Solved Basic Structure of the Skin 1. Complete the following ... - Free Printable

I'll solve this anatomy problem by first examining the diagram of thin skin and then answering the questions based on my knowledge of skin structure.

First, look closely:
The image shows a detailed cross-section of human thin skin with various structures labeled. I can see the epidermis with its different strata (stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, stratum basale), the dermis with papillary and reticular layers, hair follicles, sebaceous glands, sweat glands, blood vessels, adipose cells in the subcutaneous tissue, and nerve endings. The question asks me to label specific structures and answer several questions about skin anatomy.

Since I need to answer specific questions about skin structures and functions, I'll proceed to answer them based on my knowledge of human anatomy.

Solution:

a. Lamellar granules contain glycolipids that prevent water loss from the skin.
- These are also called "membrane-coating granules" or "Odland bodies" and are found in the stratum granulosum. They release lipids that form a waterproof barrier.

b. Fibers in the dermis are produced by fibroblasts.
- Fibroblasts are the primary cell type in the dermis responsible for producing collagen, elastin, and reticular fibers that provide structural support.

c. Glands that respond to rising androgen levels are the sebaceous glands.
- Sebaceous glands produce sebum (oil) and become more active during puberty when androgen levels increase, which is why acne often develops during adolescence.

d. Phagocytic cells that occupy the epidermis are called Langerhans cells.
- These are dendritic cells that function as part of the immune system, capturing antigens and presenting them to T-cells.

e. A unique touch receptor formed from a stratum basale cell and a nerve fiber is a Merkel disc (or Merkel corpuscle).
- These are mechanoreceptors that detect light touch and are associated with Merkel cells in the stratum basale.

f. The layer present in thick skin but not in thin skin is the stratum lucidum.
- Thick skin (found on palms and soles) has five epidermal layers, including the stratum lucidum, while thin skin has only four layers.

g. The anchoring junctions that hold the cells of the stratum spinosum tightly together are desmosomes.
- Desmosomes are specialized intercellular junctions that provide strong adhesion between keratinocytes, giving the stratum spinosum its "spiny" appearance under the microscope.

5. The substance manufactured in the skin (but not a secretion) to play a role elsewhere in the body is vitamin D.
- When UVB radiation from sunlight hits the skin, it converts 7-dehydrocholesterol in the epidermis to previtamin D3, which is then converted to vitamin D3 (cholecalciferol). This vitamin D3 is then transported to the liver and kidneys where it is converted to its active form, calcitriol, which regulates calcium absorption in the intestines and plays a crucial role in bone health and immune function.