Each of the following statements concerning hair is true except

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: stratum basale. Melanosomes, which contain melanin pigment responsible for skin color, are produced and released by melanocytes in the stratum basale layer of the epidermis. Melanocytes transfer melanosomes to neighboring keratinocytes, providing protection against UV radiation. The other choices are incorrect because melanosomes are not released from the reticular layer of dermis (B), stratum corneum (C), or hypodermis (D). The stratum corneum is the outermost layer of the epidermis composed of dead skin cells, while the hypodermis is primarily involved in fat storage and insulation.

Correct Answer: B

Rationale: The correct answer is B: melanin. Melanin is the pigment responsible for determining the color of the skin, hair, and eyes. Albino individuals lack melanin production, leading to their characteristic lack of pigmentation. Perspiration (A), carotene (C), and hemoglobin (D) are not affected by albinism. Perspiration is produced by sweat glands, carotene is a pigment found in fruits and vegetables, and hemoglobin is a protein in red blood cells responsible for carrying oxygen.

Correct Answer: A

Rationale: The correct answer is A: dermatologist. A dermatologist is a physician who specializes in diagnosing and treating disorders of the skin. They undergo specific training in dermatology, making them experts in skin conditions. Sweat glands (B) are not physicians but structures in the skin. Keratosis (C) refers to a skin condition characterized by rough, scaly patches. Dysplastic Nevi (D) are atypical moles that may require monitoring by a dermatologist but do not specialize in treating skin disorders.

Correct Answer: D

Rationale: The correct answer is D because an irregular border on a mole can be indicative of melanoma, a type of skin cancer. It is crucial to identify and address any concerning skin lesions promptly to prevent potential complications. A: Numerous striae are common and not typically a cause for immediate concern. B: Thickened and yellow toenails may indicate a fungal infection but are not as concerning as a potential melanoma. C: Silver-colored scaling on elbows and knees may suggest conditions like psoriasis, which are important to address but not as urgent as a suspicious mole.