Chapter 5 Flashcards
Define organ
Two or more tissue types that form a recognizable shape that carries out specific functions
Define organ system
Two or more organs working together physically or physiologically to perform a set of tasks
What are the two layers of the skin?
What layer isn’t part of the skin?
The epidermis and dermis are the top two layers
The hypodermis is the deepest and isn’t part of the skin
Describe the epidermis
Most superficial layer of skin
Made of stratified squamous epithelium
95% of cells are keratinocytes
No blood vessels
Describe the dermis
Deep to epidermis
Highly vascularized
Loose connective tissue and dense irregular tissue
Contains sensory receptors
Describe the hypodermis
Mostly adipose tissue, also has loose connective tissue. Vascularized.
It anchors the skin to deep structures like muscle and bone.
What does the skin protect us from?
Protect against mechanical trauma (stretching, pressure, abrasions)
Protect against pathogens (contains immune cells and sebum has antimicrobial properties)
Protects against environment (uv light, secretes hydrophobic chemicals to keep salt and water inside)
How does the skin allow for sensation?
Allows nervous system to perceive changes in internal and external stimuli
What are functions of the epidermis?
Protects against mechanical injury, water loss, and effects of harmful chemicals and pathogens
What are the functions of the epidermis?
Protects against mechanical injury, water loss, harmful chemicals and pathogens
What are the (up to) 5 layers in the epidermis?
Stratum basale
Stratum spinosum
Stratum granulosum
Stratum lucidum (thick skin only!)
Stratum corneum
What are other cells found in the epidermis?
Dendritic cells (found in stratum spinosum) they process foreign materials
Merkel cells (scattered throughout stratum basale) about 98% of the layer
Melanocytes (also found in stratum basale)
