prenatal development (dev psy)

part 2 prenatal development

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