This micrograph illustrates a mouse adult secondary follicle in the ovarian cortex which surface is covered by a layer of cuboidal or columnar mesothelial cells (M). The secondary follicle shows the fluid-filled antrum (A), but the nucleus of the oocyte (O) surrounded by zone pellucida (ZP) does not lie in this section. The stratum granulosum (SG),a stratified epithelium composed of granulosa cells, surrounds the oocyte. At the periphery of the follicle, the several layers of rounded cells in theca interna (TI) is highly vascularized and have the features of typical steroid-secreting cells. External to theca interna (TI) is the less well-defined theca externa (TE) consisting of spindle-shaped cells.

This micrograph illustrates a mouse adult secondary follicle in the ovarian cortex. The secondary follicle shows the fluid-filled antrum (A), but the nucleus of the oocyte (O) surrounded by zone pellucida (ZP) does not lie in this section. The stratum granulosum (SG),a stratified epithelium composed of granulosa cells, surrounds the oocyte. At the periphery of the follicle, the several layers of rounded cells in theca interna (TI) is highly vascularized and have the features of typical steroid-secreting cells. External to theca interna (TI) is the less well-defined theca externa (TE) consisting of spindle-shaped cells. The basement membrane (BM) separates the granulosa cells from the theca interna (TI).

This electron micrograph illustrates a secondary follicle in the ovarian cortex. The secondary follicle shows the fluid-filled antrum (A), but the nucleus of the oocyte (O) surrounded by zone pellucida (ZP) does not lie in this section. The stratum granulosum (SG),a stratified epithelium composed of granulosa cells, surrounds the oocyte. The basement membrane (BM, yellow arrows) separates the granulosa cells from the theca interna (TI) which is highly vascularized and have the features of typical steroid-secreting cells.

The right electron micrograph is an enlargement of the box in the top-left image and shows the oocyte cytoplasm (O) of a secondary follicle surrounded by zone pellucida (ZP). Several process (green arrows) of granulosa cells (G) extend into the zona pellucida (ZP).

This electron micrograph shows the oocyte (O) of a secondary follicle surrounded by zone pellucida (ZP). Several process (green arrows) of granulosa cells (G) and numerous microvilli from the oocyte (red arrows) extend into the zona pellucida (ZP). The oocyte cytoplasm (O) exhibit specialized cortical granules (blue arrows) located just beneath the plasma membrane.

Numerous microvilli from the oocyte (red arrows) extend into the zona pellucida. The oocyte cytoplasm (O) exhibit specialized cortical granules (blue arrows) located just beneath the plasma membrane.

This electron micrograph shows several process (green arrows) of granulosa cells (G) extending into the zona pellucida (ZP).

Two nuclei of granulosa cells (G) with many mitochondria (M) and a desmosome (orange arrow) are shown.

The right electron micrograph is an enlargement of the box in the top-left image. The basement membrane (BM, yellow arrows) separates the granulosa cells (G) from the theca interna (TI) which is highly vascularized and have the features of typical steroid-secreting cells. Lipid droplets (blue arrows) appear in the cytoplasm of the theca interna cells. Part of a blood vessel (BV) is observed at the top right corner.

Cells in the theca interna have many lipid droplets (blue arrows) and mitochondria (M).

Cells in the theca interna have many lipid droplets (blue arrows) and mitochondria (M).

This micrograph illustrates the mucosa of the uterine tube which exhibits several longitudinal folds. The mucosa is lined with simple columnar epithelium with ciliated and nonciliated cells. Ciliated cells (red arrows) could be identified by the presence of cilia and basal bodies. In contrast, nonciliated cells, also called peg cells, are identified by the absence of cilia and basal body.

The mucosa of the uterine tube is lined with simple columnar epithelium with ciliated and nonciliated cells. Ciliated cells (red arrows) could be identified by the presence of cilia and basal bodies. In contrast, nonciliated cells (black arrows), also called peg cells, are identified by the absence of cilia and basal body.

This electron micrograph shows the mucosa of the uterine lined with simple columnar epithelium with ciliated (C) and nonciliated (NC) cells. Ciliated cells could be identified by the presence of numerous cilia (red arrows) and basal bodies. In contrast, nonciliated cells (NC), also called peg cells, are identified by the absence of cilia and basal body.

The mucosa of the uterine is lined with simple columnar epithelium with ciliated (C) and nonciliated (NC) cells. Ciliated cells (C) could be identified by the presence of numerous cilia (red arrows) and basal bodies. In contrast, nonciliated cells (NC), also called peg cells, are identified by the absence of cilia and basal body.

Numerous cilia with cross sections (blue arrow) and longitudinal section (red arrow) are shown on the apical of ciliated cells (C). The 9+2 microtubule arrangement of the cilia in which two central microtubules are surrounded by 9 microtubules at the periphery of the cilia could be seen in the image. The basal bodies lack the central micro tubule pair and its arrangement is 9+0 (yellow arrows). A desmosome (green arrow) could be observed at the junction of ciliated (C) and nonciliated (NC) cells.

Numerous cilia with cross sections (blue arrow) and longitudinal section (red arrow) are shown on the apical of ciliated cells. The 9+2 microtubule arrangement of the cilia in which two central microtubules are surrounded by 9 microtubules at the periphery of the cilia could be seen in the image. The basal bodies lack the central micro tubule pair and its arrangement is 9+0 (yellow arrows). A desmosome (green arrow) could be observed at the junction of ciliated (C) and nonciliated (NC) cells.