• Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off

Card Range To Study



Play button


Play button




Click to flip

Use LEFT and RIGHT arrow keys to navigate between flashcards;

Use UP and DOWN arrow keys to flip the card;

H to show hint;

A reads text to speech;

72 Cards in this Set

  • Front
  • Back

What is cleavage?

Cell division of a zygote, in which the number of cells increases without an change in the size of the zygote.

What is a blastocyst?

An early stage of embryo development.

What is implantation?

The attachment of the embryo to the endometrium.

What is the chorion?

The outer embryonic structure of a developing embryo that will contribute to the placenta.

What is the amnion?

A fluid-filled extra-embryonic structure.

What is human chorionic gonadotropic hormone (HcG)?

An embryonic hormone that maintains the corpus luteum.

What is the amniotic cavity?

The fluid filled cavity surrounding the developing embryo.

What is the extra embryonic coelom?

The body cavity between the amnion and the chorion.

What is the yolk sac?

A membranous sac that forms during embryo development of most vertebrates; in humans, it does not contain yolk.

What is the placenta?

The site for the exchange of nutrients and wastes between mother and fetus.

What is chorionic villi?

Vascular projections of the chorion.

What is the allantois?

Extra embryonic structure that contributes to the blood vessels of the placenta.

What is the umbilical cord?

Structure that connects the fetus to the placenta.

What is the first trimester?

The period during pregnancy from contraception until the end of the third month.

What is gastrulation?

Process by which a gastrula is formed.

What is a gastrula?

Stage of embryonic development in which the embryo is composed of three layers; ectoderm, mesoderm, and endoderm.

What is the ectoderm?

The outer layer of cells in an embryo.

What is the mesoderm?

The middle layer of cells in an embryo.

What is the endoderm?

The inner layer of cells in an embryo.

What is the second trimester?

The period during pregnancy from the fourth month to the end of the sixth month.

What is the third trimester?

The period during pregnancy from the seventh month until birth.

What are teratogens?

Any medication, chemical, infectious disease, or environmental agent that might interfere with the normal development of a fetus or embryo.

What is partuition?

The act of giving birth; labour.

What is relaxin?

A hormone produced by the placenta prior to labour; causes the ligaments within the pelvis to loosen.

What is oxytocin?

A hormone from the pituitary gland; causes strong uterine contractions.

What is prolactin?

A hormone produced by the pituitary gland and associated with milk production.

What is the first step of fertilization to implantation?

1. Ovulation

What is the second step of fertilization to implantation?

2. Fimbraie sweeps egg to fallopian tubes where fertilization occurs to create a zygote. The acrosome allows the sperm to get through the egg's protective barrier. Sperm is ejaculated and travels from the cervix to uterus. The zygote receives 23 chromosomes from the sperm cell and 23 from the oocyte. Several sperm attaches to ovulated oocytes, but only one fuses.

What is the third step of fertilization to implantation?

The zygote undergoes a number of cellular division on it's way to the uterus. Cleavage occurs, and cells of the zygote gets progressively smaller until the morula is formed (a ball of cells).

What is the fourth step of fertilization to implantation?

Cells move around to create an outer ring of cells and an inner mass. As the zygote reaches the uterus, it developed into a fluid-filled structure called a blastocyst.

What is the fifth step of fertilization to implantation?

While in the uterus, the blastocyst attaches to the endometrial wall. This is implantation.

Draw a diagram of the blastocyst.

Draw a diagram of fertilization to implantation.

What is the first step of development?

The outer layer of the blastocyst produces 2 membranes.

What two membranes are produced by the blastocyst.

1. Amnion - creates a protective sac that encloses the fetus in a fluid (amniotic fluid) filled environment. This cushions the fetus and prevents temperature fluctuations while allowing freedom of movement.

2. Chorion - finger-like projections implant into endometrium and are fetal contributions to the placenta. Projections called chorionic villi creates a large surface area between maternal and fetal blood supplies. Secretes HcG (human chorionic gonadotropic hormone).

In order for pregnancy to continue what female process cannot occur? How can this be ensured?

Menstruation cannot occur because any shedding of the endometrium would dislodge the embryo from uterus. In order to maintain the endometrium, progesterone and estrogen levels must be maintained. High levels means negative feedback, and LH levels must be maintained to sustain the corpus luteum.

How can the woman endometrium be maintained during pregnancy.

In the chorion, human chorionic gonadotropic hormone is produced. This maintains the corpus luteum for the first trimester until the placenta is functioning and produces estrogen and progesterone.

What is the second step of development?

Gastrulation - the process of the inner cell mass in the blastocyst forming the different germ layers. This forms the gastrula.

What are the three germ layers?

Outer - ectoderm (forms hair, nails, sweat glands, nervous system, eyes, ears, teeth, mouth lining)

Middle - mesoderm (forms muscles, blood vessels + blood, kidneys + reproductive structures, connective tissue, cartilage, bone)

Inner - endoderm (forms liver, pancreas, thyroid, bladder, lining of digestive system, and respiratory tract)

What is the third step of development?

Placenta forms from cells from the endometrium and the fetus. This is the site of nutrient and waste exchange through diffusion, which allows the passage of drugs, some antibodies, and viruses.

What is the fourth step of development.

The allantois - an extension of the endoderm - forms. The blood vessels found in the placenta comes from the allantois, and the blood vessels give rise to the umbilical cord (connects embryo to placenta).

Draw and label a diagram of a baby in womb.

Where is and what is the purpose of the amniotic cavity?

Between the amnion and embryo, a fluid filled sac that insulates the embryo and fetus from infection, dehydration, impact, and changes in temperature.

