Lecture 29 3/25/24

Question 1

How are spermatozoa lost from the female repro tract?

Answer 1

-retrograde transport
-phagocytosis by leukocytes

Question 2

In which animals is semen ejaculated into the cranial vagina?

Answer 2

-cow
-sheep
-rabbit
-primates
-dog
-cat

Question 3

In which animals is semen deposited into the cervix/cervical lumen?

Answer 3

-pig
-horse
-camelids

Question 4

Why do neutrophils target sperm?

Answer 4

they are seen as foreign material in the female repro tract

Question 5

What is post-breeding endometritis?

Answer 5

large migration of neutrophils from the uterine mucosa to the uterine lumen

Question 6

Why is it important that estradiol and prostaglandins stimulate the uterine muscularis?

Answer 6

the contractions propel spermatozoa in both cranial and caudal directions

Question 7

What are the two types of mucus produced by the cow cervix?

Answer 7

-sialomucin, which is of low viscosity
-sulfomucin, which is of high viscosity

Question 8

Why does the viscosity of cervical mucus matter?

Answer 8

sperm can swim through lower viscosity mucus, but they are trapped and flushed out by more viscous mucus

Question 9

What type of mobility pattern is seen in sperm that reach the oviduct?

Answer 9

hyperactive, in order to facilitate sperm-oocyte contact

Question 10

Where does capacitation initation occur?

Answer 10

-in the cervix for sperm ejaculated in the vagina
-in the uterus/isthmus for sperm ejaculated in the cervix

Question 11

Why must the female repro tract strip the seminal plasma coating off of the sperm?

Answer 11

to allow for the sperm to bind to the zona pellucida of the oocyte

Question 12

What is required for sperm to bind to the zona pellucida?

Answer 12

specific zone-binding proteins on the sperm membrane overlying the acrosome

Question 13

What are the glycoproteins on the zona pellucida?

Answer 13

-zona protein 1: structural
-zona protein 2: structural
zona protein 3: receptor for sperm membrane proteins

Question 14

What are the two binding sites on the sperm plasma membrane?

Answer 14

-zona binding region: adheres sperm to zona pellucida
-acrosome reaction promoting region: binds to ZP3 protein

Question 15

What is the acrosomal reaction?

Answer 15

fusion of the sperm plasma membrane and the outer acrosomal membrane

Question 16

What are the purposes of the acrosomal reaction?

Answer 16

-enable sperm to penetrate zona pellucida
-expose equatorial segment so that it can fuse with oocyte plasma membrane

Question 17

What is vesiculation?

Answer 17

the formation of many small vessels when the sperm plasma membrane fuses with the outer acrosomal membrane

Question 18

What is acrosin?

Answer 18

the main enzyme that hydrolyzes zona proteins

Question 19

What is the perivitelline space?

Answer 19

space between the zona pellucida and the oocyte plasma membrane

Question 20

What happens once the sperm penetrates the zona pellucida?

Answer 20

the plasma membrane of the oocyte fuses with the membrane of the equatorial segment and the fertilizing sperm is engulfed

Question 21

What is the cortical reaction?

Answer 21

exocytosis of cortical granules, resulting in the zona block

Question 22

What is the zona block?

Answer 22

biochemical changes in the zona pellucida that prevent polyspermy by preventing the penetration of more than one sperm

Question 23

What is syngamy?

Answer 23

the fusion of the male and female pronuclei to form the zygote

Question 24

What is an embryo?

Answer 24

an organism in the early stages of development

Question 25

What is included in a conceptus?

Answer 25

-embryo during early embryonic stage -embryo and extraembryonic membranes during preimplantation stage -fetus and placenta during post-attachment stage

Question 26

What is a fetus?

Answer 26

potential offspring that is still within the uterus but is generally recognizable as a member of a given species

Question 27

What are cleavage divisions?

Answer 27

mitotic divisions undergone by a zygote

Question 28

What does it mean for blastomeres to be totipotent?

Answer 28

describes the ability of a single cell to give rise to a complete, fully formed individual

Question 29

What is a morula?

Answer 29

solid ball of blastomere cells in which the cells can no longer be accurately counted due to the number

Question 30

What is a blastocyst?

Answer 30

morula with a distinct, recognizable cavity

Question 31

What are the two separate structures in a blastocyst?

Answer 31

-inner cell mass -trophoblast

Question 32

What do the structures of the blastocyst give rise to?

Answer 32

-inner cell mass: body of embryo -trophoblast: chorion/fetal component of placenta

Question 33

When does the blastocyst become a free-floating embryo?

Answer 33

after it hatches out of a crack/fissure in the zona pellucida

Question 34

What is the function of progesterone on the uterus during embryonic development?

Answer 34

stimulates the production of uterine milk to nourish the embryo

Question 35

How can a cyst be differentiated from an embryo on ultrasound in a mare?

Answer 35

-measured over multiple days -cyst will remain in roughly the same location and stay roughly the same size -embryo will move between uterine horns and grow rapidly

Question 36

What is maternal recognition of pregnancy?

Answer 36

the series of events by which the conceptus signals its presence to the dam and the pregnancy is enabled to continue

Question 37

Which factor is involved in maternal recognition of pregnancy in ruminants?

Answer 37

interferon tau

Question 38

Which factor is involved in maternal recognition of pregnancy in sows?

Answer 38

estradiol

Question 39

Which factor is involved in maternal recognition of pregnancy in mares?

Answer 39

-somewhat unknown -HSP/estradiol/potentially physical

Question 40

Which factor is involved in maternal recognition of pregnancy in primates?

Answer 40

hCG

Question 41

Why is a factor not needed for maternal recognition of pregnancy in cats and dogs?

Answer 41

the repro cycle in these animals occurs in such a way that the CL will not regress and terminate the pregnancy

Question 42

What is true implantation?

Answer 42

phenomenon in rodents and humans in which the conceptus buries itself in the endometrium

Question 43

What is implantation in most species?

Answer 43

the attachment/fixation of the conceptus to the endometrial surface

Question 44

What is the embryonic vessel?

Answer 44

structure in which the embryo proper develops into the fetus while the envelop develops into the extraembryonic membranes