Ch 50 Flashcards
What does the reproductive system lack that every other physiological system has?
Homeostasis
What are the 6 types of asexual reproduction?
single cell division, fission, budding, specialized cells, fragmentation, and parthenogenesis
asexual reproduction
a single parent endows its offspring with genes identical to its own
What are the pros to asexual reproduction?
it’s energy efficient and is most successful in a stable environment
single cell division
this is the same thing as mitosis
budding
part of the parent’s body grows and separates from the rest of the body
fragmentation
the parent’s body breaks into pieces and each piece can grow into a new animal
parthenogenesis
‘virgin development’, a form of asexual reproduction in which an unfertilized egg develops into an adult animal, the adult is typically haploid, parthenogenesis is common among insects (typically honeybees and wasps) and crustaceans
Pros and cons of sexual reproduction
cons: it’s complicated, males may be wasted, cost of meiosis, and lack of founder effect; pros: variability
external fertilization
mating partners typically release eggs into the water simultaneously (ex. frogs or fish)
internal fertilization
male delivers sperm into the female’s body
hermaphroditism
single individual produces eggs and sperm (ex. earthworms), some hermaphrodites, such as tapeworms, are capable of self-fertilization, but typically, two animals come together and fertilize each other’s eggs and each animal inseminates the other
testes
tissues responsible for hormone and sperm production
sperm
travel through multiple male reproductive tissues
penis
houses urethra for urination and ejaculation of sperm
male sex hormone
testosterone
What are gametes?
gametes only have half of the DNA, so when they meet they form a full human set of DNA, gametes are eggs and sperm
Where is sperm formed and what are the organs, in order, that it must pass through to get out of the penis?
made in the testis, it is stored in the epididymis until it’s ready to be ejaculated, when ready it travels through the vas deferens, it goes through 3 glands (seminal vesicle, prostate, and bulbourethral) that add things to it, and then it goes through the ejaculatory duct and leaves via the urethra
Where are the testes located? What do they contain?
they are housed in the scrotum, the contain the seminiferous tubules, where sperm production takes place
What do interstitial cells secrete?
testosterone (males drive crazy on the INTERstate because of testosterone
What do sertoli cells produce?
produce signaling molecules and a fluid that nourishes sperm cells (Sertoli=Sperm)
seminiferous tubules
small, twisty tubes that are surrounded by sperm producing cells
penis
three columns of erectile tissue, two cavernous bodies, one spongy body that surrounds the urethra (erectile tissue becomes engorged with blood and causes erection)
flaccid penis vs erect
blood can flow in and out easily, in erect penis, the dorsal veins are constricted so the blood can’t get out (also the artery is dilated so more blood gets in)
flagellum
the tail on the sperm that helps the sperm swim to the egg
Another word for egg?
ovum/ova
zygote
is formed when sperm and egg unite, a zygote is a fertilized egg
Which type of reproduction (asexual or sexual) is the fastest and most efficient way to reproduce?
asexual reproduction
When is asexual reproduction favored? What type of environment?
An unchanging, stable environment
spermatogenesis
the process of sperm cell production, occurs in the testes, but more specifically it takes place within a vast tangle of hollow tubules, the seminiferous tubules, within each testis; spermatogonium (diploid)->primary spermatocyte (diploid)->two secondary spermatocytes (haploid)->four spermatids (haploid)->spermatids which then develop into four mature sperm (haploid)
What cells form a blood-testis barrier? What is a blood-testis barrier?
sertoli cells form this barrier that prevents harmful substances from entering the tubule and interfering with spermatogenesis, this barrier also prevents sperm from passing out of the tubule into the blood, where they could stimulate an immune response
scrotum
serves as a cooling unit, maintaining sperm below body temperature since sperm cells cannot develop at body temperature
What is the order of structures that sperm passes through?
seminiferous tubules->epididymis->vas deferens->ejaculatory duct->urethra->release from body
Structures of a sperm cell
plasma membrane, acrosome, mitochondria, flagellum, nucleus, head, midpeice
acrosome
a large vesicle covering part of the nucleus that differentiates from the Golgi complex, the acrosome also contains enzymes that help the sperm penetrate the egg
mitochondria
located in the midpeice of the sperm, the mitochondria provide the energy for movement of the flagellum
inguinal canals
connect the scrotum to the pelvic cavity
What do seminal vesicles secrete?
a fluid rich in fructose and prostaglandins into the vasa deferentia, the fructose provides energy for the sperm after they are ejaculated, prostaglandins stimulate contractions in both male and female reproductive tracts-these contractions help transport the sperm down the male reproductive tract and up the female tract to the oviduct where fertilization occurs, the seminal vesicles also secrete fibrinogen which clots the semen, the fluid secreted by the seminal vesicles accounts for about 60% of the semen volume
What does the prostate gland secrete?
