Pregnancy Control and Maintenance

Question 1

Loss of sperm is due to…

Answer 1

Retrogade transport - cervix is a physical barrier, removes abnormal sperm
Mucus Types - sialomucin (low viscocity, helps) - sulfomucin (high viscocity washes out)
Phagocytosis - oestradiol gathers neutrophils in tract - engulf spermatozoa

Question 2

How is diploidy achieved?

Answer 2

Single sperm needs to fuse with oocyte
Fusion releases phospholipase
Phospholipase releases inositol triphosphate and diacylglycerol
Inositol triphosphate - causes Ca Release
Diacylglycerol - protein kinase C stimulates phosphorylation of proteins

Question 3

What is the role of calcium?

Answer 3

Release of cortical granules digest stuff in ZP site, prevents sperm fusion
Reactivates meiosis 2

Question 4

Disorders of ploidy?

Answer 4

Anueploidy - many haploid chromosomes fused - form tumours, embryo loss

Question 5

What is cleavage?

Answer 5

Rapid mitotic cell division no cell growth

Question 6

What are the stages of cleavage?

Answer 6

A Zygote with 2 blastomeres
Morula - around 16-32 cells of blastomeres
Blastocyst - group which form an embryoblast at one pole and a blastocyst cavity with a trophoblast

Question 7

What is gastrulation?

Answer 7

Formation of germ cell layers from cavity ectoderm, mesoderm, endoderm

Question 8

What is a spontaneous ovulator?

Answer 8

regular frequency no copulation

Question 9

What is an induced ovulator?

Answer 9

require stimulation of vagina to cause ovulation

Question 10

What is the process of induced ovulation?

Answer 10

AP are passed through the CNS, innervate the hypothalumus, causes a surge of GnRh

Question 11

What forms after the germ layers?

Answer 11

Three extra membranes - Amnion, chorion, allantois allowing for placentation to occur

Question 12

What does antiluteotrophic mean?

Answer 12

prevents the effects of prostaglandin

Question 13

What does luteotrophic mean?

Answer 13

enhances the survival of corpus luteum

Question 14

Why are cats and dogs awkward?

Answer 14

As in dogs the CL is long lived and in cats its the same duration as pregnancy

Question 15

Delayed implantation is caused by two things?

Answer 15

Faculative diapause - metabolic stress

Obligate diapause - environmental conditions

Question 16

What is the placenta?

Answer 16

An organ from the conceptus to the dam

Question 17

What does the placenta do?

Answer 17

Endocrine functions - takes over pregnacny maintenance and stimulates mammary glands

Question 18

What is histiotrophic support?

Answer 18

Nutrition for the conceptus from secretions & breakdown of tissues,

Question 19

What is haemotrophic support?

Answer 19

Prevents potential damage, highly vascularized, removes metabolic waste

Question 20

How is a placenta classified?

Answer 20

By the arrangement of villi and the contact between the mother and the foetus

Question 21

Diffuse placenta?

Answer 21

Is full and is in a horse and pig

Question 22

Cotyledonary placenta?

Answer 22

Is in circular dots and is in a cow and sheep

Question 23

Zonary placenta?

Answer 23

Fixed in one zone and is in a cat and dog

Question 24

Discoidal placenta?

Answer 24

Placenta in a disc at the top in a human and mouse

Question 25

The number of layers retained in the…

Answer 25

maternal portion of the placenta varies in species

Question 26

SYNEPITHELIOCHORIAL (binucleated cells)

Answer 26

In cattle the layers in maternal placenta

Question 27

Foetus must get what from the maternal blood?

Answer 27

Glucose

Question 28

What occurs in early pregnancy?

Answer 28

Progesterone stimulates maternal appetite - deposition of fat stores

Question 29

What occurs in late pregnancy?

Answer 29

placental lactogen mobilises fat from these deposits