BIO 30 reproductuive system topic 5 and 6

what happens when sperm recahes the egg

the acrosome releases enzymes to digest the jelly-like coating surrounding the egg

zygote

first single cell of new life

sperm nucleus and egg nucleus (n) fuse to form

zygote

chorion (trophoblast)

outer layer of blastocyst which forms placenta and the amnion

gas/nutrient/waste exchange

inner cell mass

develops into embryo

from ovulation to implantation: day 1

first cleavage - cell divides by mitosis

from ovulation to implantation: day 4

16 - 32 cell stage. ball of cells is called a morula

from ovulation to implantation: day 5

the cells being to move aroound to form an inner and outer layer of cells

from ovulation to implantation: day 6

the two layers of cellsa rrange temselves around a hollow fluid filled vaicty called the blastocoel, the actual cell mass is called a blastocyst

from ovulation to implantation: day 7

Implantation- the blastocyst, by means fo villi and enzymes secreted by the chorion implants itself in the endometrium, resulting in pregnancy. the chorion secretes hCG, a hormone which stimulates the corpus luteum to produce progesterone and estrogen for the first 3 months

totipotent cells

stem cells from the blastocyst that are undifferentiated and used for stem cell research

1

zygote

2

mitosis

3

hCG

4

morula

5

blastocyst

6

chorion

7

day 14

gastrula

3 germ layers. neurulation

neurulation

formation of neural tube (develops into brain and spinal cord)

ectropic pregnancy

a fertilizaed egg has implanted outside the uterus and usually in the fallopian tube

outer layer of the blastocyst (the chorion) starts to secrete

hCG when it implants in the endometrium on day 7 which causes morning sickness and is measure in a pregnancy test

how can a msicarriage occur

placenta doesnt start making progeerstone and estrogen after corpus luteum stops making it

gastrulation

process in which the inner cell mass of blastocyst turns into 3 Germ layers

what day does blastocyst become gastrula

day 7

ectoderm (outer)

skin (epidermis), nervous system

mesoderm (middle)

sekelton, muscles, gonads

endoderm (inner )

lining of the digestive and respiratory systems and endocrine glands

morphogenesis

biological processs that causes an organism to develop its shape. e.g. formation of blastocyst, gastrula, germ layer, etc

amnion

Inner membrane of outer layer of blastocysts

beomes fluid-filled sca that protects embryo from infection, impact and temperature fluctations

allantois

forms the foundation of tne umbilical corn and becomes part of the bladder

yolk sack

in outer animals: provides nutrients

small in humans and forms blood cells

placenta

allows echange of some substances between mother and fetus

DOES NOT EXHANGE BLOOD CELLS FROM EITEHR MOTHER OR FETUS

placenta exchange from mother

nutrients, oxygen, antibotics, viruses, drugs, alciohol

placenta exchange from fetus

metabolic wastes (CO2, urea)

when is placenta formed

when villi from chorion extend from endometrium and is not fully developed until 2nd trimester

placenta secretes

estrogen and progesterone during 2nd and 3rd trimester

umbilical cord

rope like structure that forms after 8 weeks, runs from belly button of fetus to placenta

carries _ arterie(s) and _ Vein(s)

2,1

arteries from umbilical cord carry what kind of blood from fetus to mother

deoxygenated

veins from umbilical cord carry what kind of blood from mother to fetus

oxygenated

1

placenta

2

chorion

3

amnino

4

cervical plug/mucus - helps keep out pathogens

5

uterus

6

amniotic fludi

7

umbilical cord

8

umbelical vein - carries oxygenated blood

9

umbilical arteries - carry deoxygenated blood

10

cervix

11

vagina

1st trimester

mainly organogenesis

sex develops

most susceptible to environmetnal factors (teratogens)

chorion secrets hCG

organogenesis

development of organs

teratogens

substances that increase chance of birth defects

Alcohol effect

can cause FASD

tobacco effect

can cause hidnered fetal growth

cannabis effect

affects the brain, heart, intestines and can cause sudden infant death syndrome (SIDS)

1

males

2

glans penis

3

penis shaft

4

scrotum

5

females

6

clitois

7

labia minor

8

labia major

abdomiinal cabity

where female and male sex organs origniate

2nd trimester

grow adn refinement of tissues; hair and fingernails grow

organs contineu to form, carilage skeleton replace by bone

fetus can survive outside womb at end of this trimester (with medical support)

placenta secretes progesterone and estrogen

third trimester

fetus grows rapidly

organs sytem increase in size

fat is depsited

repsiratory and ciruclator system allow for air breathing

tesstes decend into scrotum

parturition

low levels of progesterone to labor onset

high estrogen levels trigger oxytocin receptors in myometrium

rythmic uterine contrations signal labor

cervix beings to dilate

aminiotic membrane bursts (water breaks)

labour hormones

prostaglandins, relaxtin, oxytocin, prolatin

prostaglandins

local area hormone that works with oxytocin causing uterine contractions

relaxin

produced by placenta, relaxes ligaments in pelvix which ease passage of baby

oxytocin

produced by hypothalamus and stored in posterior pituitary, positive feedback causes uterine contractions

prolactin

produced by anterior pituitary, causes mamary glands to produce milk

1st stage of birth

dilation (labour)

2nd stage of birth

expulsion (delivery)

3rd stage of birth

placental delivery

episiotomy

incision is made iwth scalpel to increase size of vaginal opening

caesarean section

incision in abdomen and uterus

epidural analgesia

needle inserted into the epiusural space in the spine which provides pain relief during labor by blocking sensoru pain receptors essentially making one numb from waist down

colostrum

yellowish fluid produced by mammary glands during first days after birth which are high in protein and antibodies to protect baby

________ is produecd after birth when levels of ________ and _______ drop. this initates milk production

prolactin, estrogen, progesterone

chorionic villus sempling

a thin tube is guided throguht the cervix or a needle is inserted into the uterus to remove a sample of choronic villus cells from the placenta for genetic testing

amniocentesis

neddle withdraws amniotic fluiid smaple containing fetal cells which are used for genetic/kartotyping/hormone tests

ultrasound imaging

soundwaves sent through body are used to visulaize internal structures

1

liver

2

stomach

3

colon

4

uterus

5

fetus

6

bladder

7

bone

8

vagina

9

pancreas

10

small intestine

11

placenta

12

anus