Structural Abnormalities and Birth Defects Flashcards
Structural or functional abnormality in development present at birth.
Congenital anomaly (birth defect)
Irregular, anomalous, abnormal, or faulty formation or structure.
Malformation
Resulting from maternal mechanical factors
Congenital deformation
Resulting from abnormal embryologic development, usually genetic.
Congenital malformation
Chromosomal
Congenital disorders
Birth trauma
Specific birth defects
Causes of abnormalities
Hereditary factors received from ancestors passed genetically to offspring. Form strand of DNA and associated proteins in the nucleus of eukaryotic cells. Composed of thousands of genes located at specific positions within this, function in the transmission of hereditary information.
Chromosomes
How many chromosomes does each individual have?
46 (23 pairs)
Determine body functions and appearance (eye and hair color, for example). There are 22 pairs of these (44 total).
Autosomal Chromosomes
Determine the sex of an individual. There are 2 of these (1 pair).
females- XX
makes- XY
Sex Chromosomes
True or false?
All somatic (body) cells have 46 chromosomes; reproduce by mitosis; divide into identical daughter cells, each with 46 chromosomes.
True
These cells have 46 chromosomes; reproduce by meiosis, and result in gametes.
Ovum- 23 chromosomes
Sperm- 23 chromosomes
Germ (sex) cells
Formed by pairing of genes
Alleles
Both genes are dominant, or both genes are recessive.
Homozygous alleles
One gene is dominant, the other is recessive
Heterozygous alleles
Too few chromosomes present.
Monosomy
Too many chromosomes present.
Trisomy
Lacking one X chromosome (44 autosomes and one X chromosome) and is clinically a female. Have a short, broad chest with underdeveloped breasts, cardiac malformations, ovaries, uterus. Sexually immature, infertile, and mental retardation is common (but with hormone replacement, normal intelligence and life).
Turner’s Syndrome
2X plus 1Y chromosome (too many sex chromosomes), is clinically a male. Usually sterile, underdeveloped prostate, testes, no facial hair, enlarged breasts, large hands and feet, long arms and legs.
Klinefelter’s Syndrome
Trisomy 21, three copies of chromosome 21 (too many autosomes)
mental retardation, short and curved 5th finger, characteristic facial appearance (flat nasal bridge, low-set ears, slanted eyes, heart defects).
Down’s Syndrome
Trisomy 18 - three copies of chromosome 18 (too many autosomes)
usually fatal within 3 months due to multiple congenital defects, cleft lip and palate, severe mental and motor retardation.
Edward’s syndrome
Trisomy 13- three copies of chromosome 13 (too many autosomes)
physical abnormalities: microcephaly, polydactyly, syndactyly, heart defects
generally death in infancy
Patau Syndrome
Anything that adversely affects normal cellular development in the embryo or fetus, can damage fetal or ovarian DNA inducing congenital fetal malformation.
examples: infectious agents, radiation and other factors
Teratogen
group of symptoms and birth defects in infants born to mother who consumed alcohol/narcotics during pregnancy.
includes mental challenges, decreased physical development, hyperactivity, microcephaly
Fetal alcohol/ fetal narcotic syndrome
group of infections acquired by women during pregnancy and transmitted to the child in the womb. 3-9 week of pregnancy exposure may result in the baby’s death or serious complications.
TORCH teratogens
TO-xoplasmosis
R-ubella (german measles)
C-ytomegalovirus (CMV)
H-erpes virus
TORCH teratogens
Rubella virus crosses the placenta to the fetus, causes microcephaly, learning disorders, deafness, and heart defects.
Congenital rubella syndrome
radiation
nutritional deficiencies
condition of the mother (age, fluid retention and poor diet, hormonal imbalance, physical injury, maternal radiation, infection, metabolic disorders, drugs and medications)
Etiology of congenital disorders
Physical or psychological injury sustained by an infant during birth
-infections (gonorrhea, herpes in birth canal),
physical trauma, lack of oxygen, umbilical cord strangulation
Birth Trauma
Grossly deformed fetus
-conjoined twins, parasitized fetus
Monsters
Abnormal development of epiphyseal cartilage
- rare, short statue, disproportionately short arms and legs, large head and characteristic facial features
- 80% have two parents of average height
Achondroplasia (hereditary dwarfism)
Due to hypopituitarism (hyposecretion of growth hormone)
-4’ tall with normal body proportions, normal intelligence
Pituitary dwarfism
Hypersecretion of growth hormone, enlarged bones of skull, arms and legs
Hyperpituitarism