[BIO 130 LAB] 2 Spermatogenesis & Spermiogenesis.pdf

SPERMATOGENESIS & SPERMIOGENESIS BIO 130 LAB INTARMED 2030 | Dr. Vitor | LU2 SEM 1 | SY. 2024-2025 Primary Diploid Spermatidogenesis TABLE OF CONTENTS Gametocyte (2n) I...

SPERMATOGENESIS & SPERMIOGENESIS BIO 130 LAB INTARMED 2030 | Dr. Vitor | LU2 SEM 1 | SY. 2024-2025 Primary Diploid Spermatidogenesis TABLE OF CONTENTS Gametocyte (2n) I. Gametogenesis Secondary Haploid Spermatidogenesis II. Spermatogenesis Gametocyte (n) A. Anatomy of the Testis B. Stages of Sperm Maturation Gametid Haploid Spermiogenesis a. Spermatogonia (n) b. Primary Spermatocytes Gamete Haploid Spermiation c. Secondary Spermatocytes (n) d. Spermatids e. Spermatozoa III. Frog Testis Micrographs IV. Rat/Mouse Testis Micrographs I. GAMETOGENESIS Process by which diploid/haploid cells (primordial germ cells) divide and differentiate to form mature haploid gametes Occurs through meiotic division of gametocytes Initial stage of embryonic development Figure 1: Gametogenesis of male and female gametes Function of gametes: ○ To survive environment different from gonad (e.g. II. SPERMATOGENESIS reproductive tract of female or external environment during external fertilization) ○ To recognize homologous cells of other sex but Process of development and maturation of male same species and participate in events relating to gametes fertilization (especially crucial for external Undifferentiated germ cells (spermatogonia) fertilization) transform into mature male gametes (spermatozoa) ○ To provide sufficient genetic/cytoplasmic Begins in the embryonic testis and is completed in materials for the development of a new organism sexually mature testis Spermiogenesis ○ Process that transforms spermatids into Cell Type Ploidy Female spermatozoa ○ Transforms the cell’s cytoplasm, nucleus, Golgi Gametogonium Diploid Oocytogenesis apparatus, mitochondria and centrioles (2n) ○ A subphase of spermatogenesis Primary Diploid Ootidogenesis Gametocyte (2n) ANATOMY OF THE TESTIS Secondary Haploid Ootidogenesis Gametocyte (n) Tunica albuginea ○ Thick white fibrous capsule surrounding the testes ○ Also found inside the testes creating partitions or septae, dividing the testes interior into conical Cell Type Ploidy Male lobules Leydig cells Gametogonium Diploid Spermatocytogenesis ○ Interstitial cells located in between seminiferous (2n) tubules ○ Have a close affinity with blood vessels BIO 130 LAB LU 2 SEM 1 | IMED 2030 Page 1 of 6 DE LUNA, MD; BAGNOL, JKT; ESGUERRA, KGM; REYES, JCDC SPERMATOGENESIS & SPERMIOGENESIS BIO 130 LAB INTARMED 2030 | Dr. Vitor | LU2 SEM 1 | SY. 2024-2025 ○ Secrete testosterone SPERM MATURATION Seminiferous tubules ○ Compartmentalized ovoid structures within the lobules Spermatogenesis ○ House the different spermatogenic cells ➔ Defined as the process of development and Rete testis maturation of the spermatozoa or the male ○ Plexus uniting each tubule within a lobule gametes ○ Connects to the efferent ductules ➔ Sperm maturation starts in the embryonic testis Efferent ductules and is completed in the sexually mature testis ○ Sperm ducts that drain the rete testis, pass 5 types of spermatogenic cells: through the tunica albuginea and feed into the ○ Spermatogonia epididymis ○ Primary spermatocytes Basement membrane/basal lamina ○ Secondary spermatocytes ○ Cells that line the seminiferous tubules ○ Spermatids Sertoli cells ○ Spermatozoa ○ Triangle-shaped nurse cells found by the basal SPERMATOGONIA _______________________________________________________ lamina ○ Aid in the development of sperm cells Youngest cells in the series First form in sperm maturation Appearance: round cells with round nucleus and occupies the basal layer of spermatogenic cells Nearest to the basal membrane/basal lamina of seminiferous tubules Have darkly stained nuclei Type A: replacement cells Type B: cells that become spermatocytes Figure N. Spermatogonium in Rat testis. Figure N. Anatomy of the testis, low power objective (frog specimen). PRIMARY SPERMATOCYTES _______________________________________________________ Spermatogonia becomes primary