Sperm
Sperm are the
swimming, fighting parts of the complicated reproduction process that gives
birth to more and more of us each day. So how does this process occur? It all
starts with the building blocks of life and the composition of spermatozoa.
Sperm
Composition
The sperm has a
few different components, with all the "good stuff" being stored in
the head. The file with this information (DNA) is called the nucleus and it
will eventually be the only thing to merge with the female’s egg. The
blueprints for life exist in this most tiny of spaces; the coding that will
eventually determine so much of the physical life that we enjoy.
The only way
for this life coding to get where it needs to go, is by "swimming."
This action actually refers to their motility, which means that they can move
on their own. To create motion the spermatozoa have a tail that is lined with
mitochondria, which drive the swimming motion of the sperm. Mitochondria are
sub-cellular, meaning that they are smaller than the cells that they inhabit,
and their function is to take various types of nutrients found in the body and
converts it into energy, thus allowing them to perform all sorts of useful
tasks - like reducing the effects of your hang over.
Sperm Lifecycle
Having an
understanding of the basic make-up of the sperm’s physical structure, we can
now examine how sperm are created, spend their lives and are involved in the
birth of new life.
Sperm
Production or Spermatogenesis
Thirteen years
for men (and a little younger for women) marks the beginning of puberty and the
initiation of sperm production in the male. It can take between 64 to 72 days
for the generation of a new sperm cell.
Men must be
constantly making new sperm, in rapid overlapping production schedules, because
during every ejaculation he expels roughly a quarter of a billion spermatozoa.
This is a very rigorous schedule for the body to maintain, so keeping the
system healthy is of utmost importance. For information on how to keep all the
pistons firing properly, please refer below to Sperm Count.
The sperm begin
their lives in two glands located in the scrotal sac, directly beneath the
penis. Initially spermatozoa cross the testis and the efferent ducts to rapidly
pass into the epididymis where they are stored. Sperm resides in the caput (or
head), then the corpus (or body) and finally in the cauda (or tail) of the
epididymis. As sperm navigate to the epididymis they change significantly to
become motile, change shape and undergo physical alterations. Once located in
the epididymis they stay and grow into maturity until they are ready for
discharge then are mixed with semen and "released".
During the
growth phase of these future fertilizing “warriors”, a gland known as the
anterior pituitary produces hormones that put hair on men’s chest (FSH) and the
manly voice in their throat (LH), as well as all those other characteristics
that make men more distinguishable from women.
Sperm Delivery
Once the
spermatozoa are ready to get out into the world, they move along to the vans
deferens and then hook up with the urethra. Along the route to the seminal
fluid (that serves as a vehicle for the sperm) it gets some key ingredients
added to it. The seminal vesicles add fructose (sugar) and prostaglandins to
the sperm; together they promote and regulate the sperm’s health while in
transition. The prostate secretes a non-acidic fluid that gives semen its
colour, and the Cowper’s gland produces a mucus-like fluid that acts as a
lubricant.
The male body
also has a system of neutralizing the acidity of any potential urine that may
remain in the urethra. All these different fluids and sperm make up what is
known as semen, which is ejaculated out of the body through a series of soft
muscular movements that are initiated during arousal and subsequent
stimulation. As the body approaches a state of orgasm, marking the release of
sperm in semen, the muscles that control the prostate, urethra and testicles
all contract. They lift the scrotum and all the muscles force the sperm out
through the urethra at almost 45 km/h. This whole process takes about 3 to 10
seconds, though this amount of time tends to decrease over a man’s lifetime.
Theories also
suggest that the contractions associated with female orgasms pull sperm from
the vagina to the cervix, where it's in a better position to reach the egg.
Sperm, in the vagina, can only survive about six hours due to the acidic
vaginal secretions. The cervical mucus present when ovulation is near, is more
alkaline and more hospitable to sperm. The egg white consistency of the
cervical mucus helps the sperm move more easily through the vagina to the
cervix, increasing the chance that the sperm will be in the correct location
for fertilization to occur...
The Final Leg
So how do sperm
manage to negotiate their way from the vagina through the deep caverns of a
woman’s cervix, tubes and ovum?
1.
The fact is,
that like a "moth to a flame" or a "fish to a lure", the
female body produces a "scent" that is either produced by the egg
itself or perhaps more generally the woman’s reproductive tract. This process
is known as "chemo attraction," and makes the sperm swim
aggressively; charging towards their destiny, and the lottery of procreation.
2.
Upon their
arrival at the egg, the sperm completely envelope it's outer shell (known as
the extra cellular coat).
3.
After docking,
the egg undergoes some fundamental changes that allow one sperm to break
through the protective coat of the egg and merge, fusing into one.
4.
Sometimes sperm
that have undergone this chemical change can exhibit increased motility or
hyperactivity, and with a little extra shake in their step continue on toward
the nucleus.
5.
The sperm now
moves through the outer membrane.
6.
From this point
on the two nuclei merge, potentially creating of a new, and thoroughly unique
organism.
Sperms
Male
fertility depends on sperm quality and quantity, which can be affected by a
variety of things. There are steps you can take to maximize your fertility and
make sure your sperm are top performers.
