Spermatogenesis and influencing factors

Question 1

sperm production from what cells

Answer 1

the primordial germ cells.

Question 2

Two distinct phases during the development are?

Describe them

Answer 2

Spermatocytogenesis- Clonal expansion and maturation through mitotic and meiotic process

Spermiogenesis- Differentiation into mature sperm cells

Question 3

When does this process start?

Answer 3

puberty ( under testosterone) and continues lifelong

Question 4

What happens in Spermatocytogenesis- first and second phase

Answer 4

immature cells undergo mitotic division (1 germ cell splits into 2) - lasts about 2 weeks

2nd phase - meiotic division - have half the nuclear component

Question 5

spermatids are functional but not able to under go ?

Answer 5

fertilisation - need to undergo structural changes into mature cell

Question 6

Spermiogenesis– what happens

Answer 6

spermatids acquire a functional capacity - mature sperm cells are created

Question 7

Why do chromosomes need to be haploid?

Answer 7

will fertilise egg with another 23 chromosomes

Question 8

What is the first step in chromosomal division

Answer 8

One mitotic division- Spermatogonium to primary spermatocyte-duplication, diploid chromosomes number(46)

Question 9

What is the second step in chromosomal division?

Answer 9

First meiotic division- primary spermatocyte to secondary spermatocyte, two cells with haploid chromosome number(23)

Question 10

What is the 3rd step in chromosomal division?

Answer 10

secondary spermatocyte to spermatid, two cells with haploid chromosome number(23)

Question 11

what is the 4th step in chromosomal division?

Answer 11

maturation of spermatids into functional sperm cells

Question 12

Factors affecting spermatogenesis (3)

Answer 12

Medical, lifestyle or combination - can lead to decline in male fertility / fertility issues

Question 13

Factors affecting spermatogenesis 1- Medical - what are the 2 categories

Answer 13

Pretesticular- Problem with the hormonal control

Testicular- Problem at the site of production

Question 14

Medical factors affecting spermatogenesis - Pretesticular

Answer 14

• Functional- excessive weight loss, gain
• Intracranial tumours, cysts, bleed
• Prolactinoma in ant pituitary
  Medications- opiates, external testosterone, steroids(body building)
  Genetic- Kallmann’s syndrome

Question 15

Medical factors affecting spermatogenesis - Testicular

Answer 15

Surgery- orchidectomy, orchidopexy
STI
Mumps orchitis
Testicular trauma or torsion 
Radiotherapy or chemotherapy
Genetic- Klinefelter’s (46 XXY), Y-chromosome microdeletion

Question 16

Factors affecting spermatogenesis 2- environmental/lifestyle factors

Answer 16

can be from the mother or father

Question 17

Steps to reduce the impact of factors affecting fertility? give examples

Answer 17

Improve lifestyle- normal BMI, stop smoking, alcohol in recommended limits, healthy diet, exercise, adjustments to occupational exposure
Optimise underlying medical condition
Stop medications or switch to alternative pregnancy compatible medications
Reduce STI risk and treat promptly if diagnosed.
Fertility preservation- sperm freezing prior to surgery or cancer

Question 18

What should a normal sperm count be? what is a low sperm count called

Answer 18

oligospermia

15mil/ml

Question 19

a sign of cystic fibrosis is a

Answer 19

absent vas deferens