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
Define Reagents for Determination of the Iodine Number of Lipids? The following reagents are required to conduct this experiment. 1. Hanus solution (Iodine monobromide solut

Q. What is the adnexal organ of the digestive system in which bile is stored? How does this organ react to the ingestion of fat rich food? Bile is concentrated and stored in th

A v i a n tuberculosis Tuberculosis in poultry has not remained a big threat in list of diseases due to commercialization of poultry business. It is a contagious chronic di

What event marks the beginning of the menstrual cycle? What is the blood concentration of FSH, LH, estrogen and progesterone in this phase of the cycle? By convention the menst

A large leaf on a plant in bright sunshine evaporates 5 grams of water per hour. Cooling the leaf through evaporation in this manner enables the plant to eliminate heat energy at t

Define Work Capacity that is relevant to sports nutrition? There are generally two areas of work capacity that is relevant to sports nutrition one is aerobic capacity and the o

Food Applications Dextran can be used in food products, as it is capable of moisture retention and inhibition of crystallization of sugar. The properties of dextran as gelling

Why Physical Activity is important for weight loss? You are already aware that exercise plays an important role in initiating and sustaining weight loss along with dietary and

Q. Find the Modalities in stress testing? In addition to electrocardiographic stress testing, there are various newer modalities that can be very useful in the determination o

What are the differences and similarities between the bacterial and eukaryotic cell membranes?