Flashcards in Ch. 3 Prenatal Development and Birth Deck (33)
What are Chromosomes?
Strings of genetic material in the nuclei of cells.
What are Gametes?
Cells that unite at conception (ova in females, sperm in males)
What is a Zygote?
Single cell created when sperm and ovum unite.
What is Deoxyribonucleic Acid (DNA)?
Chemical material that makes up chromosomes and genes.
What are Genes?
Pieces of genetic material that control or influence traits.
What are Gonads?
Sex glands (ovaries in females; testes in males)
What is a Genotype?
The unique genetic blueprint of each individual.
What is the Phenotype?
An individual's particular set of observed characteristics.
What is the Dominant-Recessive Pattern?
Pattern of inheritance in which a single dominant gene influences a person's phenotype but two recessive genes are necessary to produce an associated trait.
What is Polygenic Inheritance?
Pattern of inheritance in which many genes influence a trait.
What is Multifactorial Inheritance?
Inheritance affected by both genes and the environment.
What is the Cephalocaudal Pattern?
Growth that proceeds from the head downward.
What is the Proximodistal Pattern?
Growth that proceeds from the middle of the body outward.
What is the Germinal Stage?
The first stage of prenatal development, beginning at conception and ending at implantation (approximately 2 weeks).
What is Implantation?
Attachment of the blastocyst to the uterine wall.
What is the Placenta?
Specialized organ that allows substances to be transferred from mother to embryo and from embryo to mother, without their blood mixing.
What is the Umbilical Cord?
Organ that connects the embryo to the placenta.
What is the Amnion?
Fluid-filled sac in which the fetus floats until just before it is born.
What is the Embryonic Stage?
The second stage of prenatal development, from week 2 through week 8, during which the embryo's organ systems form.
What are Neurons?
Specialized cells of the nervous system.
What is Organogenesis?
Process of organ development.
What is the Fetal Stage?
The third stage of prenatal development, from week 9 to birth, during which growth and organ refinement take place.
What is Viability?
Ability of the fetus to survive outside the womb.
What is the Cell Body?
The part of a neuron that contains the cell body and is the site of vital cell functions.
What are Synapses?
Tiny spaces across which neural impulses flow from one neuron to the next.
What are Axons?
Taillike extensions of neurons.
What are Dendrites?
Branchlike protrusions from the cell bodies of neurons.
What are Glial Cells?
The "glue" that holds neurons together to give form to the structures of the nervous system.
What are Teratogens?
Substances, such as viruses and drugs, that can cause birth defects.