Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

ASC223 > Intro to embryo development > Flashcards

Intro to embryo development Flashcards

1
Q

Fertilisation -> implantation chronologic events occurring…

A

Fertilisation -> 1st cleavage (zona pelucida) -> 2 cell stage -> 4 cell stage -> 8 cell stage -> morula -> blastocyst -> implantation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Define the events involved in embryonic cleavage…

A

a series of rapid (mitotic) divisions following fertilisation

  • cell size gets smaller from that of the zygote
  • absence of cell growth between
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Cells resulting from the cleavage process?

A

blastomeres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Outline the events of cleavage…where does it occur? how long? secretions?

A

Occurs in isthmus
contraction propels embryo forward
4-5 days in most domestics to uterus
secretions from epithelial lining - provide nutrients & proteins for dev

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is a morula?

A

solid ball of cells (16 - 64 blastomeres)
Formed near the end of cleavage processes
Surrounded by the zona pellucida

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

mammalian and non-mammalian cleavage are not the same. What are some differences?

A

mammalian:
- small no. of oocytes produced at ovu.
- small in size
- occur inside organism
- primary cleavage controlled by embryo genome
non-mammalian:
- large no. of oocytes produced at ovu.
- large in size
- Occurs outside the organism
- Primary cleavage events controlled by maternal genome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

For implantation to occur, what must happen?

A

blastocyst must shed the zona pellucida

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What happens at implantation?

A

process of apposition, adhesion and attachment of the embryo to the uterine lining

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are some factors that aid the ‘sticking’ of the blastocyst to the extracellular matrix?

A

collagen, laminin, fibronectin, hyaluronic acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Timing of implantation & onset of placentation varies between species. Give an example of 2 species where it is varied.

A 
Entry to uterus: 
- sheep: 3 - 4
- horse: 6
Placentation begins:
 - sheep: 15 - 20
 - horse: 35 - 40
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How is implantation classified?

A

according to relationship between blastocyst and uterine lumen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Define central implantation…spp eg?

A

blastocyst remains within uterine lumen eg. carnivores

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Define eccentric implantation…spp eg?

A

blastocyst lies within uterine crypt or recess eg. mouse/rat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Define interstitial implantation…spp eg?

A

conceptus invades the uterine wall eg. man & chimps (fastest process)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

The main roles of foetal/extraembryonic membranes…

A

protection, nutritional & excretory requirements for dev. embryo. Has 4 major membranes: yolk sac, amnion, chorion and allantois

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe the yolk sac… function? origins?

A

1st membrane formed
involved with early haemtopoiesis & angiogenesis
houses nutrients for embryo
originates from extraembryonic endoderm

17
Q

Describe the amnion… function? origins?

A

fluid-filled sac that surrounds the foetus.
1st layer of protection for embryo
secretions from GI & resp. tract
originates from ectoderm

18
Q

Why is the amnionic fluid important?

A

…cushions the foetus

  • allows unrestricted movement
  • prevents pressure-related growth abnormalities
  • acts as lubricant when ruptured at birth
19
Q

Describe the chorion… function? origins?

A
  • surrounds all other embryonic membranes and foetus
  • mid layer of protection
  • Participates in formation of foetal component of placenta
  • originates from extraembryonic mesoderm
20
Q

Describe the allantois… function? origins? spp variation, maybe focus on birds…

A
  • stores urinary waste
  • very large
  • mediates gas exchange & Ca+ transport
21
Q

Outline what happens in abnormal allantoic development… gene involved…

A
  • Fox 01 essential for allantois & CV morphogenesis

- Fox 01 (-/-) may cause pericardial oedema & death

22
Q

What is the placenta? functions?

A 
Organ of metabolic interchange between mother and foetus
Large surface area for: 
 - nutrition
 - excretion
 - immune defences
 - endocrine
23
Q

What is placentation?

A

the structural organisation and mode of attachment of the placenta

24
Q

What are the components of the placenta? maternal? foetal?

A 
Maternal:
 - endothelial lining
 - connective tissue
 - epithelial lining of uterine lumen
Foetal:
 - trophoblastic outer layer of chorionic sac
 - connective tissue
 - endothelial lining the allantoic capillaries
25
Q

What provides nutritional requirements of embryo/foetus?

A 
maternal blood stream
uterine milk (fat & glycogen)
26
Q

Re. Classification of Placentae…characteristics of diffuse placenta…spp. eg…? draw

A

placental zone covers almost entire surface of chorionic sac
looks kinda like a long slug
HORSE & PIG

27
Q

Re. Classification of Placentae…characteristics of cotyledonary placenta…spp. eg…? draw

A

Placental zone restricted to specialised cotyledons (develop in response to chorionic contact – caruncles)
caruncles permanent arranged in rows
COWS & SHEEP

28
Q

Re. Classification of Placentae…characteristics of zonary placenta…spp. eg…? draw

A

Placental zone in band around central region
Complete in dogs & cats
incomplete bears and mustelids (ferrets, skunks, weasels)

29
Q

Re. Classification of Placentae…characteristics of discoid placenta…spp. eg…? draw

A

Placental area 1or 2 disc shaped area
Man, rodents 1 disc
Monkeys 2 disks

30
Q

The placenta at birth differs among species. List the term for these differences and provide spp. eg’s

A

Deciduate -
- Invasion & destruction of maternal tissue results in shedding of maternal tissue
– Maternal haemorrhage may occur
– Occurs in CARNIVORES, PRIMATES & RODENTS
Non- deciduate
• Virtually no loss of maternal tissue at parturition
– Occurs in RUMINANTS, HORSES, PIGS

31
Q

Name a Fetal membrane abnormality and describe…

A

excessive fluid in the amnion or allantois -> hydrops
Visible as distension of the abdominal wall
Associated with abnormalities of the fetal digestive system such as oesophageal atresia (closing of oesophagus).
Most common in cattle

32
Q

What is placental insufficiency? What does it result in?

A

insufficient blood supply to placenta that shows:
- abnormal thinning
- calcification
- infarcts
Results in: foetal distress, preeclampsia, foetal loss

ASC223 (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions