FERTILISASI: Ovum & Spermatozoa

DISKUSI KELOMPOK Kelompok 1 1. Kelompok 2 1.

Struktur ovarium

Fertilization: 1. Sperm maturation a. Occurs in the male genital tract: - in the epididymis is stimulated by epididymal proteins - in the urethra by mixture with secretions of the seminal vesicle, prostate and bulbo-urethral glands b. Is associated with changes in cell surface glycoprotein c. Results in: - the progressive motility - the ability to fertilize an oocyte

2. Sperm Capacitation are: a. Occurs in the female genital tract b. Is stimulated by secretions in the vagina , uterus, and uterine tubes c. Results in capacity to pass through the corona radiata

Sperm Capacitation Fertil Fresh Fertil ? ejaculate Kapasitasi Perubahan pd Protein seminal Plasma & reorganisasi Lipid dan Protein membran sperma, Influx Ca, cAMP , pH intrasel  Motilitas hiperaktif Transpot gamet Inkubasi di media fertilisasi Bbrp jam

Capacitation and fertilization Capacitation and fertilization. (A) capacitation, sperm develop hyperactivated motility, the ability to respond to chemotactic signals and acrosome reaction-inducing signals. Capacitated sperm penetrate the cumulus and reach the zona pellucida. Contact with the zona pellucida triggers acrosome reactions, permitting sperm to penetrate to the oocyte surface and fuse with the oocyte. Multiple steps in this process are controlled by capacitation. (B) Simple model of CFTR function during capacitation, in which HCO3 − entry through CFTR stimulates an sAC/PKA cascade leading to the activation of downstream effectors and to capacitation.

The tyrosine phosphorylation signaling pathways in capacitation The tyrosine phosphorylation signaling pathways in capacitation. Three major signaling pathways, namely cAMP/PKA-dependent pathway (pathway I), receptor tyrosine kinase pathway (pathway II), and non-receptor protein tyrosine kinase pathway (pathway III).

Spermatozoa-Zona Pellucida Zona pellusida (ZP) Binding Interaksi receptor-ligand (species specificity) Kelp KH (glikoprotein) di ZP berfungsi seperti receptor sperma; stimulasi fusi membran plasma dg membran akrosom luar Receptor sperma → bbrp mcm protein

3. Acrosome reaction are: a. Is stimulated by sperm-binding glycoprotein molecules in the zona pellucida (ZP3, ZP1 and ZP2 ligands) b. Is accompanied by Ca2+ influx into sperm c. Results in the release of acrosomal enzymes, which include hydrolytic enzymes d. Involves fusion of the acrosome membrane and plasma membrane e. Is necessary for sperm penetration through the zona pellucida

Acrosome Reaction

Penetrasi Zona Pellucida Keberhasilan penetrasi menembus ZP dipengaruhi oleh: kekuatan ekor spermatozoa (motilitas) kombinasi enzim akrosomal Sperm Zona pellusida (ZP) Menerobos

ZP Sperm-Oocyte Binding Sperm Membran oosit Binds & Fuses Sperm * Proses binding pd bag posterior (post-acrosomal) spermatozoa * Molekul yang berperan→ glikoprotein : Fertilin * Peran fertilin: mengikat membran plasma oosit dan induksi fusi

Aktivasi telur & Reaksi Cortical Oosit mature Egg Metafase Sperm Fertilisasi egg activation Faktor yang mempengaruhi: Konsentrasi Ca  tinggi Kelengkapan meiosis II Cortical reaction → eksositosis, granula kortikal tampak pendek stlh fusi sperma-oosit. Granula kortikal menghslkan bbrp enzim al. protease → difusi dlm ZP diikuti eksositosis dr telur dan mengubah struktur ZP . Komponen granula kartikal juga berinteraksi dgn membran plasma oosit.

The Zona Reaction Reaksi zona Struktur ZP ZP mengeras Infertil Blok polispermia Katalis protease ZP mengeras Rusak reseptor Sperm di ZP Hambat sperma Masuk ZP Infertil

Polyspermy two or more sperm make it into the egg polyspermy occurs genetic material condensed into chromosome is attracted to the extra sperm causing abnormal development and death of the embryo many sperm and toxic conditions can lead to polyspermy Polyspermy is a significant problem for fertilization

Dua mekanisme menghambat polispermia: Spermatozoa memicu masuknya ion Na depolarisasi, yang menghambat pengikatan spermatozoa lain (fast block) Spermatozoa merangsang pelepasan ion Ca  fusi vesikula kortikal secara exositosis dengan membran plasma, dengan melepaskan tripsin-protease untuk merusak ikatan spermatozoa pada membran vitelline, ruang kosong tersebut diisi oleh cairan, shg membran vitelline membentuk dinding lebih permanen (slow block).

Organel sitoplasma zigot hampir seluruhnya dari oosit: mitokondria DNA hampir seluruhnya oosit penyakit genetik mitokondria umumnya diwariskan melalui ibu Gen dalam DNA mitokondria oosit diperlukan untuk fosforilasi oksidatif Sebagian besar penyakit mitokondria mempengaruhi otot dan saraf, contoh pewarisan penyakit mitokondria adalah: - Miopati mitokondria (mempengaruhi otot) - Atrofi optik Leber (mempengaruhi saraf optik)

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