Stanescue L1 Part 2

Front 1

normal female somatic cells contain __ copies of the X chromosome

Back 1

2 copies of X

Front 2

normal male somatic cells contain __ copies of the X chromosome

Back 2

1 Copy of X

Front 3

This occurs in female cells so that males and females have the same number of X chromosomes:

Back 3

inactivation of X chromosome

Front 4

When does X-inactivation occur?

Does it matter which X is inactivated (paternally/maternally derived)?

Back 4

X-inactivation occurs during the 1st week of embryonic development

Front 5

Where can the barr body be seen in the cell?

Back 5

Periphery of nuclear membrane

Front 6

When can the sex of a zygote be determined?

Back 6

End of 1st week- beginning of 2nd week.

Front 7

What does MIS stand for? What does it do?

Back 7

MIS: Mularian Inhibiting Substance

- It allows Y chromosome to induce change so that the zygote becomes male, secreation of TDF occurs (testes develop)

Front 8

Primordal cells arrive at the ovary at what week?

Back 8

Week 4

Front 9

if testes develop when does that occur?

Back 9

7th week

Front 10

Oogonia become ---

Back 10

Primary oocytes

Front 11

The fetus has all its primary oocytes by what month?

Back 11

5th month

Front 12

Are any oogonia present at birth?

Back 12

NO

Front 13

True or false: At birth, a female has her entire supply of primary oocytes?

Back 13

True!

Front 14

When primary oocytes are formed they remain frozen (Diplotene stage) in this phase...until what age?

Back 14

Prophase I until puberty

Front 15

Each month this many primary oocytes mature...

how many reach full maturity?

Back 15

15

usually only one reaches full maturity, completing meiosis I

Front 16

When a primary oocyte completes meiosis I, what does it produce?

Back 16

A secondary oocyte and 1st polar body

Front 17

The secondary oocyte will complete meiosis II...

Back 17

Only if it is fertilized, otherwise it remains in metaphase II

Front 18

Does the 1st polar body undergo a second divison?

Back 18

it can creating 2 polar bodies, however it usually degenerates.

Front 19

What is the product of a secondary ooctye?

Back 19

- It produces an mature oocyte (egg) + 1 polar body

Front 20

If the secondary oocyte does not get fertalized...

Back 20

cell degenerates 24 hours after ovulation

Front 21

Where does fertilization occur?

Back 21

In the uterine tube

Front 22

Up to how many secondary oocytes are ovulated in a woman's life?

Back 22

480 (40 x 12)

- 12 secondary oocyte ovulations per year

Front 23

The process to produce mature sperm is divided into 3 phases:

Back 23

1. spermatocytogenesis
2. meiosis
3. spermatogenesis

Front 24

Primary spermatocytes arise from:

Back 24

spermatogonia

Front 25

There are 2 types of spermatogonia:

Back 25

Type A --undifferentiated stem cells that produce more A and B cells

Type B --undergo further mitosis to form more sprmatogonia OR may enter meiosis to form Primary spermatocytes

Front 26

Spermaids undergo ___ to become ___

Back 26

- spermatogenesis

- spermatozoa (sperm)

Front 27

Name the 3 parts of sperm

Back 27

- Acrosome
- Nucleus
- Flagella

Front 28

Describe acrosomal formation

Back 28

- large membrane-bound vesicle that overs the anterior two-thirds of the sperm nucleus (specialized lysosome)

Front 29

What is contained in the acrosome?

Back 29

Enzymes that aid in penetrating the egg's corona radiata and zona pellicida

Front 30

Fertilization occurs

Back 30

in uterine (fallopian) tube

Front 31

Clevage:

Back 31

mitotic cell divison of the zygote that form cells called blastomeres

*Embryo size remains the same, but blastomeres become smaller

Front 32

Morula:

Back 32

A ball of 12 or more blastomeres

- 3 or 4 days after fertilization
- Enters uterus from uterine (fallopian) tube

Front 33

Blastocyst:

Back 33

Fluid-filled cavity forms inside morula

Front 34

Describe the inner cell mass (embryoblast) of the blastocyst

Back 34

gives rise to embryo and some extraembryonic tissue

Front 35

Describe the trophoblast of the blastocyst

Back 35

a thin outer layer of cells that enclose the embryoblast and blastocyst cavity; contributes to formation of placenta (connection b/w developing baby and mom)

Front 36

how can one determine the size of the embryo

Back 36

by measuring the crown-rump length (CRL): the tip of the cranium to heel of feet

Front 37

An embryo refers to:

Back 37

A developing human that extends to the end of week 8

*All major structures are present, but only heart and circulation are functional

Front 38

Conceptus refers to:

Back 38

both the embryo and its adnexa (appendages, amnion, chorionic sac, umbilical vesicle/yolk sac) or associated membranes

Front 39

Amnion (amniotic sac):

Back 39

the innermost extraembryonic membrane, enveloping the embryo and contains amniotic fluid

Front 40

Chorionic [gestational] sac:

Back 40

multilayered, outermost fetal membrane

- also called membrana serosa
- becomes part of fetal placenta

Front 41

primordium:

Back 41

refers to earliest stage of development of an organ or structure

Front 42

Fetus refers to

Back 42

developing human from week 9 to birth

Front 43

abortion:

Back 43

premature stoppage in development of embryo or fetus

* earlier than 24 weeks

Front 44

Miscarriage:

Back 44

refers to spontaneous abortion of fetus and its membranes before middle of second trimester

*First 20 weeks