Fig. 2
From: Genetic causes of male infertility: snapshot on morphological abnormalities of the sperm flagellum
Ultrastructural defects of the MMAF phenotype. a, d control individual; (b, c, e, f) MMAF individual. Pictures from Aminata Touré. a Human spermatozoa with the head on the left, and the flagellum on the right side. The flagellum is divided into two main compartments: the midpiece, which comprises the mitochondrial sheath, and the principal piece, characterized by the presence of a fibrous sheath surrounding the axoneme. b, c Sperm from MMAF individual display incomplete flagellum with short midpiece and abnormal fibrous sheath disposition (b); some sperm lack flagellum and display a large cytoplasmic bag with unassembled axonemal and peri-axonemal components (c). d Transversal section of the axoneme showing the regular microtubule organization with 9 microtubule doublets surrounding the central pair (9 + 2), in normal sperm. e, f In MMAF individual, the axoneme often display a lack of the central pair or total disorganization. Ac: acrosome; Ax: axoneme; CP: central pair, ODF: outer dense fibers; FS: fibrous sheath; LC: longitudinal column, MTD: microtubule doublets, M: mitochondria; N: nucleus