lab 16 Flashcards
what is spermatogenesis? where does it occur?
the process of sperm production,
occurs in the seminiferous tubules
what are the most immature sperm cells?
spermatogonia
when does sperm star being produced?
age 10-12, during puberty
explain the process and steps in spermatogenesis
- repro hormones stimulate spermatogonia (2n) to divide by mitosis into primary spermatocytes.
- primary give rise to 4 sperm cells which each undergo meiosis 1 to produce 2 haploid secondary spermatocytes.
- secondary undergo meiosis 2 to produce 4 haploid spermatids.
- differentiation, all cell div stops and the cells have a specific function.
- spermatids are then transformed into spermatozoa (sperm) by growing flagellum and shedding most of its cytoplasm.
what are the gonads of the male?
testes
what are the accessory organs of the male repro? what do they make?
seminal vesicles
prostate gland
bulbourethreal glands.
they make semen which carries the sperm during ejaculation
what makes testosterone? what is its function?
interstitial and leydig cells.
needed for spermatogenesis and the development of sexual characteristics in the male.
what is the pathway of sperm?
testes
epididymis
vas deference
ejaculatory duct
urethra
what is the scrotum
cutaneous sac that holds the testes
what is the epididyms
surrounds testes, accessory duct,
where sperm matures and is stored, and transports it to vas deferens
what is the vas deference?
transports sperm to urethra and forms the spermatic cord (suspends testes) with blood vessels and nerves
what is the ejaculatory duct?
transport sperm and fluids from the ampulla and seminal vesicles to the urethra
what is the ampulla?
where vas deference enlarges and joins w seminal vesicles
what is the urethra?
allows passage of urine and semen,
extends from bladder to penis
what are the 3 regions of the urethra?
prostatic urethra
membranous urethra
penile urethra
what are the female gonads?
ovaries
what are ovaries?
produce gametes
produce estrogen and progesteron after fertilization
what are the uterine tubes?
extend from ovary to uterus,
transports egg
what is the infundibulum?
expanded funnel between ovary and fallopian tube,
catches and moves eggs along
what are fimbriae?
finger like projections on infundibulum that contain cilia to create currents in peritoneal fluid that propel ovulated oocte from ovary to fallopian tube
where does fertilization occur?
fallopian tubes anytime up to 24 hrs after ovulation
what is the uterus?
receives a fertilized egg and protects the fetus while it grows and develops
what are the regions of the uterus?
body- largest part
cervix- inferior, connects to vagina
what are the layers of the uterine wall?
perimetrium- continuation of visceral peritoneum.
myometrium- composes uterine wall, and has 3 musc layers that produce contractions.
inner endometrium- 2 functional layers, stratum functionalis which line the uterine cavity, and the stratum basalis
what is the site of fertilization?
the functional layer of the inner endometrium or fallopian tube
what is shed in menstration
the functional layer.
the basal layer stays behind to build another functional layer for the next cycle
what is the vagina? what is its epithelium?
muscular canal that runs from cervix to exterior of the body.
serves as a passage way for birth and menstrual flow.
nonkeritanized stratified squamous epithelium
what are the regions of the ovary?
cortex- contains follicles and corpora lutea.
medulla- interior portion composed of loose CT and blood vess
what is oogenesis?
process of egg production,
occurs in the ovary,
typically produces one eggs each cycle
when does the production of eggs in a woman occur
before she is born
what are the steps of oogenesis?
- begins w primary oocyte (2n).
- primary goes thru meiosis, but pauses at prophase 1 until estrogen is released.
- primary divs into secondary oocyte and first polar body. where it will pause again.
- meiosis 2 is completed when secondary oocyte is fertilized by sperm. it divs into an ovum (n) and second polar body.
The secondary oocyte is surrounded by what?
Zona pellucida and corona radiata (outer layer of granulosa cells).
A series of rapid mitotic divisions occur as the zygote is transported towards the uterus and the zygote becomes 2-, 4-, 16-, 32-celled. What are these divisions called?
Cleavages
When the ovum that has been fertilized with the sperm, it undergoes and completes meiosis II to make a cell that is?
pronuclei
The pronuclei rupture to cause what?
They cause the chromosomes to mix. The haploid cells of the ovum and the haploid cells of the sperm fuse together to create a diploid zygote.
What are blastomeres?
A cell formed by cleavage of a fertilized ovum.
4th day post fertilization what is the zygote?
solid sphere of cells called morula
what is a blastocyte?
when the morula divdes and makes a hollow cav and accumulates fluid and the zona pellucida disinegrates
After hitting the blasocyst stage, what process begins to occur
The differentiation of cells begins as an inner cell mass forms which will become the embryo and the outer cells are the trophoblast which forms part of the placenta
Around how many days does the blastocyst adhere to the endometrium of the uterus and begins implantation?
