Which organ of the body is known as 'Jack of all trades' -

Correct Answer: C

Rationale: The correct answer is C: Skin. The skin is known as the 'Jack of all trades' because it performs multiple functions such as protection, regulation of body temperature, sensation, and synthesis of Vitamin D. It acts as a barrier against pathogens and harmful substances, regulates body temperature through sweat production, contains sensory receptors for touch, pressure, and pain, and plays a role in the synthesis of Vitamin D when exposed to sunlight. Rationale for other choices: A: Kidney - While the kidney plays a crucial role in filtering waste and maintaining electrolyte balance, it doesn't perform as wide a range of functions as the skin. B: Brain - The brain is the control center of the body, responsible for processing information, coordinating movements, and regulating bodily functions. However, it doesn't have the same versatility in functions as the skin. D: All of the above - This choice is incorrect because not all organs mentioned (kidney, brain) are known as the 'Jack of all

Correct Answer: B

Rationale: The correct answer is B: Keratin. Keratin is a structural protein found in the skin that forms a protective barrier to reduce water loss. It is abundant in the outermost layer of the skin, the epidermis, helping to prevent dehydration. A: Keratin is the same as the correct answer, so it is not the correct choice. C: Melanin is a pigment that gives color to the skin and provides some protection against UV radiation, but it does not directly reduce water loss. D: Eleidin is a precursor to keratin in the skin, but it is not the protein responsible for reducing water loss.

Correct Answer: B

Rationale: The correct answer is B: desmosomes. Desmosomes are specialized cell junctions that firmly attach keratinocytes together in the epidermis. Desmosomes provide mechanical strength and stability to the epidermis by forming strong connections between adjacent cells. Elastic fibers (choice A) provide elasticity to tissues but are not involved in cell-to-cell connections. Keratin (choice C) is a fibrous protein that forms the structural basis of keratinocytes but does not directly connect them. Prekeratin (choice D) is a precursor to keratin and is not involved in cell-cell adhesion.

Correct Answer: A

Rationale: Rationale: A: Scalp hairs do not grow constantly; they have a growth cycle with periods of growth and rest. B: The cortex of the hair is indeed composed of hard keratin, providing strength and structure. C: Terminal hairs are indeed heavier and more pigmented than vellus or intermediate hairs. D: Club hair is indeed hair that has stopped growing and is in the resting phase. Therefore, the correct answer is A as it is the only statement that is not entirely accurate.

Correct Answer: A

Rationale: The correct answer is A because epidermal ridges do not extend into the dermis. The ridges are formed by the epidermis and serve to increase friction for grasping objects. Choice B is correct as epidermal ridge patterns are genetically determined. Choice C is also correct as the ridges interconnect with dermal papillae for stability. Choice D is incorrect as epidermal ridges do contain increased numbers of free nerve endings, contributing to the sense of touch.