Male Repro: Sperm Formation

Question 1

Spermatogenesis

Answer 1

Formation of Sperm Cells from spermatogonia (mother cells)
-haploid

Question 2

Seminiferous Tubules

Answer 2

Contain all stages of sperm development
- spermatogonia, primary spermatocytes, secondary spermatocytes, spermatids, spermatozoa

Question 3

Leydig Cells

Answer 3

In between tubules
- secrete testosterone
- interstitial endocrinocyte

Question 4

Order of cell types from basement membrane to lumen

Answer 4

1. basement membrane
2. spermatogonia
3. primary spermatocyte
4. secondary spermatocyte
5. spermatid
6. spermatozoa 7. lumen

Question 5

Sertoli cells

Answer 5

within tubule, extend from basement membrane to lumen
- form blood testis barrier
- supporting cells that regulate sperm production
-support, protect, and nourish developing sperm cells
-produce fluid and control release of sperm into lumen
-secrete inhibin which slows sperm production by inhibiting FSH

Question 6

Spermatogonia

Answer 6

mitotically active

Question 7

Spermatocytes

Answer 7

undergo meiosis

Question 8

Spermiogenesis

Answer 8

Differentiation of spermatids into spermatozoa
- mitochondria inferior to head
-acrosome and cell membrane cover nucleus

Question 9

Sperm morphology (spermatozoon)

Answer 9

-Adapted for reaching and penetrating a secondary oocyte
-head contains DNA and acrosome
- midpiece contains mitochondria to form ATP
-tai is flagellum used for locomotion

Question 10

Fertilization requirements

Answer 10

• sperm is deposited into female tract
• consistency of cervical mucous in cervix allows sperm to pass or not
• Lumen of uterus and oviducts: sperm undergoes capacitation, an induced change that allows the sperm to undergo subsequent acrosome reaction

Question 11

Fertilization in vicinity of ovum

Answer 11

Usually in ampulla in oviduct
- secretion from ovum induces sperm to undergo an acrosome reaction, releasing acrosomal hydrolytic enzymes that may facilitate sperm entry through the cumulus and zona pellucida of ovum
-sperm enter ovum, subsequent sperm excluded
- fusion of the female and male pronuclei yields a nucleus with 23 pairs of chromosomes, beginning a new individual

Question 12

Testicular Steroidogenesis

Answer 12

2 cells and 2 gonadotrophins
-LH stimulates T synthesis by Leydig Cells
- FSH stimulates synthesis of inhibin by sertoli cells
- negative feedback
-leydig and sertoli cells both regulate spermatogenesis