biological beginning (M2)

Question 1

What is the human genome project?

Answer 1

It was an international, multidisciplinary effort to explore and map the human genome (completed in 2003)

Question 2

What is the significance of the human genome project?

Answer 2

is the first step to understanding the nature of hereditary diseases and finding ways to identify individuals who are at risk of transmitting a given disease. Also opens up the potential to screen fetuses for genetic diseases.

Question 3

What are some of the negatives of the human genome project?

Answer 3

privacy and ethical implications

Question 4

how many sperm are ejaculated by the male?

Answer 4

200-300 million

Question 5

What is the ampulla?

Answer 5

the outer third of the fallopian tubes where fertilization takes place

Question 6

How long is an ovum considered fertile for?

Answer 6

24 - 48 hours after ovulation

Question 7

How long is sperm considered healthy and highly fertile for?

Answer 7

24 hours, the sperm degrades over time and has a life span of 48-72 hours

Question 8

What is the outer layer of the ovum called?

Answer 8

The zona pellucida

this layer will remain through fertilization and degrade just before implantation

Question 9

When is the moment of fertilization?

Answer 9

when the nucleus of the sperm combines with the nucleus of the ovum

Question 10

What is the fertilized cell called?

Answer 10

a zygote (zygotes are unicellular)

Question 11

How long does it take to reach the uterus?

Answer 11

3 days

Question 12

Define cleavage

Answer 12

a time when the zygote undergoes rapid mitotic division.

Question 13

Define morula

Answer 13

blastomeres form a solid ball of 12-16 cells known as a morula, which than differentiates into blastocyst and trophoblast.

Question 14

What is a blastocyst?

Answer 14

The inner mass of the embryo

Question 15

What is a trophoblast?

Answer 15

The outer layer of the embryo

Question 16

Define blastomere.

Answer 16

The very small, early mitotic cells of the zygote

Question 17

What do pregnancy tests test for?

Answer 17

The presence of EPF which is secreted by the trophoblastic cells 24-48 hrs after fertilization.

Question 18

What is the endometrium?

Answer 18

the inner mucous membrane of the uterus.

Question 19

What 3 types of diciduas does the endometrium become after implantation?

Answer 19

Diciduas Capsularis - covers the blastocyst
Diciduas Basalis - directly under the blastocyst
Diciduas Versa - lines the rest of the uterine cavity

Question 20

10-14 days

Answer 20

1. blastocyst develops into germ layers (ectoderm, mesoderm, and endoderm)
2. development of the chorion and the amnion

Question 21

what is the chorion?

Answer 21

the first membrane to form. encloses the amnion, embryo, and yolk sac

Question 22

Define Chorionic Villi.

Answer 22

outbranchings of the chorion into depressions in the uterine wall forming the fetal portion of the placenta

Question 23

What is the amnion?

Answer 23

it is a sac that contains amniotic fluid. It expands until it comes in contact with the chorion. It protects baby from movement.

Question 24

What is the Yolk sac?

Answer 24

it is the early site of blood cell production for the embryo and lasts about 6 weeks until the fetus’ liver can take over. At this point the yolk sac becomes incorporated into the umbilical cord.

Question 25

Explain the structure of the umbilical cord.

Answer 25

``` Formed from the amnion -one large vein for oxygenated blood -two smaller arteries for deoxygenated -Wharton's jelly (fatty substance that protects the veins average length 22 inches ```

Question 26

What is a cotyledon?

Answer 26

they connect/anchor the placenta into the uteran wall

Question 27

What are the three stages of prenatal development?

Answer 27

germinal period - fertilization to blastocyst embryonic - blastocyst to development of three layers fetal stage - 10 weeks to birth

Question 28

What prenatal stage is the most volatile?

Answer 28

embryonic - this is where deformities, damage, and spontaneous abortions are likely to occur

Question 29

What do they check the placenta after birth for?

Answer 29

the absence of cotyledons. If a cotyledon is left attached to the uterus can result in hemorrhage.

Question 30

What is the process of fraternal twins?

Answer 30

fraternal twins is the result of two eggs being released and both being fertilized (dizygotic) and implanted in the uterine wall. Development is normal just times 2 (2 placentas, chorions, etc) and little risk of damage.

Question 31

What is the process of identical twins?

Answer 31

single egg is fertilized and inner cell mass splits in two.

Question 32

Explain the implications of when the division occurs in identical twinning.

Answer 32

within 3 days - most ideal, can result in having 2 of everything similar to fraternal 5 days after - one of everything but 2 amnions 7-13 days (after development of amnion) - this is the least favourable. have one of everything. High risk of deformities and lower chance of survival

Question 33

Define phenylketonuria (PKU)

Answer 33

chromosome abnormality | baby cannot metabolize the proteins in mother's milk

Question 34

What is down syndrome?

Answer 34

Has an extra chromosome | severity of the disease depends on the location of the extra chromosome

Question 35

What is sickle-cell anemia?

Answer 35

Red blood cells are hooked shape. Tend to clump together or can get stuck while traveling through the cardiac system.

Question 36

What is Klinefelter syndrome?

Answer 36

23rd (sex) chromosome has an extra X. | results in: small testes, acquisition of breasts, and abnormally tall

Question 37

What is turner syndrome?

Answer 37

23rd (sex) chromosome is missing an X. | results in shortness, kidney problems, webbing on the neck, underdeveloped breasts, and mental retardation

Question 38

What is XYY syndrome?

Answer 38

the extra Y chromosome has little effect, slight increase in height.

Question 39

What are the 4 prenatal diagnostic tests?

Answer 39

Amnioncentesis: draws amniotic fluid with a syringe to test (done after 16 wks, risk of miscarriage) Ultrasound Sonography: 17 wks, used to look/observe abnormalities Chorionic Villi test: tests for function of placenta. can cause hemorrhage Maternal Blood Test (alpha-fetoprotein test AFP): tests for downsyndrome. Oftend false positive

Question 40

What is infertility?

Answer 40

Defined as being infertile or having fertility problems after 1 year of unsuccessful attempts at pregnancy

Question 41

5 methods of assisted reproduction (25-30% success rate)

Answer 41

IVF - invitro fertalization - egg fertilized in a lab than transferred to the uterus GIFT - gamete intrafallopin transfer - sperm and egg are insterted into fallopian tube ZIFT - zygote intrafallopian transfer - egg is fertilized and transferred to the fallopian tubes. much earlier stage of development than IVF ICSI - intracytoplasmic sperm injection - single sperm is injected into an egg in a dish then implanted into the uterus

Question 42

How does fertilization occur?

Answer 42

sperm around the ovum release enzymes to break down the acid in the corona radiata. takes a lot of sperm to degrade the outer layer enough for a single sperm to penetrate the zona pellucida. Once penetration occurs, the zona pellucida undergoes a chemical reaction and becomes impermeable. Then the nuclear envolopes are removed and the haploid chromosomes join together to form a diploid daughter cell.

Question 43

What are the two outer layers of the ovum?

Answer 43

``` zona pellucida (inner layer) corona radiate (outer layer, contains acid) ```

Question 44

What are the important fetal developments?

Answer 44

4 wks: fetal heart begins to beat 8 wks: all body organs are formed 8-12 wks: fetal heart rate can be heard by ultrasound Doppler device 16: fetus looks like a baby, sex can be determined 20 wks: hair, eyebrows, and eyelashes present. Baby starts moving 24 wks: fetal respiratory movements begin 28 wks: eyes open and close. respiratory is complete 32: has fingernails and toenails, and is more pink 38+: baby fills uterus and begins getting antibodies from mother