Spermatogenesis and Male Tract

Question 1

Male gonadal cell types and origin

testis descend when?

Answer 1

Spermatogonia: Germ cell
Sertoli cell: epithelial
Leydig: interstitial tissue
Myoid: “

7-8th month fetal life

Question 2

Cryptorchidism

Answer 2

Failure of testes to descend. Causes infertility (high temp) Incomplete and maldescent

Question 3

How do testosterone levels change in early development until puberty?

Answer 3

Leydig cells produce from weeks 8-10.

Fetal peak, then drops. ‘Brain programming’
Neo-natal peak: ‘Gonad programming’
Pre-pubertal: virtually none
Pubertal: Raises

Question 4

What happens at puberty?

Answer 4

Marked increase in proliferation of spermatagonia.
Cords develops seminiferous tubules
Sperm production commences

Question 5

Overview of testis tract

Answer 5

ST’s to rete testis to epididymis to vas deferens

Question 6

Spermatogenesis.

Answer 6

The change of spermatagonia to spermatazoa by spermatocytogenesis, meiosis and spermiogenesis

Question 7

Sertoli cell features

Answer 7

Envelop germ cells. Have tight junctions to separate spermatagonia from spermatocytes (immune protection)

Question 8

Spermatocytogenesis

_____ (on basal lamina), _divide. One remains as stem cell, one continues and these proliferate by mitosis and move through Sertoli junctions

Answer 8

Spermatogonia (on basal lamina), 2n divide. One remains as stem cell, one continues and these proliferate by mitosis and move through Sertoli junctions

Question 9

Meiosis 1 and 2

1: After passing the _____ ____, ____ spermatocytes. Are ____. The process is ____
After meiosis 1, are now _____ spermatocytes. These are _____. Short half life. Meiosis 2 occurs to form ____ (also haploid)

Answer 9

1: After junctional complex, Primary spermatocytes. Are large. The process is slow
After meiosis 1, are now secondary spermatocytes. These are haploid. Short half life. Meiosis 2 occurs to form spermatids (also haploid)

Question 10

Spermiogenesis (forms spermatozoa)

Answer 10

Golgi phase: On one end, Golgi apparatus forms vesicles, proacrosomal granules.
Cap phase: Vesicles fuse to form acrosome, sits on top of nucleus
Acrosomal: elongates
Maturation

Question 11

What is the cycle of the ST’s? (how long does it take a spermatogonia to reach etc)

Answer 11

about 74 days
Spermatozoa are released in waves due to during spermatogenesis are always linked.

At any one point production is discontinuous by collectively continuous. About 300-600 sperm/second/g of tissue. 100-150million per day. Ejaculate 150-300 million

Question 12

Hormonal control of spermatogenesis (diagram (33)? go through all the hormones)

Answer 12

GnRH: causes FSH and LH release
LH: targets LEYDIG cells. Causes T production.
FSH: Targets Sertoli cells, which produce inhibin, ABP and other proteins.
T: Has many fates. Plasma T acts on target organs such as the epididymis, prostate, seminal vesicles; Negative feedback (GnRH, LH); Turns into DHT (plasma and local area effects); Sertoli cell, turns into DHT or E2.
E2: prepubertal E from sertoli cells, rest from plasma T. so Neg feebcack.
ABP: Binds to T and DHT to concentrate in ST’s. T goes to germ cells and the ST lumen.
Inhibin: neg feedback on FSH

Question 13

Effect of T and DHT on spermatogenesis

Answer 13

Need for meiosis (1st division); spermatid maturation; stimulates ABP.

Question 14

Role of E2 in males

Answer 14

Negative feedback

Enhances action of androgens e.g induces fibromuscular growth, needed for spermatogenesis

Question 15

Male tract things for me to take note

Answer 15

Ejaculatory duct, where seminal vesicle emptys contents (within prostate)
utricle where prostate empties contents
Cowpers/Bulbourethral glands: ant to prostate
Glands of Littre line urethra

Question 16

Sperm Maturation where and what happens

Answer 16

Epididymis (1-21 days)
Increased disulphide bonds formed. Increases stiffness and ability to swim
Concentrates by absorbing water

Question 17

Semen constituents and fraction.

Seminal fluid vs prostatic

Answer 17

Spermatozoa 10, seminal 10-30 and prostatic fluid 45-80

Seminal: fructose, PG’s, pH 7.3 white part
Prostatic: acid phosphatatse, citric acid, spermine pH 6.5

Question 18

What are the two phases of ejaculation

Answer 18

Emission: emission of semen from ducts and gland, by smooth muscle. Sympathetic control

Expulsion: Movement of semen out by contraction of somatic muscle bulbospongiosus and ischiocavernosus. Parasympathetic control

Question 19

Fractionation of ejaculate

Answer 19

1) fluid from bulbourethral and Litre glands
2) presperm, prostatic rich portion
3) Middle portion: SV plus sperm rich from epididymis/ampulla
4) viscous part from SV

Question 20

Neural control of ejaculation

1) Sensory stimulus received and travels to the ____ centre at __.
2) The erigentes nerve (_________) causes ________/SM relaxation of the penis/ clitoris and labium min.
3) This sensory information is taken to the _______ centre at ___ and the erection centre.
4) First, the hypogastric nerve (____________) from __ travels to the SV’s, _______, vas deferens and _____ ___ _______ ______ to causes SM contraction. This is ________.
5) The ________ nerve (___________) causes the somatic muscles bulbospongiosus, ischiocavernosus and the _____ _____ ______ to contract. This is ______

Answer 20

1) erection; S2
2) parasympathetic; vasodilation
3) ejaculation; L1;
4) Sympathetic; L1; Prosate; internal bladder sphincter; emission
5) pudendal; parasympathetic; external urethral sphincter expulsion

Question 21

Male infertility assessment

Answer 21

Liquification- should occur in 15min
Volume <1ml bad
Sperm conc <1.5 million/mL bad
Motility percent of active sperm > 40%
Motility Grade good/moderate forward progess, poor, twitching
Morphology
Debris e.g WBC's in them is bad

3 or more sub optimum, will struggle

Also Testosterone levels, frequency of emission and temperature

Question 22

Male infertility assessment

Think about semen and sperm things to look at

Answer 22

Liquification- should occur in 15min
Volume <1ml bad
Sperm conc <1.5 million/mL bad
Motility percent of active sperm > 40%
Motility Grade good/moderate forward progess, poor, twitching
Morphology
Debris e.g WBC's in them is bad

3 or more sub optimum, will struggle

Also Testosterone levels, frequency of emission and temperature