Sperm flagella. Medical search. Frequent questions

PL: flagella) (Latin for 'whip' or 'scourge') is a hairlike appendage that protrudes from certain plant and animal sperm cells, and from a wide range of microorganisms to provide motility. (wikipedia.org)
Across the three domains of Bacteria, Archaea, and Eukaryota the flagellum has a different structure, protein composition, and mechanism of propulsion but shares the same function of providing motility. (wikipedia.org)
In aquatic habitats, gametes are released into the water where sperm acquire motility and navigate to the egg. (elifesciences.org)
A flagellum (plural, flagella ) is a long, whip-like projection or appendage of a cell composed of microtubules (long, slender, protein tubes) and used in motility. (newworldencyclopedia.org)
Motility is only achieved when the sperm presents a fully functional flagellum, is capable of producing energy to fuel the movement, and suffers epididymal maturation and capacitation. (bioone.org)
Since sperm is a transcriptionally silent cell, motility depends on the activation and/or inhibitions of key signaling pathways. (bioone.org)
This review describes and discusses the main signaling pathways involved in primary and hyperactivated motility, as well as the bioenergetic mechanisms necessary to produce energy to fuel sperm motility. (bioone.org)
Understanding the signaling pathways behind sperm motility can help pinpoint the cause of male infertility and uncover targets for male contraception. (bioone.org)
Sperm motility depends on energy availability, intact flagellum and the crosstalk of several signaling pathways that lead to an increase of tyrosine phosphorylation of key proteins. (bioone.org)
Maria João Freitas , Srinivasan Vijayaraghavan , and Margarida Fardilha "Signaling mechanisms in mammalian sperm motility," Biology of Reproduction 96(1), 2-12, (20 December 2016). (bioone.org)
A research team led by Professor Mitsuyasu Hasebe of the National Institute for Basic Biology revealed that the MADS-box genes control sperm motility and cell division and elongation of the stem of gametophores, using the moss Physcomitrella patens . (nibb.ac.jp)
knockout male mice showed severe subfertility with a defect in sperm motility as well as a significant disorganization in the fibrous sheath. (biologists.com)
In mammals, adenosine 3', 5'-cyclic monophosphate (cAMP) is known to play highly important roles in sperm motility and acrosomal exocytosis. (plos.org)
It is involved in flagellar movements and motility, and in cellular events that occur in the sperm head, that will lead to successful interaction with the egg and to fertilization [ 1 , 2 ]. (plos.org)
Thus, observations indicate that the FS plays important roles in energy metabolism, ATP generation for sperm motility, calcium signaling, and as a scaffold for signaling molecules in addition to its role as a structural girdle surrounding the outer dense fibers and axoneme. (biomedcentral.com)

However, the precise mechanism through which groups of cilia and flagella lock into sync with one another is not entirely clear. (cam.ac.uk)
Cilia and flagella are comprised of a microtubular backbone, the axoneme, which is organized by the basal body and surrounded by plasma membrane. (antibodies-online.com)

Microorganisms such as bacteria and many eukaryotic cells propel themselves with hair-like structures known as flagella, which can exhibit a variety of structures and movement patterns. (scienceopen.com)
In some bacteria the flagellum can also function as a sensory organelle, being sensitive to wetness outside the cell. (wikipedia.org)
Bacteria and archaea do not have dynein or microtubules in their flagella, and they move using a rotary mechanism. (wikipedia.org)
Unlike bacteria, eukaryote flagella have an internal structure comprised of nine doublets of microtubules forming a cylinder around a central pair of microtubules. (newworldencyclopedia.org)
Many different types of cell, including sperm, bacteria and algae, propel themselves using whip-like appendages known as flagella. (cam.ac.uk)
For more on the strange world of sperm, bacteria, and other tiny creatures , or to learn how to swim in corn syrup, check out my blog post on the subject, also featured in The Best Science Writing Online 2012. (ted.com)
This is why sperm and bacteria use corkscrew shaped flagella instead of a paddle. (ted.com)
Many biological micro-organisms, including bacteria, 12,13 sperm cells, and some algae, 14 swim in circular and helical trajectories near the surface or in chemical gradients. (aip.org)

