Question

All are true about skin except:

• A. Both dermis & ectoderm are derived from ectoderm
• B. Skin accounts for total of 15% of body weight
• C. Most of the cells in skin are keratinocytes derived from ectoderm
• D. Dermis is made up of type1 and type 3 collagen in 3:2 ratio

Answer 1

The Correct Option is A

To determine which statement about the skin is incorrect, let's evaluate each option:  

1. Both dermis &ectoderm are derived from ectoderm: This statement is incorrect. The ectoderm gives rise to the epidermis but not the dermis. The dermis is derived from the mesoderm.
2. Skin accounts for total of 15% of body weight: This is true. The skin is the largest organ of the body and does constitute about 15% of an individual's total body weight.
3. Most of the cells in skin are keratinocytes derived from ectoderm: This is accurate. Keratinocytes make up the majority of cells in the epidermis and are derived from the ectoderm.
4. Dermis is made up of type 1 and type 3 collagen in 3:2 ratio: This is also true. The dermis is primarily composed of type 1 collagen, and type 3 collagen is present in a complementary role, often in a 3:2 ratio.

In conclusion, the incorrect statement is the first one: Both dermis &ectoderm are derived from ectoderm.