Chapter 4
The Integumentary System and
Body Membranes
HAP
Susan Chabot
Lemon Bay High School
Classification of Body Membranes
• Epithelial Membranes
– Cutaneous Membranes = The Skin
– Mucous Membranes
– Serous Membranes
• Connective Tissue Membranes
– Synovial Membranes
Cutaneous Membranes
• The Skin
Mucous Membranes
• Lines body cavities that open to the outside,
such as THOSE OF HOLLOW ORGANS of
the RESPIRATORY, DIGESTIVE,
URINARY, REPRODUCTIVE systems.
• Adapted for ABSORPTION or SECRETION
• The lining of the RESPIRATORY and
DIGESTIVE tracts secrete large amounts of
Protective, lubricating mucus.
Serous Membranes
• Lines body cavities that are closed to the
exterior.
• Occur in pairs
– Parietal: lines the wall of the ventral body
cavity.
– Visceral: covers the outside of the organ in
that cavity.
• Serous Fluid: thin, watery fluid secreted by
the membranes.
• Function/Importance of Serous Fluid: allows
the organs to slide easily across one another
without creating friction.
Synovial Membranes
• Composed of soft
connective tissue
• Contain NO epithelial
cells
• Line the capsules
surrounding joints
• Provides smooth,
lubricating fluid to
cushion during
muscle movement.
Cutaneous Membranes: The Skin
Functions
• Protection from
–
–
–
–
–
–
Mechanical Damage
Chemical Damage
Bacterial Damage
Ultraviolet Radiation
Temperature Damage
Desiccation/Drying out
• Temperature control: sweat and
goosebumps
• Excretion of urea and uric acid
• Synthesis of vitamin D
Appendages of Skin/Glands
Accessory Structures that provide
specific functions to the Integumentary
System.
• Cutaneous Glands – Exocrine
– Sebaceous Glands/OIL GLANDS
• Sebum – antimicrobial properties and keeps
skin soft.
Appendages of Skin/Glands
– Sudoriferous Glands/SWEAT GLANDS
• Eccrine/Merocrine – produces watery sweat for
evaporative cooling to control body
temperature.
– Widely distributed all over the body
– Sweat – mostly salt water and other waster
materials
• Apocrine – produces oily sweat
– Located in Axilla and Groin
– Becomes active during puberty
Layers of The Skin
EPIDERMIS
Composed of 5 Layers/strata
• Innermost – Stratum basale = dividing layer
• S. spinosum
• S. granulosum
• S. lucidum
• Outermost – S. corneum
CHARACTERISTICS
• Avascular – lacks rich blood supply
• Most cells are keratinocytes that produce KERATIN
• Average person sheds 40 pounds of skin in a lifetime
• Completely new epidermis every 25 – 45 days
• Melanin production is performed by MELANOCYTES
in the s. basale during UV exposure.
DERMIS
• AKA hide
• Strong and elastic
• Made of dense fibrous connective tissue
2 Regions of the Dermis
Papillary layer = Most superficial layer of the dermis
• Dermal papillae attaches DERMIS to s. basale
– Forms fingerprints which provide gripping action for fingers
• Provides nourishment to the s. basale to keep those cells
dividing.
Reticular layer = Deepest layer of the dermis
• Contains blood vessels, sweat and oil glands, and pressure
receptors.
• Phagocytes prevent bacteria from entering interior of body
– NONSPECIFIC
• Collagen (protein) provides toughness for attachment
• Elastin (protein) provides flexibility and elasticity.
• Maintains body temperature by promoting sweat production
and release and contraction of muscles for goosebumps.
HYPODERMIS
• Made of adipose tissue = FAT
• Deepest layer of the skin
• Anchors skin to underlying tissues/organs.
• Provides shock absorption and insulation
NORMAL Skin Pigments
3 main pigments contribute to skin color
• Melanin: yellow, reddish brown, dark brown,
black. Protection from UV light.
• Carotene: orange-yellow fat soluble vitamin
that can be stored in adipose tissue.
• Hemoglobin: red; found in red blood cells.
The more blood in the area, the more red the
skin appears.
ABNORMAL Skin Coloration
Cyanosis: blue cast to skin due to low blood
oxygen levels or poor circulation.
Erythema: redness due to blushing,
inflammation, fever, high blood pressure
Pallor: pale skin due to anemia (low RBC), low
blood pressure, loss of blood flow.
Jaundice: yellow cast due to bile build up;
signifies liver damage
Bruises: loss of blood due to injury. Color
changes to bruise occur as pigments are
broken down.
Albinism
Jaundice
Erythema
Jaundice
Cyanosis
Vitligo