It plays a key role during sperm capacitation [ 3 - 6 ] and the acrosomal exocytosis [ 7 - 10 ], where it affects different intracellular signalling pathways. (plos.org)
CABYR is a polymorphic calcium-binding protein of the sperm fibrous sheath (FS) which gene contains two coding regions (CR-A and CR-B) and is tyrosine as well as serine/threonine phosphorylated during in vitro sperm capacitation. (biomedcentral.com)
Control of the low voltage-activated calcium channel of mouse sperm by egg ZP3 and by membrane hyperpolarization during capacitation. (umassmed.edu)
Ion channels, phosphorylation and mammalian sperm capacitation. (umassmed.edu)
Sodium and epithelial sodium channels participate in the regulation of the capacitation-associated hyperpolarization in mouse sperm. (umassmed.edu)
Involvement of cystic fibrosis transmembrane conductance regulator in mouse sperm capacitation. (umassmed.edu)
Identification of proteins undergoing tyrosine phosphorylation during mouse sperm capacitation. (umassmed.edu)
Biphasic role of calcium in mouse sperm capacitation signaling pathways. (umassmed.edu)
Flow cytometry analysis reveals that only a subpopulation of mouse sperm undergoes hyperpolarization during capacitation. (umassmed.edu)
Sperm Capacitation and Acrosome Reaction in Mammalian Sperm. (umassmed.edu)
Only a subpopulation of mouse sperm displays a rapid increase in intracellular calcium during capacitation. (umassmed.edu)
Capacitation increases glucose consumption in murine sperm. (umassmed.edu)

Egg water from the amphibian Bufo arenarum modulates the ability of homologous sperm to undergo the acrosome reaction in the presence of the vitelline envelope. (umassmed.edu)
Starvation induces an increase in intracellular calcium and potentiates the progesterone-induced mouse sperm acrosome reaction. (umassmed.edu)

The similarities between bacterial flagella and bacterial secretory system structures and proteins provide scientific evidence supporting the theory that bacterial flagella evolved from the type-three secretion system (TTSS). (wikipedia.org)
These findings suggest that while channel proteins found in sperm cells from different species look similar and serve similar roles, they are activated in ways that can be very different. (elifesciences.org)
These proteins include dynein, a molecular motor that can cause flagella to bend, and propel the cell relative to its environment or propel water or mucus relative to the cell. (newworldencyclopedia.org)
For the calcium to enter, a sperm protein known as CatSper needs to join with similar proteins in the flagella. (medicalnewstoday.com)
SPAG16 encodes 2 major proteins that associate with the axoneme of sperm tail and the nucleus of postmeiotic germ cells, respectively (Zhang et al. (antibodies-online.com)
Potential virulence components include flagella ( 5 , 6 ), invasion proteins ( 7 ), and toxins ( 8 , 9 ). (cdc.gov)

Starting transients in sea urchin sperm flagella. (rupress.org)
In sea urchin sperm, a cyclic nucleotide-gated K + channel (CNGK) mediates a cGMP-induced hyperpolarization that evokes Ca 2+ influx. (elifesciences.org)

This channel is activated by signalling molecules inside cells, called 'cyclic nucleotides', and its activity ultimately leads to calcium ions flowing into the sperm cell's tail. (elifesciences.org)
This influx of calcium ions in turn controls the beating of the tail and, thereby, steers the sperm cell towards the egg. (elifesciences.org)
In a multicellular organism, cilia or flagella can also extend out from stationary cells that are held in place as part of a tail goes into a layer of tissue. (newworldencyclopedia.org)
In order for the sperm cell to increase mobility, calcium must also pass through its outer membrane and enter the "tail," or flagella, which it uses to propel itself along. (medicalnewstoday.com)
The fact that they're attached to the sperm tail instead of floating around in solution enables the enzymes to efficiently pass the substrate along from point to point and get the most "bang for the buck" from a sugar molecule, according to Travis. (sciencedaily.com)
Figure 346 from Chapter 14 (Sperm Flagellum) of 'The Cell, 2nd Ed.' by Don W. Fawcett M.D. Top panel: A cross section of sperm tail of the cecidomyid fly, Diplolaboncus tumorificus shows mitochondria. (cellimagelibrary.org)
Copying a molecular design they discovered in the sperm tail, Travis and his colleagues, including Baker Institute Research Scientist Dr. Roy Cohen , have developed a device that can diagnose stroke in less than ten minutes using less than a drop of blood. (cornell.edu)
Getting sperm tail enzymes to do important work. (cornell.edu)
Sperm are interesting because of their role in reproduction, but the Travis lab is also putting components of the long sperm tail to work for other purposes. (cornell.edu)
Building on their past studies of sperm's energy-making enzymes, Dr. Travis and his colleagues have mimicked the way these enzymes are organized in the tail, called a "flagellum", to create enzyme machines powered by sugar. (cornell.edu)

