Human Anatomy and Physiology I
Chapter 5 -- Review Questions
1. Describe the hypodermis. Is it part of the skin?
Yes, it’s part of the skin. The hypodermis is the innermost and thickest layer of the skin. It cushions the body and helps regulate skin and body temperature.
2. Describe the composition of the epidermis.
The epidermis is made up of Stratified Squamous Epithelium.
3. Name and discuss the four cell types found in the epidermis. (Give the structure and function of each) * Keratinocytes- 90% filled with keratin and have a waterproof barrier. * Melanocytes- 8% produce melanin pigment and pass them to the keratinocytes. * Langerhans cells- phagocytes from the immune system and are easily damaged by UV light * Merkle cells- located in deepest layer of hairless skin and they are the sensory transduction.
4. Name the five epidermal layers from the outside of the skin to the inside. Tell the structure of each. * Stratum Corneum- Most superficial layer; 20–30 layers of dead cells represented only by flat membranous sacs filled with keratin. Glycolipids in extracellular space. * Stratum Lucidum- Clear, translucent layer. Only found in palms and soles. * Stratum granulosum- Three to five layers of flattened cells, organelles deteriorating; cytoplasm full of lamellated granules (release lipids) and keratohyaline granules. * Stratum spinosum- Several layers of keratinocytes unified by desmosomes. Cells contain thick bundles of intermediate filaments made of pre-keratin. * Stratum basale- Deepest epidermal layer; one row of actively mitotic stem cells; some newly formed cells become part of the more superficial layers. See occasional melanocytes and epidermal dendritic cells.
5. Describe the composition of the dermis layer.
Dense irregular fibrous connective tissue.
6. Name and discuss the two layers of the dermis.
* Papillary region- areolar connective tissue, elastic fiber. Dermal papillae are mound-like projections to increase the surface area for nutrition from capillaries. * Reticular region- dense irregular tissue. Collagen and elastic fibers give strength, elasticity, and extensibility.
7. Name and discuss three pigments that contribute to skin color. * Melanin- yellow to black. Made in melanocytes. Found in mucous membranes, areolas, penis, nipples, face and extremities. Melanin production protects against UV radiation. * Carotene- yellow orange pigment in the dermis. Used in the synthesis of a vision pigment. * Hemoglobin- because the skin is translucent. The red color in the skin is due to this because the oxygen carrying pigment in red blood cells.
8. Discuss each of the following conditions, including causes of each: * Erythema- skin redness due to exercise, embarrassment, high blood pressure, etc. * Pallor- paleness of the skin due to cold temperatures, anemia, and stress. * Cyanosis- bluish cast to the skin due to no oxygen. Found in babies that aren’t breathing and heavy smokers/emphysema. * Jaundice- yellow/orange tint to the skin due to internal hemorrhage, liver problems, and removal of red blood cells. * Bronzing- metallic appearance of the skin. Found in Addison’s Disease. * Bruising- black and blue marks (contusions).
9. How does sun exposure affect the skin? What are some substances that can increase the skin’s sensitivity to the sun?
Exposure to the sun causes pre-cancerous and cancerous skin lesions, benign tumors, wrinkles, freckles, discoloration of the skin, and the destruction of elastic and collagen tissue. Substances that can increase sensitivity to the sun are prescription drugs, pain relievers, lotions, perfumes, skin care products, some sunscreens, and certain types of food.
10. What are sudoriferous glands, and where are they located?
They are sweat glands and they are located throughout the body.
11. What is sweat composed of and what are two...