Anatomy and Physiology: Exam 2
Functions of the Integumentary System (ANS- -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?(ANS- -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?(ANS- -Glands release sweat for evaporative cooling
- Vasoconstriction
- Vasodilation
Define: Vasoconstriction
(ANS- narrowing of blood vessels, reduces heat loss
Define: Vasodilation
(ANS- widening of blood vessels, increases heat loss
What are the 2 main parts of the integumentary system?(ANS- Epidermis- outer layer Dermis- underlying connective tissue *Hypodermis not really part of the skin!*
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What does the epidermis primarily consist of?(ANS- keratinized stratified squamous epithelium
What are the epidermal derivatives?(ANS- glands, hair, nails
What are the 4 main cell types in the epidermis?(ANS-
- Karatinocytes
- Melanocytes
- Tactile (Merkel) cells
- Dendritic (Langerhans) cells
Keratinocytes (functions) (ANS- most numerous cell type, make fibrous protein keratin
Melanocytes (functions) (ANS- synthesize pigment called melanin
Tactile cells (functions and 2nd name) (ANS- also called Merkel cells, receptors for the sense of touch, associated with a dermal nerve fiber
Dendritic cells (functions and 2nd name) (ANS- macrophages (big phagocytic cells) that kill microbes
What are the layers of the epidermis (list from bottom up)?(ANS-
- Stratum basale
- Stratum spinosum
- Stratum granulosum
- Stratum lucidum
- Stratum corneum
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What layer of the epidermis is only found in thick skin?(ANS- Straum lucidum
How many layers are found in the stratum basale?(ANS- 1 layer
What cells are found in the stratum basale?(ANS- stem cells, keratinocytes, melanocytes, tactile (merkel) cells
What is the importance of the stem cells in the stratum basale?(ANS- makes it mitotically active, the stem cells divide and give rise to keratinocytes
How many layers are in the stratum spinosum?(ANS- 8-10 layers
What is the appearance of the cells in the stratum spinosum, and why?(ANS- The cells are flattened, which happens as they are pushed upward
What is contained in the stratum spinosum?(ANS- Keratinocytes, dendridic (langerhans) cells
In which epidermis layers do keratinocytes produce waterproofing substances?(ANS- Stratum spinosum, stratum granulosum
What are the waterproofing substances produced by the keratinocytes?(ANS- keratin, lipids
How many layers are in the stratum granulosum?(ANS- 3-5 layers
In what layer do the nuclei and organelles begin to degenerate in the keratinocytes?(ANS- stratum granulosum
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