Unit 4: Reproduction Flashcards
What are the components of the male reproductive system? (9)
- testes
- scrotum
- epididymis
- penis
- urethra
- prostate
- seminal vesicle
- bladder
- vas deferens
Testes (2)
- produces sperm
- it is outside the body because the optimal temperature for producing sperm is below body temp
Epididymis
finishes sperm production
Vas deferens (2)
- the tube where sperm leaves
- passes through prostate
What are the components of the female reproductive system? (8)
- fallopian tube
- ovary
- uterus
- bladder
- urethra
- vagina
- cervix
- large intestine
Ovaries
where eggs are produced
Fallopian Tube
- where gametes will be released
- this is where pregnancy occurs
Uterus
where the zygote implants itself, develops, and becomes a fetus
Cervix
junction between vagina and uterus
When does puberty begin in males? (2)
- upon an increase in testosterone production
- starts around age 13 or 14
Where is testosterone produced?
the testes
What do high testosterone levels cause?
the display of secondary sex characteristics
What are the male secondary sex characteristics? (8; choose 4 or 5 to remember)
- increase in bodily hair (chest and face)
- the larynx grows and the voice deepens
- seminal fluids are produced and ejaculation is possible
- genitals increase in size
- testes drop away from the body
- bones and skeletal muscle undergo growth
- personality development
- changes in behavior
When does puberty begin in females? (2)
- increased release of estrogen by the ovaries
- begins around age 13 or 14
What do higher estrogen levels cause?
the display of secondary sex characteristics
What are the female secondary sex characteristics? (4)
- breasts increase in size
- pubic and armpit hair increases
- genitals increase in size
- pelvis growth and adipose tissue is deposited around it
How many hormones are the menstrual and ovarian cycles controlled by?
4
What hormones control the menstrual and ovarian cycles? (4)
- estrogen
- progesterone
- LH
- FSH
Where are estrogen and progesterone secreted from?
the ovaries via the corpus luteum
Where are LH and FSH secreted from?
anterior pituitary gland
Where does oogenesis take place?
in the ovaries
What are the stages of oogenesis? (6)
1) diploid oogonium (stem cell) divide by mitosis, then grow into large diploid primary oocytes
2) Primary oocytes being to go through meiosis I and follicle cells grow around them
3) Follicle matures and grows in size
4) After puberty begins, ovulation occurs and meiosis I is complete
5) Corpus luteum grows
6) Corpus luteum degenerates, completing cycle
What part of oogenesis takes place before birth? (2)
- the division of the oogonium into primary oocytes
- females are born with around 500,000 of them
What happens during oogenesis after puberty? (3)
- ovulation occurs
- haploid secondary oocyte travels through fallopian tube to the endometrium
- Meiosis also produces polar body
What happens if a secondary oocyte is not fertilized?
the secondary oocyte is shed from the menses
Polar Body (PB)
small unfunctional cell that is broken down then absorbed into the body
What happens if a secondary oocyte is fertilized?
meiosis II occurs to become a haploid ovum with another polar body
Where does spermatogenesis occur?
in the seminiferous tubules of the testes
What are the stages of spermatogenesis? (5)
1) Diploid spermatogonium (stem cell) divides by mitosis
2) Spermatogonium divide by mitosis and grow into diploid primary spermatocytes
3) Phase I of meiosis (beginning after puberty) produces haploid secondary spermatocytes
4) Phase II of meiosis produces haploid spermatids which are nourished by Sertoli cells and differentiate into spermatozoa
5) Spermatozoa mix fluids to become semen
How many steps are there to fertilization?
6
What is the process of fertilization? (6)
- Sperm enter woman and become fully capacitated; they use chemical signals to reach the egg as it swims past the cervix and into a fallopian tube
- Hundreds of sperm bind to zona pellucida, triggering
acrosome reaction - Proteases in the acrosome are released, digest zona pellucida and allow sperm to reach plasma membrane
- A single sperm membrane fuses with the egg plasma membrane; the egg prevents more sperm from entering
- Oocyte performs meiosis II
- Nuclei of sperm and egg undergo mitosis. A 2-celled diploid zygote is formed.
How does the egg prevent more sperm from binding to its plasma membrane? (2)
- fast block polyspermy
- slow block polyspermy
Fast block polyspermy
when the oocyte’s membrane depolarizes
Slow block polyspermy
Cortical granules in the egg react with the zona pellucida, forming a tough, impermeable layer
How long can an oocyte be fertilized after ovulation?
12-24 hours
For how long can sperm remain viable?
4 days
What happens after fertilization?
the zygote migrates towards the
endometrium, while undergoing cleavage
How many steps are there to early embryo development?
6
What is the process of early embryo development? (6)
- Ovulation
- Fertilization
- Cleavage begins after fertilization
- After 4-5 days, the embryo (now blastocyst) reaches the end of the fallopian tube
- Blastocyst (made up of 100 cells) implants into the endometrium
- Enzymes in the blastocyst allow it to penetrate the
endometrium, and the endometrium begins to envelop the blastocyst
Blastocyst (3)
- hollow ball of cells
- outer layer called trophoblast; later develops into placenta
- inner mass develops into embryo; contains pluripotent stem cells
Placenta
structure connected to the uterus where nutrients are exchanged between the mother and child
What does the placenta do? (3)
- Through the umbilical cord, components are exchanged between fetal and maternal blood
- secrete estrogen and progesterone after 2 months
- BLOOD IS NOT EXCHANGED
What is a structural component of the placenta?
chorionic villi, which increase the
surface area for exchange
What types of things are exchanged between mother and child? (2)
- glucose
- oxygen
Amniocentesis (2)
- the removal of amniotic fluid which contains fetal cells
- fetal cells are tested for chromosomal abnormalities
How many steps are there to in vitro fertilization (IVF)?
