OVARIAN AND UTERINE CYCLES BY DR SHIVRAM BHAT

QUESTIONS Primordial follicle ( Short Answer) Primary follicle ( SA) Secondary follicles ( SA) Tertiary follicle ( SA) Graafian follicle - diagram ( SA) Corpus luteum ( SA) Corpus albicans ( SA) Folliculogenesis ( Short essay) Graafian follicle (SE)

FEMALE SEXUAL CYCLES Birth – Puberty Menarche – Menopause Post menopause

CONTENTS Ovarian cycle Uterine cycle

LEARNING OBJECTIVES To learn about cyclical events occurring in ovary leading to folliculogenesis To learn about cyclical events seen in uterine endometrium. To know about other changes occurring due to female hormones To know about some of the applied aspects

PHYSIOLOGICAL CHANGES IN Ovaries Endometrium Cervix Vagina Breasts Body and Mind

HORMONES

OVARIAN CYCLE

OVARIAN FOLLICLES Each follicle consists of an immature egg called an oocyte Cells around the oocyte are called: Follicle cells (one cell layer thick) Stimulated to mature by FSH from the pituitary gland Granulosa cells (when more than one layer is present) Thecal cells: Cells in the ovarian stroma Thecal & granulosa cells work together to produce estrogen A protective layer of glycoprotein forms around the egg called the zona pellucida 9

FOLLICLE DEVELOPMENT 1. 2. 3. 4. 5. Primordial follicle: one layer of squamouslike follicle cells surrounds the oocyte Primary follicle: two or more layers of cuboidal granulosa cells enclose the oocyte Secondary follicle: has a fluid-filled space between granulosa cells that coalesces to form a central antrum Graafian follicle: secondary follicle at its most mature stage that bulges from the surface of the ovary Corpus luteum : ruptured follicle after ovulation 10

OVARY HISTOLOGY 11

OVARY HISTOLOGY 12

Primary Follicle 1° Oocyte (arrested in prophase I) Nucleus Primordial follicle Zona pellucida Thecal cells Granulosa cells 13

SECONDARY FOLLICLE Fluid-filled antrum 14

GRAAFIAN FOLLICLE 15 Fluid filled antrum Oocyte 2° Granulosa cells Stalk Corona radiata Zona pellucida

CORPUS LUTEUM After ovulation, the remains of the follicle are transformed into a structure called the corpus luteum. If a pregnancy occurs, it produces progesterone to maintain the wall of the uterus during the early period of development.

CORPUS ALBICANS If fertilization does not occur, the corpus luteum will begin to break down about 2 weeks after ovulation. Degeneration occurs when fibroblasts enter the corpus luteum and a clump of scar tissue forms called the corpus albicans.

OVARIAN CYCLE Monthly changes that occur in the ovary during a woman’s reproductive life. Each month FSH stimulates primordial follicles to grow and mature (follicular phase) Ovulation- release of the egg (LH) Luteal phase the corpus luteum produces progesterone that maintains uterine walls If fertilization does not occur, the corpus luteum degenerates, within 2 weeks into a mass of scar tissue called the corpus albicans

FOLLICULOGENESIS

GRAAFIAN FOLLICLE

GRAAFIAN FOLLICLE

UTERINE CYCLE

UTERUS 27

UTERINE HISTOLOGY Endometrium Simple columnar epithelium Stroma of connective tissue and endometrial glands Stratum functionalis: Shed during menstruation Stratum basalis: Replaces stratum functionalis each month Myometrium 3 layers of smooth muscle Perimetrium Visceral peritoneum 28

UTERINE HISTOLOGY 29

ENDOMETRIUM 30 Simple columnar epithelium Endometrial glands

ENDOMETRIUM Proliferative phase: glands and blood vessels scattered throughout the functional zone with little or no branching. New glands form and endometrium thickens. Secretory phase: glands are enlarged and have branches. Preparing the endometrium for implantation If no implantation then endometrium breaks down and menstruation begins.