The uterine tube extends bilaterally from the uterus to the region of the ovary and provides the environment for the fertilisation and early development of the embryo. The tube is composed of a mucosa, muscularis and serosa. The mucosa is highly folded and convoluted in these sections. The uterine tube is lined by simple columnar epithelium composed of ciliated and non-ciliated cells. The non-ciliated cells are also called secretory cells and may contain secretory granules, evident at the EM level (see TEM Uterine tube). Look for examples of these cells.
How does the structure of the uterine tube differ histologically along its length?
What are fimbria? What is their function?
What important biological process may occur at the ampulla?
What substance is responsible for maintaining the uterine tubule mucosa in a functional state?
Slide 94 x 40
x 100 Slide
94 x 100 Slide
94 x 400
Slide AD064 x 40 Slide AD064 x 400
With a x4 objective or projection microscope, examine the structure of the uterus noting the endometrium, myometrium, the serosal layers (are they present in #94?) and the uterine arteries and veins within the connective tissue of the broad ligament of the uterus (Demo ADO64). With a x10 objective, examine the uterine mucosa or endometrium. Note the coiled arteries within the endometrium.
What epithelium lines the lumen of the uterus? Describe the cellular character of the lamina propria or endometrial stroma. Does it resemble mesenchyme?
Examine the myometrium noting the interlacing bundles of smooth muscle fibres and large blood vessels present. Slide 94 demonstrates the thickness of the myometrium in the adult uterus. The myometrium is composed of the following layers but they often appear indistinct:
(a) a thin longitudinal layer lying immediately beneath the endometrium;
(b) a thick layer containing many blood vessels, which constitutes the bulk of the uterine wall (stratum vasculare);
(c) an outer thin longitudinal layer lying beneath the serosal surface of the uterus.
The demonstration slides (H8487 and AD068 to AD072) show the structure of the endometrium in different stages of the menstrual cycle (from secretory stage onwards for ADO slides). Correlate these stages with blood hormone levels. The lumen of the glands, the spaces between the connective tissue cells in the lamina propria and the morphology of the blood vessels change during the cycle. You should be able to distinguish histologically between menstrual, proliferative and secretory phases of the uterine cycle.
Early Proliferative Phase Demonstration Slide (H8487)
In contrast to the juvenile uterus (demonstration slide) the endometrium of this slide contains uterine glands, which in the follicular phase are straight tubular glands lined by a simple columnar epithelium. The mesenchyme-like stromal cells of the lamina propria lie in an abundant ground substance. Note the prominent blood vessels within the endometrium.
Proliferative Phase (4-14 days) Demo H8485
The compact (stratum compactum), spongy (stratum spongiosum) and basal (stratum basale) layers of the endometrium are indistinct. Some of the uterine glands, having increased in number and size, are coiled. They are still lined by simple columnar epithelium. Very little secretion is present. Note that the clear space around the glands is a shrinkage artefact.
Early Secretory Phase (14-18 days) Slide B (AD068)Slide AD068 x 100 Slide AD068 x 400
The endometrium has increased in thickness considerably. The uterine glands have also increased in number and are coiled. Some secretion is present in the glands. The stromal cells are densely packed in the compact layer, in the spongy layer they are separated by tissue fluid of oedema. The compact and spongy layers are less distinct in Demo H8486.
(20-21 days) Slide C (AD069)
In this phase there is maximum secretory activity of the endometrium. The uterine glands are highly coiled and are distended with secretion. The epithelial cells vary in function. Epithelium of the glands shows apical secretory blebs or a mucous secretory change. The lamina propria is markedly oedematous.
Late Luteal Phase
days) Slide D (AD070), Human Uterus H&E Demo H8486 b & c
Dilated uterine glands have a saw-tooth appearance and contain secretion. Nuclei of the epithelial cells are in the basal position and active secretion is prominent. Oedema of the lamina propria is more prominent from day 23-25 and is reduced from day 25-28. The spiral arteries present in the endometrium are more easily observed in Demo H8486b and c.