Intriguingly, in addition to the MMAF phenotype very analogous to the previous report , the two patients notably presented abnormal morphology of sperm heads , the sperm mitochondrial sheath was obviously disorganized, and the sperm annulus were almost defective. (bvsalud.org)
Mice homozygous for a null allele exhibit male infertility associated with abnormal sperm flagellum morphology and function. (jax.org)

Primary cilia are immotile, and have a structurally different 9+0 axoneme rather than the 9+2 axoneme found in both flagella and motile cilia. (wikipedia.org)
One conclusion made in this study is that the flagellum of sperm cells are formed in a unique way that we named cytoplasmic ciliogenesis, as in this type of ciliogenesis the cilium axoneme is exposed to the cytoplasm. (utoledo.edu)
The fibrous sheath (FS), a unique cytoskeletal structure specific to the sperm, surrounds the axoneme and outer dense fibers and consists of two longitudinal columns connected by closely arrayed semicircular ribs. (biomedcentral.com)

Unexpectedly, the CNGK channel is located in the heads of this fish's sperm cells rather than in the tails. (elifesciences.org)
Eventually, using modified progesterone, the team isolated the enzyme alpha/beta hydrolase domain containing protein 2 (ABHD2) from the sperm tails. (medicalnewstoday.com)
The idea to tether the enzymes, says co-author Alex Travis, Associate Professor of Reproductive Biology at the Baker Institute for Animal Health, came from the hardworking enzymes tethered to the shafts of sperm tails. (sciencedaily.com)
Flagella are the little tails that some cells use to propel themselves. (kjv-asia.com)

In contrast, eukaryotic cells use flagella that resemble elastic rods and exhibit a beating motion: internally generated stresses give rise to a series of bends that propagate towards the tip. (scienceopen.com)
Eukaryotic flagella and cilia are identical in structure but have different lengths and functions. (wikipedia.org)
The three types of flagella are bacterial, archaeal, and eukaryotic. (wikipedia.org)
Eukaryotic flagella-those of animal, plant, and protist cells-are complex cellular projections that lash back and forth. (wikipedia.org)
In eukaryotic cells , flagella are active in movements involving feeding and sensation. (newworldencyclopedia.org)

It is located in the sperm head rather than the flagellum and is controlled by intracellular pH, but not cyclic nucleotides. (elifesciences.org)
The term undulipodium is used for an intracellular projection of a eukaryote cell with a microtuble array and includes both flagella and cilia. (newworldencyclopedia.org)
Sperm intracellular cAMP levels depend on the activity of adenylyl cyclases, mostly SACY, though transmembrane-containing adenylyl cyclases are also present, and on the activity of cyclic nucleotide phosphodiesterases (PDE) whose role is to degrade cAMP into 5'-AMP. (plos.org)
As in somatic cells, sperm intracellular cAMP concentration is regulated by the opposite action of two enzymes: the adenylyl cyclases (AC), which synthesize cAMP from ATP, and the phosphodiesterases (PDE), which break the phosphodiester bond of cAMP to form 5'-adenosine monophosphate (AMP). (plos.org)

Sperm flagellum abnormalities characterized by abnormal distribution of periaxonemal structures are observed in addition to sperm head shape anomalies. (jax.org)

Intracytoplasmic sperm injection ( ICSI ) was used to assist fertilization for the patient with MMAF. (bvsalud.org)
suspect that this unusual swimming behaviour guides sperm through a small hole in the protective coating of fish eggs, which eventually leads to fertilization. (elifesciences.org)
The authors conclude: "Progesterone-activated endocannabinoid depletion by ABHD2 is a general mechanism by which progesterone exerts its genome-independent action and primes sperm for fertilization. (medicalnewstoday.com)
Moreover, in the stem, the increase of the length prevented water supply to the tip, in which sperm swim for fertilization. (nibb.ac.jp)
The MADS-box genes are critical for fertilization in two ways: providing enough water for sperm swimming and producing movable flagella. (nibb.ac.jp)

The main sperm components were similar as for other Dipteran subspecies, while the ultrastructure revealed distinguishing features in the zone of overlap and anterior flagellar region. (up.ac.za)

Other differences among these three types are: Bacterial flagella are helical filaments, each with a rotary motor at its base which can turn clockwise or counterclockwise. (wikipedia.org)
Bacterial flagella are helical filaments that rotate like screws. (newworldencyclopedia.org)

