Exam 5: Breeding Behavior, Early Pregnancy, and Maternal Recognition

Question 1

Describe the process of an erection

Answer 1

Arterial blood comes in and sinusoids fill
Venous outflow restricted by contraction of ischiocavernosis muscles
Pressure builds in corpus cavernosum
Retractor penis muscle relaxes
Erection and protrusion occur

Question 2

What initiates the cascade leading to erectionl?

Answer 2

Nitric oxide

Question 3

What control is the cascade leading to erection under?

Answer 3

Parasympathetic

Question 4

What is ejaculation?

Answer 4

Propulsive discharge of semen from the penis

Question 5

What causes ejaculation?

Answer 5

Stimulation of glans penis

Question 6

What can the glans penis stimulation be duplicated with?

Answer 6

Artificial vagina

Question 7

What control is ejaculation under?

Answer 7

Sympathetic

Question 8

What do you get from ejaculation?

Answer 8

Rhythmic contraction of urethralis, bulbospongiousus, and ischiocavernosus muscle leading to wavelike expulsion

Question 9

What occurs concurrently with ejaculation?

Answer 9

Emission

Question 10

What is emission?

Answer 10

The fluid being released from the accessory sex glands

Question 11

What is the duration of ram copulation?

Answer 11

1 to 2 seconds (1 pelvic thrust with foreleg clasp)

Question 12

What is the volume of ram ejaculation?

Answer 12

0.8 to 1 mL

Question 13

What is the duration of bull copulation?

Answer 13

1 to 3 seconds (1 pelvic thrust with foreleg clasp)

Question 14

What is the volume of bull ejaculation?

Answer 14

3-5 mL

Question 15

What is the duration of stallion copulation?

Answer 15

20-60 seconds (multiple pelvic thrusting, flagging of tail followed by inactive phase)

Question 16

What is the volume of stallion ejaculation?

Answer 16

75-120 mL

Question 17

What is the duration of boar copulation?

Answer 17

5 to 20 minutes (rapid pelvic thrusting to engage penis in cervix. When penis is engages thrusting stops and ejaculation commences accompanied by somnolence)

Question 18

What is the volume of boar ejaculation?

Answer 18

200-250 mL

Question 19

What contributes to the large volume of ejaculation in boars?

Answer 19

Accessory sex glands are large

Question 20

What are the stages of breeding in dogs?

Answer 20

First stage coitus (1-2 min)
The turn (2-5 sec)
Second stage coitus (5-45 min)

Question 21

What completes the “tying” in second stage coitus in dogs?

Answer 21

Bulbus glandis

Question 22

What species use the cranial vagina as the site of semen deposition?

Answer 22

Bull
Ram
Buck
Dog
Tom

Question 23

What species use the intra cervical as the site of semen deposition?

Answer 23

Boar

Question 24

What species use the intra uterine as the site of semen deposition?

Answer 24

Stallion

Alpaca

Question 25

What is used as the site of semen deposition in AI?

Answer 25

Intra uterine

Question 26

What are the 3 stages of sperm transport?

Answer 26

Short, rapid sperm transport (2-10 minutes) Colonization of reservoirs (cervix and UTJ) Slow prolonged release of sperm cells

Question 27

When does fertilization occur?

Answer 27

When a minimum number of sperm cells reach the site of fertilization

Question 28

What does it mean when you say that sperm use the buddy system?

Answer 28

The depend on each other to get to the ovum even though only one will be successful

Question 29

What plays a role in the transport of sperm cells?

Answer 29

Elevated tone and motility of female tract under the influence of estrogen Prostaglandins in semen have a similar effect

Question 30

What are the 2 phases in the transport of sperm cells?

Answer 30

Rapid phase | Sustained phase

Question 31

Describe the rapid phase

Answer 31

Sperm reach oviduct in few minutes

Question 32

Describe the sustained phase

Answer 32

Sperm reside at ostium and slowly enter oviduct | Sperm reservoir

Question 33

Describe the colonization of reservoirs

Answer 33

Huge numbers of sperm are trapped in folds of the cervix | Cervical mucus directs sperm towards the cervical crypts where a reservoir is formed

Question 34

What does a large reservoir mean?

Answer 34

More sperm are available to move towards oviduct for longer period of time

Question 35

Where is the reservoir at for species that ejaculate into uterine horns?

Answer 35

UTJ

Question 36

What happens to almost all sperm cells shortly after breeding?

Answer 36

They are lost

Question 37

What percentage of sperm cells are lost after AI in cows?

