Ch.29 Development and Inheritance study guide (not finished)

What is Differentiation?

This the gradual process by which immature, unspecialized cells take on specific, characteristic physical features and functions to become mature, specialized cell types.

What is Inheritance?

The transfer of genetically determined traits and characteristics from parents to their offspring across generations.

Fusion of two haploid gametes, each containing 23 chromosomes- producing a zygote containing 46 chromosomes is known as ___________

fertilization

Acrosome releases protein-digesting enzymes to penetrate _______________ and reach oocyte surface; aka acrosome reaction

corona radiata

After sperm binds to sperm receptors in the zona pellucida, two enzymes are released. State their names and their collective function

hyaluronidase and acrosin; function is to break down protective layers of ovum like corona radiata, to allow the sperm to fuse with egg’s plasma membrane

Oocyte activation is what?

the biological process by which a resting egg is triggered to begin embryonic development.

What is polyspermy?

the fertilization of a single egg by more than one sperm cell, which generally results in an abnormal number of chromosomes and a non-viable embryo

_____________ is the fusion of a female pronucleus and male pronucleus

Amphimixis

_________ consists of three integrated trimesters, each 3 months long

gestation (prenatal development)

What are two general processes that occur in the pre-embryonic period of the first trimester? What are two general processes that occur in the embryonic period of the first trimester?

Pre-embryonic: rapid cellular division (cleavage) to form a multicellular structure, followed by the implantation of this blastocyst into the uterine wall.

Embryonic: the formation of the three primary germ layers (gastrulation) and the beginning of organogenesis, where all major body organs and systems start to develop

What does cleavage produce?

Zygote becomes a pre-embryo, develops into multicellular blastocyst; ends when blastocyst contacts uterine wall

_________ begins with attachment of blastocyst to endometrium of uterus **

implantation

__________ is the process in which the placenta develops to permit exchange between maternal and embryonic blood

placentation

Formation of viable embryo is known as ___________

embryogenesis; establishes foundations for all major organ systems

the __________ stage occurs after 3 days of cleavage and produces a pre-embryo reaching the uterus on day 4 or 5

morula

blastomeres in the morula form a __________, a hollow ball

with an inner cavity known as the _______________

blastocyst; blastocoele

The outer layer of cells of a blastocyst is called __________ which provides nutrients to the developing embryo

trophoblast

blastocyst have a second group of cells called the ___________ which in time will form the embryo

inner cell mass

__________ are cells closest to interior of blastocyst

Cytotrophoblast

_____________ is the outer layer which erodes a path through the uterine epithelium by secreting hyaluronidase

Syncytiotrophoblast

_____________ is a fluid-filled chamber thats created as inner cell mass separates from trophoblast

Amniotic cavity

What is an eptopic pregnancy?

Implantation occurs somewhere other than within uterus; embryo is not viable

As development proceeds, _______ occurs releasing RNA molecules, polypeptides, and small proteins that affect the differentiation of other embryonic cells

induction

what are the three germ layers

ectoderm, mesoderm, endoderm

________ will form body of embryo and internal organs

embryonic disc

Extra-embryonic ________ support embryonic and fetal development; what are they?

membranes;

Yolk sac, Amnion, Allantois, Chorion

Why is the yolk sac important?

Primary nutrient source for early embryonic development, important site for blood cell formation

Why is the amnion important?

Amniotic fluid is produced (surrounds and cushions developing embryo or fetus)

Why is the allantois important?

gives rise to the uterine bladder

why is the chorion important?

Blood vessels develop; first step in creation of functional placenta

what is the body stalk? yolk stalk?

body= connection between embryo and chorion, carries blood to an from placenta

yolk= narrow connection between endoderm of embryo and yolk sac

_______ is the thin portion of endometrium, which no longer participates in nutrient exchange as placenta grows

capsular decidua

Placental functions are now concentrated in the ____________, a disc-shaped area in the deepest portion of the endometrium

basal decidua

________ is the rest of uterine endometrium, no contact with chorion

parietal decidua

_____________ connects the fetus and placenta and contains allantois, placental blood vessels, and yolk stalk

umbilical cord

Blood flows from fetus to placenta through paired umbilical _________; Blood returns to fetus in single umbilical _________

arteries; vein

Events in first 12 weeks establish basis for __________

organogenesis (organ formation)

in which trimester does the amnion and chorion fuse, creating amniochorionic membrane

2nd trimester

Most organ systems become able to function without maternal assistance in the ____ trimester

3rd

Placental hormones are synthesized by ________________ and released into maternal bloodstream

syncytiotrophoblast

list and describe the placental hormones

Human chorionic gonadotropin (hCG): Appears in maternal bloodstream soon after implantation; blood or urine samples provides reliable indication of pregnancy

Human placental lactogen (hPL): Prepares mammary glands for milk production

Placental prolactin: Helps convert mammary glands to active status

Relaxin: Increases flexibility of pubic symphysis, permitting pelvis to expand during delivery, dilation of cervix, Suppresses release of oxytocin delaying labor contractions

(progesterone/estrogens)

what are maternal adaptations during pregnancy

Respiratory rate and tidal volume

Blood volume (almost 50%)

Nutrient intake (10%-30%)