Ion permeabilities in mouse sperm reveal an external trigger for SLO3-dependent hyperpolarization. (umassmed.edu)
Src Kinase Is the Connecting Player between Protein Kinase A (PKA) Activation and Hyperpolarization through SLO3 Potassium Channel Regulation in Mouse Sperm. (umassmed.edu)
Cdc42 localized in the CatSper signaling complex regulates cAMP-dependent pathways in mouse sperm. (umassmed.edu)

Human sperm diluted in buffer imaged at room temperature within two hours of ejaculation. (cellimagelibrary.org)
We hypothesize that a similar atypical centriole structure is found in the human sperm and are currently searching for it. (utoledo.edu)

The team first exposed sperm to a chemical that inhibits a particular class of enzyme, because they suspected that the molecule that acts on CatSper might feature within that class of enzymes. (medicalnewstoday.com)
These sperm enzymes efficiently turn sugars into energy that powers the flagellum and moves the sperm along. (sciencedaily.com)

causes male infertility due to multiple morphological abnormalities of the sperm flagella. (bvsalud.org)
A previous study suggested that loss of CFAP47 function is involved in multiple morphological abnormalities of the sperm flagella (MMAF) in humans and mice . (bvsalud.org)

The bacterial flagellum is made up of protein subunits of flagellin. (wikipedia.org)
The bacterial flagellum is driven by a rotary engine (Mot complex) made up of protein, located at the flagellum's anchor point on the inner cell membrane. (wikipedia.org)
We previously identified a 66 kDa axonemal protein (Ci-Axp66.0) in sperm of the ascidian Ciona intestinalis , Here we found that Ci-Axp66.0 shows sequence similarity to the DC2 subunit of the Chlamydomonas outer arm docking complex. (bioone.org)
CABYR protein gradually migrates into the sperm flagellum and localizes to the FS of the principal piece during steps 15-16. (biomedcentral.com)

Many protists with flagella are known as flagellates. (wikipedia.org)
In Protozoa - a diverse group of single-celled, microscopic or near-microscopic protist eukaryotes that commonly show characteristics usually associated with animals-those organisms with flagella ( flagellates ) are generally placed in the phylum Zoomastigina (or Mastigophora), whereas those with cilia (ciliates) are placed in phylum Ciliophora. (newworldencyclopedia.org)
Flagellates move by whipping the flagella on the flagellate side to side. (newworldencyclopedia.org)

Flagella use a whip-like action to create movement of the whole cell, such as the movement of sperm in the reproductive tract. (newworldencyclopedia.org)
This is an important advance in explaining how sperm become hypermotile in the female reproductive tract. (medicalnewstoday.com)

A gram-negative bacterium Helicobacter pylori for example uses its multiple flagella to propel itself through the mucus lining to reach the stomach epithelium, where it may cause a gastric ulcer to develop. (wikipedia.org)

Accessory bodies arising from the zone of overlap are flanked by smaller to large mitochondrial derivatives into the anterior flagellum. (up.ac.za)

For example, bacterial flagella are helically shaped and driven at their bases by a reversible rotary engine, which rotates the attached flagellum to give a motion similar to that of a corkscrew. (scienceopen.com)
Archaeal flagella (archaella) are superficially similar to bacterial flagella in that it also has a rotary motor, but are different in many details and considered non-homologous. (wikipedia.org)
The atomic structure of both bacterial flagella as well as the TTSS ("injectisome") have been elucidated in great detail, especially with the development of cryo-electron microscopy. (wikipedia.org)
Bacterial flagella are entirely outside the cell membrane (plasma membrane) and are normally visible only with the aid of an electron microscope . (newworldencyclopedia.org)

The flagellum of eukaryotes usually moves with an "S" motion and is surrounded by cell membrane . (newworldencyclopedia.org)
A sperm cell moves by means of a single flagellum. (newworldencyclopedia.org)

Calcium in the flagellum controls sperm navigation. (elifesciences.org)
In zebrafish sperm, a more alkaline pH inside the cell causes calcium ions to flow in and this influx of calcium ions triggers a unique spinning-like swimming movement that is different from the swimming of other sperm from other species. (elifesciences.org)
C2CD6 regulates targeting and organization of the CatSper calcium channel complex in sperm flagella. (umassmed.edu)

This study confirms sperm structure diversity between brachyceran subspecies and support its relationship with nematoceran subspecies. (up.ac.za)

The engine is powered by proton-motive force, i.e., by the flow of protons (hydrogen ions) across the bacterial cell membrane due to a concentration gradient set up by the cell's metabolism (Vibrio species have two kinds of flagella, lateral and polar, and some are driven by a sodium ion pump rather than a proton pump). (wikipedia.org)

