OVERVIEW OF REPRODUCTION. M. A. Kai-Kai. Learning Objectives. Understanding: A natomy of the male and female reproductive systems Structure of the gonad as a cytogenic and endocrine organ.
OVERVIEW OF REPRODUCTION
M. A. Kai-Kai
OVERVIEW. The female
Reproductive tract of bitch
1.Different parts of the female reproductive system each with specific functions.
2.Transient seasonal changes in structure and function.
3 Functional sequence of the femalegametogenesis/
4. Age changes in structure
Body of uterus
Female animals can be:
fertilisation at ampulla-isthmic
2.Mediastinum(M) and rete testis.
Femaleoogenesis and folliculogenesis
in foetal gonad and before puberty
--gonocytes undergo mitosis
--primordial and primary follicles form in ovary
--prespermatogonia form in testis.
--begins at puberty
-- in ovary folliculogenesis and oogenesis form hierarchy of folliclesovulation.
--male germ cell undergo morphogenesischange in cell morphology.
--Oogenesis in femaleova
--Spermatogenesis in malespermatozoa
1.Dimensional criteria. Size
--thickness of the theca and granulosa layer
--degree of vascularisation
--position of antral cavities
--degree of vascularisation
--quantity of muscle fibres and interstitial tissue.
3.Normal functional follicles e.g. corpus luteum
1. Foetal gonad, gonocytes undergo mitosis and induced into meiosis(MIF).
--meiosis I arrested in prophase I, forms primary oocyte.
2.Puberty-->FSH,LH,secretion leads to follicular development and oocyte maturation.
--hormonal influence-->growth, meiosis I and meiosis II in oocyteforms secondary oocyte.
events in ovulation.
--co-ordinates growth and maturation of oocyte and granulosa cells.
--eostrogen is mitogeniccells proliferate.
--theca cells and zona pellucida(ZP) form.
--more FSH,oestrogen receptors
--formation of Corona radiata
--granulosa cells secrete follicular fluid into intercellular clefts
--intercellular spaces coalesce into single antrum
--follicular liquorcontainsnutrients and hormones.
--granulosa cells distributed into peripheral parietal layer,coronaradiata and cumulus oophorus .
--the CR support and accompany the oocyte at ovulation.Ovum devoid of CR do not fertilise.
--hormonal surge leads to increase in enzyme activity(collagenase)
--increased intrafollicular pressure.
1.Renewal of spermatogenic stem cell
2.Reduction of chromosome to haploid state by meiosis.
3. Metamorphogenesis of a convential cell into a flagella spermatozoa.
mitosis of stem cell spermatogonia A.
2. Meiosisreduction division
Golgi phasegolgi membrane forms cap over nucleus.(1,2).
Acrosome phaseformation of Acrosome from Golgi.(3)
Formation of flagellum.
--organisation of contractile axoneme
--organisation of mitochondria in
middle piece and principal piece
--organisation of dense fibrous sheath.
PC. Posterior centriole
DC. Distal centriole
1.Ova ovulated from ovary, transported through uterine
2.Sperm deposited in vaginatransportedcapacitation, acrosomecapacity to fertilise.
3.Fertilisation at ampulla-isthmic junction.
4.Zygote transportedimplantated in endometrium.
1. Binding of sperm to
2. Acrosome reaction:
3. Penetration of Zona Pellucida
The cortical reaction
4.Fusion of plasma membranes of sperm
5.Sperm nucleus enters oocyte, forms pronucleus,
meiosis II complete.
1. Female born with definite number of post mitotic follicles and gametes needed in life.
2. Meiosis begins in the fetal ovary, is arrested at prophase I and is resumed at puberty.
3. Meiosis imitated once in a definite group of cells
4. Differentiation of gametes occurs while diploid in the first meiotic prophase
5. Gamete has typical cellular structure.
6. There are more variations in the mechanisms oogenesis according to patterns of reproduction
1. Male gametes undergo mitosis throughout life, but Sertoli cells are post mitotic
2. Meiosis starts at puberty.
3. Meiosis initiated continuously in a mitotically dividing stem cell population.
4. Differentiation of gametes occurs while haploid after meiosis ends.
5. The spermatozoa has atypical structure.
6 There is less variation in the mechanisms of spermatogenesis.
1. Alberts, B; Johnson, A; Lewis, J; Martin, R; Roberts, K; & Walter, P(2002).
The Molecular Biology of the Cell. 4th.Edition. Garland Science Chapter 20.
2. Dyce, K; M.,Sack, W;O, & Wensing, C;J;G.(2006). 3rd. Edition. Textbook of Veterianry Anatomy.Pages183 – 202, 435 -453
3. Neill,J;D.(editor-in-Chief). Physiology of Reproduction. 3rd.Edition. Elsevier. London.Volume 1. Page3-113.