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Flashcards in Human Development Deck (17):
1

List the 12 major stages of ontogeny, the approximate length of time involved in each, and the major events that each one includes.

1. Gametogenesis - formation of sex cells by meiosis (spermatogenesis/oogenesis)

2. Ovulation - release of secondary oocyte and accompanying corona radiata cells

3. Copulation - sex

4. Fertilization - a zygote is formed (2N)

5. Cleavage - initial mitotic divisions of the zygote

6. Gastrulation - formation of primary germ layers (endo, ecto, meso derm)

7. Organogenesis - formation of organs

8. Growth - continued formation of organs and their combination to form organ systems

9. Birth - fetus expelled from mother's repro sys
* begins to sustain life partially independant of its maternal parent

10.Maturation - changes from birth to sexual maturity

11. Senescence - physical and functional degredation (you get old)

12. Death - pretty obvious

2

List the 12 major stages of ontogeny, the approximate length of time involved in each, and the major events that each one includes.

1. Gametogenesis - formation of sex cells by meiosis (spermatogenesis/oogenesis)

2. Ovulation - release of secondary oocyte and accompanying corona radiata cells

3. Copulation - sex

4. Fertilization - a zygote is formed (2N)

5. Cleavage - initial mitotic divisions of the zygote

6. Gastrulation - formation of primary germ layers (endo, ecto, meso derm)

7. Organogenesis - formation of organs

8. Growth - continued formation of organs and their combination to form organ systems

9. Birth - fetus expelled from mother's repro sys
* begins to sustain life partially independant of its maternal parent

10.Maturation - changes from birth to sexual maturity

11. Senescence - physical and functional degredation (you get old)

12. Death - pretty obvious

3

Group the appropriate ontogenic stages into the pre-embryonic, embryonic, and fetal periods.

- from ovulation to organogenesis = 2 weeks

*this is PRE-EMBRYONIC PERIOD



- from organogenesis to initial stages of growth = 6 weeks

*this is EMBRYONIC PERIOD (most critical period!!!)

- from eight weeks after fertilization to birth

*this is FETAL PERIOD

4

State several synonyms for sexual intercourse.

- copulation
- coitus
- sexual intercourse

5

Explain the logic behind each of the major forms of birth control.

- the main goal of birth control is to

1. prevent implantation
2. prevent ovulation
3. kill sperm
4. overall to keep a girl from being pregnant!

6

Explain the logic behind each of the major forms of birth control.

- the main goal of birth control is to:

1. prevent implantation
2. prevent ovulation
3. kill sperm
4. overall to keep a girl from being pregnant!

7

Explain the logic behind each of the major forms of birth control.

- the main goal of birth control is to:

1. prevent implantation
2. kill sperm
3. keeping sperm and ova separated

8

Define a woman's fertile period relative to when ovulation and sexual intercourse occur.

1. during ejaculation, sperm that enter uterus undergo change called capacitation (necessary to complete ability to fertilize)

2. sperm are transported up uterine tube via peristalsis (prostaglandin) and they normally meet ovum (secondary ooctye)

3. when sperm contact egg they must break through granulosa cells (corona radiata) and zona pellucida

-this is possible by acrosome (digestive enzyme)

4. once sperm encounters zona pellucida a chem change occurs which blocks other sperm from entering

5. penetration by sperm induces 2nd meiotic division and zygote forms!

*if fertilization doesn't occur it degenerates 12-24 hours after fertilization!

*fertilization can't occur if copulation occurs more than 24 hours after ovulation

* sperm can survive 48 hours in female reproductive tract and so fertilization can occur from coitus occuring 1-2 day BEFORE ovulation

9

Differentiate monozygotic and fraternal twins.

Monozygotic Twins - fertilization of one ova

- division of conceptus during early cleavage
- if they fail to separate conjoined "siamese" twins may result

Dizygotic Twins - fertilization of two ova

10

Discuss cleavage using the terms morula, blastocyst, embryoblast, trophoblast, and implantation.

