Lecture #13 Study Guide Flashcards
Know the definitions of:
a. gamete
b. fertilization
c. blastocyst
d. gastrulation
e. involution
f. zygote
a. gamete-sex cell(sperm cell or ovary cell)
b. fertilization-fusion of male and female genetic material.
c. blastocyst-a hollow ball of cells surrounding a central cavity.
d. gastrulation-the development of the three primary germ layers following cleavage and implantation.
e. involution-postpartum shrinkage of the uterus back to its pre-pregnancy volume. (the process of tissue catabolism in the uterus due to the body preparing thr uterus for another fertilized egg later on.
f. zygote- fertilized egg
Know the functions of the following hormones as it relates to labor and delivery
a. Oxytocin
b. Relaxin
c. Human Chorionic Gonadotropin
d. Prolactin
a. Oxytocin-stimulates the secretion of milk.
b. Relaxin-for pubic symphysis and dilation
c. Human Chorionic Gonadotropin-secreted by embryo shortly after conception. Prevents disintegration of the corpus luteum.
d. Prolactin-stimulates milk production
What is a blastocyst?
32 cells in the inner cell mass of a zygote that will form everything in the embryo proper that it will need in its final stage of development like a placenta, lungs, blood cell, bone cell, skin cell,etc. for example.
What are the three primary embryonic germ layers and what tissues will each of them give rise to in an adult?
Ectoderm-layer of inner cell most closets to the amniotic cavity.
Will form(in the adult):
-Outer covering (epidermis)
-Central nervous system organs
Endoderm-layers of inner cell mass that borders blastoclasts(inner most germinal layer)
Will form in adults:
-Inner mucosal linings
-Some internal organs
Mesoderm-between endoderm and ectoderm(middle germinal layer)
Will form in adults:
-Muscles and Bones
-Many internal organs
What are the possible reasons for the onset of labor?
-Placental and ovarian hormones
-uterine contractions and oxytocin
-prostaglandin
-Relaxin for pubic symphysis and dilation
Where is the ovarian follicle located in regard to the structure of the ovary?
The ovarian follicle is a fluid filled sac in the ovary that contains an egg that has not yet matured for sperm fertilization.
What are the functions and characteristics of the following extraembryonic membranes?
a. placenta
b. umbilical cord
c. yolk sac
d. amnion
e. chorion
a. placenta:
-complete development by the third month
-the site of gas and nutrient exchange.
-maintains fetus
a. area of oxygen and nutrient diffusion from maternal to fetal blood
b. area of carbon dioxide and waste diffusion from fetal to maternal blood
c. easy drug passage through placenta
-protection of fetus from microorganisms
-pregnancy maintenance by hormone secretion of progesterone to help maintain the uterine lining once the corpus luteum degenerates.
b. umbilical cord:
-vascular connection between mother and fetus.
a. one umbilical vein carrying oxygen and nutrient rich blood from the placenta to the fetus.
b. two umbilical arteries that carry carbon dioxide and wastes away from the fetus to the placenta.
-contains Wharton’s jelly as supporting connective tissue.
-completely surrounded by a layer of amnion.
c. yolk sac:
-primary source of embryonic nourishment(food)
-site of early blood formation
-eventually becomes part of the umbilical cord and non-functional
d. amnion:
-Encases the embryo creating a cavity/sac filled with amniotic fluid
-Eventually fuses with and becomes the inner lining of the chorion
-thin protective membrane.
e. chorion:
-Completely surrounds the embryo and later the fetus.
-Becomes a major portion of the placenta.
What is the zona pellucida and the corona radiate?
The zona pellucida-(pellucid = “transparent”) is a transparent, but thick, glycoprotein membrane that surrounds the cell’s plasma membrane.
-It is also a ring of cells along with the eggs in the ovarian follicle that many sperm cells bind to but only once sperm cell penetrate the secondary oocyte.
corona radiate-an outer layer of follicular (granulosa) cells that form around a developing oocyte in the ovary and remain with it upon ovulation.
Know the three stages of labor and delivery.
Dilation stage:
-Time of onset of labor to complete cervix dilation (10cm)
-Regular contractions
-amniotic sac rupture
Expulsion stage:
-The time from complete cervix dilation to delivery
Placental stage:
-Time from delivery of baby to expulsion of the placenta
-Regular contractions
-Blood vessel constriction to prevent hemorrhage
What is the role of epinephrine in the fetus during delivery?
-Baby is hypoxic (low oxygen) due to head compression during birth
-Secretes high amounts of epinephrine and norepinephrine
-Provides protection for the baby against stresses of birth
-Prepares baby for life after uterine living
-Clears baby’s lungs for breathing
-Mobilizes nutrients to baby
-Rich vascular supply to baby’s brain and baby’s heart
When does cytokinesis occur in a gamete?
30 hours after fertilization.
