Heredity and Prenatal Development Flashcards
Rod-shaped structures found in cells. Humans contains 46 ________ organized into three pairs.
Chromosomes
_______ are the biochemical materials that regulate the development of traits
Genes
Genes are segments of strands of ______
DNA
The 23rd pair are ________ which look different from other chromosomes and determine our sex
Sex chromosome
A zygote that divides into two cells that seperate so that each develops into an individual with the same genetic makeuo
Monozygotic twins
Two ova in the same month and they are each fertilized by different sperm cells they develop into two fraternal twins
dizygotic twins
people who bear one dominant gene and one recessive gene for a trait are said to be _______
carriers
An abnormality caused by an extra chromosome on the 21st pair resulting in 47 chromosome. Round face protruding tongue, a broad flat nose, and a slopping fold of skin over the inner corner of the yes. deficit in cognitive development and motor development
Down’s Syndrome
A number of disorders stem from an abnormal number of sex chromosomes and are therefore called
sex-linked chromosomal abnormalities
males with XYY sex chromosomal structure were once called
supermales
_________ which is caused by an extra X sex chromosome, XXY males produce less testosterone than normal males. Secondary sex characteristics, voice, hair do not develop properly. Eventually develops enlarge breast
Klinefelter syndrome
__________ has a single X chromosome. The external genital of such girls are normal however their ovaries are poorly developed and they produce little estrogen. Shorter than average and are infertile
Turner Syndrome
Has an XXX sex chromosome, normal in appearance, show lower than average language skills and poorer memory for recent events. vagina is normal, increase incidence of infertility
Triple X syndrome
The enzyme disorder in which is transmitted by a recessive gene. Cannot metabolize an amino acid called phenylalanine, so it builds up in their bodies and impairs the functioning of the central nervous system, resulting in mental retardation.
Phenylketonuria PKU
A fatal progressive degenerative disorder and a dominant trait. Uncontrollable muscle movements
Huntington’s Disease
Cause by a recessive gene, common in african americans. Red blood cells take on the shape of a sickle and clumo together obstructing small blood vessels and decreasing the oxygen supply
Sickle Cell Anemia
Cause by a recessive gene. It causes the central nervous system to degenerate resulting in death. most commonly found in Jewish Families
Tay-Sachs Disease
Caused by a recessive gene.Hereditary among European Americans. Excessive production of thick mucos that clogs the pancreas and lungs
Cystic fibrosis
A procedure for drawing and examing fetal cells sloughed off into amniotic fluid to determine the presence of various disorders
Amniocentesis
A method for the prenatal detection of genetic abnormalities that samples the membrane enveloping the amniotic sac and fetus through the vagina
Chorionic villus sampling (CVS)
Sound waves too high in pitch to be sensed by the human hear . obtain information about the fetus
Ultrasound
the set of traits we inherit from our parents are referred as
genotypes
The actual set of traits that we exhibit are called our
Phenotype
The union of an ovum and a sperm cell
Conception
List fourcharacteristics of OVA
- women have 300,000-400,000 ova in each ovary
- only ovulate 500 during our lifetime
- produce estrogen and progesterone
- menstruation cycle
The inner lining of the uterus
endometrium
Sperm __ sex chromosomes swims faster than Sperm __ chromosome.
Sperm Y, and Sperm X
Prenatal development is divided into three periods, name them and the duration of their cycle
Germinal period (1-2 weeks) Embryonic period (2-8 weeks) Fetal period (8 weeks- birth)
The period from conception to implantation is called the
Germinal stage
A stage within the germinal period of prenatal development in which the zygote has the form of a sphere of cells surrounding a cavity of fluid
blastocyst (baby)
the platelike inner part of the blastocyst that differentiates into the ectoderm. mesoderm, endoderm of the embryo
Embryonic disk
The outer part of the blastocyst from which the amniotic sac, placenta, and umbillical cord develop
Trophoblast
The stage of prenatal development that last from implantation through the eight week of pregnancy; it is characterized by the development of the major organ system
Embryonic Stage
Development follows ______ and _________ trends
cephalocaudal ( head to tail)
proximodistal (near to far)
the outer layer of cells of the embryonic disk, _______ develops into the nervous system, sensory organs, nails, hair, teeth, and outer layer of skin
Ectoderm
The inner layer, ______ forms the digestive and respiratory system, the liver, and the pancreas
endoderm
The ________ develops into the excretory, reproductive, and circulatory system, the muscles, the skeleton, and the inner layer of the skin
mesoderm
By the __ week , genetic code asserts itself, causing sex organs to differientiate
7th week
_______ secretes hormones that preserve pregnancy, prepare breast for nursing and stimulate contractions
Placenta
male sex hormones, testosterone
androgens
The _____ stage lat from the third month to birth, major organ systems have been formed, further maturation of fetal organ systems and dramatic gains in size. Respond to external stimulation
Fetal stage
The birth of a dead fetus due to malnutrition, and maternal obesity
stillbirth
Environmental influences or agents that can damage the embryo or fetus
teratogens
In this usage, a period during which an embryo is particularly vulnerable to a certain teratogen. Most vulnerable in the fourth through eight weeks
Critical period
A synthetic hormone used to maintain pregnancy that can cause masculinization of the fetus
Progestin
High doses of vitamin __ & ___ have been associated with central nervous system damage, small head size and heart defects
A and D