an alkaline fluid that neutralizes the acidic secretions of the vagina, this is important because sperm are more active and survive longer in a slightly alkaline environment, prostate gland secretion also contains clotting enzymes and prostate-specific antigen (PSA)–the clotting enzymes act on fibrinogen from the seminal vesicles, producing fibrin which clots the semen, when semen is ejaculated, the clotted semen helps keep the sperm in the female reproductive tract while the penis is withdrawn, the clot is then broken down by PSA, and mobile sperm make their way through the female reproductive tract to the ovum
What do the bulbourethral glands secrete?
release a mucous secretion that lubricates the penis, facilitating its penetration into the vagina
glans
the tip of the penis
prepuce
foreskin
What is the principle androgen in males?
testosterone
What is testosterone classified as?
a steroid
Where is testosterone produced and what is it produced by?
it is produced by interstitial cells between the seminiferous tubules in the testes
puberty
the period of sexual maturation during which the secondary sex characteristics begin to develop and the individual becomes capable of reproducing
primary sex characteristics (in males)
growth of the reproductive organs and spermatogenesis
secondary sex characteristics (in males)
develop during puberty, includes the growth of facial and body hair, muscle development, and the increase in vocal cord length and thickness that causes the voice to deepen
What are the steps (in order) that occur to regulate male reproduction?
1:Hypothalamus secreted Gonadotropic Releasing Hormone (GnRH), which stimulates the anterior pituitary, 2:Pituitary secretes Follicle Stimulating Hormone (FSH) and Leutinizing Hormone (LH), 3:FSH stimulates Sertoli cells to secrete Androgen-Binding Hormone (ABH) and other signaling molecules necessary for spermatogenesis, LH stimulates interstitial cells to secrete testosterone, 4:Testosterone stimulates Sertoli cells, leading to stimulation of spermatogenesis, 5:testosterone maintains secondary sex characteristics, 6:Testosterone inhibits GnRH secretion by hypothalamus and FSH and LH secretion by pituitary, 7:Inhibin, secreted by the testes, inhibits FSH secretion
Gonadotropic Releasing Hormone (GnRH) (in males): what gland secretes it, it’s target tissue, and its function
secreted by the hypothalamus, GnRH’s principle target tissue is the anterior pituitary and its function is to stimulate the release of FSH and LH
Follicle-stimulating hormone (FSH) (in males): what gland secretes it, target tissue, and function
secreted by the anterior pituitary, its target tissue is the testes, its function is to stimulate the development of seminiferous tubules and to stimulate spermatogenesis
Luteinizing hormone (LH) (in males): what gland secretes it, it’s target tissue, and its function
secreted by the anterior pituitary, its target tissue is the testes, and its function is to stimulate interstitial cells to secrete testosterone
testosterone (in males reproductive regulation): what gland secretes it, target tissue, and function
secreted by the testes, its target tissue is general tissue around the body, its function before birth is to stimulate the development of primary sex organs and descent of testes into scrotum, at puberty it is responsible for growth spurts and it stimulates the development of reproductive structures and secondary sex characteristics, in adults testosterone maintains secondary sex characteristics and stimulates spermatogenesis
inhibin (in regulation of male reproduction): what gland secretes it, its target tissue, and its function
secreted by the testes, its target tissue is the anterior pituitary, its function is to inhibit FSH secretion
What are the female gonads?
ovaries
oogenesis: what is it? where does it begin?
oogenesis is the process of ovum production and it begins in the ovaries
describe the process of oogenesis
before birth, hundreds of thousands of oogonia are present in the ovaries, all of a female’s oogonia form during embryonic development, no new oogonia are formed after birth, during prenatal development, the oogonia increase in size and become primary oocytes, by the time of birth, they are in the prophase of the first meiotic division, at this stage, they enter a resting phase that lasts throughout childhood and into adult life
What makes up a follicle?
a primary oocyte and the granulosa cells surrounding it
granulosa cells
cells that surround the developing oocyte and are part of the follicle; produce estrogens and inhibin
theca cells
the layer of connective tissue cells that surrounds the granulosa cells in an ovarian follicle; stimulated by luteinizing hormone (LH) to produce androgens, which are converted to estrogen in the granulosa cells
What is the sequence (in order) of oogenesis?
oogonium (diploid)->primary oocyte (diploid)->secondary oocyte + first polar body (both haploid)->(after fertilization) ovum + second polar body (both haploid)
What are the polar bodies?
they are small cells produced during oogenesis that do not form into ovum, they dispose of unneeded chromosomes with a minimal amount of cytoplasm, these polar bodies eventually degenerate
How many ova are produced from each primary oocyte?
one
How often does ovulation occur? What is this cycle called?
every 28 days, the ovarian cycle
endometrium
lining of the uterus, every month the endometrium thickens in preparation for possible pregnancy, but if a female doesn’t get pregnant the endometrium breaks down and is bled out with cells and other things during the menstrual cycle
What do oogonia do before birth? How do they do this?
they divide many times before birth by mitosis
When does meiosis occur within female reproduction?
