Term
| What period of time is encompassed by embryological development? |
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Definition
| The first 8 weeks of development. |
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Term
| What is a prenatal called after 8 weeks? |
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Definition
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Term
| What are the steps of fertilization? |
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Definition
1. Penetration of Corona radiata and zona pellucida by enzymatic action of many sperm.
2. When a single sperm makes contact with the oocyte membrane, membrane fusion occurs.
- This triggers oocyte activation, and the completion of meiosis. A polar body is formed during this process.
-Female Pronucleus formation.
-Spindle formation/cleavage preparation. Male pronucleus forms.
- Migration of male pronucleus to center and amphimixis.
- Cytokinesis (producing first cleavage) |
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Term
| How long after fertilization does the first cleavage division appear? |
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Definition
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Term
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Definition
| The fusion of the two nuclei that creates the first diploid cell of the new human life (conception). |
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Term
| What cells are produced by the cleavage of the zygote? |
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Definition
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Term
| How long does cleavage last? |
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Definition
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Term
| The solid ball of cells created after a few days. |
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Definition
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Term
| Mostly hollow ball created near the seventh day of cleavage. |
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Definition
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Term
| Components of the blastocyst. |
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Definition
Trophoblast: Outer shell of cells
Inner cell mass: Cells in group inside trophoblast.
Blastocoele: Empty portion of blastocyst |
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Term
| What will eventually become of the inner cell mass? |
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Definition
| It will become the embryo. |
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Term
| What will eventually become of the trophoblast? |
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Definition
| It will eventually become the amnion. |
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Term
| Describe the key events of implantation. |
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Definition
1. Blastocyst formation
2. Implantation
3. Trophoblast development
4. Formation of amniotic cavity |
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Term
| What happens during the implantation phase? |
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Definition
- Blastocyst erodes endomet. lining and starts moving inward.
- The blastocyst will be completely enveloped by day 10. |
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Term
| Describe trophoblast development stage |
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Definition
1. Rapid divi. of trophoblasts in contact with endomet.
2. Cells near blastocoele form cellular trophoblast layer.
3. Cells closer to endometrium become syncytium.
4. Villi extend from syncytial troph. into endometrium. |
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Term
| What happens to the endometrial tissue as the trophoblast moves into it? |
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Definition
| It is broken down for nourishment. |
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Term
| Describe the early formation of the amniotic cavity. |
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Definition
~ 9th day:
-The inner mass layer separates from the cell. troph along a plane parallel to the surface of the endomet.
- This creates a void
- Inner mass cells migrate around the edges of the cell troph cells to create a layer of inner mass cells that surround this void, which will become the amn. cav. |
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Term
| What are the lacunae of the trophoblast? |
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Definition
| Voids in the syncytial troph. through which maternal blood will begin percolating to provide nutrient/waste exchange. |
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Term
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Definition
| The migration process that produces the three embryonic germ layers. |
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Term
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Definition
- Flat disk of two layers of inner mass cells.
- The two layers are termed superficial (facing TROPHOBLAST SEP.) and deep (facing BLASTOCOELE). |
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Term
| Describe the migratory activities that create the amnion and yolk sac. |
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Definition
-Superficial cells migrate around void between them and the cell. trophs. to create AMNION cav.
- Deep cells of blastodisc migrate along inner wall of other trophoblast cells, enveloping blastocoele. These cells then separate. The space enveloped by the deep cells becomes the yolk sac. |
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Term
| Describe the origin of the germ layers. |
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Definition
Ectoderm: From the superficial blastodisc layer.
Mesoderm - From ectoderm cells that migrate inward from the sides of the blastodisc and push through the PRIMITIVE STREAK into the space between the ectoderm and endoderm.
Endoderm: Deep layer cells of blastodisc |
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Term
| Four extra embryonic membranes. |
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Definition
Yolk Sac
Amnion
Allantois
Chorion |
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Term
| Complete formation of yolk sac. |
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Definition
| Formed by migration of blastodisc cells initially, the yolk sac is completed when mesoderm cells migrate and encompass the ectoderm layer. The yolk sac provides a reservoir of nutrients for the developing embryo. |
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Term
| Complete formation of amnion. |
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Definition
| Similar to the yolk sac, cells from the blastodisc migrate to form the inner layer of the amnion. Later, mesoderm cell migrate around the initial layer, forming the outer portion of the membrane. |
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Term
| Complete formation of chorion |
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Definition
| A layer of mesoderm cells migrates and forms an inner layer of the trophoblast. These two groups of cells are called the chorion. The chorion serves as the principle structure of exchange between embryo and mother, and will later develop into the placenta. Villi of the chorion grow inward into the endometrium and dissolve endometrial blood vessels. |
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Term
| Complete formation of allantois. |
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Definition
| The allantois void invaginates into the stalk a small amount initially. The base of the allantois becomes the urinary bladder. |
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Term
| How is the body stalk formed? |
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Definition
| In the process of migrating around the cell. trophs to form the chorion, a stalk of mesoderm tissue forms and the embryo becomes attached to the chorion only via th mesoderm tissue of the body stalk. |
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Term
Time:
Chorion creation:
Head fold:
Tail fold:
Umbilical stalk:
Umbilical cord: |
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Definition
Chorion creation: 2w
Head fold: 3w
Tail fold: 4w
Umbilical stalk: 5w
Umbilical cord: 10w |
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Term
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Definition
- Mesoderm extensions in the core of the tropho. villi that are in contact with maternal blood.
