Abstract
The spermatozoa are the male gamete produced in the seminiferous tubule through spermatogenesis. The spermatozoa are derived from germinal epitheliums that undergo a series of mitotic divisions followed by meiotic divisions to produce early stages of haploid gamete called spermatids (spermatocytogenesis).
The spermatids undergo differentiation to transform spermatozoa (spermiogenesis). The Sertoli cells play a pivotal role in spermiogenesis by providing nutrients to the spermatozoa. The spermatozoa are released from the Sertoli cells through spermiation. The spermatozoa released from the Sertoli cells are rarely motile without any fertilizing capability. During epididymal transit, the spermatozoa acquire some proteins required for protection against reactive oxygen species (ROS), gaining progressive motility and fertilizing ability. The spermatozoa are then mixed with the secretion of the accessory sex glands known as seminal plasma at the pelvic urethra and expelled out through a synchronized physiological event called ejaculation. The chapter encompasses the process of spermatogenesis and sperm maturation during epididymal transit, the formation of seminal plasma and its composition, the neuroendocrine regulation of ejaculation and physiobiochemical properties of semen, including different biomarkers of sperm maturity divided into two subchapters, spermatogenesis and semen.P. K. Das (X) ∙ J. Mukherjee ∙ D. Banerjee
Department of Veterinary Physiology, West Bengal University of
Animal & Fishery Sciences, Kolkata, West Bengal, India
© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2023
P. K. Das et al. (eds.), Textbook of Veterinary Physiology, https://doi.org/10.1007/978-981-19-9410-4_20
Graphical Abstract
Description of the graphic: The spermatogenesis involves the synchronized process of cell division (1) through which the spermatogonium (stem cells) is developed into a haploid male gamete, spermatozoa.
The entire process is controlled by endocrine factors associated with the hypothalamic- pituitary-gonadal (HPG) axis (2). Various stressors affect spermatogenesis mainly through the hypothalamic-pituitary-adrenal axis (3). Through spermiogenesis (4), mature spermatozoa have distinct head, neck, mid-piece, and tail (5) with progressive motility. The evaluation of spermatozoa viz. sperm motility (6), the proportion of morphologically normal (7) and abnormal (8) spermatozoa, and sperm concentration (10) are the essential pre-requisites to screen the semen for successful fertilization using various conventional techniques as well as (11) advanced computer-assisted semen analyser (12).Keywords
Spermatogenesis ∙ Epididymal transit ∙ Ejaculation ∙ Semen ∙ Spermatogenic efficacy
Learning Objectives
• Mechanism of spermatogenesis and the factors affecting it
• Epididymal transit of spermatozoa and its physiobiochemical alterations to gain motility and fertilizing capability
• Formation of seminal plasma
• Ejaculation and its associated events
• Physio-biochemical composition of semen
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