BIOS 251 Week 4 Case Study: Tissue

Student Name

Chamberlain University

BIOS-251 Anatomy & Physiology I

Prof. Name:

Date

Required Resources

For this activity, you are required to review the following resources:

Textbook.
Weekly Concepts.
A minimum of one scholarly source.

Scenario/Summary

Steven and Brenda were excited about the birth of their first child, Garth. Garth’s first year was joyful, and he appeared to develop normally except for some blistering of the skin due to trauma. By the time Garth turned three, Brenda noticed deformities in his nails. During a routine physical examination, she informed the pediatrician, who decided to monitor the condition without immediate intervention. When Garth turned four, he developed thickening of the palms and soles of his feet, accompanied by a gradual loss of eyebrow hair. His thick eyelashes also began to thin. At the age of five, hyperhidrosis over his nose and cheeks was noted. A dermatologist’s evaluation revealed that Garth had a genetic mutation in the plakophilin gene, leading to epidermolysis bullosa, a form of ectodermal dysplasia.

Deliverables

The following questions have been addressed based on the scenario:

1. Five Different Layers of the Skin
The skin has five distinct layers:

Layer	Description
Stratum Basale	The deepest layer of the epidermis, separated from the dermis by the basement membrane. It contains melanocytes and is attached to the membrane by hemidesmosomes (Saladin, 2019).
Stratum Spinosum	This layer contains desmosomes that connect neighboring cells and dendritic cells crucial for immune responses (Saladin, 2019).
Stratum Granulosum	Made up of diamond-shaped cells containing keratohyalin and lamellar granules. Keratohyalin helps in keratin bundle formation, while lamellar granules secrete glycolipids to bond cells (Saladin, 2019).
Stratum Lucidum	A clear layer found in thick skin such as the palms and soles, consisting of eleidin, a byproduct of keratohyalin (Saladin, 2019).
Stratum Corneum	The outermost layer composed of dead keratinocytes, which act as a protective barrier. This layer’s thickness varies, especially in calloused areas, and contains defensins as part of immune defense (Saladin, 2019).

2. Four Different Cell Junctions

Type of Junction	Function
Tight Junctions	These create a barrier by joining neighboring cell membranes, regulating the movement of larger molecules and water. They help maintain cell polarity and osmotic balance (Saladin, 2019).
Adhering Junctions	Found in tissues subjected to stretching, such as the skin, these junctions provide strong connections and allow cells to function collectively (Saladin, 2019).
Desmosomes (Anchoring)	Anchoring junctions that provide mechanical strength by connecting adjacent cells, critical for tissues like the myocardium (Saladin, 2019).
Gap Junctions	These junctions form intercellular channels that enable direct communication and exchange of ions and small molecules between cells (Saladin, 2019).

3. Purpose of the Plakophilin Gene
The plakophilin gene plays a crucial role in cell-to-cell adhesion by being a part of the desmosomes. Found primarily in the myocardium, it is essential for directing the synthesis of plakophilin 2, organizing the cytoskeleton, and regulating protein biosynthesis (Saladin, 2019).

4. Disruption Caused by Plakophilin Gene Mutations
A mutation in the plakophilin gene significantly disrupts cell-to-cell interactions, particularly in the myocardium. This can lead to severe heart conditions, such as arrhythmogenic right ventricular cardiomyopathy, which impairs normal cardiac function (Neuber et al., 2010).

5. Link Between Plakophilin Gene Mutation and Hyperhidrosis
Hyperhidrosis, characterized by excessive sweating, can result from mutations in the plakophilin gene. Such mutations affect the structure and function of desmosomes, disrupting fluid regulation in the body, which can contribute to abnormal sweat production (Syrris et al., 2006).

References

Neuber, S., Mühmer, M., Wratten, D., Koch, P. J., Moll, R., & Schmidt, A. (2010). The desmosomal plaque proteins of the Plakophilin family. Dermatology Research and Practice. Retrieved January 29, 2022, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2879962/.

Saladin, K. (2019). Anatomy and Physiology: The Unity of Form and Function (9th ed.). McGraw-Hill.