Studied by 10 people
period between conception and birth
NORMAL RANGE - 37 - 41 weeks
GESTATIONAL AGE - first day of last menstrual cycle
GESTATION (PAGBUBUNTIS)
fertilization to 2 weeks
Zygote has the following activities:
Forms a protection against repeated penetration from additional sperms
Repeated cell division by mitosis
Fertilization to implantation (attachment of blastocyst to the uterine wall) takes 2 weeks
GERMINAL PERIOD/ STAGE OF THE OVUM
Begins once implantation has occurred
2nd-8th week after conception
2nd – 9th week of gestation: human-like
Beating heart (3rd week)
External genitals
Face with mouth, eyes & ears
Arms & legs
Trunk & limb musculature
Gross movements
EMBRYONIC PERIOD
fluid-filled membrane that encases the developing embryo
AMNIOTIC SAC
Connect the baby & the mother Provide nourishment Site for gas exchange Connected to the embryo by the UMBILICAL CORD
PLACENTA
development of the organ systems
Brain growth and development begins during the embryonic stage
ORGANOGENESIS
happens during embryonic period
expulsion from the uterus of an embryo or fetus that is unable to survive
SPONATANEOUS ABORTION/ MISCARRIAGE
Three basic layers that arise from the inner cell mass of the blastocyst:
ECTODERM –outer layer
MESODERM – middle layer
ENDODERM – inner layer
Epithelial linings of the respiratory tract Tonsils, thymus, lungs, liver, pancreas Gastro Intestinal Tract
Central NS/Peripheral NS
Epithelium of sensory organs
Epidermis
Enamel of the teeth
Epithelial lining of other organs
Hair
Nails
ECTODERMAL DERIVATIVES
Skeletal system
Muscle cells
Dermis & subcutaneous tissue
Pleural & pericardial cavities
Cardiovascular & Lymphatic system
Gonads
Cortical portions of the suprarenals
MESODERMAL DERIVATIVES
Ninth week of pregnancy until birth
Appearance of bone cells signals this stage It is a critical period for brain development
Fetus is structurally complete: Development is FUNCTIONAL not structural
FETAL PERIOD
bones & external genitalia are discernible
4th-5th MONTHS
Swallows, hiccups, opens & closes eyes, makes facial movements, flex & extends limbs, sucks thumb
Still cannot survive independently
5 MONTHS
9 WEEKS – structural remodeling of some organs 1
0 weeks – face is recognizably human 12 weeks – gender is distinguishable. Lung division successively occurs 🡪 bronchi 🡪 bronchioles…
20 – 24 weeks – primitive alveoli; surfactant production. (absence of alveoli, lungs are useless for gas exchange)
3rd trimester (7mo-9mos) – weight triples, length doubles as body stores of protein, fat, iron , and calcium increases
SOMATIC DEVELOPMENT
environmental agent that can interfere with normal prenatal development
Associated with gross physical & mental abnormalities
Infectious agents
Chemical agents (mercury, thalidomide, ethanol, antiepileptic drugs)
High temperature
Radiation
TERATOGENS
Prenatal period has the highest rate of morbidity & mortality!!! Spontaneous abortions most often in the 1st trimester
THREATS TO FETAL DEVELOPMENT
Prenatal exposure to cigarette smoke is associated with
Low Birth Weight
Shorter length
Smaller head circumference
Decreased IQ
Increased rates of Learning Disabilities
Severe maternal starvation
Low Birth Weight
Psychologic stress during pregnancy
Caffeine
Paternal factors
PRENATAL RISK FACTORS
Very young mothers
35 y/o above (risk of chromosomal problems)
Maternal age
Nutrition
3-4 lbs/month (25-30 lbs during pregnancy)
Maternal health
Release of adrenalin and other hormones (affects brain and sex organ development)
Maternal stress
German measles (rubella) CONGENITAL RUBELLA
SYNDROME – deafness, heart defects, MR,
cataracts
Syphillis- sensitive at 16th -18th week
Acquired Immune Deficiency Syndrome (AIDS)
Maternal infections and diseases
Thalidomide
Nicotine/alcohol intake (LBW, prematurity, death,
Fetal Alcohol Syndrome)
illicit drugs
Maternal drugs
Chromosomal damage
Microcephaly
Brain malformation
Mental retardation
Radiation
Note 
Flashcard (41)