents, toxic chemicals, radiation.
