General Instructions:
- Copy the given assignment of practical in fair practical copy of biology.
- Make the use of black pen for heading and sub-headings and blue pen for writing other content.
- Work should be presentable.
- Make well labelled and proper diagram as provided in this assignment.
Spot No.5
Aim: To study and identify different stages of gamete development from T.S of mammalian ovary through permanent slide.
Materials required: Compound microscope, permanent slides of T.S of mammalian testis.
Theory: In all males organism, gamete formation takes in their gonads i.e testis and ovary. The process of gamete formation is called as gametogenesis which is of following two types.
- Spermatogenesis (formation of male gamete sperms)
- Oogenesis (formation of female gamete ova)
Procedure:
- Clean the slide and microscopes eye and objective lens with the help of cleaning paper.
- Place slide in the stage of microscope. Observe it under low power of microscope followed by high power.
Observation:
- Each ovary is lined by germinal epithelium which is surrounded by visceral peritoneum. Beneath the germinal epithelium a connective tissue is present called as tunica albuginea
- Underlying it is layer of stroma in which ovarian cycles are present in different stages.
- Pre-mordial follicle: It consists of primary oocytes surrounded by single layer of granulosa cells.
- Pre-antral follicle: A non-cellular material zona pellucida is formed between primary oocytes and granulosa cell. A theca layer begins to form tunica albuginea and starts making boundary of granulosa cell.
- Early-antral follicle: A fluid filled space called antrum is formed between the granulosa cell and the antral fluid is secreted by granulosa cell themselves.
- Graafian follicle/ Matyre follicle: Ovulation occurs in this stage. Antrum is expanded and some graulosa cells accumulate to lift the ovum by forming a cellular mount called cumulus oophorous
- After ovulation, the follicular cells which are present in empty follicle form a glandular endocrine structure called as corpus luteum which secreted progesterone.
- Corpus albicans is formed by degeneration of cropus luteum.
Precautions
- Always handle microscope carefully.
- Observe slide under low power followed by high power.