Sperm motility
Encyclopedia
Sperm motility describes the ability of sperm
to move properly towards an egg
. This can also be thought of as the 'quality' of the sperm, which is a factor in successful pregnancies, as opposed to the 'quantity'. Sperm which do not properly 'swim', will not reach the egg in order to fertilize it. Sperm motility in mammals also facilitates the passage of the sperm through the cumulus oophorus
and zona pellucida
, which are a series of layers that surround the ovulated egg-cell plasma membrane of a mammalian oocyte
. For example, in the wood mouse Apodemus sylvaticus, sperm aggregates form mobile trains that possess an enhanced fertilization capability because they are better suited to navigate the viscous environment of the female reproductive tract. The trains move in a sinusoidal motion, individual spermatozoa have impaired fertilization capacity.
It may also depend upon the effectiveness of sperm motility in response to certain factors released from eggs. The migration of sperm through the female reproductive tract (internal fertilisation) or in water (external fertilisation) to reach the egg is key to successful fertilization.. Successful fertilization also depends on the ability of sperm to penetrate extracellular matrix surrounding eggs.
The sperm motility is activated by changes in intracellular ion concentration. The change in concentration that signals the mechanism is different among species. In marine invertebrates
and sea urchins, the rise in pH to about 7.2-7.6 activates ATPase
which leads to decrease in potassium, thus induces membrane hyperpolarization
. As a result, sperm motility is activated.. The change in cell volume which alters intracellular ion concentration can also contribute to the activation of sperm motility. In some mammals, sperm motility is activated by increase in pH, calcium ion and cAMP
, yet it is suppressed by low pH in the epididymis
.
In mammals, spermatozoa mature functionally through a process which is known as capacitation
. When spermatozoa reach isthmic oviduct
, their motility have been reported to be reduced as they attach to epithelium. Near the time of ovulation, hyperactivation occurs. During this process, the flagellar moves with high curvature and long wavelength.. Hyperactivation is initiated by extracellular calcium; however, the factors that regulate calcium level is unknown..
Without technological intervention, a non-motile or abnormally-motile sperm is not going to fertilize. Therefore assessing the fraction of a sperm population that is motile is perhaps the most widely-used measure of semen quality
making sperm motility an important factor of it. Insufficient sperm motility is a common cause of subfertility or infertility
.
2. Zig-zag Moving
3. Vibrating
4. Non-Motile
Sperm
The term sperm is derived from the Greek word sperma and refers to the male reproductive cells. In the types of sexual reproduction known as anisogamy and oogamy, there is a marked difference in the size of the gametes with the smaller one being termed the "male" or sperm cell...
to move properly towards an egg
Ovum
An ovum is a haploid female reproductive cell or gamete. Both animals and embryophytes have ova. The term ovule is used for the young ovum of an animal, as well as the plant structure that carries the female gametophyte and egg cell and develops into a seed after fertilization...
. This can also be thought of as the 'quality' of the sperm, which is a factor in successful pregnancies, as opposed to the 'quantity'. Sperm which do not properly 'swim', will not reach the egg in order to fertilize it. Sperm motility in mammals also facilitates the passage of the sperm through the cumulus oophorus
Cumulus oophorus
The cumulus oophorus , also called discus proligerus, is a cluster of cells that surround the oocyte both in the ovarian follicle and after ovulation...
and zona pellucida
Zona pellucida
The zona pellucida is a glycoprotein membrane surrounding the plasma membrane of an oocyte. It is a vital constitutive part of the latter, external but of essential importance to it...
, which are a series of layers that surround the ovulated egg-cell plasma membrane of a mammalian oocyte
Oocyte
An oocyte, ovocyte, or rarely ocyte, is a female gametocyte or germ cell involved in reproduction. In other words, it is an immature ovum, or egg cell. An oocyte is produced in the ovary during female gametogenesis. The female germ cells produce a primordial germ cell which undergoes a mitotic...
. For example, in the wood mouse Apodemus sylvaticus, sperm aggregates form mobile trains that possess an enhanced fertilization capability because they are better suited to navigate the viscous environment of the female reproductive tract. The trains move in a sinusoidal motion, individual spermatozoa have impaired fertilization capacity.
It may also depend upon the effectiveness of sperm motility in response to certain factors released from eggs. The migration of sperm through the female reproductive tract (internal fertilisation) or in water (external fertilisation) to reach the egg is key to successful fertilization.. Successful fertilization also depends on the ability of sperm to penetrate extracellular matrix surrounding eggs.
The sperm motility is activated by changes in intracellular ion concentration. The change in concentration that signals the mechanism is different among species. In marine invertebrates
Marine invertebrates
Marine invertebrates are animals that inhabit a marine environment and are invertebrates, lacking a vertebral column. In order to protect themselves, they may have evolved a shell or a hard exoskeleton, but this is not always the case....
and sea urchins, the rise in pH to about 7.2-7.6 activates ATPase
ATPase
ATPases are a class of enzymes that catalyze the decomposition of adenosine triphosphate into adenosine diphosphate and a free phosphate ion. This dephosphorylation reaction releases energy, which the enzyme harnesses to drive other chemical reactions that would not otherwise occur...
which leads to decrease in potassium, thus induces membrane hyperpolarization
Hyperpolarization
Hyperpolarization has several meanings:* Hyperpolarization occurs when the strength of the electric field across the width of a cell membrane increases...
. As a result, sperm motility is activated.. The change in cell volume which alters intracellular ion concentration can also contribute to the activation of sperm motility. In some mammals, sperm motility is activated by increase in pH, calcium ion and cAMP
Cyclic adenosine monophosphate
Cyclic adenosine monophosphate is a second messenger important in many biological processes...
, yet it is suppressed by low pH in the epididymis
Epididymis
The epididymis is part of the male reproductive system and is present in all male amniotes. It is a narrow, tightly-coiled tube connecting the efferent ducts from the rear of each testicle to its vas deferens. A similar, but probably non-homologous, structure is found in cartilaginous...
.
In mammals, spermatozoa mature functionally through a process which is known as capacitation
Capacitation
Capacitation is the penultimate step in the maturation of mammalian spermatozoa and is required to render them competent to fertilize an oocyte.This step is a biochemical event; the sperm move normally and look mature prior to capacitation....
. When spermatozoa reach isthmic oviduct
Oviduct
In non-mammalian vertebrates, the passageway from the ovaries to the outside of the body is known as the oviduct. The eggs travel along the oviduct. These eggs will either be fertilized by sperm to become a zygote, or will degenerate in the body...
, their motility have been reported to be reduced as they attach to epithelium. Near the time of ovulation, hyperactivation occurs. During this process, the flagellar moves with high curvature and long wavelength.. Hyperactivation is initiated by extracellular calcium; however, the factors that regulate calcium level is unknown..
Without technological intervention, a non-motile or abnormally-motile sperm is not going to fertilize. Therefore assessing the fraction of a sperm population that is motile is perhaps the most widely-used measure of semen quality
Semen quality
Semen quality is a measure of the ability of semen to accomplish fertilization. Thus, it is a measure of fertility in a man. It is the sperm in the semen that are of importance, and therefore semen quality involves both sperm quantity and quality...
making sperm motility an important factor of it. Insufficient sperm motility is a common cause of subfertility or infertility
Infertility
Infertility primarily refers to the biological inability of a person to contribute to conception. Infertility may also refer to the state of a woman who is unable to carry a pregnancy to full term...
.
Classifications
1. Straight Moving2. Zig-zag Moving
3. Vibrating
4. Non-Motile