Glomerular filtration rate (50%)

Sizes of uterus and mammary glands

child birth is also known as _________

paturation

progesterone vs oxytocin during labor

progesterone- inhibits contractions to prevent early birth

oxytocin- contracts the uterus and promotes birth

list and describe the three stages of labor

dilation- onset of true labor, cervix dilates, contractions increase steadily, water breaks

expulsion- cervix dilates 10cm, intense contractions, fetus emerges in vagina

delivery- birth of fetus

placental- ejection of placenta, or afterbirth

If the vaginal canal is too small to permit the passage of the fetus, posing acute danger of perineal tearing, an ___________ may be performed. An incision through the perineal musculature enlarging the passageway

episiotomy

what are the 5 areas of a newborns apgar score; what score indicates a healthy baby

Heart rate, breathing, skin color, muscle tone, and reflex response; score of 8-10

describe the difference between immature and premature labor

immature- 25-27 weeks, low survival rate

premature- 28-36 weeks, with care high survival rate

A __________ delivery is needed when fetus faces mother's pubis instead of sacrum

Forceps

a ______ birth occurs when the fetuses begs or buttocks enter vaginal canal before the head. Umbilical cord can become constricted cutting off placental blood flow often resulting in a __________

breach; c section

what are risk factors for a cesarian section

advanced maternal age, diabetes, obesity, breach position, and multiple births

what is the difference between dizygotic twins and monozygotic twins

dizygotic- fraternal twins; two separate oocytes are ovulated and fertilized

monozygotic- identical twins; separation of blastomeres early in cleavage or splitting of inner cell mass before gastrulation; formed from same pair of gametes

when blastomeres or embryonic disc fail to completely split _________ twins occur

conjoined twins

list and describe the stages of life

Neonatal- birth to 1 month

Infancy- through 1st year

Childhood- infancy to adolescence

Adolescence- sexual and physical maturation (puberty)

Maturity- adulthood

At maturity, development ends and the process of aging, or _______________, begins, leading ultimately to death.

senescence

what occurs during the neonatal period

Respiratory, circulatory, digestive, and urinary systems begin functioning independently; Ability to control body temperature develops

Ingested by the infant during the first 2 or 3 days of life, _____________ contains more proteins and far less fat than breast milk. Many of the proteins are antibodies that may help the infant ward off infections until its own immune system becomes functional.

colostrum

what does breast milk consist of

water, proteins, amino acids, lipids, sugars, and salts

also lysozyme-enzyme

Milk becomes available to infants through the ____________ reflex

milk ejection

weaning, or the withdrawal of mother's milk, typically _______ years after birth

1-2

Growth in infancy through childhood occurs under direction of what circulating hormones

Growth hormone, Adrenal steroids, Thyroid hormones

what three major hormonal events occur during puberty?

gonadotropin-releasing hormone (GnRH) increases

circulating levels of FSH and LH increase rapidly

Ovarian or testicular cells become more sensitive to FSH and LH

What are the effects of aging on organ systems

Loss of elasticity in skin- wrinkling

Decline in bone deposition, weak bones and degenerative changes in joints

Reductions in muscular strength and ability

Impairment of coordination, memory, and intellectual function

Reductions in production of, and sensitivity to, circulating hormones

Decreased peristalsis and muscle tone in urinary system, and reduction in glomerular filtration rate

Functional impairment of reproductive system, which eventually becomes inactive

what is the difference between chromosomes and genes

chromosomes- contain dna and proteins

genes- Functional segments of DNA

22 of the 23 pairs of chromosomes are __________, the 23rd pair is __________

autosomes; sex chromosomes

the ________ is a gene's position on a chromosome

locus

Various forms of a given gene called __________ determine precise effect of gene on phenotype

alleles

Codominance vs incomplete dominance

Codominance - both alleles show up in the phenotype (ex. black and white speckled chickens),

Incomplete Dominance - a mixed phenotype (ex. grey chickens)

polygenic inheritance

occurs when multiple genes determine the phenotype of a trait

In ______________, one gene suppresses the other. As a result, the second gene has no effect on the phenotype. In _______________ gene action, dominant alleles on two genes interact to produce a phenotype different from that seen when one gene contains recessive alleles

suppression, complementary

X vs Y chromosome

X- females; carries more genes than Y

Y- males; sperm can give x or y

x linked genes

Found on X chromosome; affect somatic structures

________________ greatly increases genetic variation among gametes

genetic recombination

crossing over vs translocation

crossing over- homologous chromosomes become rearranged during synapsis; overlapping segments trade places

translocation- recombination between non homologous chromosomes

______________ results in specific (and usually reversible) chemical modifications, or markings, of DNA and its associated proteins which dictate whether the gene is expressed or not (silenced).

genetic imprinting

_____________ is the study of inherited traits that are not due to changes in a person's genotype or DNA sequences; works by activating or inactivating specific genes

Epigenetics

___________ is the percentage of individuals with a particular genotype that show "expected" phenotype

Penetrance

____________ is the extent to which particular allele is expressed when it is present

Expressivity

____________ are factors that result in abnormal development

Teratogens

______________ mutations are the result of random errors in DNA replication. Such mutations can cause the production of abnormal alleles

spontaneous