Anatomy and Physiology Exam 2 Questions & Answers Latest Updated

Functions of the Integumentary System - Answer -Resistance to trauma and infection -Prevents loss or gain of water -Vitamin D synthesis -Sensory receptors for heat, cold, touch, texture, pressure, vibration, and tissue injury -Thermoregulation How does skin resist trauma and infection? - Answer -Skin has low pH to reduce bacteria and fungi -Cells are packed closely together with tough protein called keratin Name 3 ways the integumentary system thermoregulates? - Answer -Glands release sweat for evaporative cooling - Vasoconstriction - Vasodilation Define: Vasoconstriction - Answer narrowing of blood vessels, reduces heat loss Define: Vasodilation - Answer widening of blood vessels, increases heat loss What are the 2 main parts of the integumentary system? - Answer Epidermis- outer layer Dermis- underlying connective tissue *Hypodermis not really part of the skin!* What does the epidermis primarily consist of? - Answer keratinized stratified squamous epithelium What are the epidermal derivatives? - Answer glands, hair, nails What are the 4 main cell types in the epidermis? - Answer - Karatinocytes - Melanocytes - Tactile (Merkel) cells - Dendritic (Langerhans) cells Keratinocytes (functions) - Answer most numerous cell type, make fibrous protein keratin Melanocytes (functions) - Answer synthesize pigment called melanin Tactile cells (functions and 2nd name) - Answer also called Merkel cells, receptors for the sense of touch, associated with a dermal nerve fiber Dendritic cells (functions and 2nd name) - Answer macrophages (big phagocytic cells) that kill microbes What are the layers of the epidermis (list from bottom up)? - Answer - Stratum basale - Stratum spinosum - Stratum granulosum - Stratum lucidum - Stratum corneum What layer of the epidermis is only found in thick skin? - Answer Straum lucidum How many layers are found in the stratum basale? - Answer 1 layer What cells are found in the stratum basale? - Answer stem cells, keratinocytes, melanocytes, tactile (merkel) cells What is the importance of the stem cells in the stratum basale? - Answer makes it mitotically active, the stem cells divide and give rise to keratinocytes How many layers are in the stratum spinosum? - Answer 8-10 layers What is the appearance of the cells in the stratum spinosum, and why? - Answer The cells are flattened, which happens as they are pushed upward What is contained in the stratum spinosum? - Answer Keratinocytes, dendridic (langerhans) cells In which epidermis layers do keratinocytes produce waterproofing substances? - Answer Stratum spinosum, stratum granulosum What are the waterproofing substances produced by the keratinocytes? - Answer keratin, lipids How many layers are in the stratum granulosum? - Answer 3-5 layers In what layer do the nuclei and organelles begin to degenerate in the keratinocytes? - Answer stratum granulosum What do the cells look like in the stratum granulosum and why? - Answer They continue to flatten because of accumulation of keratin How many layers are in the stratum lucidum, and what do they look like? - Answer 3-4 layers of translucent cells Why are the cells in the stratum lucidum translucent? - Answer the clear protein named eleidin How many layers are in the stratum corneum? - Answer up to 30 layers What do the layers of the stratum corneum consist of? - Answer dead scaly keratinized cells What are 2 of the main purposes of the stratum corneum? - Answer resistance to abrasion and water loss What are the layers of the dermis (from top to bottom)? - Answer Papillary layer Reticular layer What is the papillary layer made of? - Answer areolar CT What is the reticular layer made of? - Answer irregular CT and adipose What do you find in the papillary layer? - Answer Meissner's corpuscles (touch receptors) Dermal papillae (upward extensions) What do you find in the reticular layer? - Answer Pacinian corpuscles (pressure receptors) Hair follicles Sebaceous (oil) glands Sudoriferous glands What is the 2nd name for the hypodermis? - Answer subcutaneous Where is the hypodermis located? - Answer beneath the dermis What are the main functions of the hypodermis? - Answer energy reservoir and thermal insulation Why can drugs be injected into the hypodermis? - Answer it is highly vascular What is the hypodermis made of? - Answer areolar CT and adipose tissue What makes the color in the skin? - Answer Color caused by pigments produced by melanocytes What causes differences in skin color? - Answer differences in quantities, distribution, and break down of pigments What are 2 types of pigments and what is their color? - Answer -eumelanin- brownish black -pheomelanin- reddish yellow What are 3 types of abnormal coloration? - Answer Cyanosis, albinism, vitiligo Cyanosis - Answer blueness of skin due to deficiency of oxygen Albinism - Answer genetic lack of melanin Vitiligo - Answer autoimmune disorder leading to depigmentation in patches of skin What causes tanning of the skin? - Answer exposure to UV radiation, which causes an increased production of melanin by melanocytes and spreading of melanin to keratinocytes Describe the evolution of skin color - Answer Strong correlation between skin color and strength of sunlight across the globe; people in north evolved fair skin to absorb more UV light for vitamin D production, dark skin in tropics to block out sun