semen

Question 1

in a lab setting, if you took many sperm from the tail of the epididymus, and you placed them on a freshly ovulated ovum, would fertilization occur

Answer 1

no, because the sperm have not had any cholesterol or glycoproteins removed

Question 2

where does sperm go after leaving the seminiferous tubule

Answer 2

enter the epididymis

Question 3

what is capacitation

Answer 3

need to have proteins added/removed and phosphorylation of other proteins for fertilization to occur

Question 4

what is the role of the epididymis

Answer 4

-some endocytosis of debris/dead sperm
-reabsorption of fluid from seminiferous tubule

Question 5

what are the new proteins added in the epididymis

Answer 5

-PH-20: a hyaluronidase that helps break through cumulus (breaks extracellular matrix)
-CRISP1: sperm - zona pellucida interaction

Question 6

what is the vas deferens

Answer 6

two tubes that carry sperm from epididymis to the urethra via peristalsis

-sperm held in ampullae until ejaculation

Question 7

what are the glands in the male reproductive system

Answer 7

1. seminal vesicles
2. prostate
3. bulbo-urethral (cowper’s)

-secretion from these glands mix with sperm to form semen

Question 8

what does the prostate gland secrete

Answer 8

-prostate-specific antigen (PSA): helps dissolve coagulated semen; dissolving cervical mucous

Question 9

what do seminal vesicles secrete

Answer 9

-semenogelin 1: sperm coagulation, increases viscosity of semen

Question 10

what does the bulbo-urethral gland secrete

Answer 10

-mucus
-alkaline pH
-often secreted first to clean out urethra

Question 11

how do sperm get close as possible to ovum

Answer 11

coitus

Question 12

why is it that a drug designed to lower blood pressure has the effect of causing an erection (viagra)

Answer 12

-relaxes smooth muscle of blood vessels
-when vessels dilate in penis, increase blood flow into penis

Question 13

how does an erection form

Answer 13

blood vessels of corpora cavernosa and corpus spongiosum become relaxed so that more blood can enter area

Question 14

how does ejaculation work

Answer 14

-waves of peristalsis (likely due to oxytocin) increase in smooth muscle of epididymis, vas deferens, the glands and the urethra, which expel semen into urethral bulb
-sphincter leading to bladder closed
-bulbo cavernous muscle stimulated by sympathetic nervous system, producing forceful contraction

Question 15

how does sperm move toward the oviduct

Answer 15

-sperm first encounter cervix
-sperm then ascend the uterus toward the oviducts with help from uterine contractions

Question 16

how does capacitation involve initiating/increasing motility and preparing the acrosomal cap

Answer 16

1. removal of cholesterol
2. phosphorylation of proteins involved in motility

Question 17

what is the removal of cholesterol due to

Answer 17

-albumin in vagina/cervix/uterus
-increasing motility

Question 18

what is the removal of phosphorylation of proteins due to

Answer 18

activation of adenylate cyclase

Question 19

the levels of HCO3- in the ovary tract are 5x higher than they are in the epididymis. what effect does the increase in HCO3- have on sperm motility

Answer 19

increases it

Question 20

how does sperm capacitation work to enter the ovary tract

Answer 20

-HCO3- enters cell
-activates soluble AC
-increasing cAMP and PKA
-increasing phosphorylation of various proteins involved in motility

Question 21

why does sperm need to become hyperactive

Answer 21

-they need to dislodge themselves from epithelial cells of oviduct
-need to increase motility to get through dense matrix of cumulus oophorus
-need to increase motility to get through zona pellucida

Question 22

what happens to sperm in the presence of progesterone

Answer 22

opens Ca2+ channel

Question 23

how does progesterone affect sperm

Answer 23

-activates CatSper channels on sperm
-resulting influx of Ca2+ leads to hyperactivation, chemotaxis, and acrosome reaction
-sperm comes in contact with progesterone, has receptors that respond to Ca2+ channels

Question 24

how does low and high levels of progesterone affect hyperactivation

Answer 24

-low: attract and hyperactivation
-high: starts acrosome reaction

Question 25

what does sperm need to get past to fertilize ovum

Answer 25

1. cumulus oophorus
2. zona pellucida
3. membrane of ovum

Question 26

how does CRISP1 drive the acrosome reaction in the zona pellucida

Answer 26

-receptors on sperm head (CRISP1) recognize antigens on zona pellucida called ZP3
-activation of CRISP1 receptor leads to transient increase in Ca2+ via CatSper channels
-transient rise in Ca2+ activates internal Ca2+ stores, leading to exocytosis

Question 27

how do the receptors on sperm and ovum recognize each other

Answer 27

izumo on sperm and juno on ovum help pull plasma membrane together and fuse

Question 28

what does the activation of IP3 pathway lead to

Answer 28

-massive Ca2+ influx via IP3 receptors in ovum
-meiosis finishes
-cortical granules exocytose

Question 29

from whom do you get your mitochondria

Answer 29

mother

Question 30

what happens to mitochondria from your dad

Answer 30

-ubiquitinated during spermatogenesis
-destroyed early in zygotic life