- third day after fertilization has occurred, the conceptus consists of a solid mass of cells called a MORULA

* it has also completed its slow journey down the uterine tube and has entered the uterus

- fourth day the center of the morula is filled with fluid and the resulting "hollow" ball of cells is called a BLASTOCYST

- inner cells on one side of blastocyst from the INNER CELL MASS (EMBRYOBLAST)

*forms definitive embryo!!!

- outer cells are called TROPHOBLAST

*these interact with the lining cells of the uterus to effect IMPLANTATION (NIDATION)

* some cells of the blastocyst secrete a hormone called chorionic gonadotropin that helps maintain the corpus luteum of the ovary (prevents the sloughing off of the uterine lining)

11

Indicate the basic tissue disposition of each of the three primary germ layers.

* after implantation occurs, the embryoblast undergoes significant differentiation resulting in two distinct layers : ectoderm and endoderm

* this is followed by the third layer (mesoderm)

1. Ectoderm - forms the nervous tissue and the epithelium covering the outer body surface

2. Mesoderm - form the c.t. and the muscle tissue as wells as the kidneys and the epithelium of the serous membranes and blood vessels

3. Endoderm - forms the lining epithelium and glands of the visceral body systems

12

Name the four extraembryonic membranes and state the functions of each one.

1. Amnion - derived from ecto and mesoderm

* forms a fluid- filled, balloon-like sac which envelopes the embryo
- contains cells that slough off the surface of the fetus or amniotic lining and amniotic fluid can be aspirated by needle biopsy (amniocentesis) - cells can be examined for genetic defects

2. Chorion - derived from ecto and mesoderm

*forms the fetal contribution to the placenta

3. Yolk Sac - forms from endoderm and mesoderm

*out- pouching of the primitive gut which produces blood cells for early embryo and some of its cells migrate into developing gonads to become spermatogonia or oogonia

4. Allantois - forms from endoderm and mesoderm

*helps form blood cells, the umbilical vessels, and participates in the formation of the urinary bladder
*forms tube called URACHUS - joins apex of urinary bladder to umbilical cord

(patent urachus if it persists after birth)

13

Name the four extraembryonic membranes and state the functions of each one.

1. Amnion - derived from ecto and mesoderm

* forms a fluid- filled, balloon-like sac which envelopes the embryo
- contains cells that slough off the surface of the fetus or amniotic lining and amniotic fluid can be aspirated by needle biopsy (amniocentesis) - cells can be examined for genetic defects

2. Chorion - derived from ecto and mesoderm

*forms the fetal contribution to the placenta

3. Yolk Sac - forms from endoderm and mesoderm

*out- pouching of the primitive gut which produces blood cells for early embryo and some of its cells migrate into developing gonads to become spermatogonia or oogonia

4. Allantois - forms from mesoderm and endoderm and mesoderm

*helps form blood cells, the umbilical vessels, and participates in the formation of the urinary bladder
*forms tube called URACHUS - joins apex of urinary bladder to umbilical cord

(patent urachus if it persists after birth)

14

Name the three stages of labor and the major event associated with each one.

1. Dilation stage: cervical canal dilates to 10 cm and the amnion usually ruptures

2. Expulsion stage: the fetus is delivered by forceful uterine and abdominal contractions

3. Placental stage: the placenta is expelled

15

Name the three stages of labor and the major event associated with each one.

* average pregnancy is 266 day +/- 2 weeks

1. Dilation stage: cervical canal dilates to 10 cm and the amnion usually ruptures

2. Expulsion stage: the fetus is delivered by forceful uterine and abdominal contractions

3. Placental stage: the placenta is expelled

16

Name the six postnatal periods and indicate the period of time associated with each one. (it is not possible to be exact on some of them)

1. Neonatal period - from birth to first month

2. Infancy - from first month to 2 yrs

3. Childhood - 2 yrs to adolescence

4. Adolescence - starts at puberty (11 girls/ 13 boys)

- no clear cut point to when adolescence ends and adulthood begins

5. Adulthood

6. Senescence

7. Death

17

Differentiate congenital from hereditary and define gerontology and teratology.

Congenital - abnormalities detected at birth

Hereditary - abnormalities that are genetically transmitted and may not be seen till later in life

Gerontology - science of aging

Teratology - science involved in detection and classification of physical abnormalities of neonates and fetuses