Download Integumentary System - Killingly Public Schools

Integumentary System
• Skin and its
appendages
• Largest and most
visible organ of the
body
• Distinct regions
– Epidermis
– Basement Membrane
Zone
– Dermis
– Subcutis/Hypodermis
Integumentary System
• Functions:
– Enclosing barrier preventing the loss of water, electrolytes, and
cells
– Protection from the environment
– Allowing motion
– Temperature regulation
– Storage
– Pigmentation
– Immunosurveillance
– Production of vitamin D
– Sensory perception
– Excretory secretions
Epidermis
• outer layer
• provides protection
from foreign
substances
• composed of several
cells:
–
–
–
–
Keratinocytes
Melanocytes
Langerhans cells
Merkel cells
Epidermis
• Keratinocytes
– provide a protective layer
– constantly being renewed
(keratinization)
• new skin cells are created
near the base of the
epidermis and migrate
upwards, producing a
compact layer of dead
cells on the skin surface
• keeps in fluids, salts, and
nutrients
• keeps out infectious or
foreign agents
Epidermis
• Melanocytes
– located at base of
epidermis, outer root
sheath of hairs, and
ducts of sebaceous
and sweat glands
– produce melanin
(pigment)
• helps protect cells from
UV radiation
Epidermis
• Langerhans Cells
– part of immune system
– damaged when exposed to
excessive UV light
and glucocorticoids (antiinflammatory drugs)
– play an important role in
the skin's response to
foreign substances
• Ex: rash development if
animal is exposed to an
irritant
Epidermis
• Merkel Cells
– help provide animals
with sensory
information from
whiskers
Basement Membrane Zone
• located at the base of
the epidermis,
connecting it to the
dermis
• protective barrier
between the
epidermis and the
dermis
Dermis
• supports and nourishes the
epidermis and skin
appendages (via blood
vessels)
– blood vessels also regulate
skin and body temperature
• sensory nerves are located in
the dermis and hair follicles
• secretes proteins: collagen
and elastin
– give support and elasticity
• immune cells defend against
infectious agents
Subcutis/Hypodermis
• innermost layer
• contains
subcutaneous fat and
muscles
• fat provides:
– Insulation
– reservoir for fluids,
electrolytes, and
energy
– shock absorber
Skin Appendages
• hair follicles, oil and
sweat glands, and
claws
• grow out of the
epidermis and dermis
Skin Appendages
• hair follicles
• cats and dogs are compound
– follicles have a central hair
surrounded by 3 to 15 smaller
secondary hairs all exiting
from one pore
– born with simple hair follicles
that develop into compound
hair follicles.
• growth of hair is affected by
nutrition, hormones, and
change of season
• size, shape, and length of hair
are controlled by genetics and
hormones
Skin Appendages
• coat protects the skin from
physical and UV light damage
• coat helps regulate body
temperature
– trapping dead air space
between secondary hairs
conserves heat
• cold-weather coat is longer
and finer to facilitate heat
conservation
– coat can also help cool the
skin
• warm-weather coat has
shorter, thicker hairs and
fewer secondary hairs
• anatomic change allows air to
move easily through the coat
Skin Appendages
• Oil Glands (sebaceous
glands)
– secrete sebum into the hair
follicles and skin
– present in large numbers
near the paws, back of the
neck, rump, chin, and tail
area
• Sebum
– mixture of fatty acids
– keeps skin soft, moist, and
pliable
– Makes coat look shiny
– has antibiotic properties
Skin Appendages
• Sweat glands
– on feet
– minor role in cooling
Hereditary Hair Loss (Alopecia)
• born totally or partially without
hair
• hairlessness can also develop
with age
• can be associated with
abnormal teeth, claws, and
eyes, or with skeletal and other
developmental defects
• prone to hair follicle infections
and inflammation caused by
foreign objects
Albinism
• always associated with pink or
pale irises
• visual defects and increased
risk of skin damage from
sunlight
• some animals with extreme
piebaldism (spotted or
blotched with black and white)
or dominant white have
associated nervous system
abnormalities or deafness in
one or both ears
Ringworm
•
infection of skin, hair, or claws caused
by a dermatophyte (fungus);
ZOONOTIC
•
develop circular, bald, scaly patches
with broken hairs in ring-like whirls
•
common areas: face, ear tips, tail, &
feet
•
Diagnosis:
–
•
fungal culture, UV lamp, and skin
scraping (microscope)
Treatment: antifungal medications,
medicated shampoos, isolation,
disinfect all fomites