concept 3b reproduction

Question 1

SRY gene

Answer 1

sex-determining region Y
on the Y chromosome
codes for the transcription factor that initiates testis differentiation–> formation of male gonads

Question 2

male reproductive structures

Answer 2

testis 
seminiferous tubules
epididymis
vas deferens 
seminal vesicle 
ejaculatory duct 
prostate gland 
bulbourethral gland 
urethra 
penis

Question 3

testes

Answer 3

have 2 functional components: seminiferous tubules and interstitial cells (of Leydig)
seminiferous tubules produce sperm, they are highly coiled and nourished by Sertoli cells
cells of Leydig secrete testosterone and other male sex hormones (androgens)
testes located in the scrotum and hang below the penis

Question 4

ejaculation

Answer 4

sperm travel through the vas deferens to the ejaculatory duct at the posterior edge of the prostate gland
2 ejaculatory ducts fuse and form the urethra which carries sperm through the penis

Question 5

seminal fluid

Answer 5

mixes with sperm as it passes through reproductive tract
produced by seminal vesicles, prostate gland, and bulbourethral gland
combination of this and sperm is known as semen

Question 6

seminal vesicles

Answer 6

contribute fructose to nourish sperm
give fluid mildly alkaline properties to sperm so they are able to survive acidic conditions of female reproductive system

Question 7

prostate gland

Answer 7

give fluid mildly alkaline properties to sperm so they are able to survive acidic conditions of female reproductive system

Question 8

bulbourethral glands

Answer 8

produce clear viscous fluid that cleans out any remnants of urine
lubricates the urethra during sexual arousal
pre cum

Question 9

spermatogenesis

Answer 9

formation of haploid sperm through meiosis
occurs in seminiferous tubules
spermatogonia–> primary spermatocytes –> secondary spermatocytes–> spermatids–> spermatozoa (mature sperm)

Question 10

sperm

Answer 10

when matured they are very compact
consists of a head, that contains genetic material
mid piece which generates ATP from fructose (filled with mitochondria)
flagellum for motility
head is covered by acrosome and is necessary to penetrate the ovum

Question 11

female reproductive structures

Answer 11

ovaries 
fallopian tube 
uterus 
cervix 
vagina

Question 12

ovaries

Answer 12

produce estrogen and progesterone

consists of thousands of follicles, multilayered sacs that nourish and protect immature eggs

Question 13

oogenesis

Answer 13

production of female eggs
all oogonia is produced during fetal development
at birth oogonia have gone through DNA replication and called primary oocytes, they stay in this phase until puberty
after this one primary oocyte per month will complete meiosis I producing secondary oocyte, where it is then arrested in metaphase II until fertilization occurs

Question 14

oocytes

Answer 14

have 2 layers: zona pellucida and corona radiata
zona pellucida surround oocyte and contains compounds for sperm cell binding
corona radiata is outside the zone pellucida and adhere to oocyte during ovulation
fertilization occurs when sperm penetrates these 2 layers

Question 15

hormone control on sexual development

Answer 15

before puberty hypothalamus inhibits production of gonadotropin-releasing hormone
at start of puberty this hormone is released and triggers anterior pituitary gland to synthesize and release follicle-stimulating hormone and luteinizing hormone
these hormone trigger sex hormone that develop and maintain reproductive systems

Question 16

male sex hormones

Answer 16

androgens assist in male sexual differentiation
during childhood androgens are low
testosterone is produced by testes and increases during puberty and sperm production
FSH stimulates Sertoli cells and sperm maturation
LH stimulates interstitial cells to produce testosterone

Question 17

testosterone

Answer 17

develops and maintains the male reproductive system
role in development of secondary sexual characteristics, hair, deep voice, growth pattern
production remains high through adulthood and declines w/ age
has negative feedback w/ hypothalamus and anterior pituitary to limit production

Question 18

estrogens

Answer 18

secreted in response to FSH
development and maintenance of female reproductive system and secondary characteristics, breasts, hip widening
in embryo, develops reproductive tract
in adults, leads to thickening of uterus in preparation for implantation of zygote

Question 19

progesterone

Answer 19

secreted by the corpus luteum in response to LH
development and maintenance of endometrium, not thickening (role of estrogen)
by end of first trimester of pregnancy it is supplied by the placenta, corpus luteum atrophies

Question 20

menstrual cycle

Answer 20

follicular phase
ovulation
luteal phase
menstruation

Question 21

follicular phase

Answer 21

begins when the menstrual flow, shedding the uterine lining
decreased levels of estrogen and progesterone
increased FSH and LH
these hormones work to develop ovarian follicles
day 1-14
estrogen begins to regrow uterine line

Question 22

ovulation

Answer 22

estrogen reaches threshold which causes pink in LH and FSH
surge in LH induces ovulation
ovulation is the release of the ovum from the ovary into the abdominal cavity (and into the fallopian tube)
day 14-15

Question 23

luteal phase

Answer 23

LH causes ruptured follicle to form corpus luteum which secretes progesterone
progesterone rises and estrogen stays high
progesterone maintains uterine lining for implantation
day 17-28

Question 24

menstruation

Answer 24

implantation does not occur 
corpus luteum loses stimulation from LH 
progesterone levels decline 
uterine lining is shed 
decrease in estrogen and progesterone stimulates GnRH to begin next cycle

Question 25

pregnancy

Answer 25

fertilization has occurred
resulting zygote develops to blastocyst and is implanted in uterine lining
secrete human chorionic gonadotropin (hCG)

Question 26

menopause

Answer 26

as woman age ovaries are less sensitive to FSH and LH
this results in ovarian atrophy
estrogne and progesterone levels drop, endometrium atrophies and menstruation stops
physical and physiological changes occur, flushing, hot flashes, bloating, headache, and irritability
usually at age 45-55