Answer 37

60%

Question 38

What percentage of sperm cells reach the site of fertilization?

Answer 38

0.007%

Question 39

What removes many sperm cells after breeding?

Answer 39

Neutrophils

Question 40

What is capacitation?

Answer 40

Final maturation process which allows sperm to fertilize the ovum

Question 41

Where does capacitation occur?

Answer 41

Female reproductive tract

Question 42

What does capacitation involve?

Answer 42

Both physiological and biochemical processes

Question 43

What does sperm undergo in capacitation?

Answer 43

Changes that are required prior to penetration of the ovum | Phospholipid bilayer is altered permitting the acrosome reaction to occur

Question 44

What happens in capacitation?

Answer 44

Seminal plasma coats the sperm with proteins that are stripped away when in the female tract Sperm are now able to bind in the zona

Question 45

What does capacitation prevent?

Answer 45

Premature acrosome activation until sperm are at the site of fertilization

Question 46

Is capacitation reversible?

Answer 46

Yes

Question 47

What does seminal plasma contain?

Answer 47

Decapacitation factor

Question 48

What does the acrosome reaction occur in the presence of?

Answer 48

Oocytes

Question 49

What is the acrosome reaction?

Answer 49

An orderly fusion of sperm's plasma membrane and the outer acrosomal membrane

Question 50

What does the acrosome reaction do?

Answer 50

Allows sperm to penetrate and digest its way through the zona of the oocyte Exposes equatorial segment for later fusion with plasma membrane of oocyte

Question 51

What are pre-requisites for oocyte penetration?

Answer 51

Capacitation and acrosome reaction

Question 52

What is the oocyte activated by?

Answer 52

The fusion with the sperm

Question 53

What happens after the acrosome reaction?

Answer 53

Meiosis that was arrested in metaphase II is resumed

Question 54

What mediates polyspermy prevention?

Answer 54

Cortical granules

Question 55

What happens if the fertilization of oocyte is done by more than one spem?

Answer 55

Leads to polyploid nucleus | Death

Question 56

What are the 2 mechanisms of polyspermy prevention in order?

Answer 56

Zona block | Vitelline block

Question 57

What happens in a zona block?

Answer 57

Zona undergoes biochemical changes that prevent other sperm from penetrating the zona

Question 58

What does a vitelline block do?

Answer 58

Prevents oocyte plasma membrane from fusing with more sperm

Question 59

What is syngamy?

Answer 59

Fusion of male and female pronuclei at time of fertilization

Question 60

What is an embryo?

Answer 60

Organism in the early stages of development but cannot be distinguished

Question 61

What is a fetus?

Answer 61

Developing offspring that is still within the uterus but is recognizable as a specific species

Question 62

Describe maternal recognition

Answer 62

Luteolysis must be prevented for early embryo to survive High progesterone levels must be maintained to maintain pregnancy Conceptus must prevent luteolysis by signaling its presence in the uterus

Question 63

What happens if the signal from the conceptus is inadequate of mistimed?

Answer 63

MRP will not occur and luteolysis will occur leading to pregnancy loss

Question 64

What normally happens in an animal that is not pregnant?

Answer 64

There is no embryo No maternal recognition of pregnancy factor Oxytocin is released from CL Binds oxytocin receptors on endometrium and stimulated PGF2α release CL is lysed and new cycle begins

Question 65

What happens in a pregnant ewe, doe, and cow?

Answer 65

Blastocyst produces interferon-τ from day 13-21 after ovulation IFN-τ binds to endometrium and inhibits oxytocin receptor synthesis PGF2α is dependent on a threshold number of oxytocin receptors being present Pregnancy is maintained

Question 66

What happens in a pregnant sow?

Answer 66

Conceptus produces estradiol as signal for MRP E2 begins being produced at day 11 Causes PGF2α to be “rerouted” toward the uterine lumen Luminal PGF2α has no access to circulation and thus cannot cause luteolysis Must have at least 2 conceptuses in each horn for pregnancy to be maintained

Question 67

What happens in a pregnant mare?

Answer 67

Presence of conceptus b/w days 12-14 prevents luteolysis Conceptus must migrate often to signal its presence (remains spherical unlike ewe, cow, and sow) Precise proteins are not yet known

Question 68

What happens in a pregnant dog and cat?

Answer 68

Both have obligatory diestrus period after ovulation that last as long as or longer than gestation CL of pregnancy and CL of normal cycle have similar lengths This is why P4 has no use as a pregnancy test in dogs and cats