Normal sperm characters
Normal ejaculate volume is between 2 and 6 ml.
Sperm quantity
- More than 20 million sperm per millilitre of semen.
- Of the millions of sperm in the ejaculated semen, only about 200 actually reach the egg in a woman's Fallopian tube.
- But, just one is needed to fertilize the egg.
Sperm quality
- Sperm shape and structure
(morphology) are equally important
- More than one-third of your sperm
are of normal shape and structure
- More than 30% normal forms is a
strict criteria
- A normal sperm has an oval head
and a long tail that propel it forward
- Sperm with large, small, tapered
or crooked heads or kinky, curled or double tails are less likely to
fertilize an egg
Motility
- To reach the egg, sperm have to move on their own — wriggling and swimming the last few inches to reach and penetrate the egg
- Most likely to be fertile if at least half of your sperm are moving
- Normal humans typically have total sperm motility of greater than 50% or 25% progressively motile sperm.
How to improve the sperm quality
- Take a multivitamin- A daily
multivitamin with selenium, zinc and folic acid
- Eat plenty of fruits and
vegetables- are rich in antioxidants
- Reduce stress- stress might
interfere with certain hormones needed to produce sperm
- Get regular exercise- But don't
overdo it. Men who exercise to exhaustion show a temporary change in
hormone levels and a drop in sperm quality.
- Watch your weight- too much or too
little body fat may disrupt production of reproductive hormones
- Quit using tobacco and limit
alcohol
- Avoid anabolic steroids
- Avoid lubricants during sex- personal
lubricants, lotions and even saliva can interfere with sperm motility.
However, vegetable-oil-based lubricants are okay
Separating facts from fictions
- Sitting on a bicycle saddle for more than 30 minutes at a time — especially if you also wear tight bicycle shorts — may raise your scrotal temperature and affect sperm production.
- Prolonged cycling can cause genital numbness — a sign of damage to delicate nerves and arteries.
- An illness that causes a fever can affect sperm production and sperm quality. But it won't affect fertility for two to three months, since it takes sperm 75 days to mature.
- Sperm counts are higher in the winter and lower in the summer. This may be because cooler temperatures are associated with increased sperm production.
Semen analysis
A
semen analysis measures the amount of semen a man produces and determines the
number and quality of sperm in the semen sample. Results of a semen analysis
are usually available within a day. Normal values may vary from lab to lab.
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Semen analysis
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Semen
volume
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Normal:
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1.0–6.5 milliliters (mL) per ejaculation
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Abnormal:
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An abnormally low or high semen volume is
present, which may sometimes cause fertility problems.
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Liquefaction
time
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Normal:
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Less than 60 minutes
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Abnormal:
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An abnormally long liquefaction time is
present, which may indicate an infection.
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Sperm
count
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Normal:
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20–150 million sperm per milliliter (mL)
0 sperm per milliliter if the man has had a
vasectomy
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Abnormal:
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A very low sperm count is present, which may
indicate infertility. However, a low sperm count does not always mean that a
man cannot father a child. Men with sperm counts below 1 million have
fathered children.
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Sperm
shape (morphology)
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Normal:
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At least 70% of the sperm have normal shape
and structure.
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Abnormal:
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Sperm can be abnormal in several ways, such
as having two heads or two tails, a short tail, a tiny head (pinhead), or a
round (rather than oval) head. Abnormal sperm may be unable to move normally
or to penetrate an egg. Some abnormal sperm are usually found in every normal
semen sample. However, a high percentage of abnormal sperm may make it more
difficult for a man to father a child.
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Sperm
movement (motility)
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Normal:
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At least 60% of the sperm show normal
forward movement.
At least 8 million sperm per milliliter (mL)
show normal forward movement.
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Abnormal:
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Sperm must be able to move forward (or
"swim") through cervical mucus to reach an egg. A high percentage
of sperm that cannot swim properly may impair a man's ability to father a
child.
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Semen
pH
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Normal:
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Semen pH of 7.1–8.0
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Abnormal:
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An abnormally high or low semen pH can kill
sperm or affect their ability to move or to penetrate an egg.
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White
blood cells
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Normal:
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No white blood cells or bacteria are
detected.
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Abnormal:
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Bacteria or a large number of white blood
cells are present, which may indicate an infection.
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Fructose
level
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Normal:
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300 milligrams (mg) of fructose per 100
milliliters (mL) of ejaculate
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Abnormal:
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The absence of fructose in the semen may
indicate that the man was born without seminal vesicles or has blockage of
the seminal vesicles
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Certain conditions may be associated with a low or absent sperm
count. These conditions include Orchitis, Varicocele, Klinefelter syndrome,
radiation treatment to the testicles, or diseases that can cause shrinking
(atrophy) of the testicles (such as mumps).
If a low sperm count or a high percentage of sperm abnormalities
are found, further testing may be done. Other tests may include measuring
hormones, such as Testosterone, Luteinizing Hormone (LH), Follicle Stimulating
Hormone (FSH), or Prolactin. A small sample (biopsy) of the testicles may be
needed for further evaluation if the sperm count or motility is extremely low.
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