Term
| What 4 things does testicular function require? |
|
Definition
-pulsatile GnRH secretion (3-6qh)
-high concentrations of T in the seminiferous tubules
-low concentrations of T in the systemic blood
-adequate LH receptors in Leydig cells |
|
|
Term
| What produces androgen-binding proteins? What do they do? |
|
Definition
-Sertoli cells
-binds specifically to testosterone and DHT |
|
|
Term
| What hormone is sertoli cell function dependent on? |
|
Definition
|
|
Term
| How do Testosterone, Estradiol, and DHT concentrations affect GnRH secretion? |
|
Definition
|
|
Term
| How can we use LH to test for lack of gonads? |
|
Definition
| -no gonads = no E2/T2 to negatively feedback to LH thus [LH] waaaaay high |
|
|
Term
| What hormone is the largest controller of GnRH? |
|
Definition
|
|
Term
| Production of normal numbers of fertile spermatozoa requires what 4 things? |
|
Definition
-endocrine regulation of the testicle
-mitotic divisions of the spermatogonia
-meiotic divisions resulting in haploid spermatids
-morphologic transformation of spermatids into spermatozoa |
|
|
Term
| At which point during development do spermatogonia cross the blood testis barrier? |
|
Definition
-when their chromosomes double
-aka when meiosis begins |
|
|
Term
| Describe spermatogenesis in general. |
|
Definition
-goes in waves in different areas of the seminiferous tubules doing specific jobs
-each scycle takes an equal amount of time |
|
|
Term
| When discussing spermatogenesis, when is meant by "stage"? |
|
Definition
| -specific cell association |
|
|
Term
| When discussing spermatogenesis, what is stage duration? |
|
Definition
| -time required for completeion of one stage |
|
|
Term
| When discussing spermatogenesis, what is a cycle? |
|
Definition
| -progression through sequence of all stages |
|
|
Term
| When discussing spermatogenesis, what is cycle duration? |
|
Definition
| -time required to complete one cycle |
|
|
Term
| Overall, approximately how long does spermatogenesis take? |
|
Definition
|
|
Term
| How many cycles take place during spermatogenesis? |
|
Definition
|
|
Term
| Why is knowing the length of spermatogenesis important clinically? |
|
Definition
| -current sperm are the result of an insult or lack of insult from two months ago |
|
|
Term
| Where do sperm acquire maturity? Where do they acquire maximal fertility? What are these changes called? |
|
Definition
-epididymus
-female tract: uterus
=capacitation |
|
|
Term
| REVIEW SLIDES 30 AND 31 FOR SPERM HEAD ABNORMALITIES |
|
Definition
|
|
Term
| True or FAlse: If a sperm looks normal, it will function nromally too. |
|
Definition
| -FALSE, any issue that can cause a sperm to look abnormal can affect its function and even if it looks normal its function may still be compromised |
|
|
Term
| Definition: Compensable sperm deficiency |
|
Definition
| -seminal deficiencies that preclude sperm reaching site of fertilization but CAN be overcome by increasing sperm numbers |
|
|
Term
| Definition: Uncompensable sperm deficiency |
|
Definition
| -seminal deficiencies which may not preclude sperm reaching site of fertilization and CANNOT be overcome by increasing sperm dosage |
|
|
Term
| True or FAlse: There are no highly efficient bulls which emit more than 17% abnormal sperm. |
|
Definition
|
|
Term
| What is the first defect to occur when sperm are challenged? |
|
Definition
|
|
Term
| Describe a tapered/pyriform sperm head. |
|
Definition
| -looks squeezed longitudinally |
|
|
Term
| What is a diadem seminal defect? Aka a crater defect. |
|
Definition
| -looks like a string of perals |
|
|
Term
| What does a knobbed acrosome defect look like in sperm? |
|
Definition
| -looks like it has been hit with a hammer |
|
|
Term
| What does a microcephalic sperm look like? |
|
Definition
|
|
Term
| What is the most common sperm defect? |
|
Definition
|
|
Term
| What are the common causes of mid-piece reflex abnormalities? |
|
Definition
-freezing
-hypotonic solution |
|
|
Term
| What causes a dag seminal defect? |
|
Definition
-due to fracturing of the outers tructural support of the mid-piece resulting in severe coiling
-aka a tailstone defect |
|
|
Term
| What does a proximal seminal droplet indicate? |
|
Definition
|
|
Term
| What does a distal droplet indicate? |
|
Definition
|
|
Term
| In which species is an abaxial tail significant? |
|
Definition
|
|
Term
| What often causes a bent principal piece in sperm and distal mid-piece reflexes without a distal dropet? |
|
Definition
|
|
Term
| What is the typical cause of sperm with detached heads? |
|
Definition
