Spermatogenesis

Question 1

Male reproductive anatomy

Answer 1

Question 2

Testes outlined

what they do?

Answer 2

Produce sperm and store it

Produce hormones which regulate spermatogenesis.

Well-vascularised, well-innervated.

Normal volume of testes approximately 15-25ml.

measured by orchidometer…

Question 3

Testicular stucture

Answer 3

Question 4

Seminiferous epithelium

Answer 4

Question 5

what are Tight Junctions?

Answer 5

Exist between Sertoli cells forming blood-testis barrier.

Open to allow passage of spermatogonia prior to completion of meiosis.

Divides into basal and adluminal compartments.

Protects the spermatogonia from immune attack.

Allows specific enclosed environment for spermatogenesis which is filled with secretions from Sertoli cells.

Question 6

Stages of spermatogenesis

Answer 6

Spermatogonia

-
Primary spermatocyte

Secondary spermatocytes

-
Spermatids
->
Spermatozoa (spermiogenesis)

Question 7

Spermatogonia

Answer 7

Germ cell on basement membrane, capable of mitotic or meiotic division to produce primary spermatocytes or more spermatogonia by mitosis. They are diploid.

Question 8

Primary Spermatocyte

Answer 8

Cell committed to differentiative pathway, primary spematocyctes are 46XY diploid.

They move into the adluminal compartment and duplicate their DNA to produce sister chromatids which exchange genetic material and enter meiosis I.

Question 9

Secondary Spermatocytes

What have they undergone?

Answer 9

Secondary spermatocyctes have undergone meiosis I to give 23X + 23Y haploid number of chromosomes arranged as sister chromatids.

Question 10

Spermatids

What occurs to give our spermatids?

Answer 10

Meiosis II occurs to give 4 haploid spermatids. Round spermatid to elongated spermatid differentiation.

Question 11

Spermiogenesis

Answer 11

maturation of spermatids into spermatozoa

Question 12

What happens at Spermatozoa?

Answer 12

Mature sperm extruded into the lumen.

The movement into the lumen is controlled by Sertoli cell secretions.

Factors produced by sertoli cells are required for development

Question 13

Hypothalamic-Pituitary-Gonadal axis
FEMALES

(look at the feedback)

Answer 13

Question 14

Hypothalamic-Pituitary-Gonadal axis
Males

(look at the feedback)

Answer 14

Question 15

Androgen production in the testis
Summary (study this well)

Answer 15

Question 16

Leydig cells contain which receptors and primarily do what?

Answer 16

LH receptors and primarily convert cholesterol into androgens.

Question 17

After androgens are made in leydig cells, they cross over and⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀

Answer 17

stimulate Sertoli cell function and thereby control spermatogenesis.

Question 18

Sertoli cells contain which receptors? and convert androgens to?

Answer 18

Sertoli cells contain FSH receptors and convert androgens to oestrogen.

Question 19

FSH establishes a quantitatively normal ______ _____ population, whereas androgen..

Answer 19

FSH establishes a quantitatively normal Sertoli cell population, whereas androgen initiates and maintains sperm production

Question 20

FSH acts on sertoli cells and produces which types of proteins?

Answer 20

Androgen-binding proteins (ABP)

ABP binds to testosterone and concentrates the testosterone within seminiferous epithelium to aid with spermatogenesis

Question 21

InhibinB is produced primarily by _____ _____ in response to ____

Answer 21

InhibinB is produced primarily by Sertoli cells in response to FSH

Question 22

Inhibin B reduces ____ production by the _______ ______.

Answer 22

Inhibin B reduces FSH production by the anterior pituitary.

Question 23

Seminal fluid consists of secretions from:

Answer 23

seminal vesicles, prostate, bulbo-urethral gland combined with epididymal fluid

Question 24

Role of seminal fluid

Answer 24

• Transport of sperm through the male reproductive tract
• Coagulation of the ejaculate and creating a sperm deposit in the vagina
• Creation of a neutral to slightly alkaline buffered milieu in the vagina to protect spermatozoa from the acidic vaginal milieu.
• Activation and augmenting the motility of the sperm cells
• Coating the sperm cells with capacitation inhibitors

-Supplying nutrients for the sperm cells