What is the role of the spiral arteries in menstruation?
Menstrual Phase (1-4 days) Slides E (AD071), Human Uterus H&E Demo H8487
Slide AD071 x
Slide H8487 x 100
The endometrium is decreased in height and shows loss of tissue from the surface. Note the integrity of the basal endometrial layer.
How does the endometrium resurface?
Now compare slide 94 with the above series. Which phase of the menstrual cycle is seen in slide 94?
To conclude, go back to your graph of the reproductive hormones during the 28 day menstrual cycle from the previous practical. You should now be able to explain the relationship between these hormones and both the ovary and uterus.
Cervix Human H&E Slide 94a
Human Demo Slide H8495
Human Trichrome slide 01G-Demo
Examine slide 94a with a x4 objective starting at the periphery of the tissue. Look particularly at the epithelium and the way in which it changes as you pass from the vagina/cervix into the uterus.
What type of epithelium lines the vagina and covers the portion of the cervix that projects into the vagina? What is the name given to this region of the cervix? What is the name of the opening of the cervix that exists in this region?
What is the transition (transformation) zone and why is it a pathologically important region?
Follow the epithelium into the entrance of the cervical canal and note the abrupt change in epithelium. Now examine the tissue under higher magnification. Identify the columnar cells of the endocervix. Note the characteristics of the cervical glands. Sometimes the glands become closed off and are converted to cysts (Nabothian Cysts). Examine the lamina propria. The arterioles are not coiled.
How do the glandular secretions of the cervix change over the menstrual cycle? Does this have any clinical implications for fertility? What is the Spinnbarkeit test?
Vagina Human Gomori's trichrome Slide 97
Vagina Human H&E Demo H8460
Glycogen in Vagina Human Demo HC111
Examine the slide with both the x4 and x10 objectives. Note type of epithelium, the vascular lamina propria and the muscle layer, which is organised in 2 indistinct, intermingling smooth muscle layers. There are no glands in the vagina. Under the influence of oestrogen, the epithelial cells synthesise and accumulate glycogen. Positive staining for glycogen (bright red) is observed in the more superficial cells of the epithelium (slide HC111).
How would you differentiate a slide of vagina from one of oesophagus?
How is the vaginal epithelium lubricated?
What are Bartholin's glands? What are they also known as? What are they homologous to in the male?
Mammary Gland Human H&E Slide 98
Mammary glands are quite often described in connection to the skin because of their evolutionary origin (they are modified sweat glands). The mammary gland is a compound tubuloacinar (or alveolar) gland joined to ducts which open at the nipple. Slide 98 is a section of resting mammary gland. Ducts, derived from lactiferous ducts, and their branches are arranged in lobes separated by dense interlobular connective tissue septa. The duct elements are surrounded by a loose cellular intralobular connective tissue. Using the x40 objective note the flattened nuclei of myoepitheliocytes in association with the duct epithelium. Secretory units (alveoli) are not present.
Active Mammary Gland Cat H&E Slide 99
Slide 99 is a section through the nipple of an actively secreting mammary gland. Identify the lactiferous duct. The lobules of the gland are separated by connective tissue septa and contain distended secreting alveoli. In the alveolar cells, secretory droplets accumulate in the apical cytoplasm, while the nucleus is displaced basally. This is not always apparent in slide 99.
Upon what hormones does the mammary gland depend?
By what mechanism do cells of mammary gland secrete?
Post Menopausal Mammary Gland Human H&E
Inactive Mammary Gland Human H&E Demo H7545
Look for secretory tissue and duct systems.
Nipple and areola, Demo slide 16
Identify the lactiferous ducts as they converge at the projection of the nipple. Also identify the presence of sebaceous glands opening directly onto the surface of the skin in this region (remember: sebaceous glands are normally associated with hair follicles).