They noted that the sperm remained inactive, suggesting that CatSper was not directly involved in the process. (medicalnewstoday.com)

A new biohybrid micro-robot is developed by capturing bovine sperm cells inside magnetic microtubes that use the motile cells as driving force. (scienceopen.com)
In general, sperm cells become attracted to egg cells by various chemical or physical signals. (elifesciences.org)
In 2009, researchers identified a potassium ion channel, called CNGK, that starts the electrical signal in the sperm cells of sea urchins. (elifesciences.org)
including some of the researchers involved in the 2009 work - now report that the CNGK channel also exists in the sperm cells of a freshwater fish, the zebrafish. (elifesciences.org)
The group used high-speed imaging and microscopy to observe the flagella of two physically separated cells of a species of green alga called Volvox carteri . (cam.ac.uk)
Scientists have discovered the "switch" that activates sperm cells to travel to the egg, potentially paving the way for new methods of male contraception and infertility treatment. (medicalnewstoday.com)
Sperm cells are not very mobile. (medicalnewstoday.com)
With the ABHD2 inactivated, progesterone was unable to activate the sperm cells. (medicalnewstoday.com)
Earlier this year, Medical News Today reported that stem cells could be used to create sperm in order to overcome male infertility that results when meiosis does not occur. (medicalnewstoday.com)
Sperm cells have flagella, but so do many single-celled organisms. (kjv-asia.com)
From the metachronal synchronisation of tracheal cilia to transport mu- cus, to the propulsive undulatory motion of sperm flagella, cells of all shapes and sizes use filament-like structures in a variety of fluid environments. (bham.ac.uk)

In some bacterial species, the flagella twine together helically outside the cell body to form a bundle large enough to be visible in a light microscope . (newworldencyclopedia.org)

The flagella in eukaryotes have dynein and microtubules that move with a bending mechanism. (wikipedia.org)
Prokaryotes may have one or many flagella for locomotion, but these differ significantly from flagella in eukaryotes. (newworldencyclopedia.org)
The structural similarity of cilia and eukaryote flagella, and the substantial differences between flagella in eukaryotes and prokaryotes, is such that some authorities group cilia and eukaryote flagella together and consider cilium simply a special type of flagellum-one organized such that many flagella (cilia) may work in synchrony (Patterson 2000). (newworldencyclopedia.org)
These structures are quite unrelated to the flagella of eukaryotes . (newworldencyclopedia.org)

These results suggest that Ci-Axp66.0 is a component of the outer arm dynein docking complex in the axonemes of Ciona sperm. (bioone.org)

Hamster sperm fertilizing a hamster oocyte. (cellimagelibrary.org)
This scanning electron micrograph shows hamster sperm fertilizing a hamster oocyte. (cellimagelibrary.org)
The goal of sperm is to fertilize the oocyte. (bioone.org)

Courtship and mating among scorpions involves a complex series of ritualized acts leading up to sperm transfer to females via an external stationary spermatophore (1-4). (scielo.br)
and the flagellum which represents the free, distal end of the spermatophore, and in some species can stretch to forty times its length (6). (scielo.br)
The whip-scorpions reproduce by indirectly transferring sperm through a spermatophore. (bvsalud.org)

Building on his expertise in sperm biology, Dr. Travis and his team have developed a male fertility test that scores the likelihood that a man's sperm will be able to successfully fertilize an egg. (cornell.edu)

Experiments in the 1940s demonstrated that the flagella of bull sperm tend to synchronise when they swim close to one another, connected only through the fluid surrounding them. (cam.ac.uk)
Traveling is extremely arduous for microscopic sperm -- think of a human trying to swim in a pool made of. (ted.com)

Ca 2+ induces spinning-like swimming, different from swimming of sperm from other species. (elifesciences.org)
Ca2(+) induces spinning-like swimming, different from swimming of sperm from other species. (zfin.org)

Out of these, 18% were diagnosed with a male-related infertility problem, 14% of which related to sperm or semen. (medicalnewstoday.com)
Indications for performing a postcoital test include semen hyperviscosity, increased or decreased semen volume with good sperm density, or unexplained infertility. (medscape.com)

This is where the sperm and egg meet and combine to form a fertilized egg, also known as a zygote. (proprofs.com)
We started our life as a single cell (the zygote) that was produced when the sperm fertilized the egg. (utoledo.edu)

