Embrology

Question 1

Where does fertilization take place?

Answer 1

Fallopian tube

Specifically, fertilization occurs in the ampulla of the fallopian tube.

Question 2

What is capacitation in the context of sperm?

Answer 2

Physicochemical changes that make sperm capable of fertilizing the ovum

Capacitated sperm acquire motility and can penetrate the zona pellucida.

Question 3

How long does it take for capacitated sperm to penetrate the zona pellucida?

Answer 3

About 7 hours

Question 4

What is the pathway of sperms from the testes to ejaculation?

Answer 4

Spermatogenesis → Seminiferous tubules → Rete testis → Efferent ductules → Epididymis → Vas deferens → → Ejaculation → Prostatic urethra

This pathway involves various structures where sperm mature and are transported.

Question 5

What is spermatogenesis?

Answer 5

Formation of spermatozoa from primordial germ cells

This process includes several stages, including mitosis and meiosis.

Question 6

What temperature is required for spermatogenesis?

Answer 6

Lower than core temperature (5°C lower, around 32°C)

The lower temperature is crucial for optimal sperm production.

Question 7

How long does the entire process of spermatogenesis take?

Answer 7

74 days

Question 8

What is the role of Sertoli cells in spermatogenesis?

Answer 8

Support and nourish developing sperm cells

Sertoli cells are essential for the maturation of spermatozoa.

Question 9

What are spermatids and how do they form?

Answer 9

Haploid cells formed from secondary spermatocytes undergoing meiosis

Spermatids undergo morphological changes to become mature spermatozoa.

Question 10

What is the ploidy of primary spermatocytes?

Answer 10

Diploid (2N, 46 chromosomes)

Question 11

What type of cell division do spermatogonia undergo?

Answer 11

Mitosis

Question 12

What is the mnemonic used to remember the stages of spermatogenesis?

Answer 12

Mighty PleaseD Meiting Secx)y Happy

Question 13

What occurs during the independent assortment of chromosomes in spermatogenesis?

Answer 13

Separation of paternal and maternal chromosomes during meiosis

Question 14

What is the significance of the temperature being maintained at lower than core temperature for the testes?

Answer 14

Essential for spermatogenesis

Question 15

What happens to spermatids after they are formed?

Answer 15

Undergo morphologic changes to form mature spermatozoa

Question 16

What is the function of NODAL in embryogenesis?

Answer 16

Formation of primitive streak

NODAL is crucial for establishing the body plan during early development.

Question 17

What does Lefty regulate in embryonic development?

Answer 17

Formation of mesoderm

Lefty plays a role in mesoderm formation and asymmetry.

Question 18

Which growth factor is associated with neural tube formation?

Answer 18

Sonic Hedgehog (SHH)

SHH is vital for the development of the neural tube.

Question 19

What is the role of WNT-7 in limb development?

Answer 19

Organizes limbs in anteroposterior axis

WNT-7 is crucial for proper limb patterning.

Question 20

What do Homeobox (HOX) genes influence in embryogenesis?

Answer 20

Body segmentation and limb positioning

HOX genes determine the identity of body segments.

Question 21

What is the function of Bone morphogenic factors (BMP 1-9)?

Answer 21

Bone formation and mesoderm differentiation

BMPs are involved in the regulation of bone growth and development.

Question 22

What developmental process is PAX6 involved in?

Answer 22

Lens vesicle differentiation

PAX6 is critical for eye development.

Question 23

True or False: Mis-expression of the HOXB8 gene can alter the position of forelimbs during development.

Answer 23

True

Alterations in HOX gene expression can lead to limb malformations.

Question 24

Fill in the blank: _______ is involved in the development of the midbrain.

Answer 24

Insulin-like Growth Factors (IGF)

IGFs are crucial for various developmental processes including brain development.

Question 25

What are the roles of Fibroblast growth factors (FGF)?

Answer 25

Cell division, migration, and angiogenesis ## Footnote FGFs are important for various aspects of embryonic development.

Question 26

Which growth factor is implicated in the over-expression causing cyclops (single median eye)?

Answer 26

PAX2 ## Footnote Abnormal expression of PAX2 can lead to severe eye malformations.

Question 27

What is a consequence of SHH mutations?

Answer 27

Holoprosencephaly ## Footnote SHH mutations can disrupt normal brain development, leading to holoprosencephaly.

Question 28

What is the effect of Insulin-like Growth Factor 1 (IGF-1)?

Answer 28

Bone growth ## Footnote IGF-1 plays a significant role in promoting bone growth.

Question 29

What does IGF-2 primarily influence during development?

Answer 29

Fetal growth ## Footnote IGF-2 is essential for normal fetal growth and development.

Question 30

What is the significance of the zone of polarizing activity (ZPA)?

Answer 30

Expression of SHH organizes limbs in anteroposterior axis ## Footnote The ZPA is critical for limb patterning and development.

Question 31

Fill in the blank: The regression of the paramesonephric duct is associated with _______.

Answer 31

Mullerian Inhibiting Factor ## Footnote This factor is key in sexual differentiation in embryos.

Question 32

What is the process of spermatogenesis?

Answer 32

Formation of sperm cells from spermatogonial stem cells ## Footnote Spermatogenesis involves several stages leading to mature sperm.

Question 33

True or False: Apoptosis is a significant process during embryogenesis.

Answer 33

True ## Footnote Apoptosis is essential for shaping organs and removing unnecessary cells.