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39 Cards in this Set
- Front
- Back
Genes
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coded sequences of information by which cellular organisms regulate their embryologic development, metabolic functioning, growth and reproduction.
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- Chromosomes
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small, threadlike strands of DNA and proteins (contains thousands of genes lined up in a specific sequence)
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- DNA
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composed of deoxyribose (a five carbon sugar), a phosphate group and nitrogen containing base subunits (purines and pyrimidines)
- Purines - adnenine and guanine - Pyrimidines - thymine and cytosine |
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Human DNA - double stranded spiral - consists of:
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- Genetic information
- 46 chromosomes/23 chromosome pairs - 22 pair of autosomes - 1 pair of sex chromosomes • X • Y |
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Karyotype:
Used to determine: |
pictorial analysis of the number, form, and size of an individual’s chromosomes
Used to determine: determines sex of a child presence of chromosomal abnormalities |
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Mitosis:
Meiosis: |
single cell division, new cells have same # of chromosomes
germ cell division in which new cells decrease chromosome number by half. |
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Autosomal Chromosomal Abnormalities
Common Types: |
occurs during meiosis when a pair of chromosomes fails to separate and one resulting cell contains both chromosomes and the other contains none
- Trisomy 21 - Downs syndrome Risk w/ mothers age: 25yo 1 in 1250; 40yo 1 in 100 - Trisomy 18 – Edwards Syndrome - Trisomy 13 – Patau Syndrome |
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2 types of Sex Chromosome Abnormalities
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- Turner’s syndrome (X) females – appear as female but lacking sex organs, may have external organs.
- Klinefelter’s syndrome – (XXY) – males – poorly developed 2ndary sex characteristics, small testes. Usually infertile, tall, and effeminate. |
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Conception:
3 Periods and Weeks Gestation for each |
union of a single egg and sperm; marks the beginning of pregnancy; 1st of last menstrual cycle is day 1.
– Preembryonic Period (weeks 1-3) – Embryonic Period (weeks 4 to 8) – Fetal Period (weeks 9 to 40) |
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Prembrionic Period
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(Weeks 1-3)
- Ovulation o Release of Ovum from the ruptured ovarian folicle o High estrogen levels – increase motility of fallopian tubes o Cilia – propels ovum through the tube to the uterine cavity o Fertile – 1-2 days after ovulation - Ejaculate o Sperm – 200 to 500 million sperm. Swim towards ovum. 4-6 hours to reach ovum. o Viability -in reproductive system for 24-72 hours. |
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Fertilization
takes place in: Summary of |
Ampulla (outer 1/3 of fallopian tube)
Zygote travels to uterus -> Cleavage:cellular replication (3-4 days) -> Implantation: attachment to endometrium (6-10 days after conception) |
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Decidua
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what uterine lining is called when implantation occurs
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Chorionic villi:
becomes: |
fingerlike projections that grow into the endometrium. Very vascular – provides nutrients and oxygen.
becomes: fetal side of the placenta, contains the major umbilical vessels |
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Amnion
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forms the wall of the amniotic cavity
cells produce amniotic fluid |
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Cotyledons
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15-20 sections of the placenta (look like cauliflower) meaty and vascular
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Placenta
- developed by __wk., grows until__ Main Function: Other functions: |
developed by wk 12; grows until wk 20.
Main: diffusion of gases and nutrients to baby. Other: • Respiration:diffusion of oxygen from maternal blood to fetus • Nutrition: carbohydrates, water, fats, proteins and mineral pass from maternal blood into the fetal system • Excretion: end products of fetal metabolism cross the placenta into maternal circulation • Protection • Endocrine: barrier that protects fetus from harmful substances secretes - estrogen, progesterone, HCG, human placental lactogen • Immunity: to diseases (smallpox, diphtheria, measles) passed to the fetus from maternal antibodies |
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Embryonic Period 3 Major Developments
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(weeks 4 - 8)
1) Organogenesis – external organs and organ systems formed. Rapid formation, potential for malformations. 2) Primitive circulatory system - heartbeat begins end of 3rd week -4 chamber heart - 4th and 5th week -complete development by end of embryonic period 3) Umbilical cord -5th week |
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Umbilical cord
Function of umbilical vein and arteries: -How long at term gestation: -Wharton's jelly: -Nuchal cord: |
Vein: blood to fetus, O2 blood from mother to baby
2 Arteries: blood from fetus to mother (chorionic villi) •1% umbilical cords contain only 2 vessels •term gestation = 30-90 cm long •Wharton’s jelly - connective tissue – yellowish stringy – protects vessels in the cord. •nuchal cord – cord around the neck |
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Fetal Period
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(weeks 9 - 40)
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Placenta
development and structure |
Begins to form at implantation
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Fetal circulatory system
Ductus venosus foramen ovale Ductus arteriosus |
O2 blood from placenta → umbilical vein → fetal liver → ductus venosus (bypasses liver) → inferior vena cava → mixture with deoxygenated blood in vena cava → right atrium → foramen ovale (blood from RA to LA)→ LA → LV → aorta → major organs → RV → pulmonary artery → lungs → LA → ductus arteriosus (bypasses the lungs) → aorta
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Priority organ systems for the fetus in order.
