exam 3 (ch 10-12 + assisted repro technologies)

what are the 7 hormones involved in the process of regulating male behavior and spermatogenesis?

1. GnRH

2. FSH

3. LH

4. T

5. DHT

6. Estradiol

7. Inhibin

what are the 3 diff major stages of spermatogenesis?

1. proliferation

2. meiosis

3. differentiation

proliferation

mitosis: normal cell division

stem cell renewal: every round amnt of sperm produced doubles

meiosis

meiotic division where 2n chromosomes segregate to 1n (diploid to haploid)

differentiation

transformation from round spermatid to fully formed spermatozoa and attainment of fxnal characteristics of cell

why must differentiation occur?

to allow the sperm to swim up the repro tract of the female and if it fails so does fertility

how long is spermatogenesis in the bull?

61 days

how long is spermatogenesis in the ram?

46 days

how long is spermatogenesis in the boar?

72 or 74 days

how long is spermatogenesis in the human?

74-76 days

why is it recommended to do the breeding soundness exam 60 days before we start the breeding season?

bc of length of spermatogenesis in order to identify any problems and allow it to complete b4 it starts

how does the male never run out of sperm cells?

stem cells are able to redifferentiate and process over again becoming A1 spermatogonia; stem cell renewal

what are the only 2 cell types in the body that can undergo meiosis?

the oocyte and the sperm which are gametes (germ cells)

what is another reason why the male is capable of producing so many more gametes than the female?

meiotic division in the sperm increases #s bc they double amnt of sperm produced

does the male make 256 identical sperm, how do we have genetic uniqueness of sperm?

no, in meiosis we have crossing over where the arms of the chromosome translocate and move

what 4 phases is differentiation broken into?

1. golgi phase

2. cap phase

3. acrosomal phase

4. maturation phase

what 2 major events occur in the golgi phase?

1st formation of the proacrosomal granule

2nd migration of the proximal and distal centrioles move to the base of the nucleus (earliest beginnings of formation of the tail)

what produces the acrosomal granule?

the golgi apparatus and it right on top of the nucleus

what occurs during the cap phase?

the acrosomic vesicle spreads and forms a cap over the nucleus as well as formation of the ax

what happens if this cap doesn’t form correctly?

our sperm will not be able to bind and fertilize

what is our nucleus doing during the beginning of the acrosomal phase?

getting more stream like

why does the nucleus need to become more stream like?

bc the ultimate fxn of sperm is to swim upstream through the vaginal and cervical secretions through the uterus cervix then oviduct

what is the main process during the acrosomal phase?

DNA condensation where we’re DNA into the tightest structure

what happens during this DNA condensation period?

histones wrapped around the DNA gets removed allowing DNA to squish tg to condense in a tiny package (then we form the neck)

before time of fertilization what must happen?

we have to decondense; bring the histones back

what’s happening in the cytoplasm?

we’re excreting it all out since we no longer need the cytoskeleton components, the golgi, or the ER

what do we have during the maturation phase?

a fully condensed head attached to the neck w/ a formed middle piece including all mitochondria congregated in 1 region, attached to the tail (principle piece)

what is the package?

the DNA

what is the fuel system?

the mitochondria

what is the compulsion system?

the tail

what does the neck do?

holds the head in place

what are the ER, golgi, and cytoskeleton components imp for?

cellular survival and fxn in the long term

we can’t produce proteins without what?

the golgi and the ER

what are proteins?

fxnal units of cells

what does the mitochondrial helix do?

maximizes propulsion from the tail since the tail has coarse fibers that give rigidity and pulse creating movement

how does the male continuously produce sperm on a wider lvl?

every 13.5 days one spot in the seminiferous tubule releases sperm, then a diff spot does the same while at a diff stage in this process, then another spot as well and so on, and all of this is unsynchronized allowing continuous release of sperm

why did stage Iv spermatids grow tails?

they’re going through differentiation

what process are spermatocytes undergoing?

meiosis

what process are A and I spermatogonia undergoing?

mitosis (proliferation)

what is occurring at 1 spot of the seminiferous tubule?

all 3 stages of spermatogenesis

how long is the cycle of seminiferous epithelium in the bull?

