Fertilization & First Week of Development

These flashcards cover key vocabulary and concepts related to fertilization and early embryonic development.

Fertilization

A series of processes leading to the union of sperm and egg.

Ovulation

The release of a mature oocyte from the ovary.

Luteinizing hormone (LH)

A hormone that triggers ovulation and stimulates the final maturation of the follicle.

Corpus luteum

A temporary endocrine structure involved in the menstrual cycle which produces progesterone.

Endometrial cycle

A cycle that prepares the uterine lining for potential implantation of an embryo.

Acrosome

A cap-like structure in sperm containing enzymes crucial for penetration of the egg.

Zona pellucida

The protective glycoprotein layer surrounding an oocyte.

Sperm capacitation

A process sperm must undergo to gain the ability to fertilize an egg.

Perivitelline space

The area between the oocyte's plasma membrane and the zona pellucida.

Cleavage

The rapid mitotic divisions of the zygote after fertilization.

Morula

A solid ball of cells that forms from the division of the zygote.

Blastocyst

A hollow sphere of cells formed from the morula, capable of implantation.

Trophoblast

The outer layer of the blastocyst, contributing to placenta formation.

Embryoblast

The inner cell mass of the blastocyst that will form the embryo.

Acrosomal reaction

The process by which the sperm releases enzymes to penetrate the zona pellucida.

Hyaluronidase

An enzyme released by sperm to help penetrate the corona radiata.

Ectopic pregnancy

Implantation of the embryo outside the uterus, often in a uterine tube.

Progesterone

A hormone that helps prepare the endometrium for pregnancy.

Blastocyst implantation

The process by which the blastocyst attaches to the uterine lining.

Gap junctions

Channels that allow communication between cells in the inner cell mass.

Cortical reaction

The release of enzymes that prevent additional sperm from fertilizing the egg.

Zygote

The fertilized egg that results from the union of sperm and egg.

Primary oocyte

An immature female germ cell that undergoes meiosis to become a mature oocyte.

Oocyte transport

The movement of the oocyte through the uterine tube towards the uterus.

Male pronucleus

The nucleus of the sperm after it has entered the egg.

Female pronucleus

The nucleus of the egg after it has completed its second meiotic division.

Fertilization phases

The three main stages of fertilization: penetration of corona radiata, zona pellucida, and fusion of membranes.

Zona reaction

A change in the zona pellucida after fertilization that prevents polyspermy.

Calcium influx

A significant increase in calcium ions that triggers various fertilization processes.

Cumulus oophorus

A cluster of cells that surround the egg in the ovarian follicle.

Ejaculation

The process of expelling sperm from the male reproductive tract into the female.

Spermiogenesis

The final stage of sperm development that takes place in the epididymis.

Uterine tube

The structure that transports the oocyte and is the site of fertilization.

Oocyte maturation

The final stages of development that the oocyte undergoes to become ready for fertilization.

Tight junctions

Connections between cells that prevent leakage of fluids and maintain structure.

Embryonic polarity

The orientation of the embryo that establishes dorsal and ventral sides.

Integrins

Proteins that mediate the attachment of the blastocyst to the uterine lining.

First meiotic division

The initial division during oocyte maturation that results in a secondary oocyte and a polar body.

Granulosa cells

Cells that surround and nourish the developing oocyte within the follicle.

Sperm receptor molecules

Surface molecules on the egg that facilitate recognition and binding of sperm.

Zona hardening

The process that makes the zona pellucida impermeable to additional sperm after fertilization.

Fibroblast growth factors (FGFs)

Proteins that influence the differentiation of cells in the early embryo.

Embryo development stages

The distinct phases an embryo goes through post-fertilization, including cleavage and morula formation.

Metaphase

A stage during cell division where chromosomes align in the center of the cell.

Fluid penetration

The process where uterine fluid enters the morula, aiding in blastocyst formation.