SCIENCE TEST: REPRODUCTION Flashcards
crossing over
when genetic material is exchanged between chromosomes during meiosis
haploid
HALF set of chromosomes
meiosis
the process by which one diploid cell divides into 4 haploid cells
zygote
first diploid cell produced as a result if fertilization, first cell of the newly created organism
fertillization
joining of egg and sperm, when two haploid cells fuse to form a diploid zygote
diploid
full set number of chromosomes
somatic cell
any diploid (full set) body cell
gamete
sperm and egg
any haploid cell
tetrad
a group of 4 chromosomes which forms during MEIOSIS
meiosis
the process by which one diploid (full) cell divides into 4 haploid cells (half)
cleavage
MITOSIS of he zygote to form an embryo
homologous chromosomes
a pair of chromosomes containing similar genetic information
three phases of embryonic development
morula, blastula, gastrula
male reproductive system
- produce sperm/gametes in the testes
- deliver sperm internally to the female
female reproductive system
- peoduce eggs/gameres in ovaries
- the uterus provides a place fo rthe fetus/embryo to develop
- the vagina receives sperm
fertilization steps
- egg is released by the ovary once a month
- sperm are deposited and swim to the egg
- egg and sperm unitr in the oviduct/fallopian tube
- zygote is formed
early development
-zygote starts to divide by mitosis
-this special mitosis is called cleavage
first a morula is formed: solid ball of cells
second a blastocyst is formed :hallow ball of cells
gestation period: pregnancy stages
after the blastocyst implants, the embryo starts to develop
after 9 weeks it is called a FETUS
human pregnancy or gestation is 40 WEEKS
birth
stage one: the cervix opens and dialates
stage two: the baby exsits the uterus through the cervix abd out of the vagina canal
stage three: the placenta exists the uterus through the cervix and out if the vagina canal
menstrual cycle
- a cycle controlled by hormones
- hormones are proteins responsible for cell communication
feedback mechanism
one hormone level drops, the next hormone is triggered to be released
ex: FSH down LH high
hormones
a hormone must fit the receptor molecule on the cell membrane of the target cell to be able to deliver the message
secreting cell
cell that is making and releasing the hormone into the bloodstream
target cell
cell that is receiving the message and responding
menstrual cycle
- 28 day cycle is average
- 4 phases controlled by the four hormones: FSH, LH, ESTROGEN, PROGESTERONE
follicular phase
immature egg cell in ovary goes through meiosis to become a mature haploid (half) egg cell
the follicule cell releases ESTROGEN whicg causes the UTERUS to develop and endometrium: a ling of blood vessels and cells that will form a PLACENTA if needed.
ovulation
mature egg is released from the ovary
the PATUITARY GLAND releases LH to cause the release of the egg: OVULATION
follicle bursts open to release the egg into the Fallopian Tube
luteal phase
ovary releases hormones to tell the uterus to prepare for possible pregnancy
menstrauation
the uterus sheds the lining it created to prepare for pregnancy
if the egg is not fertilized in the fallopian tuve, it does not implant in the uterus and there is NO pregnacy
estrogen and progesterone levels drop and the uterus sheds into the endometrum lining: this is the period
FSH
released by the PITUITARY GLAND (in brain) and targets the OVARY
LH
released by the PITUITARY GLAND (in the brain) and targets the OVARY
ESTROGEN
released by the follice (OVARY) and targets the UTERUS
PROGESTERONE
released by the COROUS LUTEUM (OVARY) and targets the UTERUS
gestation period
length of pregnancy
endometrium/placenta
the “pre” placenta/materials such as nutriens and wastes are exchanged
amniotic sac/fluid
fluid in which the embryo develops
umbilical cord
connects the fetus to the placenta
is there fetal blood
NO NEVER!!!!!!!!
labor
contractions of the uterus which pushes the baby out
afterbirth
afterbirth, the placenta detaches and exists the uterus
fertility drugs
medications which enchance reproductive fertility. it is used to stimulate follicle development of the ovary
