reproduction I & II

Question 1

what is asexual reproduction?

Answer 1

when a single parent produces two offspring. the two off spring are identical/clones. there is no meiosis and no gamete fusion.

Question 2

what are examples of asexual reproduction?

Answer 2

budding, fission, parthenogenesis, fragmentation, regeneration

Question 3

what are some advantages of asexual reproduction?

Answer 3

rapid, dont need to find a mate

Question 4

what is sexual reproduction?

Answer 4

reproduction involving production and fusion of gametes (crossing over). it involves the sperm (small, motile, and flagellated) and an egg/ovum (large, nonmotile, contains nutrients for embryo) and fertilization (the fusion of sperm + egg to create the zygote)

Question 5

what are the disadvantages of sexual reproduction?

Answer 5

there is a reproductive cost, only half of population can actually reproduce

Question 6

what are the advantages of sexual reproduction?

Answer 6

promotes genetic diversity, new combinations of alleles: gets rid of harmful alleles/combinations of alleles, offspring may be more fit than parents, and more likely that some population can survive environmental changes

Question 7

what are the 2 functions of the male reproductive system?

Answer 7

produce sperm through spermatogenesis and deliver the sperm to the female reproductive tract

Question 8

what are the testes?

Answer 8

they are the male gonads (reproductive organs)

Question 9

what are the seminifernous tubules?

Answer 9

found in the testes, they are the site of spermatogenesis, a long hollow tube with a very small diameter

Question 10

what are the leydig cells?

Answer 10

they are found in the testes, they produce testosterone, other male sex hormones, they are scattered between the seminiferous tubules

Question 11

what is the epididymis?

Answer 11

a coiled tube with several functions such as transporting sperm (takes ~3 weeks), maturation of sperm, and storage of sperm

Question 12

what is the scrotum?

Answer 12

it is a skin-covered sac that contains the testes and epididymis. it is external, suspended from groin and typically cooler than the body temperature because sperm cannot develop at body temp and temp affects sperm production and longevity

Question 13

what is the penis?

Answer 13

the copulatory organ, delivers sperm into female reproductive tract, the urethra is located down the middle of the penis

Question 14

what is the anatomy of a penis?

Answer 14

consists of 3 parallel columns of tissue called the erectile tissue. during sexual stimulation NO is released causing the smooth muscle to relax and blood to rush in, the tissue swells and the veins are compressed, blood enters faster than it leaves (this is the process of an erection). the tip of the penis contains most sensory nerves and it is called the glans. the foreskins scientific name is the prepuce, it is the cuff of loose fitting skin that is often removed.

Question 15

what are the seminal vesicles?

Answer 15

one of the 3 accessory glands, a paired structure, produce fructose-rich fluid to nourish sperm after ejaculation. they also contribute prostaglandins, which stimulate uterine muscle contractions to aid sperm transport. This fluid, making up about 60% of semen volume, has a yellowish fluorescent pigment that can be forensically significant.

Question 16

what is the prostate gland?

Answer 16

one of the 3 accessory glands, located near the urethra, secretes a fluid containing anticoagulant enzymes and citrate, a nutrient for sperm. Enlargement of the prostate is common in men over 40, affecting roughly half of the population in this age group. Prostate cancer is a serious concern, with about 3% of men succumbing to the disease.

Question 17

what is the bulbourethral gland?

Answer 17

one of the 3 accessory gland, located on either side of the urethra, they are two pea-sized glands that are the first to release fluid during sexual arousal. this lubricating mucus, called bulbourethral fluid, helps neutralize any residual acidity from urine and may contain some sperm released before ejaculation.

Question 18

what is semen?

Answer 18

a mixture of sperm and fluids produced by three accessory glands. as sperm travel through the conducting tubes, they mix with these secretions, creating the final fluid that is ejaculated.

Question 19

what is the sperm path?

Answer 19

produced in the testes, sperm mature and are stored in the epididymis. From there, they travel through a pair of tubes called the vas deferens, which extend from the scrotum to the pelvic cavity. During ejaculation, sperm mix with fluids from the seminal vesicles and prostate gland as they pass through the ejaculatory ducts. The combined fluid, called semen, then travels through the urethra, the same tube that carries urine, and exits the body through the penis.

Question 20

what is spermatogenesis?

Answer 20

the production of mature sperm cells which takes about 7 weeks and occurs continuously

Question 21

what is the process of spermatogenesis?