6
What is the process of IVF? (6)
- the female’s menstrual cycle is stopped
- FSH is injected in order to stimulate growth of numerous follicles
- hCg (in place of LH) is injected to make it easier to harvest the follicles
- The oocytes are extracted and mixed with semen
- Any eggs which have fertilized are kept to be re-inserted into the woman
- The early embryos still must implant into the uterine wall in order to pregnancy to occur
Where is sperm produced?
in the seminiferous tubules
What do the seminal vesicles and prostate gland produce?
fluids that mix with sperm during ejaculation
What does semen contain? (3)
- sperm
- fructose
- alkaline mucus
Why does semen need fructose?
fructose is a sugar that allows the sperm to move
Why does semen need alkaline mucus?
to navigate the acidic environment of the urethra and vagina
How many hormones are involved in spermatogenesis?
3
What hormones are involved in spermatogenesis? (3)
- FSH
- LH
- Testosterone
What does FSH do in spermatogenesis?
activate Sertoli cells to induce primary spermatocytes to undergo meiosis I to become secondary spermatocytes
What does LH do in spermatogenesis?
stimulates secretion of testosterone by the testes
What does testosterone do in spermatogenesis?
stimulates development of secondary spermatocytes into spermatids, maintain all stages of spermatogenesis
What secretes testosterone?
Leydig cells in the testes
Sertoli cells
nourish developing sperm and are activated by FSH
How many hormones are involved in the menstrual cycle?
4
What hormones are involved in the menstrual cycle? (4)
- LH
- FSH
- Estrogen
- Progesterone
What are the stages of the ovarian cycle? (3)
- Follicular phase
- Ovulation
- Luteal Phase
What happens in the follicular phase? (5)
- begins on day 1
- FSH levels rise stimulating follicle cells to grow
- follicle releases estrogen and estrogen stimulates follicle to grow (positive feedback)
- high estrogen levels causes LH to surge and the spike causes meiosis I to complete
- 1 follicle cell grows large enough that the secondary oocyte bursts out
What happens during ovulation?
24 hours after LH surge secondary oocyte is released into the fallopian tube
What happens during the luteal phase? (4)
- follicle becomes corpus luteum
- corpus luteum mainly produces estrogen, but also produces progesterone
- corpus luteum degenerates as secondary oocyte migrates to the uterus
- if there is no fertilization, the corpus luteum degenerates, progesterone and estrogen levels fall, and FSH rises
How many stages are in the uterine cycle?
3
What are the stages of the uterine cycle?
- Menses
- Proliferative Phase
- Secretory Phase
What happens during the menses phase? (3)
- endometrium of uterus is shed along with unfertilized eff
- low levels of progesterone activates menstruation
- menstruation ends during follicular phase as estrogen levels rise
What happens during the proliferative phase? (3)
- estrogen causes endometrium to grow
- endometrium thickens and repairs itself
- this phase ends at ovulation as estrogen levels decrease and progesterone levels begin to rise
What happens during the secretory phase? (2)
- progesterone causes vascularization of the endometrium
- phase ends when corpus luteum degenerates, progesterone levels fall, and endometrium is shed
What happens to the uterine cycle if an oocyte is fertilized?
- second division of meiosis occurs and menses is inhibited
- no new follicle will develop
What does LH do in the menstrual cycle? (2)
- causes corpus luteum to grow
- causes ovulation
What does FSH do in the menstrual cycle?
stimulate follicle growth
What does estrogen do in the menstrual cycle? (3)
- stimulate LH secretion prior to ovulation
- inhibits FSH
- repairs uterine lining
What does progesterone do in the menstrual cycle? (2)
- prepares uterus for implantation
- inhibits LH and FSH
What are the components of a sperm cell? (6)
- haploid nucleus
- plasma membrane
- centriole
- flagellum
- mitochondria
- acrosome
mitochondria
produces the ATP needed to move and swim
acrosome
pouch of digestive enzymes
What are some structures in the testes? (2)
- Leydig cells
- Sertoli cells
Leydig cells (2)
- produce testosterone
- not inside the tubes
Sertoli cells (2)
- nourish developing sperm
- inside tubes
What are some of the structures in the oocyte?
- corona radiata
- zona pellucida
- plasma membrane
- cytoplasm
- haploid nucleus
Corona Radiata
go around the outside of cells, layer of follicle cells that stick around the egg
Zona Pellucida
extra layer of glycoproteins
Cytoplasm
contains centrioles and cortical granules
What hormones are needed throughout pregnancy? (2)
- estrogen
- progesterone
What does the blastocyst secrete when it implants into the uterus?
hCG
hCG
prevents the corpus luteum from degenerating, allowing continued secretion of progesterone and estrogen
Amniotic Sac (3)
- surround developing embryo
- acts as a shock absorber
- helps with temperature regulation
What is the process of birth? (4)
- pregnancy ends as progesterone levels fall, it allows oxytocin to be made
- oxytocin causes the uterine walls to contract and the contractions cause more oxytocin to be released (positive feedback)
- The cervix opens and the amniotic sac bursts, releasing amniotic fluid
- Fetus is pushed out the uterus, the umbilical cord is cut, and the placenta is expelled
