Anatomy II: Chapter 28

What is the term for the events that occur from fertilization until the infant is born?

pregnancy

______ is known as the development of offspring of pregnant woman.

Conceptus

_______ is the time from last menstrual period until birth (~280 days)

Gestation period

A(n) _______ refers to the conceptus from the time of fertilization until the end of the 8th week.

embryo

The term "fetus" refers to the conceptus during which stage of development?

From week 9 until birth

Infancy refers to what period of human development?

The period from birth to 2 years of age.

What occurs during fertilization?

The sperm’s chromosomes combine with those of the secondary oocyte to form a zygote

_______ is a process that sperm must undergo after entering the female reproductive tract.

Capacitation

Sperm must be ______ before they can penetrate oocyte

capacitated

Sperm follow "olfactory trail" to reach oocyte which means they…

smell the egg

What allows a sperm to breach the outer coverings of the oocyte during fertilization?

The acrosomal reaction, which releases enzymes to clear a path

What ensures that only one sperm penetrates the oocyte during fertilization?

The zona pellucida becomes impenetrable after the first sperm enters

As sperm nucleus moves toward oocyte nucleus it swells to form ________.

male pronucleus

Meiosis II is completed by the oocyte and the resulting ovum nucleus swells to become ________.

female pronucleus

What is the moment when membranes of two pronuclei rupture and chromosomes combine?

Fertilization

Once the sperm nucleus enters the ovum, it is called a ____.

zygote

What stage of development is reached at approximately 72 hours after fertilization?

Morula (16 or more cells)

What happens around day 4 of embryonic development?

The morula hollows out and fills with fluid to become an early blastocyst

What are fluid-filled hollow sphere composed of trophoblasts cells and inner cell mass?

Blastocysts

What is the role of trophoblast cells during early pregnancy?

display immunosuppressive factors and adhesion molecules, and participate in placenta formation

What does the inner cell mass develop into during early embryonic development?

The embryonic disc, which becomes the embryo and the three embryonic membranes

________ begins 6–7 days after ovulation

Implantation

What is the primary function of human chorionic gonadotropin (hCG) during early pregnancy?

to maintain the secretion of progesterone and estrogen by the corpus luteum

Where is human chorionic gonadotropin (hCG) initially secreted from during pregnancy?

the trophoblast cells, and later the chorion

Where is the yolk sac located in the early embryo?

On the ventral surface of the embryo

What is the mall outpocketing at caudal end of yolk sac?

allantois

The allantois is the structural base for the _______.

umbilical cord

What helps form the placenta?

Chorion

The ________ encloses embryonic body and all other membranes,

chorion