Ch. 29 Development and Inheritance

Question 1

Fertilization

Answer 1

occurs when a sperm and an oocyte (egg) combine and their nuclei fuse

Question 2

Explain haploid and diploid

Answer 2

each reproduction cell is a haploid cell containing half of the genetic material needed to form a human being; their combination forms a diploid cell

Question 3

Zygote

Answer 3

the single cell resulted from fertilization and contains all of the genetic material needed to from a human– 1/2 from mother and 1/2 from father

Question 4

How much sperm is released during ejaculation?

Answer 4

hundreds of millions of sperm (spermatozoa)

Question 5

How do most sperm die before reaching the vagina?

Answer 5

they’re overcome by the acidity of the vagina or are blocked from the uterus by thick cervical mucus

Question 6

Development

Answer 6

gradual modification of anatomical structures and physiological characteristics from fertilization to maturity

Question 7

Inheritance

Answer 7

transfer of genetic material from generation to generation

Question 8

Embryonic period

Answer 8

extends from fertilization through the 8th week of development

Question 9

How does sperm pass through the uterus and uterine tubes?

Answer 9

due to contraction of the walls of the uterus

Question 10

What must sperm penetrate to fertilize an egg?

Answer 10

the corona radiata and the zona pellucida outside the oocyte’s plasma membrane

Question 11

Path of the sperm cell

Answer 11

corona radiate –> zona pellucida –> plasma membrane of secondary oocyte –> cytoplasm of secondary oocyte

Question 12

How can sperm penetrate the corona radiata?

Answer 12

with the enzymes of the sperm’s acrosome

Question 13

Receptor for sperm in the zona pellucida

Answer 13

Glycoprotein ZP3

Question 14

What happens after fertilization (at about 24hrs)?

Answer 14

the zygote begins mitotic division called cleavage

Question 15

Second cleavage

Answer 15

by the second day of fertilization where 4 cells are yielding

Question 16

What happens by the end of the third day?

Answer 16

there are 16 cells, each division yields smaller and smaller cells (blastomeres)

Question 17

What happens by the end of the fourth day?

Answer 17

the cluster of cells called a morula forms; still surrounded by the zona pellucida and is still the size of the zygote.

Question 18

Day 4 or 5 of the embryonic period

Answer 18

the morula enters the uterine cavity and is nourished by uterine milk, a glycogen-rich secretion from endometrial glands in addition to stored nutrients from the cytoplasm

Question 19

The 32-cell stage

Answer 19

the fluid inside the morula rearranged the blastomeres into a large fluid-filled blastocyst cavity (blastocoel). The mass is now called a blastocyst (still the same size as zygote)

Question 20

2 different cell populations that arose while blastocyst is formed

Answer 20

embryoblast and trophoblast

Question 21

Embryoblast

Answer 21

inner cell mass; will develop into the embryo

Question 22

Trophoblast

Answer 22

outer cell mass; will develop into the outer chorionic sac surrounding the fetus and the fetal portion of the placenta

Question 23

When does the blastocyst implant?

Answer 23

it implants to the endometrium at around 6 days after fertilization

Question 24

Where does implantation usually occur?

Answer 24

in either the posterior portion of the fundus or the body of the uterus

Question 25

Decidua

Answer 25

what the endometrium is called after implantation; it separates from the endometrium after the fetus is delivered

Question 26

What does the trophoblast develop into 8 days after implantation?

Answer 26

the syncytiotrophoblast and cytotrophoblast

Question 27

What 2 layers does the embryoblast form at around 8 days?

Answer 27

the hypoblast and the epiblast

Question 28

Amniotic cavity

Answer 28

forms from the epiblast

Question 29

Chorion Function

Answer 29

*blocks antibody production by the mother *promotes the production of T lymphocytes to suppress the immune response in the uterus *produces hCG

Question 30

Gastrulation

Answer 30

associated with the rearrangement and migration of cells from the epiblast

Question 31

First step of gastrulation

Answer 31

formation of the primitive streak

Question 32

Primitive streak

Answer 32

establishes the head and tail ends of the embryo

Question 33

Three primary germ layers

Answer 33

ectoderm, mesoderm, and endoderm

Question 34

Ectoderm

Answer 34

primary germ layer that develops into the CNS and PNS, sensory organs, epidermis, hair, and nails q

Question 35

Mesoderm

Answer 35

primary germ layer that becomes the skeleton, muscles, connective tissue, heart, blood vessels, and kidneys

Question 36

Endoderm

Answer 36

primary germ layer that goes on to form the gastrointestinal tract, liver, pancreas, and lungs

Question 37

Notochord

Answer 37

important for induction, the process where the inducing tissue stimulates development of a responding tissue to develop into a specific structure

Question 38

What does the notochord develop?

Answer 38

vertebral bodies, nucleus pulposus of vertebral discs, and the neural plate

Question 39

Neurulation

Answer 39

embryonic process that establishes the central nervous system

Question 40

Placentation

Answer 40

the process of forming the placentaq

Question 41

Placenta

Answer 41

site of the exchange of nutrients and wastes between the mother and fetus, produces hormones used to sustain the pregnancy

Question 42

Two parts of the placenta by the beginning of the 12th week

Answer 42

the fetal and maternal portion

Question 43

When do all major organs develop?

Answer 43

between the 4th-8th weeks

Question 44

Teratogen

Answer 44

any agent or influence that is able to cause developmental defects in an embryo or fetus

Question 45

Teratogen examples

Answer 45

chemicals or drugs like alcohol, viruses, antibiotics, cocaine, or some hormones

Question 46

Cigarette smoking during pregnancy causes...

Answer 46

low infant birth weight, cardiac abnormalities, anencephaly and higher infant and fetal mortality rates

Question 47

Amniocentesis

Answer 47

removing some amniotic fluid surrounding the developing fetus and analyzing it and fetal cells for genetic abnormalities

Question 48

When do hCG levels peak?

Answer 48

at about the 9th week of pregnancy

Question 49

When does the chorion secrete estrogen?

Answer 49

after the first 3 or 4 weeks of pregnancy

Question 50

When does the chorion secrete progesterone?

Answer 50

by the 6th week

Question 51

Relaxin

Answer 51

secreted by the corpus luteum and placenta -increases flexibility of the pubic symphysis and ligaments of the sacroiliac and sacrococcygeal joints and also helps dilate cervix during labor

Question 52

Human chorionic somatomammotropin (hCS)

Answer 52

helps prepare the mammary glands for lactation, helps maternal growth, and regulates metabolism in mother and fetus

Question 53

Labor

Answer 53

the process that expels the fetus from the uterus through the vagina

Question 54

How does the control of contractions occur?

Answer 54

via a positive feedback cycle

Question 55

When does true labor occur?

Answer 55

when uterine contractions occur at regular intervals

Question 56

3 stages of true labor

Answer 56

1. stage of dilation 2. stage of expulsion 3. placental stage

Question 57

Puerperium

Answer 57

following delivery, the 6 weeks for the maternal reproductive organs and physiology to return to the prepregnancy state

Question 58

Involution

Answer 58

reduction in size of the uterus `

Question 59

Prolactin

Answer 59

the main hormone in stimulating milk production -secreted by the anterior pituitary gland

Question 60

Oxytocin

Answer 60

causes the release of milk into the mammary ducts via the milk ejection reflex

Question 61

Benefits of breastfeeding

Answer 61

-The chemical composition of milk is ideal for the baby's brain development, growth, and digestion -several types of white blood cells are in the milk -antibodies are present -supports optimal infant growth -reduces several diseases