Midterm Chapter 26 Flashcards
What are autosomes?
Chromosomes other than sex chromosomes.
Female chromosomes.
XX
Male chromosomes.
XY
Sex chromosomes/sperm or ova/germ cells
X or Y
inactivated X chromosome.
Barr body
Fertilized egg.
XX or XY
The Y chromosome contains a region for male sex determination that is know as what gene?
SRY gene
List the functions of the gonads. How do the products of gonadal function differ in males and females?
Gonads produce gametes and secrete sex hormones
Female gametes - egg (ovaum) secrete estrogen, progesterone, androgens, and inhibin
Male gametes - sperm secretes androgen and inhibin
What are inhibins?
hormones that inhibit FSH secretion.
What are activins?
peptide hormones that stimulate FSH secretion
Define aromatase.
An enzyme in the testes and ovaries that convert androgens to estrogens.
Define blood-testis barrier.
tight junctions that prevent free movement of substances between blood and seminiferous tubule lumen.
Define Androgen-binding protein
Sertoli cell protein secreted into seminiferous tubule lumen, where it binds and concentrates androgens.
Define first polar body
formed by the first meiotic division of primary oocyte; disintergrates and has no function
Define acrosome
lysosome-like structure in the head of sperm; contains enzymes essential for fertilization.
Trace the anatomical routes to the external environment followed by a newly formed sperm and by an ovulated egg. name all structures the gametes pass through on their journey.
Newly formed sperm: seminiferous tubule -> epididymis -> ductus (vas) deferens -> ejaculatory duct (passing the seminal vesicles, prostate gland, and bulbourethral glands) -> urethra.
Ovulated egg: fallopian tube -> uterine cavity -> cervix -> vagina
All testosterone is produced in the testes. T/F
False - some are produced in the adrenal glands of both sexes
Only males make androgens and only females make estrogens. T/F
False - both sexes produce both hormones
Anabolic steroid use appears to be addictive, and withdrawal symptoms include psychological disturbances. T/F
True
High levels of estrogen in the late follicular phase help prepare the uterus for menstruation. T/F
False - high levels of late follicular estrogen help prepare the uterus for implantation of fertilized ovum.
Progesterone is the dominant hormone of the luteal phase of the ovarian cycle. T/F
True
What is semen? What are its main components, and where are they produced?
A sperm-fluid mixture made mostly by the accessory glands Components and source: Sperm - seminiferous tubules Mucus - Bulbourethral glands Water - all accessory glands Buffers - prostate, bulbourethral glands Nutrients - seminal vesicles, prostate, epididymis enzymes - seminal vesicles and prostate zinc - unknown Prostaglandins - seminal vesicles
Why are X-linked traits exhibited more frequently by males than females?
Males have a Y chromosome, which often does not have a gene to match one found on the X chromosome. Thus, a male may inherit a recessive X trait and will exhibit it, while a female who inherits the same recessive trait will not exhibit it if her second X chromosome has the dominant gene for the trait.
What does GnRH stand for?
Gonadotropin Releasing hormone
What does hCG stand for?
human chorionic Gonadotropine
What does SRY stand for?
sex determining region on the Y
Mullerian ducts
Female accessory ducts in the bipotential internal genitalia
Wolffian ducts
Male accessory ducts in the bipotential internal genitalia
AMH
Anti-Mullerian hormone causes mullerian ducts to regress
DHT
dihydrotestosterone - one of the dominant steroid hormones in males (along with testosterone) responsible for the developement of male external genetalia
Gamete
the eggs and sperm that unite to form new individuals
zygote
fertilized egg
germ cell
undifferentiated gonadal cells destined to produce eggs and sperm
embryo
weeks 0-8 of development
fetus
weeks 8 until birth
capacitation
sperm maturation necessary before it can fertilize an egg
zona pellucida
protective glycoprotein coat around the ovum
acrosomal reaction
enzymes help sperm penetrate the zona pellucida
cortical reaction
Chemical reaction that excludes sperm that causes the cortical granules in egg cytoplasm release their contents at fertilization to change the egg membrane properties.
menarche
the onset of puberty in girls
What happens during menopause?
women’s reproductive cycles stop completely
what happens in andropause?
men’s counterpart to menopause - testosterone production decreases
What is 5 alpha reductase?
the enzyme that catalyzes the conversion of testosterone to DHT.
What is the role of Human chorionic gonadotropine (hCG) during pregnancy?
keeps the corpus luteum from dying
what is the role of LH during pregnancy ?
no direct role in pregnancy
What is the role of human placental lactogen (HPL) during pregnancy?
regulation of maternal metabolism during pregnancy
What is the role of estrogen during pregnancy?
breast development; negative feedback signal to prevent new follicles from developing
What is the role of progesterone during pregnancy?
maintenance of the uterine lining; prevents uterine contractions; mammary gland development
What is the role of relaxin during pregnancy?
prevents uterine contractions
What is the role of prolactin during pregnancy?
milk production
Compare the actions of FSH in males and females.
stimulates gamete production on both sexes
Compare the actions of inhibin in males and females.
inhibits FSH secretion
Compare the actions of activin in males and females.
stimulates FSH secretion
Compare the actions of GnRH in males and females.
stimulates the release of FSH and LH
Compare the actions of LH in males and females.
stimulates gonadal sex hormone production;
also necessary for gamete maturation in females
Compare the actions of DHT in males and females.
testosterone metabolite responsible for fetal development of male genitalia
Compare the actions of estrogen in males and females.
present in both sexes but dominant in females; female gamete formation and some secondary characteristics
Compare the actions of testosterone in males and females.
Males: gamete formation
Both sexes: some secondary sex traits such as hair growth
Compare the actions of progesterone in males and females.
Females only - helps prepare the uterus for pregnancy
What is in control of reproduction?
The Hypothalamus
What are the strange patterns of estrogen that are not understood?
Very low estrogen = no negative feedback effect
Med estrogen = classic inhibition
High estrogen = can initiate positive feedback (such as: LH Surge -> ovulation)
Why does the corpus luteum degrade into a corpus albicans during luteal phase?
loss of hormonal support