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Brain
Heart Adrenal Glands (release epi and NE in times of stress to optimize CO in the fetus Respitory, Liver, Kidneys |
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3 special characteristics that enable the fetus to obtain sufficient oxygen from the maternal blood.
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- Hgb carries 20-33% more O2 then maternal Hgb.
- Hgb concentration is 50% greater then that of the mother. -**FHR is 110-160 bpm making CO per unit of body weight higher then that of an adult. |
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Fetal pO2
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20-32 mmHg
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Fetal Lung maturity
respiratory track begins wk__ to wk __ Surfactant present wk __, secreted by__, lines___. Function: - Fetal lung maturity weeks: __ to __. How is maturity measured? |
Embryonic period to childhood, biggest problem in preterm babies,
- Respiratory tract begins week 5 continues to week 17 Surfactant: wk 32, alveolar cells, alveoli, expands lungs. (synthetic available) - Fetal lung maturity: 35 – 37 weeks Measuring fetal lung maturity L/S ratio = 2:1 * Lecithin (alveolar surfactant) * Sphingomelin (pulmonary phospholipid remains constant in amt) When ratio is 2:1 respiratory function will take place. In diabetic mother lung maturity may be delayed beyond 37wks. Fetal stress will progress the production of Lecithen and accelerate lung maturity. |
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Oligohydramnios
Polyhydramnios |
low amniotic fluid
May discover that baby does not have kidneys, or low function. Has patient ruptured membranes? Large amounts of amniotic fluid |
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Renal system of fetus
kidney formation during wk __ Urine begins during __ Function of Amniotic Fluid |
kidney formation during wk 5
Urine 3rd month AF - bathes and coats the organ system keeping tissues soft and flexible |
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Quickening:
wks gestation it occurs |
16 - 20 weeks fetal movement is perceived by mother, felt earlier in subsequent pregnancies.
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Neurologic and Sensory systems
movements type and wk. Sound at wk__ Taste ___ Vision__ |
11-12 weeks - respiratory movements, moves extremities, changes position
Purposeful movements - response to firm touch on mothers abdomen - Sound - 24 weeks -fetal acoustic stimulation - Taste- 5th month-sweetener added to AF causes fetus to swallow twice as fast - Vision - 7th month |
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Gastrointestinal system of fetus
- Mature by __ wks - Swallows AF by |
36 wks
swallows amniotic fluid by 5 month |
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Meconium
What can cause meconium to pass in utero? |
fetal waste. Dark, green sticky. Normally passes w/in 48hours after delivery. If passed in utero can be swallowed and get into baby’s lungs (Meconium asperation syndrome – can be fatal to baby). Can be a sign of baby stress.
Mec. in utero: breech or fetal hypoxia |
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Hepatic system
Major source of energy? Why are coagulation factors NOT synthesized? |
- Glycogen stores - 9-10 weeks – major source of energy
- Iron can store for 5 months - Coagulation factors II, VII, IX, and X not synthesized b/c of lack of vitamin K in sterile fetal gut. -persists for several days after birth -prophylactic administration of vitamin K after delivery |
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Endocrine system of the fetus
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Adrenal cortex is formed in the 6th wk. Produces hormones by the 8-9th wk. At term it believed that aids in initiation of labor by lowering the maternal progesterone and stimulating production of prostaglandins.
(Insulin produced by 20th week.) |
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Reproductive system
Begins in wk__ |
7th week – XX chromosomes ovaries formed. Y chromosomes testes formed
External genitalia indistinguishable until week 12. - Male - Female |
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What 2 immunoglobulins are availabe to the fetus? How? function?
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IgG - crosses only Ig that crosses the placenta; provides passive acquired immunity to specific bacterial toxins.
IgM - fetus produces by end of 1st trimester; produced in response to blood group antigens, and some viruses. (IgA - provided by colostrum) |
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Musculoskeletal System of fetus
Bones and muscles develop at wk__ Function of fontanels? |
6th week
Fontanels - allow bones of skull to mold and move through the birth canal. |
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Integumentary system
Begins at wk__ Vernix subcutaneous fat appears at wk__ |
Begins at wk 4 as a single layer of cells.
mucous white, protects skin of the fetus, thick at 24wks, becomes scant at term. -after 32wks subcutaneous fat deposited under dermis, skin becomes less wrinkled |
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Dizygotic Twins
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- Fraternal Twins
- 2 mature ova are produced in one ovulation both fertilized by separate sperm - 2 amnions, 2 chorions, 2 placentas fraternal twins - different genes |
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Monozygotic Twins
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Identical Twins – 50% mortality rate – often have a donor and recipient – one has fluid overload the other is deficient
- develop from one fertilized ovum- divides - same sex with one genotype - 2 amnions, 2 chorions, 1 placenta – usually - genetic link is on female side. |