development, maturation, aging, and death Flashcards
(27 cards)
arise when two eggs are ovulated and fertilized in the same monthly cycle
fraternal twins
arise when a zygote divides in two during development
identical twins
Where does fertilization typically occur in the female reproductive system?
In the upper third of the oviduct (Fallopian tube).
What is formed when a sperm fertilizes an egg?
zygote
What challenges do sperm face on their journey to fertilize an egg?
Distance, vaginal pH, cervical mucus, and white blood cells.
What is the male gamete called, and what are its main parts?
Sperm; consists of a cone-shaped head, a midpiece, and a long, whip-like tail.
What is the female gamete called at the time of fertilization?
secondary oocyte
What is the function of the acrosome in the sperm?
Releases digestive enzymes to penetrate the egg.
How is polyspermy (fertilization by more than one sperm) prevented?
The zona pellucida becomes impermeable to other sperm after the first sperm enters
What triggers the completion of meiosis II in the oocyte
Entry of the sperm nucleus into the secondary oocyte.
What is the result when the sperm nucleus fuses with the ovum nucleus?
Formation of a diploid zygote.
What are fraternal twins, and how do they form?
Dizygotic twins; form when more than one oocyte is ovulated and each is fertilized by different sperm.
What are identical twins, and how do they form?
Monozygotic twins; form when one oocyte is fertilized and the embryo splits into two before the 16-cell stage.
What are the four main developmental processes after fertilization?
Cleavage, growth, differentiation, and morphogenesis
What is cleavage?
Series of cell divisions without cell growth, producing a ball of identical cells.
What is differentiation?
Process where individual cells take on specialized forms and functions.
What is morphogenesis?
The physical development and changes in shape and form of the organism.
Name the three stages of prenatal development.
Pre-embryonic, embryonic, and fetal development.
What is a morula?
A ball of 32 identical cells resulting from cleavage, entering the uterus about day 4 post-fertilization.
What is a blastocyst?
A hollow ball with an inner cell mass that will become the embryo
What is implantation?
The process where the blastocyst burrows into the endometrium, occurring about day 6 or 7 post-fertilization.
What is an ectopic pregnancy?
When the blastocyst implants in the oviduct instead of the uterus.
What are the three primary germ layers, and what do they develop into?
Ectoderm: Epidermis, nervous system, hair, nails, parts of the eye, tooth enamel
Mesoderm: Muscle, connective tissue, bone, kidneys, reproductive organs
Endoderm: Liver, pancreas, alveoli, bladder lining, lining of urethra, vagina
What are extra-embryonic membranes, and name three examples.
Membranes that extend from or surround the embryo; examples: amnion, allantois, yolk sac.
