Tissue Staining
Q.7 Epithelium covers body surfaces, lines hollow organs and also forms gland. They serve as protective covers to the underlying tissues and prevents harm caused by physical, chemical and biological agents, to a significant extent. In addition, they also act as barriers, allowing the selected entry and exit of substances across the epithelium. The glandular epithelium has secretory function. Example: Epithelium of the pancreas, stomach, intestine, kidney. The epithelium lining the stomach and intestine help to absorb nutrients. (Henrikson, Kaye and Mazurkiewicz,1997)
Q1. Micrograph A : Simple cuboidal epithelium. The cube shape of the cells and the centrally located, large, spherical nuclei has helped me in identifying the epithelium. This epithelium serves secretory and absorptive function. (Henrikson, Kaye and Mazurkiewicz,1997)
Micrograph B : Simple columnar epithelium. Single layer of tall cells with oval nulcei, helped to identify the simple columnar epithelium. The epithelium also contains mucus secreting goblet cells. Simple columnar epithelium, serves secretory and absorptive function. (Henrikson, Kaye and Mazurkiewicz,1997)
Micrograph C : Stratified squamous epithelium. The epithelium is thick and made of many layers of cells. The cell layers towards the surface are squamous type, while those at the base are more cuboidal. The top most layer of cells appears keratinised. The primary function of such epithelium is to protect underlying tissues from abrasive damage. (Henrikson, Kaye and Mazurkiewicz, 1997)
Micrograph D : Ciliated Stratified columnar/cuboidal epithelium. Multiple layers of tall columnar cells and cuboidal cells are seen in the micrograph image. The cells are ciliated. They serve protective and secretory function. (Henrikson, Kaye and Mazurkiewicz,1997)
Micrograph E : Ciliated pseudostratified columnar épithélium. The nuclei of the columnar cells are not at the same level and thus they appear stratified. But, on observing the basement membrane, it can be understood that they are single layer of cells. All the cells have a ciliated surface. The mucus secreted by the epithelium traps dust and other unwanted particles. Cilia help to move the trapped particles to the exterior. (Henrikson, Kaye and Mazurkiewicz, 1997)
Q 2: Micrograph A: Simple cuboidal epithelium can be observed lining the kidney tubules, surface of the ovary and ducts of small glands. (Henrikson, Kaye and Mazurkiewicz, 1997)
Micrograph B : Non ciliated simple columnar epithelium are found lining the digestive tract from the stomach to anal canal, gall bladder and excretory ducts. (Henrikson, Kaye and Mazurkiewicz, 1997)
Micrograph C : Keratinised stratified squamous epithelium is seen lining the skin. (Henrikson, Kaye and Mazurkiewicz, 1997)
Micrograph D : Ciliated Stratified columnar/cuboidal epithelium are seen lining the sweat gland, large glandular duct, male reproductive tract, etc. (Henrikson, Kaye and Mazurkiewicz, 1997)
Micrograph E : The ciliated pseudostratified columnar epithelium are found lining the trachea and bronchi, where they contribute to the specific functions of the organ. (Henrikson, Kaye and Mazurkiewicz, 1997)
Q3 : Under the same magnification, the skeletal muscle histology image A shows myocytes that are larger in size but few in number. Image B has small size myocytes, but more in number. Otherwise, both images look similar. It is possible that the muscle cells in image A have undergone hypertrophy. Hypertrophied muscle cells appear larger. Hypertrophy is characterized by an increase in cell size and not in cell number. The size of the myocyte increases due to the formation of new myofilaments and sarcomeres. (Eroschenko and Fiore, 2008)
Q4 : Muscle hypertrophy is characterized by an increase in muscle mass and grith. It is an adaptation process exhibited by the muscles to a regular stimuli ; the most common stimuli being exercise. Exercise increases the neural drive to the muscles to contract. This in the due course helps the muscle fiber to achieve a measurable amount of strength. Anabolic steroid can also cause muscle hypertropy. Hypertrophy is a means by which the muscles adapt to the demands of the stimuli. The synthetic pathways of the muscle cells are up-regulated in response to stimuli. (Eroschenko and Fiore, 2008)
Q5. The micrograph B shows smaller size villi when compared to micrograph A. There is also basophilic infiltration in the lamina propria, which suggest inflammatory changes. This could be a response of the small intestine to infection. (Siumed.edu, 2016)
Q6: A. The histology shows the endometrium in the proliferative stage. Hormone FSH facilitates changes happening during the proliferative phase. The endometrium appears thickened. The connective tissue structure is seen. Four distinct structures are seen in the endometrium histology on close observation: stratum compactum, stratum spongiosum, stratum basalis and myometrium. (Paxton, Adele and Peckham, 2003)
B. The histology shows the endometrium in the secretory phase. High level of LH in the blood is responsible for changes seen in this phase. The endometrial glands appear to be filled with mucous secretion. The glands are visible. The glycogen rich secretion of the gland lubricates the uterus, following ovulation. Some of the glands have a corkscrew shape. (Paxton, Adele and Peckham, 2003)
C. The histology shows the endometrium in the menstrual phase. The decrease in LH and progesterone are responsible for this phase. Shredding of uterine lining can be seen in the histology. The capillaries in the surface layer rupture and bleeding occurs during the menstrual phase. Basal layer of the endometrium is unaffected by menstrual changes. (Paxton, Adele and Peckham, 2003)
References
Eroschenko, V. and Fiore, M. (2008). DiFiore's atlas of histology with functional correlations. Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins, pp.117-120.
Henrikson, R., Kaye, G. and Mazurkiewicz, J. (1997). Histology. Baltimore: Williams & Wilkins, p.48.
Paxton, S., Adele, and Peckham, M. (2003). The Leeds Histology Guide. [online] Histology.leeds.ac.uk. Available at: http://www.histology.leeds.ac.uk/female/uterus.php [Accessed 9 May 2016].
Siumed.edu. (2016). SIU SOM Histology GI. [online] Available at: http://www.siumed.edu/~dking2/erg/smallint.htm [Accessed 9 May 2016].
