Lecture 42: Reproductive System summary

22 terms by AlexS10

Create a new folder

Advertisement Upgrade to remove ads

Conception

---:
-A secondary oocyte can be fertilized for about 24 hours after ovulation
-Sperm remain viable for up to 48 hours within the female reproductive tract
-This gives a three day window for intercourse to result in fertilization: two days before to one day after ovulation
-Fertilization usually takes place in the outer one-third of the uterine tube, but can take place in the abdominal cavity
-Sperm swim up the female reproductive tract, aided by muscular contractions of the uterus stimulated by prostaglandins in the semen
-The oocyte may also secrete a chemical that attracts sperm

Capacitation

-Sperm undergo a functional change in the female tract called ---:
-During this process the membrane around the acrosome becomes fragile, and its enzymes are released
-It requires the combined action of many sperm to allow one sperm to penetrate the oocyte

Zygote

-When the first sperm enters the egg, the cell depolarizes causing the release of calcium ions inside the cell
-This stimulates the release of granules that cause changes in the zona pellucida to prevent entry of other sperm
-Secondary oocyte completes division, and nuclei of ovum and sperm unite to form a ---

Twins

-Dizygotic or fraternal twin occur when two separate eggs are ovulated. May be of different sexes.
-Monozygotic or identical twins occur when a single egg is fertilized but dividing cells break into groups and develop into two individuals. Genetically identical (clones)

Zygote

--- undergoes rapid mitotic cell division, but these do not increase the size of the zygote -- called cleavage divisions

Morula

Cleavage produces a solid sphere of cells, still surrounded by zona pellucida -- now called a ---

blastocyst

at 4.5-5 days cells have developed into a hollow ball of cells ---
- At this stage it enters the uterus

Blastocyst

--- has an outer layer of cells called the trophoblast, an inner cell mass, and a fluid filled cavity called the bastocele

trophoblast

The --- and part of the inner cell mass will form the membranes of the fetal portion of the placenta, at the rest of the inner mass forms the embryo

Implantation

---:
-The blastocyst remains free in the uterus a short time, during which the zona pellucida disintegrates
-Blastocyst nourished by glycogen from glands of the endometrium
-At about 6 days after ovulation blastocyst implants - orient cell mass toward endometrium, and secretes enzymes which allow it to penetrate (digest) the endometrial wall. This nourishes the blastocyst for about a week after implantation

ectotopic

-Implantation can also occur in uterine tube, cervix, or the abdominal cavity
-Implantation anywhere outside the uterus is called an --- pregnancy
-It is possible for fetus to grow in the abdominal cavity, but growth inside the uterine tube causes the tube to rupture, resulting in severe bleeding

hCG

-As early as 8-12 days after fertilization, the blastocyst begins to secrete human chorionic gonadotropin or ---
-hCG keeps the corpus luteum active until the placenta can produce estrogens and progesterone
-The presence of hCG is the basis for pregnancy tests

two cavities

Inner cell mass forms --- ---:
The yolk sac and Amniotic cavity
-In humans the yolk sac produces blood cells and future sex cells
-The amniotic cavity becomes the cavity in which the embryo floats. Fluid is produced from fetal urine, and secretions from the skin, respiratory tract, and amniotic membranes

Primary Germ Layers

--- --- ---:
-In between the yolk sac and the amniotic cavity is the embryonic disc, which gives rise to the primary germ layers:
-Endoderm
-Mesoderm
-Ectoderm

Gestation Period

---- ---:
-Divided into three trimesters
-During first trimester individual starts out as a zygote, then morula, blastocyst, after implantation is called an embryo.
-Embryonic phase of development lasts from fertilization until the 8th week of gestation, when it becomes a fetus
-By day 35 the heart is beating, and eye and limb buds are present

placenta

-By month four, the rudiments of all organ systems are formed and functioning, and from then on, fetal development is primarily a matter of growth
-By the end of the third month the --- is functioning

placenta

---:
-The chorion develops into the fetal part of the placenta
-The chorionic villi connect the fetal circulation to the placenta
-Composed of both fetal and maternal tissues

Functions of the placenta

--- --- --- ---:
1 Transfer gasses
2 Transport nutrients
3 Excretion of wastes
4 Hormone production -- temporary endocrine organ -- estrogen and progesterone
5 formation of a barrier -- incomplete, nonselective -- alcohol, steroids, narcotics, anesthetics, some antibiotics and some organisms can cross

Quickening

-The first movement of fetus felt by the mother, usually occurring during the fourth or fifth month of pregnancy
-By month seven the fetus is quite active
-During the last month the fetus becomes less active (usually due to space considerations)
-At the end of pregnancy both the mother and the uterus become "irritable"
-The uterus undergoes braxton-hicks contractions: intermittent, painless contractions which can come 10 to 20 minutes apart
-Become more frequent as gestation progresses, and can be mistaken for onset of labor
-Cervix begins to thin and dilate

Labor

--- (parturition):
-Stage one- the period from the onset of true labor contractions until the cervix is completely dilated at 10 cm
-The uterine contractions cause the cervix to dilate, and the amniotic sac may rupture
-usually lasts 6-24 hours depending on the number of previous deliveries

Stage two

--- ---:
-Period from maximal cervical dilation until the birth of the baby
-Lasts minutes to an hour
-Contractions become more intense and frequent

Stage three

--- ---:
-The expulsion of the placenta
-usually occurs within 15 minutes after the birth of the baby, but can range from 5 to 60 minutes

Please allow access to your computer’s microphone to use Voice Recording.

Having trouble? Click here for help.

We can’t access your microphone!

Click the icon above to update your browser permissions above and try again

Example:

Reload the page to try again!

Reload

Press Cmd-0 to reset your zoom

Press Ctrl-0 to reset your zoom

It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

Please upgrade Flash or install Chrome
to use Voice Recording.

For more help, see our troubleshooting page.

Your microphone is muted

For help fixing this issue, see this FAQ.

Star this term

You can study starred terms together

NEW! Voice Recording

Create Set