Biology Reproductive System Flashcards
___ differs asexual reproduction in that the genetic material of two organisms combines and results in a genetically unique offspring
sexual reproduction
Sexual reproduction occurs via the fusion of two ___, the specialized cells produced by each parent
gametes
Sexual reproduction requires:
production of ___ sex cells or gametes by adult organisms
union of these cells (fertilization or conjugation) to form a zygote
development of the zygote into another adult, completing the cycle
functional
___, the production of gametes, occurs in specialized organs called gonads
gametogenesis
The male gonads, the testes, produce sperm in the tightly coiled ___ tubules
seminiferous
The female gonads, the ___, produce oocytes (eggs)
ovaries
Some species are ___, which possess both functional male and female gonads
hermaphrodites
___, or sperm production, occurs in the seminiferous tubules of the testes
spermatogenesis
In females, the process is called ___, or egg production, and occurs in the ovaries
oogenesis
___ is the union of the egg and sperm nuclei to form a zygote with a diploid number of chromosomes
fertilization
___ is practiced by terrestrial vertebrates and provides a direct route for sperm to reach the egg cell
internal fertilization
Pathway of Sperm through the male reproductive system: SEVE(N) UP Seminiferous tubules Epididymis vas deferens (also called the ductus deferens) Ejaculatory duct (Next) \_\_\_ Penis
Urethra
The ___ are located in the scrotum, an external pouch that maintains the testes’ temperature at 2 to 4 degrees lower than body temperature, a condition essential for sperm survival
testes
The sperm cells mature in the ___, a structure resting atop of testes
epididymis
FSH acts on the ___ cells, located in the seminiferous tubules, to support the development of maturing sperm cells
sertoli
LH acts on ___ cells to stimulate testosterone production in the testes
leydig
In the seminiferous tubules diploid cells called spermatogonia differentiate into ___ cells called primary spermatocytes, which undergo a meiotic division to yield two haploid secondary spermatocytes of equal size; a second meiotic division produces four haploid spermatids of equal size
diploid
After miosis, the ___ undergo a final series of changes that increase their mobility, resulting in mature sperm, or spermatozoa
spermatids
On a mature sperm, a caplike structure called the acrosome, derived from the ___, develops over the anterior half of the head
Golgi apparatus
The ___ contains enzymes needed to penetrate the tough outer covering of the ovum
acrosome
In a female, it is the follicle cells that produce ___
estrogen
Approximately once a month, an immature ovum is released (ovulation) from the ___ into the abdominal cavity and drawn by cilia into the nearby oviduct, also known as a fallopian tube
ovary
Each fallopian tube opens into the upper end of a muscular chamber called the ___, the site of fetal development
uterus
The lower, narrow end of the uterus is called the ___
cervix
The cervix connects with the vaginal canal, which is the site of sperm deposition during ___ and is also the passageway through which a baby is expelled during childbirth
intercourse
Oogenesis, the production of female gametes, occurs in the ovarian ___
follicles
At birth, most of the immature ___, known as primary oocytes, that a female will produce during her lifetime have already formed
ova
Primary oocytes are diploid cells that form by mitosis in the ___
ovary
After menarche (the first time a female menstruates), one primary oocyte per month completes meiosis I, yielding two daughter cells of unequal size - a secondary ___ and a small cell known as a polar body
oocyte
The secondary oocyte is expelled from the ___ during ovulation, while the polar body gets reabsorbed
follicle
___ (oogenesis) does not occur until fertilization
Meiosis II
The ___ cell membrane is surrounded by two layers of cells; the inner zona pellucida layer and the outer corona radiata layer
oocyte
Meiosis II occurs when the zona pellucida and corona radiata layers are penetrated by a sperm cell, yielding two haploid cells - a mature ___ and another polar body
ovum
The ovaries synthesize and secrete female sex hormones, including estrogens and ___
progesterone