6-7 days
Once the blastocyst begins adhering to the endometrium, what does the cells of the trophoblast begin to do?
They begin to develop into two layers in the area that is in contact with the endometrium.
what do the ectoderm, endoderm, and mesoderm give rise to? what were they from?
ect- from the epiblast, epidermis, glands, and nerv tissue.
end- from the hypoblas, epithelial lining and glands in dig and resp sys.
mes- comes from cells in other two layers, musc, bone, blood, heart, and kidneys
What are the two layers the trophoblast begins to make with the endometrium?
- Cellular trophoblast- inner layer
- Syncytical trophoblast- outer layer that has cells to secrete enzymes that allow the blastocyst to penetrate the uterine lining and become buried in the endometrium.
Pregnancy tests test for the presence of what hormone in blood and/or urine?
HCG which stimulates the corpus luteum of the ovary to secrete estrogen and progestrone.
where is the amniotic cav?
develops between a space within the epiblast in the inner cell mass
What is the amniotic cavity filled with? whats it purpose
Fluid derived from materal blood.
It cushions and protects the embryo from trauma and extreme temperatures. It also helps to keep fetal tissues moist.
what does it mean when someones water breaks
amnion ruptured
what cells form the yolk sac? what does the yolk sac do?
The cells at the edge of the hypoblast.
It provides nourishment to the embryo as the placenta is establishing.
Within two weeks after fertilization, the blastocyst is completely covered by what?
endometrium
The extraembryonic mesoderm and the trophoblast layers form what?
the chrion, an outer mem that surrounds embryo
During the third week of development, gastrulation takes place. What is this?
The embryonic disc epiblast and the hypoblast cell layers transform into three layers called the primary germ layers.
What is the connecting stalk? what will the connecting stalk become?
connection between mesoderm and embyronic disc and the chrion.
umbillical cord
By the end of the fourth week of pregnancy, what is present?
-Beating heart
- Precursors of skeletal muscles appear
- Elements of the nervous system are developing
- Buds are present for arms and legs
- Small discs appear for the eyes and ears
What is placentation?
process of placenta forming
The chorionic villi in the part of the uterus beneath the embryo becomes what?
placenta
when is placenta functional?
second month of pergnancy
what does the umbilical cord have?
Two umbilical arteries that carry deoxygenated blood to the placenta and one umbilical vein that carries oxygen and nutrients from the mothers to fetus.
When is an embryonic called a fetus?
in the second month or when it 3 cm long
What is an ectopic pregnancy?
when an embryo implants outside of the uterus
What is placenta previa?
placenta develops over cervix and baby cant get out
What are fraternal twins? what are identical twins?
f- twins produced from 2 eggs and 2 sperm
i- twins produced from 1 egg and one sperm
what triggers labor?
hormones like oxytocin
Oxytocin is released from the pituitary gland and operates under what type of feedback mechanism? what does it do?
positive, it increases the frequency and force of uterine contractions?
what is the first part of labor
dilation of cervix, lasts 6-12 hrs
full dilation is 10 cm
what is the expulsion phase
second phase of labor,
The fetus is pushed put, usually within 2 hours.
what is the placental phase
delivery of placenta after baby
What is breech presentation?
when baby is born feet or butt first
How do false labor pains differ from true labor pains?
f- dont get worse and stay consistantly apart
t- get worse and happen more frequent
what is nnormal temp for sperm production? How does the male reproductive system ensure that sperm is being produced at the right temperature?
3 degree C
muscs in the scrotum that move testes closer or further from body
The ejaculatory ducts pass into what gland before emptying into the urethra?
prostate gland
The penis consists of three cylindrical columns of erectile tissue. Name them.
- Corpora cavernosa (2)
- Corpus spongiosum
What are oogonia?
Female stem cells found in a developing fetus since birth and will develop into primary oocytes
At birth, how many primary oocytes are present in each ovary? at puberty?
2 mill
300 000.
Out of the 300 000 primary oocytes present at puberty, how many of them will mature and be ovulated in a female’s lifetime?
400
What is the zona pellucida?
A clear glycoprotein layer that forms between the oocyte and the granulosa cells.
what does progesterone do
helps develop placenta
After ovulation occurs, what happens to the follicle?
becomes a corpus lutem
if pregnancy doesnt occur it degenerates into scar tissue known as corpus albicans.
What is the pathway of a sperm cell from the testes to the site of fertilization of an ovulated oocyte in the female?
Testis ->
Epididymis ->
Vas deferens ->
Ejaculatory duct ->
Urethra ->
Vagina ->
Cervix of uterus ->
Body of uterus ->
Uterine tube ->
Fertilization of secondary oocyte
