Lecture 5
Integumentary System
5-1
Integumentary System
•
Consists of:
1. Skin (Epidermis &
Dermis)
2. Accessory structures
•
•
•
•
Hair
Nails
Glands
Functions
–
–
–
–
–
Protection
Sensation
Temperature regulation
Vitamin D production
Excretion
Fig. 5.1
5-2
Epidermis and Dermis
Fig. 5.2
5-3
Epidermal Cells
• Cell types
– Keratinocytes: Produce
keratin for strength
– Melanocytes:
Contribute to skin color
(pigment melanin)
– Langerhans’ cells: Part
of the immune system
– Merkel’s cells: Detect
light touch and pressure
Fig. 5.2
•Keratinization: Cells die and produce outer layer
that resists abrasion and forms permeability layer
5-4
Epidermal Strata
• Stratum Basale
– Deepest portion of
epidermis and single
layer
– High mitotic activity
• Stratum Spinosum
– Limited cell division
• Stratum Granulosum
– In superficial layers
nucleus and other
organelles
degenerate and cell
dies
Fig. 5.2
5-5
Epidermal Strata
• Stratum Lucidum
– Thin, clear zone
• Stratum Corneum
– Most superficial
and consists of
cornified cells
– Squamous in
shape, filled with
keratin
Fig. 5.2
5-6
Dermis
• Structural strength
• Two layers
– Deeper layer dense connective
tissue; stretch
marks (striae)
– Superficial layer
underneath
epidermis - loose
connective tissue
Fig. 5.6
5-7
Review Question
The layer of keratinocyte cells of the epidermis with
the highest rate of cell division is the
(a) Stratum spinosum
(b) Stratum basale
(c) Stratum corneum
(d) Stratum granulosum
(e) Stratum lucidum
5-8
Hypodermis
• Skin rests on this,
but not a part
• Also called
– Subcutaneous tissue
– Superficial fascia
• Consists of loose
connective tissue
• Types of cells
– Fibroblasts
– Adipose (fat) cells
– Macrophages
Fig. 5.6
• Subcutaneous fat
5-9
Accessory Skin Structures
• Hair
– Found everywhere on human body except
palms, soles, lips, nipples, parts of external
genitalia, and distal segments of fingers and
toes
• Nails
• Glands
– Sebaceous or oil glands
– Sudoriferous or sweat glands
5-10
Hair Structure
• Composed of shaft and root
– Shaft protrudes above skin surface
– Root located below surface and
base forms the hair bulb
– Hair follicle consists of layer of
dermis and epidermis
• Arrector pili
– Smooth muscle
– Raises hair
Fig. 5.9
5-11
Nails
• Anatomy
– Nail root proximally
– Nail body distally:
Eponychium or
cuticle
• Growth
– Grow continuously
unlike hair
Fig. 5.8
5-12
Oil and Sweat Glands
• Sebaceous glands
– Produce sebum
– Oils hair and skin surface
• Sudoriferous glands (sweat)
– Most commonly found in
palms, soles and forehead
– Also found in axillae (arm
pit), genitalia, around anus
– Ceruminous glands (cerumen
or ear wax)
– Mammary glands
Fig. 5.10
5-13
Points to Remember
• Two components to integumentary system
– Skin (epidermis & dermis)
– Accessory structures (hair, nails and glands)
• Keratinization (accumulation of keratin)
produces upper layer of cells of epidermis,
hair and nails
• Two types of glands in skin
– Sebaceous (oily)
– Sudiferous (watery)
5-14
Questions?
5-15