Primary oocytes undergo meiosis twice
Why does breast feeding after birth help the uterus recover?
breast feeding promotes recovery of the uterus because oxytocin released during breast-feeding stimulates the uterus to contract to nonpregnant size
GnRH (in females): what secretes it, target tissue, and function
secreted by the hypothalamus, it’s target tissue is the anterior pituitary, its function is to stimulate the release of FSH and LH
FSH (in females): what secretes it, target tissue, and function
secreted by the anterior pituitary, its target tissue is the ovary, its function is to stimulate the development of follicles and secretion of estrogen
LH (in females): what secretes it, target tissue, and function
secreted by the anterior pituitary, its target tissue is the ovary, and its function is to stimulate ovulation and the development of the corpus luteum
prolactin: what secretes it, target tissue, and function
secreted by the anterior pituitary, its target tissue is the breast, its function is to stimulate milk production (after the breast has been prepared by estrogen and progesterone)
oxytocin: what secretes it, target tissue, and function
secreted by the posterior pituitary, its target tissue is the uterus and the mammary glands, when its target tissue is the uterus, its function is to stimulate contraction and stimulate prostaglandin release, when its target tissue is mammary glands its function is to stimulate the ejection of milk into the ducts
estrogen (estradiol): what secretes it, target tissue, and function
it is secreted by the ovaries, its target tissues are general tissues and reproductive structures, when its target tissues are general its function is to stimulate the growth of sex organs at puberty and development of secondary sex characteristics, when its target tissue is reproductive structures its function is to induce maturation, stimulate monthly preparation of endometrium for pregnancy, and to make cervical mucus thinner and more alkaline
progesterone: what secretes it, target tissue, and function
secreted by the ovaries, its target tissue is the uterus, its function is to complete the preparation of the endometrium for pregnancy
inhibin (in female reproduction): what secretes it, target tissue, and function
secreted by the ovaries, its target tissue is the anterior pituitary, and its function is to inhibit the secretion of FSH
When is the preovulatory phase?
first two weeks of the menstrual cycle
When does ovulation occur within the menstrual cycle? What day?
about the 14th day
When is the postovulatory phase?
third and fourth weeks of the menstrual cycle
steps of the preovulatory phase
1:Hypothalamus secretes GnRH, 2:FSH stimulates follicle development, 3:LH indirectly stimulates estrogen production, 4:estrogen stimulates thickening of endometrium, 5:estrogen has a negative feedback effect on the pituitary and hypothalamus, 6:inhibin inhibits FSH secretion by pituitary, 7: high concentration of estrogen has a positive feedback effect on the pituitary and hypothalamus, 8:surge of LH stimulates ovulation; also called the ‘follicular phase’ because during this period, FSH stimulates a few follicles to begin to develop but after the first week of the menstrual cycle, typically only one follicle continues to develop
corpus luteum
the temporary endocrine tissue in the ovary that develops from the ruptured follicle after ovulation; secretes progesterone and estrogen
steps of the postovulatory phase
9:LH stimulates development of corpus luteum, 10:high concentration of progesterone strongly inhibits hypothalamus and anterior pituitary, FSH and LH secretion decreases, 11:estrogen has a negative feedback effect on the hypothalamus and anterior pituitary, 12:inhibin inhibits FSH secretion by pituitary
estrous cycles
only humans and a few primates experience menstrual cycles, all other mammals experience estrous cycles which is when the animals’ uterus reabsorbs the thickened lining of the endometrium if conception does not occur; female animals with estrous cycles are sexually receptive only during the estrus phase of the cycle of which the length and frequency vary by animal
What stimulates ovulation?
a surge of luteinizing hormone
What hormones inhibit FSH and LH in females?
estrogen and progesterone
human chorionic gonadotropin (hCG)
this is a peptide hormone that signals the mother’s corpus luteum to continue to function (the presence of hCG in urine or blood is used as an early pregnancy test), concentrations of estrogen and progesterone remain high throughout pregnancy, during the first two months the corpus luteum secretes almost all of the estrogen and progesterone necessary to maintain the pregnancy, during this time however, membranes surrounding the embryo, together with uterine tissue, form the placenta, the organ of exchange between the mother and developing embryo, by the 10th week of pregnancy, hCG secretion decreases and the corpus luteum begins to deteriorate, the placenta takes over and secretes large amounts of estrogen and progesterone
placenta
the organ of exchange between the mother and developing embryo, at around 10 weeks it takes over for the corpus luteum and secretes estrogen and progesterone to inhibit the secretion of FSH and LH so the body stops producing new follicles
What are the roles of estrogen and progesterone in maintaining pregnancy?
estrogen stimulates the development of the uterine wall, including the muscle needed to expel the fetus during delivery; progesterone inhibits uterine contractions so that the fetus is not expelled too soon; both hormones inhibit FSH and LH so that new follicles do not develop and the menstrual cycle stops during pregnancy
three stages of labor
stage 1: cervix dilates and effaces (thins), stage 2: birth, stage 3: placenta/afterbirth
What is now the most common STD in the US?
human papillomavirus (HPV)
What is PID? What causes it?
PID stands for pelvic inflammatory disease, it is a serious infection that can occur in women as a result of having chlamydia, which is what causes it
