Semen Deposition and Transport- Lecture 8

Question 1

Sperm elimination

Answer 1

Only a small portion of ejaculated spermatozoa reach the oviduct. Due to physical barriers, retrograde loss of spermatozoa, breeding-induced inflammatory response.

Question 2

Fate of dead spermatozoa

Answer 2

Eliminated

Question 3

Breeding-induced endometritis causing sperm elimination

Answer 3

Spermatozoa induce inflammation and an influx of PMNs into the uterine lumen. Activated PMNs release PGF2alpha, which causes myometrial contractions. Reaction to clear the uterus from excess spermatozoa and bacterial contaminants.

Question 4

Ejaculate consists of…

Answer 4

Live spermatozoa- ready to fertilize. Live spermatozoa- unable to fertilize. Dead spermatozoa.

Question 4

Mechanism for PMN

Answer 4

Crisp-3. Lactoferrin. PMN’s.

Question 5

Ciliar activity

Answer 5

Cilia throughout the female tract aid in sperm transport.

Question 6

Physical barriers that cause sperm elimination

Answer 6

Cervix, uterus, UTJ- a sperm barrier, and selectively allows transport of morphologically normal spermatozoa.

Question 7

Before fertilization

Answer 7

Sperm transport to the oviduct. Sperm storage in the oviduct. Release from the oviduct. Capacitation. Binding and penetration of the oocyte.

Question 8

Uterine contractility

Answer 8

Oxytocin- ferguson’s reflex. PGF2alpha- seminal plasma. Estrogen- seminal plasma.

Question 9

Oviductal contractility

Answer 9

From the utero-tubal junction to the oviductal isthmus for storage. From the isthmus to the ampulla for fertilization.

Question 9

Retrograde loss of spermatozoa causing sperm elimination

Answer 9

Oxytocin and PGF2alpha. Contractions both ascending and descending. Major loss of spermatozoa through a relaxed cervix.

Question 11

Fate of live spermatozoa ready to fertilize

Answer 11

Transport to oviductal ampulla

Question 12

Cervix for sperm storage

Answer 12

Species with intravaginal deposition of semen. Spermatozoa stored in cervical crypts and released for transport to oviduct.

Question 13

Sperm transport

Answer 13

Sperm motility, uterine contractility, oviductal contractility, ciliar activity.

Question 15

Cryopreservation

Answer 15

Seminal plasma is removed

Question 16

Semen deposition in vagina

Answer 16

Cattle, sheep, dog, rabbit, primates.

Question 17

Semen deposition in uterus

Answer 17

Horse, pig, rodents

Question 18

Caudal oviductal isthmus for sperm storage

Answer 18

Main sperm reservoir in most species. Sperm attach to the epithelium. Selective mechanism for attachment of normal sperm. Prevent capacitation- maintain intracellular Ca levels. Increased viability. Sperm released by chemotactic signal associated with ovulation.

Question 19

Fate of live spermatozoa unable to fertilize

Answer 19

Stored within female tract or eliminated.

Question 20

Sperm motility

Answer 20

Progressive motility is correlated to fertility in fresh semen. Less correlation between motility and fertility in frozen/thawed semen.

Question 21

PMN

Answer 21

Polymorphonuclear nutrophils. Once PMNs reach the uterine lumen they bind to and phagocytose spermatozoa. They also release PGF2alpha, which causes more uterine contractions. This clears the uterus.

Question 22

Role of seminal plasma

Answer 22

Selective protection of viable spermatozoa. 70% dead spermatozoa binding in the presence of seminal plasma.

Question 23

Endometrail folds for sperm storage

Answer 23

Some evidence that endometrial folds can serve as a sperm reservoir.