The Journey from testis to interaction

Question 1

Define epidiymis?

Answer 1

It is a vessel constituing by various twists a body afixed to the back of the testicle

Question 2

Epididymal anatomy

Answer 2

Long tube.

From caput to cauda end.

As the length increase, so does the maturity of the sperm.

see additional sheet 12

Question 3

Why matures the sperm in the epidydymi?

Answer 3

Fluid hyperosmotic:

Many organic solutes

Question 4

What does the epididymic do to the sperm?

Answer 4

important in sperm transport

and protecting the sperm from harmful substances

Question 5

What is important for the vas deferens?

Answer 5

Muscular

Transport to urethra

Question 6

Why are the seminal vesicles important?

Answer 6

Very active secretory glands.

Provides the majority of ejaculate fluid volume

Rih in prostaglandins and frutose.

Androgen-dependent secretory proteins

Question 7

What is the percentage of sperm occupancy in the ejactulated fluid?

Answer 7

5% is sperm

Question 8

Why is the prostate important?

Answer 8

Prostasomes and secretions high in zinc, citric acid and cholins.

Question 9

What happens during capacitation?

Answer 9

It is the period of conditioning during the sperms time in the female reproductive tract. Lasting approx. 7hrs.

Need this to be able to fertilise the egg.

Occurs in the uterine tube and involves epithelial interactions between the sperm and the mucosal surface of the tube.

See additional sheet 13

Question 10

What happens to the sperm during epididymal?

Answer 10

The plasma membrane of the epididymal spermatozoa contains a complement of surface molecules (proteins and carboyhydrates)

AS13

Question 11

What happens during the ejaculation to the sperm?

Answer 11

Surface molecules in epididymal sperm become coated with seminal proteins that mask portions of the membrane molecules

Question 12

What happens to the sperm during the capacitated stage?

Answer 12

When sperm is exposed to the female tract environment, these seminal plasma coatings are removed, thus exposing portions of the molecules that can bind to the zona pellucida of the oocyte.

Question 13

When does fertilisation occur?

Answer 13

In the ampullary region of the uterine tube

Question 14

Why is fertilisation occurs in this place?

Answer 14

As its the widest part of the tube and is close to the ovary.

Question 15

What is the percentage of sperm deposited in the vagina the enter the cervix?

Answer 15

Only 1%

Question 16

How does sperm move from the cervix to the uterine tube?

Answer 16

Occurs by muscular contractions of the uterus.

Question 17

What must sperm undergo before being able to fertilise the oocyte?

Answer 17

Capaction

Acrosome reaction

Question 18

What happens during the acrosome reaction?

Answer 18

Occurs after binding to the zona pellucida.

Induces by zona enzymes.

Reaction culminates in the release of enzymes needed to penetrate the zona pellucida.

3 phases

Question 19

Name and describe the 3 phases of acrosome reaction

Answer 19

additional sheet 14

Question 20

What happens during phase 1 of the acrosome reacton?

Answer 20

Penetration of the corona radiata

The outer protective layer of the ovum

Question 21

What is the zona pellucida made from?

Answer 21

Glycoprotein shell

Question 22

What happens during phase 2 of the acrosome reaction?

Answer 22

Sperm binds to the zona pellucida

Binding is mediated by the ligand ZP3.

This also induces the acrosome reaction.

Disintregating the acrosome- release of the enzymes (acrosin) allows sperm to penetrate the zona.

See additional sheet 14

Question 23

What happens during phase 3 of the acrosome reaction?

Answer 23

Adhesin mediated by the interactions of integrins and the oocyte and their ligands, disintregration of the sperm.

Fusion occurs between the oocyte membrane and the membran covering the posterior region of the sperm head.

Question 24

Hyperactivated motility?

Answer 24

Necessary to fertilise the egg.

Involves calcium and cAMP.

Question 25

What are the 2 theories on why hyperactivated motility is needed to penetrate the zona?

Answer 25

1. Penetrate the egg by increasing the power.
2. They are lost therefore hyperactivated to try and find the occyte

Question 26

The lost theory?

Answer 26

The uterine tube is very long and has a lot of folds.

Small in diameter though.

Allurin: the chemoattract that the ovum gives off

See additional sheet 15

Question 27

What hormone is released by the oocyte and what does it do to the sperm?

Answer 27

Progesterone

Stimulates the flow of calcium ions in sperm

Helps sperm identify and navigate towards the egg.

See additional sheet 15

Question 28

What happens during external fertilisation with the sperm trying to locate the oocyte?

Answer 28

Gametes are passiveluy mobile due to the currents.

When in range to pick up the chemotaxis- the sperm uses active motility to locate the egg.

See additional sheet 15

Question 29

What do SAPs stand for? what do they do?

Answer 29

Sperm activating peptides.

Known to effect motility

Question 30

Thermotaxis?

Answer 30

Gradient increase associated with ovulation.

When the sperm first enter the oviduct- needs to know its going in the right direction

Additional sheet 16

Question 31

Chemotaxis?

Answer 31

Oviductal fluid, egg and cumulus secrete chemo-attractants.

This is to direct the sperm to the ovum.

See additional sheet 16

Question 32

CatSper?

Answer 32

A sperm specific protein involved in hyperactivation.

Impaired mtility causes male-factor infertility.

Question 33

What are the two types of motility for the sperm?

Answer 33

1) Activated (progressive)
2) Hyperactivated (switched on by signals from the female tract- requires influx of calcium)

Question 34

Why is cAMP essential?

Answer 34

For activation

Initiation of swimming

Question 35

Why is calcium essential?

Answer 35

Primary regulator of transition to hyperactivated activity.