Histology -- Spermatogenesis Flashcards Preview

Block I: Reproduction & Sexuality > Histology -- Spermatogenesis > Flashcards

Flashcards in Histology -- Spermatogenesis Deck (34):
1

Define spermatogenesis

An elaborate process of cell differentiation starting with non-differentiated spermatogonial stem cell and terminating with a fully differentiated highly specialized motile cell called spermatozoa

2

Location of the formation of spermatozoa

Seminiferous epithelium

3

2 populations of cells composing the seminiferous epithelium

Somatic Sertoli cells

Spermatogenic cells

4

Fate of spermatogonia

Division and differentiation into spermatocytes

5

Fate of spermatocytes

Undergo meiosis to originate spermatids

6

3 phases of spermatogenesis

  1. Spermatogonial phase (proliferation, renewal and differentiation of spermatogonia)
  2. Spermatocyte phase (meiosis)
  3. Spermatid phase (spermiogenesis)

7

3 types of spermatogonia and what differentiates them from each other

  • Type Ad (dark; less active)
  • Type Ap (pale; true stem cells)
  • Type B (differentiated)

8

Amount of DNA in primary spermatocytes and why

4n (44 autosomes and an X and a Y chromosome each having two chromatin strands or chromatids) since spermatocytes replicate their DNA shortly after they form

9

4 stages of prophase of the first meiotic division of spermaocytes

  • Preleptotene
  • Leptotene
  • Zygotene-Pachytene
  • Diplotene

10

Describe the preleptotene and leptotene phases of spermatocyte division

Chromatin condenes into visible chromosomes

11

Describe the Zygotene-Pachytene of spermatocyte division

Homologous chromosomes paired

12

Describe the diplotene stage of spermatocyte division

Pairs of homologous chromosomes called tetrads (because they consist of 4 chromatids) exchange genetic material by crossing over

13

Describe what occurs afer prophase of spermatocyte division

Primary spermatocytes divide and the tetrads separate to become diads in the daughter cells

14

Amount of DNA in secondary spermatocytes

2n DNA (22 autosomes and an X or a Y chromosome [haploid])

15

Describe what occurs during the metaphase of the second division of spermatocytes

Sister chromatids separate into two haploid round spermatids 

16

Amount of DNA in round spermatids

1n amount of DNA

17

4 phases of spermiogenesis

  • Golgi phase
  • Cap phase
  • Acrosome phase
  • Maturation phase

18

Describe the Golgi phase of spermiogenesis

The Golgi apparatus forms a proacrosomic granule within an acrosomic vesicle. Centrioles start forming the axonese (tail)

19

Describe the cap phase of spermiogenesis

The acrosomal vesicle spreads to cover the anterior half of the nucleus.

20

Describe the acrosome phase of spermiogenesis

The head of the spermatid is oriented towards the basement membrane. The machete of microtubules forms and the Golgi apparatus migrates posteriorly.

21

Describe the maturation phase of spermiogenesis (4 events)

  1. Spermatid elongates
  2. Chromatin condenses
  3. Mitochondria migrate and form the mid piece of the tail (NOTE: Primary piece has no mitochondria)
  4. A residual body (surplus of cytoplasm) is formed and eliminated

22

Duration of spermatogenesis in a man

Fixed and constant at 60 days

23

Frequency at which stem cells enter spermatogenesis in a man

Regular intervals of 16 days

24

Describe how stem cells enter spermatogenesis

In groups, the members of which are connected by open intercellular bridges, which also connect the daughter cells until the end of spermatogenesis

25

What structure contains the hydrolytic enzymes necessary for he fertilization of the ovum?

Acrosomic cap structure

26

Define one generation of germinal cells

One group of cells at one stage of development

27

Number of generations of germinal cells seen in the epithelium of the seminiferous tubules

4 - 5

28

Cause of immotile cilia syndrome in men

Mutations in the dynein gene and in other genes encoding proteins required for flagellar and ciliar motility

29

Associated conditions to immotile cilia syndrome

Chronic respiratory infections (impaired motility of the cilia of the respiratory epithelium)

30

Potential use for stem cell transplantation regarding male testes

Useful in testicular cancer of young individuals (use for fertilization post-radiotherapy, which kills sperm cells)

31

Situation in which in vitro fertilization is useful

Obstructive azoospermia

32

Define ICSI

Intracytoplasmic sperm injection into oocytes

33

Define ROSNI

Round spermatid nuclear injection into oocytes

34

Define ROSI

Round spermatid injection into oocytes