The Reproductive System: Gametogenesis: Sperm

Question 1

Gametogenesis

Answer 1

Gametes are haploid cells that combine to form new combination of genes

Question 2

Gametogenesis: Male

Answer 2

Sperm
Ongoing in the testes

Question 3

Where is sperm produced?

Answer 3

Testes

Question 4

Gametogenesis: Female

Answer 4

Oocyte → Ova
Arrests during meiosis prior to birth

Question 5

Where are oocytes produced?

Answer 5

Ovaries

Question 6

Where are the testes located?

Answer 6

External to the main body cavity in the scrotum

Question 7

Tunica Albuginea

Answer 7

Dense CT
Surrounds the seminiferous tubules

Question 8

Tunica Vasculosa

Answer 8

Loose CT containing blood vessels
Found between the albuginea and tubules

Question 9

Layers of the testes

Answer 9

Epididymis
Tunica Albuginea
Tunica Vasculosa
Seminiferous tubules - Tunica Propria

Question 10

Tunica Propria

Answer 10

Layer of collagen fibers and myoid cells
Surrounds each seminiferous tubule
No fibroblasts

Question 11

What are Myoid Cells?

Answer 11

Peritubular contractile cells
Similar to smooth muscle
Have alot of RER for collagen production

Question 12

What is the function of myoid cells?

Answer 12

Contraction produces peristaltic waves that move spermatozoa and testicular fluid out of seminiferous tubules

Question 13

Where are myoid cells located?

Answer 13

On the outside of seminiferous tubules

Question 14

What are leydig cells?

Answer 14

hormone-producing interstitial cells (steriod)
surrounded by CT - between seminiferous tubules
Store a lot of lipid (foamy inside)

Question 15

When are Leydig Cells active?

Answer 15

During early fetal development
Inactive until puberty

Question 16

What activates Leydig Cells?

Answer 16

Gonadotropic pituitary hormones

Question 17

Spermatogenesis

Answer 17

Population of basal cells that divide (by mitosis) to produce additional gametes

Question 18

What gametes are produced during mitosis of spermatogenesis?

Answer 18

Spermatogonia

Question 19

What stage of gametes are produced during Meiosis I and Meiosis II during spermatogenesis?

Answer 19

Primary and secondary spermatocytes

Question 20

What is the difference between primary and secondary spermatocytes?

Answer 20

Primary have constricted chromatin
Secondary typically are not visible

Question 21

What are the haploid gametes produced by meiosis?

Answer 21

Spermatid

Question 22

What regulates spermatogenesis?

Answer 22

Sertoli cells

Question 23

Starting at Mitosis, what are the stages of Spermatogenesis and what gametes do they form?

Answer 23

Mitosis → Spermatogonia phase
Meiosis I and II → Spermatocytes phase
Spermatid phase
Residual bodies
Spermatozoa

Question 24

Why are Sertoli Cells called the “true” epithelium of seminiferous tubules?

Answer 24

All other cells present in the walls of seminiferous tubules are spermatogenic cells

Question 25

What are residual bodies?

Answer 25

Every part of early spermatids that won't be present in final spermatozoa

Question 26

Where are spermatogonia located?

Answer 26

Closest to the basal lamina

Question 27

What are the stages of spermatogenesis?

Answer 27

1. very few primary spermatocytes 2. Release of late spermatids 3. No late spermatids 4. No early spermatids 5. No early spermatids 6. Anaphase in primary spermatocytes

Question 28

Why wont you see every stage in every area of a seminiferous tubule?

Answer 28

Spermatogenesis occurs in waves

Question 29

What is the difference between spermatogesis stages in mice vs. human?

Answer 29

Mice are segmented Human are patchwork

Question 30

Describe Primary Spermatocytes histologically

Answer 30

Condensed chromatin Speckled pattern

Question 31

Describe spermatogonia histologically

Answer 31

Closest to basement membrane Round Relativly evenly stained nucleus

Question 32

Describe the difference between early spermatids and late spermatids histologically.

Answer 32

Early Spermatids → rounder, lighter Late Spermatids → Arrow head shape, darker

Question 33

What are Sertoli Cells? What are their function?

Answer 33

Supporting cells of seminiferous tubules Regulate Spermatogenesis

Question 34

Receptors for what hormones are found on Sertoli Cells?

Answer 34

FSH and testosterone

Question 35

How do Sertoli Cells regulate spermatogenesis?

Answer 35

They keep the different stages seperate by extending processes between all spermatogeneic cells as well as to seperate developing sperm from the rest of the body

Question 36

Why do developing sperm need to be seperated from the body?

Answer 36

They arent there during fetal development so exposure may result in attack from the immune system.

Question 37

Describe the process of spermatid remodeling.

Answer 37

1. Golgi forms acrosome - determining anterior pole 2. Acrosomal cap forms - Flagellum extends into lumen 3. Cytoplasm shifts to posterior as nucleus and acrosome shift to anterior 4. Remove excess cytoplasm

Question 38

Late spermatids are connected to...

Answer 38

Sertoli Cells

Question 39

Where are spermatids produced/released from?

Answer 39

Sertoli cells

Question 40

How are spermatids released?

Answer 40

By cleavage of specific junctions to become spermatozoa

Question 41

What is the path spermatids follow after release from Sertoli Cells?

Answer 41

1. Released from Sertoli Cell 2. Travel through tubuli recti (straight tubules) 3. Through the rete testis (series of channels) 4. To the Ductuli Efferentes (akak the efferent ductules)

Question 42

What is the different between straight tubules and rete testis?

Answer 42

Straight tubules → found around seminiferous tubules, lined with sertoli cells (simple columnar epithelium); nuclei with prominant nucleuolus Rete testis → found in mediastinum, simple cuboidal epithelium

Question 43

Where do all seminiferous tubules drain into?

Answer 43

Mediastinum

Question 44

What is the mediastinum?

Answer 44

Dense CT with blood vessels Contains rete testis | Somewhat similar to hilum of other organs