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M. D. TINGARI

Summary.

Ultrastructural observations were made on fowl spermatids and free spermatozoa, fixed in situ, in the lumina of the seminiferous tubules, the rete testis, the ductuli efferentes, the connecting ductules, the ductus epididymidis and different levels of the ductus deferens.

Changes occurred in the acrosome during the differentiation of the spermatid. The early ellipsoidal form of the acrosome attains a mature, elongated shape at the late spermatid stage. During this stage, remodelling and condensation of chromatin of the nuclear region also occurs. The acrosomal cap changes from a loosely fitting structure before spermiation to become relatively closely apposed to the sperm nucleus in the excurrent ducts. The plasma membrane overlying the acrosomal cap of the free spermatozoon is closely applied whilst that over the head is slightly loose and swollen, especially in the ductus epididymidis. The inner mitochondrial membrane becomes thicker when the spermatozoon reaches the rete testis.

A cytoplasmic droplet is not seen in the middle piece of the fowl spermatozoon.

It is concluded that the structural differentiation of the fowl spermatozoon is almost complete directly after spermiation, and is earlier than the achievement of the fertilizing capacity which is reported to occur in the ductus epididymidis. There is no obvious correlation at an ultrastructural level between the morphological and the functional maturation of the fowl spermatozoon.

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M. D. Tingari and K. A. Moniem

Summary. Distinct morphological regions, initial, middle and terminal segments, were distinguishable histologically; the middle segment was further subdivided into proximal, intermediate and distal parts.

PAS-positive, diastase-resistant reaction was detected in the blood vessels, subepithelial tissue and stereocilia of all segments. Acid phosphatase was demonstrated in the epithelial cells with the highest activity being in the proximal part of the middle segment. Non-specific esterase gave a similar reaction but the strongest activity was in the terminal segment. Alkaline phosphatase, adenosine triphosphatase and adenosine monophosphatase were of similar activity in the subepithelial tissue, blood vessels, stereocilia and luminal contents; the strongest reaction occurred in the middle segment. Lactate, succinate, glutamate and glucose-6-phosphate dehydrogenases were examined; LDH was more active than the others particularly in the terminal segment. Some reaction was found in the epithelial cells, subepithelial tissue and luminal contents.

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M. D. TINGARI and P. E. LAKE

Summary.

The fate of fowl spermatozoa and testicular fluid retained in the excurrent ducts, and some properties of the epithelial cells lining the ducts, were studied after ligation of the ductus deferens by light and electron microscopy. Striking changes occurred 3 or 4 weeks after ligation.

Spermatozoa accumulated cranial to the ligature chiefly in the lumina of the ductuli efferentes. They showed signs of disintegration mainly in the head where there was a disruption of chromatin and loosening of membranes. An increased amount of cell débris of unknown identity was also observed in the lumina of the ducts.

The uptake of spermatozoa by epithelial cells lining the male tract was seen in normal males but was much increased after ligation. The process was evident in the low cuboidal cells of the rete testis and in the ciliated and non-ciliated Type I cells lining the ductuli efferentes and narrow connecting ductules, and in the non-ciliated Type II cells lining the wide connecting ductules, ductus epididymidis and ductus deferens. Macrophages, containing spermatozoa, were found in the lumina of the ducts, in the subepithelial tissue and wedged between the basal lamina and the surface epithelia. All of these observations may indicate a route for the disposal of unejaculated spermatozoa in the male fowl.

Cytoplasmic vacuoles containing testicular fluid were seen in the apical parts of the ciliated cells and this may represent resorption of the fluid by these cells.

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M. D. TINGARI and P. E. LAKE

Summary.

Ultrastructural studies were made on the uterovaginal sperm-host glands from virgin and inseminated hens. Their fine structure differs only in the presence of spermatozoa in the glandular lumina. Ciliated and non-ciliated epithelial cells were present; the former occurred in the neck region of the tubular glands and merged with the general vaginal surface epithelium.

The true glandular epithelium was composed of non-ciliated cells which showed evidence of high metabolic and secretory activities. The secretion contained carbohydrate and lipid but apocrine secretion rich in glycogen was also observed occasionally. The significance of these secretions in relation to the survival of the stored spermatozoa is discussed. The non-ciliated cells contained many cytoplasmic filaments resembling tonofibrils. It is suggested that these confer contractility on the gland cells, so mobilizing the spermatozoa in response to unknown periodic stimuli associated with oviposition or ovulation.

The stored spermatozoa did not form an intimate association with the lining cells of the glands but the covering membranes of the heads of spermatozoa adhered to each other. It is suggested that this might be due to the absence of antiagglutinating factors in the sperm-host glands.