Answer 21

first embryonic germ cells divide and differentiate into spermatogonial stem cells, these stem cells divide via mitosis, some of the newly formed cells called spermatogonia (2n) reside within the walls of the seminfernous tubules, here they continue to mitotically divide, ensuring a steady supply of cells for the next stage. a small number of spermatogonia become primary spermatocytes which undergo meiosis, this results in haploid (n) cells. the primary spermatocytes divide twice, first to secondary spermatocyte, and then the four haploid spermatids which differentiate into mature sperm cells (n)

Question 22

what are the parts of a mature sperm cell?

Answer 22

head, mid piece, and tail

Question 23

what are androgens?

Answer 23

the principle sex hormones in males, testosterone is the most imporant

Question 24

how are male hormones released

Answer 24

the hypothalamus secretes gonadrotropin releasing hormone (GnRH) which causes the AP to release 2 hormones, gonadotropids-lutenizing hormone and folicle stimulating hormone

Question 25

what is the lutenizing hormone (LH)?

Answer 25

targets the leydig cells which produce/secrete testosterone and other androgens

Question 26

what is testosterone?

Answer 26

high levels in testes required for spermatogenesis, stimulates puberty which is a period of sexual maturation

Question 27

what happens during male puberty?

Answer 27

adolescent growth spurt, growth of primary male sex characteristics (sex organs), growth of secondary male characteristics such as phyical, behavior differences btwn male and female, not directly related to reproduction, facial/body hair, depp voice, muscle development

Question 28

what is a folicle stimulating hormone (FSH)?

Answer 28

stimulates the development of seminfernous tubules, stimulates steroli cells to produce and secrete androgen binding protein (ABP)

Question 29

what do androgen binding proteins do?

Answer 29

binds to testosterone and helps to maintain high testosterone levels and allows testosterone to be sequestered

Question 30

what can inhibit FSH secretion?

Answer 30

inhibit, which are peptide hormones secreted by steroli cells

Question 31

what are the functions of the female reproductive system?

Answer 31

produce ova (eggs), receive sperm, facilitate fertilization, hour and nourish the developing embryo, give birth, lactate, feed young

Question 32

what are the ovaries?

Answer 32

a female gonad located in the abdominal cavity and held in place by several ligaments. they produce gametes via oogenesis and sex hormones such as estradiol and progesterone

Question 33

what are the oviducts?

Answer 33

also known as the fallopian tubes, they extend from uterus to ovaries and collects secondary oocyte from ovary, moves the secondary oocyte to uterus via beating cilia (contractions), this is also the site of fertilization

Question 34

what is the uterus?

Answer 34

it is pear shaped and about the site of a fist, it is the size of embryonic development and expands during pregnancy, there are two layers: the myometrium (thick wall of smooth muscle, involuntary movement) and endometrium (lines lumen)

Question 35

what is the endometrium?

Answer 35

it is one of the layers of the uterus, it lines the lumen which consists of connective tissue, glands, and blood vessels. it thickens each month to prepare for pregnancy, if fertilization occurs the embryo is implanted here, if not, it is sloughed off (menstruation)

Question 36

what is the cervix?

Answer 36

the lower part of the uterus, closes the uterus and separates from the vagina, common site of cancer

Question 36

what is the vagina?

Answer 36

an elastic muscular tube that extends outside of the body, receives penis and sperm, also the birth canal

Question 36

what is the vulva?

Answer 36

it is external genitalia that covers external openings

Question 37

what is oogenesis?

Answer 37

this is the development of mature eggs! in the embryo there are two primordial germ cells (2n), mitosis occurs and creates oogonia (2n), this forms during development, there are no new oogonia after birth!, mitosis occurs again to get the primary oocyte which is present at birth and arrested in prophase of meiosis I, at birth there are about 1-2 million primary oocytes and 200k by sexual maturity, they are dormant until acted on by hormones after puberty (this all occurs in embryo), each month 6-12 follicles mature which leads to a primary oocyte growing and follicle cells proliferating, after about 1 week the largest continues while the others stop, the primary oocyte completes meiosis I 8-10 hours before its release, unequal cytokinesis occurs: 1 polary body (n) and 1 secondary oocyte (n), meiosis II begins and the secondary oocyte is arrested at metaphase II, ovulation occurs!: as secondary oocyte matures it moves to surface of ovary, the follicle cells secrete fluid, estrogens, proteolytic enzymes and break down the ovary wall, secondary oocyte is ejected into the oviduct, the corpus luteum is left in ovary after ovulation and develips into temporary endocrine gland that secretes estrogen and progesteron if sperm enters than meiosis II completes and the mature egg containing sperm head completes oogenesis, if no sperm enters the secondary oocyte disintefrates and the corpis luteum dies (luteoluysis) and menstration occurs, new follicle for next cycle

Question 38

what occurs after puberty (women)?at is a follicle and what does it contain?