13.5 days

when sperm is fully formed where does it go?

released in the lumen and then goes into the mediastinum

what is spermiation?

release of the sperm from the seminiferous tubule

spermiation event

stem cell renewal event that’s pushing these sperm closer up the lumen

what is a selection criterium for buying/raising replacement males?

measuring scrotal diameter/circumference

what does scrotal circumference tell us?

how much sperm this male is able to produce

larger testes =

more sperm production, > amnt of fertility on a larger # of females

makes w larger testes attain puberty…

faster which gets offspring faster and money sooner

there is a relationship bw testicular size and sperm quality. true or false

true

when testes are too small what is likely to happen?

sperm the testes produce are gonna have morphology issues

the same genes controlling growth of testes are controlling spermatogenesis. true or false

true

why do testes not grow to normal size?

gene expression wasn’t robust enough

scrotal circumference is a repeatable measure. true or false

true

what are 4 sperm head abnormalities?

1. crater defect

2. tapered heads

3. ruffled acrosome

4. knobbed acrosome

crater defect

DNA defect; problem w DNA fusion

tapered heads

bad motility

thinking of sperm w head abnormalities, where would fertility failure occur?

trouble penetrating the oocyte and fertilizing it; can’t release acrosomal contents to soften the ZP

what can help tapered heads?

ICSI

what are 4 sperm tail abnormalities?

1. coiled tail

2. double mid piece

3. folded tail

4. detached head

sperm quality is highly variable w/in the same male. true or false

true

what’s the big deal behind tail abnormalities?

sperm don’t get where they need to be

what is double mid piece tail abnormality?

mid piece didn’t form right, so they don’t track in the right direction and do donuts

movement isn’t enough we must have ___________ motility

progressive

what is a breeding soundness exam?

checking if the male is fertile

can I induce a morphological defect in the sperm myself?

yes, cold shock which makes bent tails/ decreased motility

what is sex sorting semen?

ability to choose sex of progeny by sorting the sperm

what are the first 2 steps to sex sorting semen?

1. collect ejaculate

2. extend it and add dye

what does the dye do?

binds to DNA at a constant rate, so the more dye taken up the more DNA sperm has

sperm that have more dye are X or Y?

X chromosome

sperm that have less dye carry what chromosome?

Y

once we add the dye we shoot a laser through the sperm in order to?

measure amnt of dye present where the computer detects the amnt of dye

sperm that have a lot of dye get what charge?

+(x)

sperm that have a small amnt of dye get what charge?

-(y)

after we assign sperm we run sperm through…

a magnetic field where is responds appropriately sorting x y and dead sperm into viles

conventional straw

unsorted sex straw w 6x more sperm giving a higher pregnancy rate

sorted straw is more expensive and double the $ for lower pregnancy rate. true or false

true

behavior is broken into what 3 periods?

1. precopulatory

2. copulatory

3. postcopulatory

precopulatory

1. seek out the mate

2. courtship

3. male must get sexually aroused

4. obtain an erection

5. and have penile protrusion

penile protrusion

penis comes outside sheath

what could cause penile protrusion to not occur?

a mass on the sigmoid flexor

how will reproduction fail?

u can’t achieve proper precopulatory behavior

copulatory behavior

1. mourning the female

2. intro mission

3. ejaculation

intromission

getting the penis into the vagina

postcopulatory behavior

1. dismount

2. refractory period

3. memory

refractory period

period of time where the male is not physiologically capable of attaining another erection to ejaculate

memory

the animal’s overall experience

activity in women increases when?

during menses and ovulation

why are males more imp in seeking out the mate?

bc the bull does it everyday and we worry abt activity and steps on the male side bc they tend to lose a lot of weight, body condition

lordosis

contraction of specific muscles that make the female rigid to accept the mage that’s abt to mount ontop of her

what does the medulla do?

integrated postural adaptation for lordosis and mounting

what does the spinal cord do?

generates signals to specific muscles for lordosis and mounting

how to check if a sow is in heat

push on her back

how to check if a doe is in heat

buck kicks her to see if she runs or locks into lordosis

how do bulls check if cows are in heat

nudge her w shoulder

fhlemen response

male brings his lip to his nose allowing fluid from urine through vomeronasal organ and select pheromones associated w estrus would be present if female is in heat

what is she safest time to handle the male bull during collection?

after he ejaculates bc he’s in the refractory period

as males are aroused what is released ?

oxytocin from the posterior pituitary

what happens after oxytocin is released?

it goes though the blood supply and down the epididymus and ductus deferens, which causes contractions moving sperm up to the accessory sex glands

more contractions we get the more sperm we get…

moved up into the ejaculatory tissue

more sperm means more

straws