spermatocytes in the growth phase of development Largest cells in the series Appearance: round cells occupying the 2nd to 4th layer of spermatogenic epithelium Large and dense round nuclei = condensation of chromatin into chromosomes ○ synapsed chromosomes (paired/connected chromosomes) appear as dark chromatin structures in their nucleus Figure N. Anatomy of the testis, high power objective (rat Figure N. Primary spermatocyte in Frog testis. specimen). BIO 130 LAB LU 2 SEM 1 | IMED 2030 Page 2 of 6 DE LUNA, MD; BAGNOL, JKT; ESGUERRA, KGM; REYES, JCDC SPERMATOGENESIS & SPERMIOGENESIS BIO 130 LAB INTARMED 2030 | Dr. Vitor | LU2 SEM 1 | SY. 2024-2025 mass in the lumen of the sexually mature seminiferous SECONDARY SPERMATOCYTES _______________________________________________________ tubule Primary spermatocytes become secondary ○ Middle piece of the tail connects with the neck and spermatocytes after: appears darker than the principal piece of the tail ○ Maturation/equatorial division and the shape of spermatozoa heads varies in some ○ reductional/meiotic division species Not commonly found in slides/seminiferous tubular ○ boar = oval sections because after primary spermatocytes ○ bull = ovoid and compact undergo Meiosis I and become secondary ○ rat = triangular with a hook spermatocytes, they immediately undergo Meiosis II to ○ rooster = long and slender with a pointed tip become daughter spermatids Appearance: may sometimes be distinguishable by their smaller size and location, concentrated towards the lumen of the tubules Have larger chromatins than primary spermatocytes, and (chromatins) are more prominent than spermatids SPERMATIDS _______________________________________________________ Embedded in the cytoplasm of Sertoli cells and emerge as small cells with short tails Figure 2: Parts of a Spermatozoa. As secondary spermatocytes divide into spermatids, the spermatids metamorphose into mature sperm cells during spermiogenesis. Spermatid Fate in Spermatozoa Two stages of spermatids: ○ Early spermatids nucleus head ○ Late spermatids Early Spermatids centriole neck of the sperm ○ Appearance: small round cells with round nucleus nucleolus; located above the layers of primary centriole axial filament of the tail spermatocytes Late spermatids cytoplasm Envelope around the ○ Appearance: small cells with oval dense compact head, middle piece and nucleus and a short tail embedded in the tail cytoplasm of Sertoli cells Golgi apparatus acrosome Sertoli cells = tall columnar cells that occur individually at regular intervals in the mitochondria Spiral filament of middle seminiferous tubule; hardly visible in most piece testis sections Table N: Fate of Spermatid Parts in the Spermatozoa. SPERM MATURATION [SUMMARY] ○ Embryonic genital ridge → primordial germ cells ○ Undifferentiated male germ cells are called the spermatogonia (initiated at the male gonads) ○ Spermatogonia becomes primary spermatocytes ○ Primary spermatocytes undergo mitotic division to become secondary spermatocytes ○ Secondary spermatocytes undergo meiotic Figure N. Spermatids in rat testis (photomicrograph). division to become spermatids ○ Spermatids undergo spermiogenesis to become mature sperm cells (spermatozoa) SPERMATOZOA _______________________________________________________ sperm cells with head, neck, and tail, which form a BIO 130 LAB LU 2 SEM 1 | IMED 2030 Page 3 of 6 DE LUNA, MD; BAGNOL, JKT; ESGUERRA, KGM; REYES, JCDC SPERMATOGENESIS & SPERMIOGENESIS BIO 130 LAB INTARMED 2030 | Dr. Vitor | LU2 SEM 1 | SY. 2024-2025 III. FROG TESTIS MICROGRAPHS BIO 130 LAB LU 2 SEM 1 | IMED 2030 Page 4 of 6 DE LUNA, MD; BAGNOL, JKT; ESGUERRA, KGM; REYES, JCDC SPERMATOGENESIS & SPERMIOGENESIS BIO 130 LAB INTARMED 2030 | Dr. Vitor | LU2 SEM 1 | SY. 2024-2025 IV. RAT/MOUSE TESTIS MICROGRAPHS BIO 130 LAB LU 2 SEM 1 | IMED 2030 Page 5 of 6 DE LUNA, MD; BAGNOL, JKT; ESGUERRA, KGM; REYES, JCDC SPERMATOGENESIS & SPERMIOGENESIS BIO 130 LAB INTARMED 2030 | Dr. Vitor | LU2 SEM 1 | SY. 2024-2025 BIO 130 LAB LU 2 SEM 1 | IMED 2030 Page 6 of 6 DE LUNA, MD; BAGNOL, JKT; ESGUERRA, KGM; REYES, JCDC