Eukaryote flagella are similar to cilia -another structure that extends out from the surface of cell and is used for movement-in that both are composed of nine pairs of microtubules (nine microtubule doublets) arranged around its circumference and one pair of microtubules (two microtubule siglets) running down the center, the 9 + 2 structure (Towle 1989). (newworldencyclopedia.org)
Movement of a unicellular organisms by flagella can be relatively swift, whether it be Euglena with its emergent flagellum or a sperm cell with its flagellum. (newworldencyclopedia.org)
A long-standing hypothesis is that movement of the fluid due to the beating flagella could be the reason they move in unison. (cam.ac.uk)
Melissa R. Miller and colleagues - from the University of California-Berkley, the University of California-San Francisco and Yale University School of Medicine in New Haven, CT - set out to pinpoint exactly what triggers the movement of the sperm. (medicalnewstoday.com)

Transmission electron micrograph of longitudinal section through mouse spermatozoon showing characteristic hooked shape of sperm head and extremely compact DNA-protamine in the nucleus. (cellimagelibrary.org)

In this particular case, the coordination of flagella plays vital roles in phenomena ranging from embryo development to respiratory physiology, and thus the search for the mechanisms underlying synchronisation can yield insights on many fronts. (cam.ac.uk)

Flagella and cilia are remarkably versatile: they transport mucus and expel pathogens from our airways, they establish the left-right asymmetry in developing vertebrate embryos, and transport human eggs through the Fallopian tube. (cam.ac.uk)

A picture is emerging of sperm channel orthologues that employ different activation mechanisms and serve different functions. (elifesciences.org)
While previous experimental findings were consistent with mathematical theories describing the fluid motion, these experiments could not exclude other mechanisms for achieving synchronisation, such as chemical signalling or physical connections between flagella. (cam.ac.uk)
Now, using a newly devised experimental procedure, researchers from the University of Cambridge have been able to disentangle the various mechanisms, and show that the fluid motion created by two beating flagella is sufficient by itself to cause them to row in sync. (cam.ac.uk)

Each cilium or flagellum beats to its own characteristic rhythm, but wherever large groups of these biological paddles are found, they tend to row in sync, as though led by a cox. (cam.ac.uk)

In moss which lost the function of all MADS-box genes, sperm flagella hardly moved. (nibb.ac.jp)
Poor sperm function is a common cause of infertility in animals and humans alike, but there are currently few easy and accurate tests for diagnosing the problems involved. (cornell.edu)
Cyclic AMP (adenosine 3', 5'-cyclic monophosphate) is an important player in sperm function. (plos.org)
K+ and Cl- channels and transporters in sperm function. (umassmed.edu)

Ttll9-/- mice sperm flagella show shortening of doublet 7, reduction of doublet 5 polyglutamylation and a stall in beating. (scienceopen.com)

Here we show that a linear chain of colloidal magnetic particles linked by DNA and attached to a red blood cell can act as a flexible artificial flagellum. (scienceopen.com)

Sperm detect these cues and generate electrical signals that control their own movements and eventually guide sperm to the egg. (elifesciences.org)

The findings may give hope to people affected by infertility due to low sperm mobility. (medicalnewstoday.com)

Echinoderm sperm nuclei are unusual in that chromatin fibers are clearly seen, allowing their diameter to be accurately determined. (cellimagelibrary.org)

However, flagella are longer and typically occur singly or in pairs, or at least much smaller numbers than cilia, which occur in large numbers (Towle 1989). (newworldencyclopedia.org)

Anatomy15

Organisms8

Diseases4

Chemicals and Drugs15

Analytical, Diagnostic and Therapeutic Techniques and Equipment11

Phenomena and Processes20

Technology, Industry, Agriculture1

Information Science4

Health Care1

Motility15

Cilia and flagella2

Bacteria8

Capacitation12

Acrosome2

Proteins6

Urchin sperm2

Tail10

Morphology2

Axoneme3

Tails4

Eukaryotic5

Intracellular4

Abnormal1

Fertilization5

Flagellar1

Helical filaments2

Mouse sperm3

Human sperm2

Enzymes2

Abnormalities2

Protein4

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Reproductive tract2

Propel itself1

Mitochondrial1

Bacterial flagella4

Moves2

Calcium3

Confirms1

Cell's1

CatSper1

Cells11

Helically1

Eukaryotes4

Dynein1

Oocyte3

Spermatophore3

Fertility1

Swim2

Species2

Semen2

Zygote2

Movement4

Nucleus1

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Fallopian1

Mechanisms3

Cilium1

Function4

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Occur1