Integumentary (Slides 1-19 Exam 1) Flashcards
What two things is the integument system composed of?
- Skin (Cutaneous membrane or integument)
- The derivatives of skin
- Hair, sweat glands, sebaceous glands, ceruminous glands, nails
What is the hypodermis?
- Not a part of the skin, but is studied with the skin
- Composed of adipose connective tissue and areolar connective tissue
What two layers make up the skin?
- Epidermis (epithelial cells)
- Dermis (Connective tissue)
The skin is considered the largets organ in the body, it makes up _____% of body weight.
7-8%
The epidermis contains 4-5 layers depending on location, name them from deepest to most superficial.
- Stratum basale
- Stratum spinosum
- Stratum granulosum
- Stratum lucidum (only found in thick skin)
- Stratum corneum
The dermis has two layers, what are they and what differentiates them?
- Papillary layer
- Interdigitation between epidermis and dermis
- Epidermal ridges and dermal papilla
- Interdigitation between epidermis and dermis
- Reticular layer
- Capillaries
- Sweat glands
- Nerve endings
- Hairs
What cells is the epidermis primarily composed of?
- Keratinocytes
- More superficial layers are composed of keratinized stratified squamous epithelium
Which layers of the epidermis contain living keratinocytes?
The deepest 3 layers
- Stratum basale
- Stratum spinosum
- Stratum granulosum
Which layers of the epidermis contain dead keratinocytes?
The most superficial two layers
- Stratum lucidum (only in thick skin and deep to the stratum corneum)
- Stratum corneum
Describe the Stratum basale layer of the epidermis
- Deepest epidermal layer
- Single layer of cuboidal cells (may also have low columnar cells)
- Attached to a basement membrane
- Separates the epidermis form the dermis
- Contains sensory nerve endings for pain and temp
- Contains three cell types
What are the three cell types found within the Stratum basale layer of the epidermis?
- Keratinocytes
- Melanocytes
- Tactile cells (Merkel cells)
Describe keratinocytes in the Stratum basale
Many keratinocyte stem cells that divide to regenerate new cells, replace old cells shed from the surface of the skin.
As the keratinocytes divide they push the newly formed cells upward towards the surface.
What do melanocytes do?
- Produce and store pigment (melanin) in response to UV light.
- Transfer pigment granules into keratinocytes which accumulate around the nucleus of the keratinocyte sheilding its DNA from UV radiation.
- Responsible for darker skin tones
What do tactile cells (Merkel cells) do?
- Are modified nerve endings
- Sensitive to touch, when compressed, release chemicals to stimulate sensory nerve endings.
What does the stratum spinosum layer of the Epidermis contain?
- Also called the spiny layer
- Contains several layers of polygonal keratinocytes
- Daughter cell from the keratinocyte stem cells in the stratum basale
- Pushed into the stratum spinosum
- Become specialized, non-dividing, keratinocytes
- Some still divide in the deepest layers of the stratum spinosum
- Daughter cell from the keratinocyte stem cells in the stratum basale
- Contains sensory nerve endings for sensing pain and temperature
- Contain epidermal dendritic cells (Langerhans cells)