Middle piece - structure of the sperm, Biology

Middle piece - Structure of the Sperm

Just behind the head, the small constriction (neck) carries a distal and a proximal centriole. The two lie at right angle to each other. The proximal centriole initiates the cleavage divisions of fertilized egg while the distal centriole provides attachment to axial filament of tail. The middle piece has mitochondria surrounding the base of the axial filament of the flagellum (tail). The mitochondria form compact and isolated clumps throughout the middle piece, or there may be a tightly coiled spiral of mitochondria around the proximal centriole of filament and distal centriole.

The mitochondria carry the oxidative enzymes responsible for oxidative phosphoryIation. Therefore, it is the 'power plant' supplying the energy to the flagellum to be used for propulsion of the sperm through the fluid medium. A dark ring is sometimes seen at the posterior end of the middle piece as a boundary between middle piece and the tail. It is known as 'ring centriole' but electron microscopic study reveals that the ring centriole does not resemble a centriole in its structure. Its origin and function are unknown.

Posted Date: 1/24/2013 6:23:55 AM | Location : United States






Your posts are moderated
Related Questions
Before the emergence of life of what gases was the earth's primitive atmosphere constituted? The earth's primitive atmosphere was fundamentally formed of methane, hydrogen, amm

Medical Nutrition Therapy Medical Nutrition Therapy  (MNT) is defined as  the  assessment of  the  nutritional status of  a client  followed  by  nutrition  therapy ranging Pon

In this section you will be introduced to a variant of Darwinian concept of natural selection which he termed sexual selection. You may have observed very distinct and striking dif

Nutritional care can be recognized as both a science and art. Can you tell why? It is considered as a science because the raped  advances in scientific knowledge provides all h


Elaborates Class Trematoda and Monogenea - Flukes? Members of this Class are commonly known as the tapeworms. They resemble a long flat tape, or ribbon, and are parasitic, livi

Consumers - Biotic Components These are also called as phagotrophs or heterotrophs. The organisms grouped under this category cannot manufacture their own food but obtain the

Animals of Estuaries The animals of estuaries and related wetlands such as marshes and swamps are tremendously important not only as denizens of their environment but also for

Assuming independent assortment, what proportion of the offspring of the cross AaBbCcDd × AabbCCdd will have the aabbccdd genotype?

An ecosystem is a self sufficient interacting system in the biosphere. Eg. forest, desert, pond etc. almost, all the ecosystem have more or less similar fundamental plan for their