Conception

he process of becoming pregnant involving fertilization or implantation or both

fetoscopy

examination of the pregnant uterus by means of an endoscope

ovum

a female sex cell (gamete)

sperm

male sex cell

zygote

cell created when sperm and ovum combine

germinal period

earliest developmental stage

blastocyst

hollow fluid filled ball

(zygote is this four days after fertilization)

placenta

permits food and oxygen to reach the baby and wastes to be carried away

villi roots

\

one of the branching processes of the surface of the chorion of the developing embryo of most mammals that help to form the placenta

ultrasound

(sonogram)

image of baby produced by ultrasound

amniocentesis

the surgical insertion of a hollow needle through the abdominal wall and into the uterus to obtain amniotic fluid especially for the determination of fetal sex or chromosomal abnormality

Chorion biopsy

 medical sample of the highly vascular outer embryonic membrane that is associated with the formation of the placenta

embryo 

an animal in the early stages of growth

endoderm

 the innermost of the three primary germ layers of an embryo that is the source of the epithelium of the digestive tract and its derivatives and of the lower respiratory tract

amniotic sac

A two-layered membrane that surrounds the embryo or Fetus in the uterus. The amniotic sac is filled withfluid in which the embryoor fetus is suspended. 

embryonic sac

formed by a thin sac around the embryos and fetuses of reptiles, birds, and mammals and containing the amniotic fluid

embryonic period

(humans) fertilization until the end of the 10th week -- precursors of all major organs are developed

Cephalocaudal

proceeding or occurring in the long axis of the body especially in the direction from head to tail

fetal period

Beginning of fetal period. Sexual differentiation continues, with male sexual organs showing more rapid development and the female remaining more neutral. buds for all 20 temporary teeth laid down. Vocal cords appear; digestive system shows activity. Stomach cells begin to secrete fluid; liver pours bile into intestine. Kidneys begin functioning, with urine gradually seeping into amniotic fluid. Other waste products passed through placenta into mother’s blood. Bones and muscles continue development, and by end of third month spontaneous movements of arms, legs, shoulders and fingers are possible.

fetus

 the young of an animal in the womb or egg, especially in the later stages of development whenthe body structures are in the recognizable form of its kind, inhumans after the end of the second month of gestation.

heredity

passing down qualities from ancestor to descendant through the genes

nature-nurture debate

debate among theorists about whether genetic  or environmental factors are more important influences on development

cell

 smallest unit of living matter capable of functioning independently  

smallest structural unit of living matter capable of functioning independently

 DNA

any of various nucleic acids that are usually the molecular basis of heredity

 chromosomes

 rod-shaped or threadlike DNA-containing structures of cellular organisms that are located in the nucleus

genes

segment of a DNA  molecule that contains instructions for production of various proteins that contribute to the body's growth and function

mitosis

 cell duplication, in which each new cell receives an exact copy of the original chromosomes

proximodistal

 physical growth that proceeds from the center of the body outward

gametes

 sex cells, sperm, and ova, which contain half as many chromosomes as regular body cells

a mature male or female germ cell  capable of initiating formation of a new diploid individual

by fusion with a gamete of the opposite sex

meiosis

the process of cell division through which gametes are formed

and in which the

chromosomes are divided in half

crossing-over

meiosis,

the exchange between chromosomes next to each other

XYY syndrome

- extra Y chromosome

- above average height, large teeth, and sometimes severe acne

-intelligence, male sexual development, and fertility are normal

- 1 in 1,000

hermaphrodite

an animal or plant having both male and female reproductive organs

Adrenogenital syndrome

dominant trait

has two dominant alleles= (homozygous) -- DD-- 

or

only one allele affects the child's characteristics (heterozygous)--Db

recessive trait

 traits like blond hair, red hair, and near-sightedness

-- bb--

result only from two recessive alleles

phenotype

an individual's directly observable physical & behavioral characteristic

(determined by genetic and environmental factors)

genotype

- an individual's genetic makeup

- determines species and unique characteristics

genome

genetic engineering

(gene therapy)

congenital defects

abnormalities

existing at or dating from birth

Down Syndrome

-mental retrdatio, memory & speech problems, limited vocab, and slow motor development

- failure of 21st pair of chromosomes to separate

-1 of 770 births

Turner's Syndrome

-missing X chromosome

-short, webbed neck, incomplete  development of sex characteristics at puberty, sterility, impared spatial intelligence

-1 in 2,500 to 8,000

- hormone therapy and spec ed

Klienfelter's Syndrome

Extra X chromosome. Tallness, body fat like female, sterility, impaired verbal intelligence, incomplete sex characteristics

-1 in 900

-hormone therapy

Sickle-cell anemia

Abnormal sickling of red blood cells

-osygen deprivation

susceptible to infection esp pneumonia

-recessive

-1 in 400 to 600    transfusions

Teratogenic

relating to, or causing developmental malformations

Fragile X Syndrome

most common inherited cause of mental retardation

- 25 to 30 percent have syptoms of autism

- impaired social interaction and delayed or absent language

Cystic Fibrosis

- recessive

- lungs, liver, & pancrea secrete large amounts of mucus leading to breathing difficulties

 1 in 2,000 to 2,500 births

Genetic counseling

fetal alcohol syndrome

fetal alcohol effects

slow physical growth

facial abnormalities

brain injury

rubella

German measles

- can cause miscarriage, physical malformations, mental retardation, and low birth weight

acquired immune deficiency syndrome

AIDS

a disease of the human immune system that is characterized cytologically especially by reduction in the numbers of CD4-bearing helper T cells to 20 percent caused by an infection with HIV blood

- causes metal retardation in fetus

RH factor

A condition that arises when the inherited blood types of mother and fetus differ

mother  (Rh-negative)

father (Rh-positive) then baby may inherit father's blood type

Monozygotic twins

identical

- have the same genetic make up

- 1 in 330 births

-zygote separates into two

Dizygotic twins

fraternal

- most common type of multile births

- results from the release and fertiliztion of two ova

Phenylketonuria

PKU

inability to metabolize the amino acid phenylalanine, contained in many proteins

-causes severe central nervous system damage in the first year of life

-recessive

-1 in 8,000