pregnancy and human development

Question 1

what is the list of female structures that sperm travels through to reach the secondary oocyte

Answer 1

vagina, cervix, uterus, uterotubal junction, fallopian tube, fertilization

Question 2

what is capacitation of sperm and what is its importance

Answer 2

capacitation enhances motility (movement) of sperm to make the acrosome membrane thin to release hydrolytic enzymes. Its important because only sperm that has had this done can release the enzymes needed to fertilize the egg

Question 3

what are the 4 major steps of fertilization and what happens in each step

Answer 3

1. sperm penetrates oocyte, forming ovum and 2nd polar body
2. sperm and ovum nuclei swell, forming pronuclei
3. pronuclei find each other and bind using spindles
4. chromosomes of each pronuclei mix, forming a zygote

Question 4

what is a fast block in polyspermy, what initiates it, and what is the significance of it

Answer 4

it is initiated when the electric potential of the egg plasma membrane switches from negative to positive
this happens when sperm binds to a receptor on the oocyte membrane causing depolarization and the repelling of nearby unattached sperm
this is important as only one sperm can bind to an egg in females

Question 5

what is a slow block in polyspermy, what initiates it, and what is the significance of it

Answer 5

it is initiated when sperm enters the oocyte triggering a surge of calcium from the oocyte
after that happens meiosis 2 is completed, sperm binding receptors are destroyed, and the zona pellucida is hardened
this is important as only one sperm can bind to an egg in females

Question 6

what is a trophoblast and what does it differentiate into

Answer 6

it is the outer layer of cells that helps form placenta chorion
it differentiates into cytotrophoblast (inner) and syncytiotrophoblast (outer)

Question 7

what is a embryoblast and what does it differentiate into

Answer 7

it is the inner cluster of 20-30 cells that will develop into several things
it differentiates into the epiblast and hypoblast

Question 8

what are the major events of blastocyst implantations

Answer 8

the events occur through days 6-12
day 6: blastocyst sticks to uterine wall
day 7: trophoblast invades uterine wall
day 9: embryoblast becomes a bi layered embryonic disc
day 11: implantation is complete, amniotic and yolk sacs form

Question 9

what are the sources of HCG (human chorionic gonadotropin) and what is the importance of it

Answer 9

syncytiotrophoblastic cells of the placenta are the source for HCG is is important as keeps corpus luteum going and promotes placentation

Question 10

what is an epiblast and what does it differentiate into

Answer 10

the epiblast is used to turn into germ layers
it differentiates into ectoderm

Question 11

what is a hypoblast and what does it differentiate into

Answer 11

the hypoblast is used to turn into germ layers
it differentiates into the endoderm

Question 12

what are the 3 primary germ layers of the gastrula and what do the structures develop into

Answer 12

Ectoderm, mesoderm, endoderm (in order from outside to deep inside)
ectoderm: develops into nervous system and epidermis of skin
mesoderm: develops into connective tissues, muscles, kidneys, and gonads
endoderm: develops into lining of digestive, respiratory, and urogenital systems and some glands

Question 13

what is the sources and functions of allantois extraembryonic membranes

Answer 13

source: pocket at the end of yolk sac
function: becomes part of urinary bladder and forms the attachment for the umbilical cord

Question 14

what is the sources and functions of yolk sac extraembryonic membranes

Answer 14

source: came from hypoblast cells and hangs from ventral surface of embryo
function: is a source of blood cells and vessels and is eventually absorbed into the developing digestive tube

Question 15

what is the sources and functions of amnion extraembryonic membranes

Answer 15

source: comes from epiblast cells and is a sac filled with amniotic fluid for embryo to float in
function: provides protection, free movement, and development area it also maintains homeostasis temperature

Question 16

what is the sources and functions of chorion extraembryonic membranes

Answer 16

source: it comes from trophoblast
function: it wraps around embryo and other membranes to enclose them it also helps form the placenta

Question 17

what are the functions of the placenta

Answer 17

the placenta is used to provide nutrition, respiratory, excretory, and endocrine functions to the developing fetus.
it also uses veins and arteries to provide oxygenated blood to the fetus (artery takes deoxygenated blood from fetus and veins bring in oxygenated blood to fetus)

