Integumentary System - Dermis

what are the 2 divisions of the dermis and what are they made of?

Papillary - superficial, 20% of dermis, made of areolar CT

reticular - deeper, 80% of dermis, made of dense irregular CT

what cells are found in the dermis

• Fibroblasts – make the ECM 

• Macrophages 

• Mast cells 

• White blood cells 

• Some smooth + skeletal muscle 

  • Skeletal: facial expressions 

  • Smooth: hairs 

papillary layer: characteristics

• Thin compared to reticular layer 

• Highly vascularized 

  • Has large networks of capillaries that provide blood supply to epidermis and allows exchange of nutrients/gases between blood and ISF 

what is dermal papillae

mounds/ridges that project towards the epidermis 

• Func: increase surface area of contact between epidermis and dermis, making a stronger connection between the 2 

tactile (meissner’s) corpuscles: where + func

found: papillary layer

sense light touch

free nerve endings: where + func

found: papillary layer

they have pain receptors called nociceptors

what part of the integumentary system makes fingerprints and how?

dermal papillae make dermal ridges which make epidermal ridges, forming fingerprints to help with friction

reticular layer: characteristics

• Highly vascularized 

• Contains pacinian/lamellar corpuscles for vibration + deep pressure

• Contains ruffini's corpuscles for stretch + deep pressure

what fibers are found in the reticular layer

The fibers in reticular layer are...: 

• Elastic 

• Collagen 

what cells are found in the reticular layer

• Macrophages 

• Mast cells 

• Dendritic dermal cells 

• Other immune cells 

  • Help monitor tissue 

  • Help prevent things from penetrating deeper 

  • Help with tissue repair/regeneration