The secretion of both estrogens and and progesterone is ___ by luteinizing hormone (LH) and follicle stimulating hormone (FSH), which, are regulated by gonadotropin-releasing hormone (GnRH)
regulated
___ are secreted by the ovarian follicles and the corpus luteum
Estrogens
Progesterone stimulates the development and maintenance of the ___ in preparation for implantation
endometrium
The follicular phase focuses on the growth of the follicle, specifically the growth of the ___
follicle
The ___ phase begins with the cessation of menses (menstruation) from the previous cycle, which results in a decrease in progesterone
follicular
Throughout the follicular phase, blood ___ levels increase, eventually triggering the next phase, ovulation
estrogen
Midway through the cycle, ovulation occurs - a mature ___ follicle bursts and releases an ovum into the fallopian tube
ovarian
___ is caused by a surge in LH that is preceded, and caused by, a peak in estrogen levels
ovulation
As ___levels increase during the follicular phase, a concentration threshold is reached that causes a positive feedback loop with the anterior pituitary, inducing the LH surge (a smaller FSH surge also occurs)
estrogen
A surge in estrogen during ovulation causes the mature follicle to burst, releasing the ovum while the follicle exterior transforms into the corpus luteum (___body)
luteal
After ___, LH levels are relatively high but begin to drop due to hormone interaction with the corpus luteum
ovulation
LH maintains the corpus luteum, which secretes estrogen and ___
progesterone
When there is an increase in estrogen and progesterone, a negative ___ loop occurs, thereby decreasing LH levels therefore the corpus luteum is on a biological timer, as it secretes more progesterone the less LH is present which causes the degradation of the corpus luteum, triggering menstruation
feedback
During the luteal phase, ___ causes the glands of the endometrium to mature and produce secretions that prepare it for the implantation of an embryo
progesterone
During menstruation, if the ovum is not fertilized, the ___ atrophies due to a decrease in LH
corpus luteum
When the corpus luteum atrophies, the resulting drop in ___ and estrogen levels causes the endometrium (with its superficial blood vessels) to shed, giving rise to the menstrual flow (menses)
progesterone
If fertilization occurs, menstruation is avoided as both the resulting ___ and the developing placenta produce hCG (human chorionic gonadotropin)
zygote
Human chorionic gonadotropin is a LH analog which maintains the corpus luteum, therefore ensuring a continuous supply of estrogen and ___ needed to maintain the uterus
progesterone
An ___ can be fertilized during the 12-24 hours after ovulation
egg
___ most often occurs in the lateral, widest portion of the fallopian tube
fertilization
Enzymes secreted by the ___ aid in penetration of the corona radiata
sperm
The acrosome is responsible for penetrating the ___; it releases enzymes that digest this layer, thereby allowing the sperm to come into direct contact with the ovum cell membrane
zona pellucida
Once in contact with the ovum cell membrane, the sperm forms a tubelike structure called the ___ process, which extends to the cell membrane and penetrates it, fusing the sperm cell membrane with that of the ovum
acrosomal
Once the sperm cell membrane fuses with that of the ovum the sperm ___ now enters the ovum’s cytoplasm
nucleus
Once the ___ nucleus enters the ovum the ovum completes meiosis II
sperm
The acrosomal reaction triggers a cortical reaction in the ovum, causing calcium ions to be released into the cytoplasm; this initiates a series of reactions that result in the formation of the ___ membrane
fertilization
The ___ is a hard layer that surrounds the ovum cell membrane and prevents multiple fertilizations
fertilization membrane
The release of Ca2+ in the ___ of the ovum also stimulates metabolic changes within the ovum, greatly increasing its metabolic rate
cytoplasm
When the metabolic rate of the ovum (having had Ca2+ released in the ___ already) increases, this is followed by the fusion of the sperm nucleus with the ovum nucleus to form a diploid zygote
cytoplasm
When the fusion of the sperm nucleus with the ovum nucleus occurs to form a diploid ___, the first mitotic division of the zygote soon follows
zygote
