Brainscape's Knowledge GenomeTM

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


See full index

ESA1 - Body Logistics > Embryology > Flashcards

Embryology Flashcards

1
Q

How many chromosomes do primary spermatocytes contain?

A

46

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

How many chromosomes do secondary spermatocytes contain?

A

23

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

What are the 4 daughter cells produced from meiosis II called in spermatogenesis?

A

Spermatids

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

What is a spermatid?

A

An immature male sex cell formed from a spermatocyte, which may develop into a spermatozoon without further division.

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

What is an oogonium?

A

An immature female reproductive cell that gives rise to primary oocytes by mitosis.

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

During fetal development, when is oogenesis paused?

A

Prophase I of meiosis I

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

True or False:

Meiosis II is not completed until fertilisation.

A

True

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

Where does fertilisation usually occur?

A

Ampullary region of the fallopian tube

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

How long are sperm viable for?

A

Five days

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

How long is the secondary oocyte viable for?

A

12-24 hours

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does sperm require to be capable of fertilisation?

A

Capacitation, meaning the tail of the sperm moves faster, causing the plasma membrane to alter

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

What is embryonic age?

A

Time since fertilisation

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

What is gestational age?

A

Time since last menstruation

Embryonic age - 2 weeks

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

What is the germinal stage?

A

Time from fertilisation to the end of the second week

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

What is the embryonic period?

A

Time from the 3rd week to the end of the 8th week

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

What is the foetal period?

A

Time from the 9th week to birth at 38 weeks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

At what day does implantation usually occur?

A

Day 6

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What does the blastocyst have to lose before it can implant?

A

Zona pellucida

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the process of losing the zona pellucida called?

A

Hatching

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the zona pellucida thought to prevent?

A

The morula/blastocyst adhering to the oviduct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is a morula?

A

A solid ball of cells resulting from division of a fertilized ovum, and from which a blastula is formed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What does the trophoblast become?

A

The yolk sac and placenta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the trophoblast?

A

A layer of tissue on the outside of a blastula, supplying the embryo with nourishment and later forming the major part of the placenta.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the normal implantation site?

A

Superior and posterior wall of the uterine cavity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Why is the 2nd week of development known as the weeks of 2s?

A
  • The trophoblast differentiates into 2 layers (cytotrophoblast and syncytiotrophoblast)
  • The embryoblast forms 2 layers (the epiblast and hypoblast - the bilaminar embryonic disc)
  • The hypoblast contributes to the formation of 2 cavities (the yolk sac and chorionic cavity)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the period from weeks 3 to 8 called?

A

Embryonic period

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What are some examples of things that can lead to major congenital malformation during the embryonic period?

A

Thalidomide, isotretinoin, warfarin, rubella

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are the key events and processes in early development?

A

Fertilisation, implantation, gastrulation, neurulation, segmentation, folding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the epiblast at the end of the second week?

A

A uniform disk

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What marks the start of gastrulation?

A

Primitive streak

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

When does the primitive streak form?

A

Start of the 3rd week

32
Q

What is gastrulation?

A

Gastrulation is a phase early in the embryonic development during which the single-layered blastula is reorganized into a trilaminar structure known as the gastrula

33
Q

What are the three germ layers?

A

Ectoderm, mesoderm, endoderm

34
Q

What does the ectoderm give rise to?

A

Organs and structures that maintain contact with the outside world

eg nervous system, epidermis

35
Q

What does the mesoderm give rise to?

A

Supporting tissues

eg muscle, cartilage, bone, heart, vascular system

36
Q

What does the endoderm give rise to?

A

Internal structures

eg epithelial lining of GI tract, respiratory tract, parenchyma of glands

37
Q

When does gastrulation begin?

A

Third week

38
Q

How does gastrulation begin?

A

Primitive streak forms in the caudal epiblast, leading to migration and invagination of epiblat cells

39
Q

Why does gastrulation occur?

A

To ensure the correct placement or precursor tissues to allow subsequent morphogenesis to take place

40
Q

What do notochord signals cause?

A

Overlying ectoderm to thicken

41
Q

What is neurulation?

A

Neurulation refers to the folding process in vertebrate embryos, which includes the transformation of the neural plate into the neural tube.