Question 18

what are the major events of neurulation and what organs/structures are formed from it

Answer 18

1. ectoderm thickens and forms neural plate
2. neural plate folds inward fusing into a neural tube
3. the end of the tube forms the brain and spinal cord for fetus
4. neural crest cells on top of neural tube migrate to form ..
   structures developed: cranial, spinal, and sympathetic ganglia nerves
   pigment cells of skin and chromaffin cells of adrenal medulla

Question 19

what structures develop from the endoderm

Answer 19

the endoderm produces epithelial lining for GI tract and its glands, urinary/gallbladders, the liver, all respiratory structures, and all reproductive structures.
it also creates the epithelium for thyroid glands and pancreas and gametes

Question 20

what is the somites mesodermal aggregate and what structures develop from it

Answer 20

it is used to create different structures for the developing fetus
this aggregate creates vertebra and ribs, dermis of skin, and skeletal muscles of neck, trunk, and limbs

Question 21

what is the intermediate mesodermal aggregate and what structures develop from it

Answer 21

it is used to create different structures for the developing fetus
this aggregate creates gonads and kidneys

Question 22

what is the lateral mesodermal aggregate and what structures develop from it

Answer 22

it is used to create different structures for the developing fetus
this aggregate creates the dermis of the skin, parietal serosa, connective tissues of body, heart, vessels, and walls of digestive and respiratory organs

Question 23

what are the major fetal development events of the heart, skeletal, and nervous system

Answer 23

8 weeks: cardio system is fully functional, all limbs and body systems are present, weak muscle contractions can happen
9-12 weeks: heartbeat is detected, skin and facial features can be seen, brain and spinal cord present
13-16 weeks: sensory organs are present, most bone and join cavities are apparent
17-20 weeks: fetal movements are faster, limbs are near final proportions

Question 24

what is a teratogen and what are some examples of known teratogens

Answer 24

a teratogen is a harmful substance that can cause severe abnormalities/death to fetus if they enter fetal blood
some teratogens include: alcohol, nicotine, drugs, chemicals, and radiation

Question 25

what are the major maternal anatomical changes that occur during pregnancy

Answer 25

the uterus expands, breasts and nipples enlarge, vagina and areola darken in color, ribs flare outwards and spine bends in more (lordosis), weight gain occurs, pelvis relaxes

Question 26

what changes occur in gastrointestinal, urinary, respiratory, and cardiovascular systems in response to pregnancy

Answer 26

GI: morning sickness from high HCG, estradiol, and progesterone. heartburn/constipation may occur
urinary: more urine production urgent urination. more pooping
respiratory: difficulty breathing from high tidal volume and dyspnea
cardio: high blood volume, cardiac output, blood circulation in veins may be low also

Question 27

what are the major events of the three stages of labor

Answer 27

dilation: babys head faces downward
expulsion: babys head extends out as its taken out
placental: placenta detaches and is removed

Question 28

what are the effects of human placental lactogen (hPL), prolactin-releasing hormone (PRH), prolactin, oxytocin, and estrogen on lactation and the structures involved

Answer 28

HPL: enlarges breasts and produces mammary glands for breastfeeding of baby
PRH: tells anterior pituitary to secrete prolactin
prolactin: produces milk production in mammary glands
oxytocin: allows breasts to contract to expel milk
estrogen: increases number of milk ducts

Question 29

what is the difference between colostrum and breastmilk and what are the benefits of them to infants

Answer 29

colostrum is produced only right after giving birth while breastmilk is what follows after that
both strengthen immune system, help with bacterial colonization in the gut, is a natural laxative, and prevents overactive inflammatory responses
it is the most easily metabolized thing for babies

Question 30

what are some of examples of birth control and what is the effectiveness of each one

Answer 30

sterilization: most effective- vasectomy, hysterectomy, tubal ligation
hormonal: semi effective-birth control pill, iud, patch, ring
physical barriers: least effective-condom diaphragm
behavioral: least effective- pull out, ovulation tracking