Where is and what is the purpose of the extra embryonic coelom?

The fluid filled space between the amnion and chorion.

Where is and what is the purpose of the yolk sac?

Site of early red blood cell formation beneath the embryo.

What is morphogenesis?

The development of an organism or part of it.

What occurs in the first trimester?

The first trimester occurs in weeks 1-12, germ layers form, heart+brain+limb buds develop, arms+legs move, suckling reflex. By the end of the trimester, external reproductive organs distinguish male from female.

*all organ systems develop, most vulnerable to teratogens

What occurs in the second trimester?

From weeks 13-24, the fetus moves enough to be noticed and organs continue to develop, and all organs have been formed. The size of fetus increases. Eyelids and eyelashes form, cartilage is replaced with bone cells, and hair covers the body.

*growth and systems continue to mature, fetal movement and reflexes such as suckling occurs.

What occurs in the third trimester?

Rapid growth of the baby - mostly layers of fat. Organ systems are already established, but continue to develop.

*Rapid growth, systems continue to mature, and many layers of fat develop.

What chromosomes make up a female, and what makes up a male?

Female = XX

Male = XY

How do hormones play a role in sex determination?

Male and female development is determinate by hormones circulating in the blood stream. Too much estrogen could mean an organism with male genes appears physically female, while too many male androgens/hormones could make one's sex hormones male even thought the genetic body is female.

What is a teratogen?

Agents capable of causing developmental abnormalities in utero. Anything the mother inhales or ingests can end up circulating in blood. These compounds can cross the placental barrier and enter fetal blood.

What are some examples of teratogens?

ex. Cigarrettes - affects size of the baby, alcohol - affects fetuses brain, etc.

What are two examples of human reproductive technology?

1. In vitro fertilization

2. Fertility drugs

How does in vitro fertilization work?

Mother is given numerous hormones to produce multiple eggs each month. The eggs are removed just before they leave the follicles in the ovaries - done under anesthetic. The eggs are fertilized with the partners sperm in a petri dish, and the zygotes are allowed to mature until the blastocyst forms. 3-4 eggs are implanted back into the uterus by a catheter, and a pregnancy test is done 2 weeks later to test success.

How do fertility drugs work?

Fertility drugs stimulate the action of pituitary hormones. Follicle development within the ovary is enhanced and the release of one or more egg cells becomes more probable. Since fertility drugs increase follicle development within the ovary, often causing multiple ovulations, the chances of having fraternal twins increases.

How does the fetus prepare for birth?

At the end of the third trimester, the fetus turns so that the front of the head faces the back bone. The fetus also drops into the birth canal.

What indicates the beginning of birth?

Uterine contractions begin, the cervix thins and dilates, the mucous plug that seals the cervix falls out, and the amnion is forced into the birth canal, which bursts. The amniotic fluid lubricates the canal. As the cervix dilates, the uterine contractions being to move the baby through the birth canal. Decreased progesterone also indicates the onset of labour.

Draw the birth feedback loop.

hypothalamus (releasing factor) ---> posterior pituitary (oxytocin) ---> uterus contracts--->

1. prostaglandins ---> contractions ---> positive feedback to uterus contracts

2. baby's head pushes against cervix to dilate ---> positive feedback to all glands.

What is the role of relaxin in partuition?

Relaxin is produced by the placenta and causes the pelvis ligaments to loosen and the cervix to soften. This makes a more flexible passageway for the baby during delivery.

What is the role of oxytocin in labour?

Oxytocin causes strong uterine contractions.

What is the role of prostaglandins in labour?

Prostaglandins causes strong uterine contractions. These appear in the mother blood prior to labour.

What is a way to induce labour?

By administering prostaglandins or pitocin- a synthetic form of oxytocin. These stimulate uterine contractions.

What are the three stages of labour?

Active phase, partition, and afterbirth.

What happens in the active phase of birth?

The cervix beings to dilate due to muscles contractions caused by oxytocin, since progesterone levels drop and no longer inhibit this hormone. These contractions become more frequent and intense - positive feedback - and the amniotic sac will break due to these contractions. This stage ends when the cervix dilates 10 cm.

What happens during partuition?

As the contractions continue, the fetus is moved down the birth canal. The hormone relaxin causes loosening of ligaments in the pelvis. Uterine contractions and pushing of the mother push the baby out of the birth canal.

What happens during the after birth?

Once the baby is born, the umbilical cord is clipped and cut, and a number of contractions expels the placenta and most of the umbilical cord.

What hormones stimulate lactation?

Prolactin, oxytocin, and estrogen.

What is the role of prolactin in lactation?

Prolactin levels rise dramatically after birth to stimulate milk production in glands in breasts to begin producing fluid. It also causes production of colostrum (fluid that resembles breast milk but lacks milk fats) that supplies the baby with antibodies.

What is the role of estrogen in lactation?

Estrogen stimulates release of large amounts of prolactin during pregnancy. Progesterone inhibits.

What is the role of oxytocin in lactation?

The suckling action of the newborn stimulates nerve endings in the areola of the breast. The sensory nerves sends info to the pituitary gland which increases oxytocin levels. Oxytocin travels through blood to the breasts and uterus causing weak contractions, moving milk to ducts and the uterus to return to pre-pregnancy size.

What is the lactation flow chart?

hypothalamus (releasing factor) ---> anterior pituitary (prolactin) ---> suckling to baby stimulates posterior pituitary ----> releases oxytocin ---> oxytocin causes muscle contractions that forces milk to milk ducts so the baby can nurse.