What is the main thing that occurs during the fetal stage?
Development
This occurs when a sperm�s chromosomes combine with those of a secondary oocyte to form a fertilized egg (zygote).
Fertilization
The sperm must penetrate what two layers to complete fertilization?
Zona pellucida
Corona radiate
What is the activation of sperm inside a woman called?
Capacitation (can live up to 6 days)
Within 12 hours, the chromosomes mix and form this in the fallopian tube.
A zygote
How long is an oocyte is viable?
12 to 24 hours
How long is sperm viable after ejaculation?
24 to 48 hours
Of the approximately 300 million sperm that are ejaculated, about how many actually reach the egg in the oviduct?
200
Name two things that can prevent sperm from making it to the egg, other than defective sperm.
Acidic vaginal environment
Destroyed by phagocytes
Upon entry of sperm, this surges from the ER and causes a cortical reaction that prevents polyspermy.
Calcium
Cortical granules release ZIPs (enzymes) that destroy what?
Sperm receptors
T or F? The human zygote undergoes a series of cleavages to produce an embryo.
True
The initial division of the zygote produces these.
Blastomeres
This is the solid ball of blastomeres that can be seen 3 days after fertilization.
Morula
Four days after fertilization, the morula hollows out and forms this.
Early blastocyst
During the implantation of the blastocyst, it consists of these cells and an inner cell mass.
Trophoblasts
After cleavage, the blastocyst is now known as this.
Gastrula
A cross section of a gastrula will show what three layers?
Ectoderm
Mesoderm
Endoderm
The embryonic disc is formed during what stage?
Gastrulation
The digestive, respiratory, and urinary systems arise from what germ layer of the embryonic disc?
Endoderm
The nervous system, sense organs, skin, nails, and hair arise from this germ layer.
Ectoderm
The bone, muscle, blood, reproductive and connective systems arise from what germ layer?
Mesoderm
What are the four extra embryonic membranes?
Amnion
Yolk sac
Allantois
Chorion
What is a transparent sac filled with amniotic fluid?
Amnion
What are three functions of the amniotic fluid and sac?
Provides a protected environment for embryo
Helps homeostasis
Allows freedom of movement preventing parts from fusing
Where does amniotic fluid come from?
Maternal blood
This hangs from the ventral surface of the embryo and is the source of the earliest blood cells and blood vessels. It also forms part of the digestive tube.
Yolk sac
This helps form the placenta by enclosing the embryonic body and all other membranes.
Chorion
What small out-pocketing at the caudal end of the yolk sac is the structural base for the umbilical cord and becomes part of the urinary bladder?
Allantois
Gastrulation sets the stage for this, which is the formation of body organs and systems.
Organogenesis
All organ systems are recognizable and the embryonic period comes to an end during which week?
8
What is the first major event of organogenesis, it gives rise to the brain and spinal cord?
Neurulation
Where is the ectoderm that forms the neural plate located?
Over the notochord
The neural plate folds inward as this.
Neural groove with neural folds
Neural folds fuse into a neural tube, the anterior end forming the brain and the remaining, the spinal cord by what day of pregnancy.
22
These cells give rise to cranial, spinal, sympathetic ganglia, and adrenal medulla.
Neural crest cells
What is parturition?
Childbirth, labor
The hormone oxytocin uses what type of feedback loop to induce labor?
Positive
What are the three stages of labor?
1. Dilation
2. Expulsion
3. Delivery of placenta
What is the four-week period immediately after birth?
Neonatal period
Physical status is assessed 1 to 5 minutes after birth by this 1 to 10 scoring system.
Apgar score
The Apgar scores these 5 areas with a score of 8 to 10 being healthy.
Heart rate
Respiration
Color
Muscle tone
Reflexes
This is the production of milk by the mammary glands.
Lactation
T or F? During early pregnancy, placental estrogens, progesterone, and lactogen stimulate the hypothalamus to release prolactin releasing factors.
False. This occurs toward the end of pregnancy.
What gland releases prolactin?
Anterior pituitary
This yellowish secretion rich in vitamin A, protein, minerals, and IgA is released during the first 2 to 3 days after childbirth.
Colostrum
Suckling initiates what type of feedback mechanism?
Positive
What hormone causes the letdown hormone?
Oxytocin
Breast milk is a natural laxative that helps eliminate meconium, preventing what?
Jaundice
T or F? Breast milk encourages bacterial colonization of the large intestine.
True
T or F? Beneficial chemicals in breast milk include IgA, complement, lysozyme, interferon, and lactoperoxidase.
True
T or F? The fats, iron, and amino acids are more easily absorbed or metabolized in cow�s milk than in breast milk.
False.
Interleukins and prostaglandins prevent what?
Overzealous inflammatory responses
What is the single most important cause of reproductive disorders?
STIs and STDs
This is a bacterial infection of mucosae of reproductive and urinary tracts.
