Brainscape's Knowledge GenomeTM

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


See full index

repro > Embryology - Development of repro > Flashcards

Embryology - Development of repro Flashcards

1
Q

3 stages of development before birth and weeks

A

Pre-embryonic (0-2)

Embryonic (2-8)

Fetal (9-birth)

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

What happens in pre-embryonic period?

A

Fertilised ovum undergoes mitosis

Morula forms (16 cells)

Blastocyst (trophoblast and inner cell mass) & blastocyst implantation

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

What happens in embryonic period?

A

Germ layers and placenta develop
Main body systems form

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

What happens in fetal period

A

Growth and development of organs further
Locomotor systems function

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

How does embryo implant?

A

Sheds zona pellucida
Blastocyst rotates and implants into endometrium of uterus

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

What happens at gastrulation?

A

Bilaminar disc (epiblast and hypoblast) forms trilaminar disc (ectoderm, mesoderm and endoderm)

Mesoderm, endoderm and Ectoderm formed from epiblast
Hypoblast forms yolk sac

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

What does endoderm become?

A

Digestive system
Liver
Pancreas
Lungs (inner)

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

What does mesoderm become?

A

Circulatory system
Lings (epithelial layer)
Skeletal system
Muscular system

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

What does ectoderm become?

A

Hair
Nails
Skin
Nervous system

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

When does the primative gut tube develop?

A

Weeks 3-4 - during craniocaudal and lateral folding

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

What does the repro system opening start as?

A

Repro tract, urinary tract and GI tract share common opening - common caudal opening cloaca

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

How does the repro system form its own opening?

A

Cloaca is split and forms urogenital sinus

(created by urorectal septum seperating it into urogenital sinus and anorectal canal)

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

How is chormosomal sex of embryo determines?

A

Sex is determined by the sperm that fertilises the oocyte - sperm is either X or Y

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

How do all gametes begin?

A

Indifferent stage - nothing determined yet
Start as primordial germ cells

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

What are the two parts of the indifferent gonad?

A

Primordial germ cells

Primative sex cords

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

How do the primative sex cords form?

A

epithelium of genital ridge proliferates and penetrates intermediate mesoderm

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

How do primordial germ cells form?

A

originate from endoderm in yolk sac - are precursors of gametes

migrate along retroperitoneum to the urogenital ridge to form indifferent gonad

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

What determines whether something will become testes or ovary?

A

Y chromosome- contains SRY gene (sex determining region on Y)

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

What is the SRY protein?

A

The testis determining factor - if SRY is present = male development

If SRY is not present = female development

20
Q

What do the primative sex cords and primordial germ cells become?

A

Both at urogenital ridge and then indifferent gonad and then…
Either testes or ovary (depending on if SRY is present)

21
Q

What does SRY gene do to males?

A

Stimulates development of indifferent gonad (primative sex cords and primordial germ cells) to form testes

Tunica albuginea forms around teste cords (seminiferous tubules, rete testis)

22
Q

What do the remaining cords CONTAIN after the SRY gene has formed the testes?

A

Germ cells

Sertoli cells (from epithelium of gland)

23
Q

What are present between the primitive cords when SRY gene present? What do these do?

A

Leydig cells - at week 8 these produce testosterone

24
Q

How does the ovary form?

A

No SRY gene present
Primitive sex cords degenerate

25
Q

What happens after primative sex cords degenerate in ovary?

A

Epithelium of gonad proliferates forming cortical cords

These surround germ cells to form primordial follicle

26
Q

Overview of development of internal genitalia

A

Male gamete Y = SRY gene is present:
Development male (eg testis, testicular hormone production and internal male duct system)

If male gamete is X = no SRY gene present
Development of female (ovary, internal female ducts like uterine tubes and uterus)

27
Q

Two ducts that develop initially in indifferent stage

A

Mesonephric (Wolffian duct) - Male

Paramesonephric (Mullerian duct) - Female

28
Q

What determines the fate of the ducts? (Wolffian and mullerian)

A

If there is functioning testes:

29
Q

What happens in males to ducts?

A

Males: testes produces Mullerian inhibiting hormone (MIH) - supresses mullerian

and produces androgens (testosterone) - supports mesonephric (Wolffian duct forms)

30
Q

What happens in females to ducts?

A

No testes producing MIH
No androgens

= paramesonephric (mullerian) ducts form

mesonephric/wolffian duct degenrates

31
Q

What did the mesonephric duct originally act as?

A

Duct for embryonic kidney
Drains to urogenital sinus (urogenitial sinus goes on to become bladder)

32
Q

How to remember ducts for male and female?

A

Male - shorter word so Mesonephric, wolffian as alpha male

Female - paramesonephric as longer word, mullerian as mum likes mulled wine

33
Q

What happens to the mesonephric duct eventually?

A

Converted into vas deferens and epididymis - these migrate with testes as they descend

34
Q

What does the paramesonephric/mullerian duct become?

A

These appear as invaginations of the epithelium of the urogenital ridge - eventually uterine tubes, uterus and upper vagina

Caudally - make contact with cloaca (urogenital sinus)

Cranially - open into abdo cavity (this is why uterine tubes open into peritoneal cavity)

35
Q

Basic components of developing external genitalia

A

Genital tubercle
Genital folds
Genital swellings

36
Q

What do these three components become in males?

A

Fusion occurs:
Genital tubercle - glans penis

Genital folds - spongy urethra

Genital swellings - scrotum

37
Q

What influences the formation of external genitalia?

A

Testis derived androgens - dihydrotestosterone

38
Q

What do the three components become in female?

A

No fusion occurs:
Genital tubercle - clitoris

Genital folds - labia minora

Genital swelling - labia majora
Urethra opens into vestibule

39
Q

How do the gonads descend from the abdomen?

A

Gubernaculum - attaches the gonad to the labio-scrotal folds below

As abdo cavity increases in volume, gonads descend

40
Q

Why is the ovary descent different to the testes?

A

Ovary descends but cannot go as far due to the uterus - blocks path

41
Q

What does this remaining gubernaculum that has not been used form in females?

A

The round ligament - connecting the uterus to the labia majora

42
Q

What is turners syndrome?

A

45 chromosomes - XO

43
Q

Phenotype turners syndrome

A

Female

Gonadal dysgenesis will occur where oocytes are absent and ovaries degenerate into streak gonads

44
Q

Some other presentations of turners syndrome

A

Short
Low posterior hairline
Heart shaped face
Broad chest with wide spaced nipples
Webbed neck
Co-arctation of aorta (narrowing)

45
Q

What is klinefelters syndrome?

A

47 XXY
Extra X chromosome

46
Q

Phenotype klinefelters syndrome?

A

Male internal and external genitalia
BUT - small testes, delayed pubertal development, lack of secondary male characteristics eg facial/body hair decrease

47
Q

What does a portion of the primative sex cord break off and become in males where SRY gene is present?

A

Rete testis

repro (22 decks)

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