1 Integumentary Integumentary System System – Skin Skin Layers Layers Divisions of the Integumentary Divisions of the Integumentary System System The integumentary system is composed of the The integumentary system is composed of the skin and it’s accessory organs. skin and it’s accessory organs. The skin has three distinct layers. The skin has three distinct layers. Epidermis Epidermis Dermis Dermis Subcutaneous fat or hypodermis. Subcutaneous fat or hypodermis. Divisions of the Integumentary Divisions of the Integumentary System System Accessory organs. Accessory organs. Hair, Nails, and Glands (sweat and oil). Hair, Nails, and Glands (sweat and oil). All of the accessory organs are based and formed All of the accessory organs are based and formed from epidermis, although they are located in the from epidermis, although they are located in the dermis. dermis. General Facts General Facts The skin has a surface area of between 1.5 and The skin has a surface area of between 1.5 and 2.0 square meters. 2.0 square meters. The skin weighs 4 The skin weighs 4-5 kg (9 5 kg (9-11 lbs). 11 lbs). Each cm Each cm 2 of skin contains: of skin contains: 70cm of blood vessels. 70cm of blood vessels. 55cm of nerves 55cm of nerves 100 sweat glands 100 sweat glands 15 oil glands 15 oil glands 230 sensory receptors. 230 sensory receptors. Skin Structure page Skin Structure page 153 (This is on 153 (This is on pg 4 of notes pg 4 of notes – You need know all You need know all of your diagrams! of your diagrams! Figure 4.4 Begin pgs 5 Begin pgs 5-6 of notes 6 of notes Look at diagrams carefully to see Look at diagrams carefully to see which layer the information is which layer the information is referring to. Remember: Structure referring to. Remember: Structure determines Function! determines Function!
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Integumentary Integumentary
System System –– Skin Skin
LayersLayers
Divisions of the Integumentary Divisions of the Integumentary
SystemSystem
�� The integumentary system is composed of the The integumentary system is composed of the
skin and it’s accessory organs.skin and it’s accessory organs.
�� The skin has three distinct layers.The skin has three distinct layers.
�� EpidermisEpidermis
�� DermisDermis
�� Subcutaneous fat or hypodermis.Subcutaneous fat or hypodermis.
Divisions of the Integumentary Divisions of the Integumentary
SystemSystem
�� Accessory organs.Accessory organs.
�� Hair, Nails, and Glands (sweat and oil).Hair, Nails, and Glands (sweat and oil).
�� All of the accessory organs are based and formed All of the accessory organs are based and formed
from epidermis, although they are located in the from epidermis, although they are located in the
dermis.dermis.
General FactsGeneral Facts
�� The skin has a surface area of between 1.5 and The skin has a surface area of between 1.5 and
2.0 square meters.2.0 square meters.
�� The skin weighs 4The skin weighs 4--5 kg (95 kg (9--11 lbs).11 lbs).
�� Each cmEach cm22 of skin contains:of skin contains:
�� 70cm of blood vessels.70cm of blood vessels.
�� 55cm of nerves55cm of nerves
�� 100 sweat glands100 sweat glands
�� 15 oil glands15 oil glands
�� 230 sensory receptors.230 sensory receptors.
Skin Structure page Skin Structure page 153 (This is on 153 (This is on pg 4 of notes pg 4 of notes –– You need know all You need know all
of your diagrams!of your diagrams!
Figure 4.4
Begin pgs 5Begin pgs 5--6 of notes6 of notes
Look at diagrams carefully to see Look at diagrams carefully to see
which layer the information is which layer the information is
referring to. Remember: Structure referring to. Remember: Structure
determines Function!determines Function!
2
Epidermis Epidermis –– page 6 of notes page 6 of notes -- fill in fill in
text box on left side of diagramtext box on left side of diagram
Slide Slide
4.10a4.10a
• Epidermis – outer layer – color code brackets
• Thick keratinized stratified squamous epithelium (4 or 5 layers)
• Avascular (hardened by keratin)
• Renews itself ~ every 35 - 45 days
• Has 4 distinct cell types
• Need to know this slide!
Dust Mites Dust Mites –– eat your dead eat your dead
keratinocyteskeratinocytes
Epidermis Epidermis –– cell cell types types –– Go to page 5 Go to page 5
of notes & fill in cell info (upper right)of notes & fill in cell info (upper right)• Keratinocytes
• Makes ups majority of epidermal cells
• produce keratin – waterproofing protein•Why important? To keep you from gaining/losing water
• Originate in deeper layers & get pushed to surface – becomes keratin filled & dies
• Reminder: Connected to each other by desmosomes & tight junctions
• Cell production & keratinization are accelerated in areas of friction