Reproductive Lecture 3 🔮🍑

Question 1

Where dose Sperm Production: Spermatogenesis take place

Answer 1

Takes place in the seminiferous tubules of the testes

Question 2

Spermatogenesis Only occurs after

Answer 2

puberty

Question 3

There are three phases to spermatogenesis

Answer 3

1. mitotic division
2. meiotic division
3. Cytodifferentiation

Question 4

huge numbers of sperm are produced constantly by the

mature male ….how much

Answer 4

300 – 600 sperm/gram of testis tissue/second

Question 5

Spermatogenesis

• At puberty the

Answer 5

primary gem cells are
reactivated
– spermatogonial stem cells.

Question 6

The spermatogonia divide by mitosis.

1 daughter cell remains undifferentiated -to

Answer 6

maintain the stem cell population.

Question 7

The other daughter cell continues to divide by

mitosis forming

Answer 7

spermatogonia.

The spermatogonia continue to divide by mitosis.

Question 8

Spermatogenesis

Where do the mitotic divisions occur

Answer 8

in the basal compartment of

the seminiferous tubules

Question 9

Spermatogonia have how many chromosomes ?

Answer 9

46

Question 10

When the mitotic divisions are complete the spermatogonia

move between

Answer 10

adjacent sertoli to the adluminal

compartment of the seminiferous tubules.

Question 11

In the adluminal compartment the cells are called

Answer 11

primary spermatocytes –they undergo meiosis

Question 12

Each of these primary spermatocytes starts with

Answer 12

n-46

Question 13

The primary spermatocytes undergo

Answer 13

meiosis I

Question 14

the DNA content …….

Answer 14

doubles - each of the spermatocytes still has46 chromosomes. (meiosis I).

Question 15

The primary spermatocytes then divide to produce

Answer 15

secondary spermatocytes

Question 16

Secondary spermatocytes have …

How ,any chromosomes and how many chromatids ?

Answer 16

23 chromosomes, each

chromosome has two chromatids.

Question 17

Secondary spermatocytes divide very rapidly by ………….. to give …………….

Answer 17

meiosis II

- to give four spermatids each with 23 chromosomes.

Question 18

Spermiogenosis Round spermatids.

Answer 18

Spermatids are still round cells and have a round

morphology

Question 19

The final process in spermatogenesis is

Answer 19

spermiogenesis in which the round spermatids
differentiate their shape and become
spermatozoa (Sperm).

Question 20

Sperm move into the

Answer 20

lumen of the seminiferous

tubules

Question 21

The midpiece on the sperm is

Answer 21

packed with mitochondria to produce energy

Question 22

The sperm head contains

Answer 22

the DNA and is covered by the acrosome a compartment filled with enzymes that are required for egg penetration.

Question 23

The excess cytoplasm of the spermatid is also lost into a structure
called

Answer 23

the residual body that is phagocytosed by the Sertoli cells after the sperm leaves

Question 24

Sertoli Cells

(inside seminiferous tubules In direct contact with…..

Answer 24

spermatogonia

Question 25

Male infertility
A common feature of infertile men is a reduced sperm count <20 million/ml
=

Answer 25

oligospermia

Question 26

no sperm =

Answer 26

azoospermia

Question 27

Male infertility

can’t swim

Answer 27

immotile

Question 28

Male infertility

• IVF- in vitro fertilisation

Answer 28

• Oocytes are harvested and fertilised ex vivo

– Requires approximately 50,000 motile sperm

Question 29

ICSI- IntraCytoplasmic Sperm Injection.

Answer 29

– A single sperm is injected directly into the oocyte
– Sperm does not even need to be motile
– Can use sperm collected by biopsy from the
testes!!!