Answer 38

a structure within the ovary and contains the primary oocyte, follicle cells (protective barrier) and zona pellucinda which is a thick glycoprotien layer between follicle cells and oocyte

Question 39

what is the corpus luteum?

Answer 39

“yellow body,” portion of follicle that is left in ovary after ovulation, it develops into temporary endocrine gland that secretes estrogens and progesterone

Question 40

what is the menstrual cycle?

Answer 40

a complex sequence of events, involves hypothalamus, anterior pituitary, ovaries, uterus, and repeats every 28 days unless fertilization + implantation occurs, this process prepares the female body for pregnancy

Question 41

what are the components of the menstrual cycle?

Answer 41

there are 2 overlapping parts: the ovarian and the uterine cycle

Question 42

what is the gist of the ovarian cycle?

Answer 42

follicular phase days 1-13 - before ovulation
ovulation: day 14
luteal phase days 15-28 - after ovulation

Question 43

what is the gist of the uterine cycle?

Answer 43

menstrual flow phase- days 1-5
proliferative phase- days ~6-13 - before ovulation
secretory phase - days 15-28 - after ovulation

Question 44

what is estrogen?

Answer 44

the principle female sex hormone, secreted by follicle cells corpus luteum, at puberty it stimulates the growth of sex organs, secondary sex characteristics such as breasts, broadening of pelvis, fat and muscle distribution, and stimulates monthly prep for pregnancy (endometrium)

Question 45

what is progesterone?

Answer 45

a female sex hormone secreted mainly by corpus luteum, it completes preparation of endometrium for pregnancy and stimulates endometrial glands to secrete nutrient rich fluid

Question 46

what is the ovarian cycle early follicular phase

Answer 46

the first phase where the hypothalamus secretes GnRH, which stimulates the AP gland to release follicle stimulating hormones (FSH) and luteinizing hormone (LH), at the start of this phase estradiol levels are low, as the follicle grows and develop in the ovary, it starts to produce increasing amounts of estradiol. this rise in estradiol leads to a surge in LH and FSH secretion

Question 47

what happens in the ovarian cycle in the late follicular phase?

Answer 47

when there are high levels of estradiol, the hypothalamus decreases its secretion of GnRH, leading to a surge in LH from the AP. this surge triggers the mature follicle to enlarge and move to the surface of the ovary where it ruptures and releases the egg (this process is ovulation, it typically occurs about a day after LH surge), the secondary oocyte is released into the oviduct

Question 48

what is the luteal phase of the ovarian cycle?

Answer 48

after ovulation, the LH causes the ruptured follicle to transform into the corpus luteum. the corpus luteum secretes progesterone and estradiol which inhibit the production of GnRH, LH, and FSH through negative feedback. this feedback helps prevent the development and release of another egg once pregnancy may have started.

Question 49

what happens in the ovarian cycle if pregnancy does not happen?

Answer 49

the low levels of FSH and LH cause the corpus luteum to disintegrate and estradiol and progesterone levels drop. with no more negative feedback on the hypothalamus it begins to secrete GnRH again which stimulates the AP to produce FSH, which initiates the next ovarian cycle by stimulating the development of new follicles in the ovaries, marking the start of a new menstrual cycle

Question 50

what is the proliferative phase?

Answer 50

the first phase of the uterine cycle and it is coordinated with the follicular phase of the ovarian cycle. the ovarian hormones stimulate the uterus to prepare for potential embryo. as the follicle grows, it produces estradiol which causes the endometrium (lining of uterus) to thicken, this phase culminates in ovulation around day 14 of menstrual cycle

Question 51

what is the secretory phase?

Answer 51

follows the proliferative phase of the uterine cycle and is coordinated with the luteal phase of the ovarian cycle, promoted by estradiol and progesterone from corpus luteum, there is further development of the endometrium, the arteries within the endometrium enlarge and the endometrial glands grow and become more coiled, these changes prepare the endometrium for possible implantation of fertilized egg.

Question 52

what are the two possible outcomes of the secretory phase?

Answer 52

if no pregnancy: the corpus luteum disintegrates and there is a drop in estradiol and progesterone levels, the arteries in endometrial lining constrict which leads to a loss of circulation and the lining disintegrates
or pregnancy!