42
Q

What does organisation of mesoderm into somites give rise to?

A

Vertebrae, ribs, intercostal muscles, spinal cord segments

43
Q

What does folding achieve?

A

Draws together the margin of the disk

  • creating a ventral body wall
  • pulling amniotic membrane around disk (embryo becomes suspended within the amniotic sac)
  • pulling connecting stalk ventrally
44
Q

What has happened by the end of the 4th week?

A

Nervous system has started to form, segments have appeared so assign specific tasks to specific cells, the embryo has folded putting everything in the right place

45
Q

What is histiotrophic nutrition?

A

Nutrition provided to the embryo NOT from the maternal blood - important in humans up to the 12th week

46
Q

What is haemotrophic nutrition?

A

Nutrition provided by the mother’s blood - important in humans from the 12th week on

47
Q

What is placenta previa?

A

If you have placenta previa, it means that your placenta is lying unusually low in your uterus, next to or covering your cervix.

48
Q

What is the syncytiotrophoblast?

A

Cells that merge together in the trophoblast

49
Q

What is cleavage?

A

Cleavage is the division of cells in the early embryo with no significant growth (stay within zona pellucida)

50
Q

After the zygote has undergone many cell divisions (cleavage) what is it now called?

A

Morula

51
Q

What is the process of compaction?

A

Within a few days after fertilization, cells on the outer part of the morula become bound tightly together with the formation of desmosomes and gap junctions, becoming nearly indistinguishable

52
Q

In the morula, what are the two distinct cell types?

A

Trophoblasts (outer layer)

Embryoblasts (inner cell mass)

53
Q

What is the cavity in the blastocyst called?

A

Blastocoel

54
Q

What does a morula become when the inner cell mass compacts further and the blastocoel forms?

A

Blastocyst

55
Q

Define blastulation

A

Blastulation is the process following the morula and precedes the gastrulation. It is marked by the presence of a blastocoel.

56
Q

When does hatching (loss of zona pellucida) occur?

A

Around 5 days after fertilisation

57
Q

What replaces the zona pellucida?

A

Underlying trophoblast layer

58
Q

Aside from the blastocoel, what other cavity is developed in the blastocyst?

(Hint - its within the inner cell mass)

A

Amniotic cavity

59
Q

In the blastocyst, what two layers arise from the inner cell mass?

A

Hypoblasts and epiblasts

60
Q

What are the layers of hypoblasts and epiblasts collectively known as?

A

Bilaminar disc

61
Q

True or False:

The gastrula is bilaminar

A

False

It is trilaminar (3 layers)

62
Q

What is the next step after gastrulation?

A

Neurulation

63
Q

Where does the notochord form?

A

Mesoderm of the trilaminar disc

64
Q

The formation of the notochord induces a change in another layer of the trilaminar disc. Which layer is this and what is the change?

A

The ectoderm - thickening, forming neural plate

65
Q

What does the neural plate go on to form?

A

Neural tube

66
Q

What are neural crest cells?

A

Neural crest cells are a temporary group of cells unique to vertebrates that arise from the embryonic ectoderm cell layer, and in turn give rise to a diverse cell lineage—including melanocytes, craniofacial cartilage and bone, smooth muscle, peripheral and enteric neurons and glia

67
Q

What is situs inversus?

A

A congenital condition in which the major visceral organs are reversed or mirrored from their normal positions.

68
Q

What does situs inversus commonly result from?

A

Immotile cilia

69
Q

When does the first pair of somites appear?

A

Day 20 in the occipital regioin

70
Q

How many pairs of somites appear a day?

A

3

71
Q

How many pairs of somites are present by end of week 5?

A

42 to 44

72
Q

As some somites disappear, how many pairs of somites are left in total?

A

31

73
Q

How do somites appear?

A

As regular block of mesoderm cells arranged around a small cavity

74
Q

What is a sclerotome?

A

The part of each somite in a vertebrate embryo giving rise to bone or other skeletal tissue.

75
Q

What are the somite derivatives?

A

Dermatome, myotome and sclerotome

76
Q

What is the future of the buccopharyngeal membrane?

A

Mouth

ESA1 - Body Logistics (14 decks)

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