| -broken passive loss of sperm reflex |
|
|
Term
| What are some teratoid seminal forms? What causes them? |
|
Definition
-mid-piece often bent or coiled over head, etc
-disturbed spermatogenesis due to massive insult to testes |
|
|
Term
| LUteolysis occurs when ovarian ______ binds to receptors on the endometrium causing a production and release of ______ which cycles up and eventually induces luteolysiss of the CL. |
|
Definition
|
|
Term
| If ultrasounding a follicle and it has a bright granulosa cell layer and a hyperechoic area directly under it, what is the dark layer? |
|
Definition
-sub granulosa cell edema
-indicates that it is nearing ovulation |
|
|
Term
| Why do we measure scrotal circumference? |
|
Definition
-strong relationship b/n testis wt and sperm production
-easier and mroe repeatable than length, width, and depth
-semen quality has high corrrelation with SC unless there has been an acute insult |
|
|
Term
| IN which animal are scrotal circumferences most variable? |
|
Definition
|
|
Term
| In addition to sperm production, what other improant factors are associate with scrotal circumference? |
|
Definition
-high heritability
-wide variation within breeds, less between
-responds rapidly to selection pressure
-releable predictor f age and puberty onest
-male offspring mature sooner
-female offspring mature sooner |
|
|
Term
| Give a quick summary of scrotal circumgerence. |
|
Definition
-reflects amount of sperm producing tissue
-sperm pdn per gm tissue is contant
-greatly influenced by age (6-10 mo)
-great variation within breeds
-less variation between breeds
-curvilinear NOT linear growth
-accurate predictor of puberty age
-bulls with large SC mature sooner
-daughters and sons mature sooner
-hgih hertiability
-responds rapdily to selection pressure
-influences semen quality |
|
|
Term
| What is the current SC threshold? |
|
Definition
|
|
Term
| What recommendations do we make to clients in reference to scrotal circumference? |
|
Definition
-consider current threshold values to be absolute minimums
-emphasize benefits of using bulls with large SC: especially important for seedstock producrs |
|
|
Term
| Tumescence (erection) is triggered by the (parasymp/symp) division of the ANS (where specifically?), causing nitric oxide (what's it do?) levels rise in the trabecular arteries and smooth muscle of the penis via cyclic GMP. |
|
Definition
-parasympathetic
-sacral plexus
-vasodilator |
|
|
Term
| During temescence, the arteries (constrict/dilate) causing the corpora cavernosa of the penis to what? What occurs simultaneously? |
|
Definition
-dilate
-simultaneous the ischiocavernosus and ulbospongiousus mm compress the vv of the corpora cavernosa restricting the egress and circulation of this blood |
|
|
Term
| Is ejaculation through the parasympathetic or sympathetic nervous system? |
|
Definition
|
|
Term
| What is indicated if there is preputial swelling immediately prescrotal? what about halfway b/n the scrotum and prepuce? |
|
Definition
-hematoma
-prepucial abscess |
|
|
Term
|
Definition
-stripping of membrane proteins by uterine factors
-over the tail = motility
-over the midpiece = metabolism
-over the head = binding ot ZP |
|
|
Term
| What is the purpose of capacitation? |
|
Definition
-hyper-activated sperm in the oviduct
-unmacking of ZP binding sites |
|
|
Term
| What is the organ of fertilization? |
|
Definition
|
|
Term
| What is the organ of pregnancy? |
|
Definition
|
|
Term
| For fertilization to occur, sperm and oocyte must meet at a time when both are viable. Give an example of behavior roles, sperm factors, and oocyte factors that affect this. |
|
Definition
-Behavior role = estrus
-Sperm factors = viability ranges from several hours to many days
-Oocyte factors = viability more restricted: several hours |
|
|
Term
| True or False: Only sperm with normal or very subtle head anomalies and hyperactive motility reach the site of fertilization (100% alive). |
|
Definition
|
|
Term
| What are the negative consequences of serious head abnormalities? What about for mid-piece and tail abnormalities? Very subtle head abnormalities? |
|
Definition
-serious head abnormalities alter hydrodynamics
-obvious midpiece and tail abnormalities severely affect motility
-very subtle head abnormlaities may participate in fertilization but may not usstain normal embryo development = therefore only selected sperm reach the site of fertilization |
|
|
Term
| In a vow with a 3-wave pattern of follicle development, the mature dominant follicles of the first and second may ovulate if the cow is given exogenous what? |
|
Definition
|
|