- Embryonic blood vessels form within these vessels and exchange nutrients and wastes with the maternal blood, which is in close proximity. |
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Term
| Time till first heart beat. |
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Definition
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Term
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Definition
| Fusion of body stalk and yolk sac. |
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Term
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Definition
| Portion of allantois, blood vessels, and yolk sac remnants. |
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Term
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Definition
2 A. --> Wastes
1 V. --> Nutrients |
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Term
| What are the 5 placental hormones? |
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Definition
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Term
| Human chorionic gonadotropin (hCG) |
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Definition
- causes the corpus luteum to remain viable, continuing to release progesterone
- released soon after implantation
- highly sensitive and specific for pregnancy |
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Term
| Human placental lactogen (hPL) |
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Definition
- sends signals to the mammary glands in preparation for milk production
- In conjunction with E, P, GH, Thyroid, activates mamm glands |
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Term
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Definition
1)Loosen the pubic symphysis joint to facilitate dilation of pelvic opening during birth.
2) Cervical dilation.
3) Pre-delivery delay of labor contraction until late pregnancy. |
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Term
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Definition
| Placental production of progesterone is sufficient to sustain endometrial lining after the first trimester. |
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Term
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Definition
| Very late in the third trimester, estrogen secretion from the placenta is a factor in the onset of labor. |
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Term
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Definition
| Organogenesis is the formation of organs in the developing embryo |
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Term
| What are the hallmark events of the 1st, 2nd, and 3rd trimesters? |
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Definition
1st: Organ system establish.
2nd: The second trimester is marked by these organs increasing greatly in complexity
3rd: The main even in the third trimester is maturation of the organs. Also, weight gain. |
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Term
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Definition
| Braxton-hicks contractions. Contractions of the uterus that "exercise" it in preparation for delivery, but are not, itself, labor contractions. |
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Term
| What are the placental factors important in the onset of labor? |
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Definition
E - increases as delivery approaches.
- Incr. U. smooth muscle excitability
- Incr. U. sens. to oxytocin.
Relaxin
- Joints loose
- Cervix dilates |
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Term
| What are the fetal factors important in the onset of labor? |
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Definition
- Growth in size and weight stretch myometrium.
- In response to increase in E., fetal Pit. releases oxytocin. |
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Term
| What does the distortion of the myometrium cause? |
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Definition
- Incr. myometrial excitability
--> spontaneous contractions |
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Term
| What is the maternal hormone response to high E levels? |
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Definition
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Term
| How does the endometrium respond to increasing E and oxytocin levels? |
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Definition
| Production of prostaglandins. |
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Term
| What hormones ultimately cause the onset of labor contractions? |
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Definition
| Oxytoc. and Prostaglandins. |
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Term
| Explain the positive feedback mechanism of labor. |
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Definition
Onset of labor -->
Incr. distortion of myometrium -->
Incr. myometrial excitability -->
Harder contractions -->
Greater myometrial distortion |
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Term
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Definition
- Dilation
- Expulsion
- Placental |
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Term
| Stages of postnatal development |
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Definition
- Neonatal
- Infant
- Childhood
- Adolescence
- Maturity |
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Term
| Three important hormones in puberty: |
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Definition
GnRH -->
T (males)
E (females) |
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Term
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Definition
- Stimulation of follicle growth in the axillae, face, genital area, and chest.
- Acceleration of bone growth, eventual closure of epiphyseal cartilages.
- Increase in muscle mass through anabolism.
- CNS effects: aggression, sexual motivation.
- Erythropoiesis, increased blood volume and hematocrit.
- Enlargement of the larynx, thickening of vocal cords that lead to deepening of the voice.
- Maturity of male sexual organs; production of sperm and accessory secretions. |
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Term
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Definition
- Stimulation of hair follicle growth in axillae and genital area.
- Development of breast tissue.
- A faster closure of epiphysial plates under the influence of estrogens, resulting in a shorter average stature.
- An increase in muscular mass, but less than in males.
- Activation of CNS centers that regulate female sexual behaviors.
- Because of menses, women need a greater amount of iron intake. Estrogens decrease blood cholesterol and atherosclerotic development.
- Normal growth of larynx/vocal cords, resulting in higher pitched voice.
- Reproductive system maturation/maintenance, as described in chapter 25. |
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Term
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Definition
| homologous chromosomes with the same allele for a given gene (e.g. alleles for brown eyes on both) |
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Term
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Definition
| homologous chromosomes with differing alleles for a given gene (e.g. an allele for brown eyes on one and blue eyes on the other) |
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Term
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Definition
| - Situation in which a heterozygous set of genes contains both a dominant and recessive allele. |
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Term
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Definition
| Involves complex phenotypes, such as hair and eye color, where the phenotype cannot be easily deduced from the different allele combinations |
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Term
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Definition
| the 1.4 million bases in the human genome that differ between individuals, and whose difference creates the noticeable uniqueness of each person |
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Term
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Definition
Down Syndrome
- Extra 21 chromosome
- Rapidly increases in freq after 40y |
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Term
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Definition
XXY
- Male pheno
- decr. androgen prod.
--> Breast enlarg.
--> Sterile |
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Term
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Definition
XO (no second X)
Female pheno.
- No 2nd sex char.
- Sterile
- Neck web. |
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Term
| Chromosome involved in Ovarian cancer |
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Definition
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Term
| Chromosome involved in Tay-Sachs disease |
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Definition
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Term
| Chromosome involved in Spinocerebellar ataxia |
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Definition
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