The CrayfishThe Crayfish
Common name CrayfishPhylum Arthropoda; subphylum Crustacea
Body PlanOrganization
LevelOrgan-systems
Symmetry BilateralCephalization PresentBody Cavity Present
Segmentation Present Cephalothorax
Internal Systems
MovementFour pairs of walking appendages.
Five pairs of swimmerets.Support Exoskeleton composed of chitin
Body Covering Exoskeleton
NutritionScavengers; will living and dead material; vegetative and animal.
Respiration Possess gills attached to walking legs
Circulation Open circulatory system
ExcretionRid nitrogenous wastes through green
glands located posterior to the antennules
NervousDorsal ganglia with ventral nerve chordPossesses compound eyes, antennules.
Reproduction Regeneration, dioecious
The Integumentary System
Hair, Skin, and Nails
Major roles of the Major roles of the Integumentary SystemIntegumentary System
● protection●maintenance of normal body
temperature● storage (of fat – adipose tissue)● synthesis (of vitamin D)●excretion (of salts, water and wastes in
sweat)●sensory perception through receptors in
skin
The Skin: Three Major LayersThe Skin: Three Major Layers
Did You Did You Know?...Know?...
At 8-10 pounds, the skin At 8-10 pounds, the skin is bodies’ largest organ!is bodies’ largest organ!
Layer One: The EpidermisLayer One: The Epidermis The epidermis is the outer
layer of skin. The thickness of the epidermis varies in different types of skin. It is the thinnest on the eyelids at .05 mm and the thickest on palms and soles at 1.5 mm.
Cells of the epidermis are constantly sloughing off and replacing themselves.
The Epidermis’ Five LayersThe Epidermis’ Five Layers Cells are shaped like columns at the base and
migrate upward, as dead cells are continuously sloughed off at the surface
•stratum corneum •stratum lucidum•stratum granulosum •stratum spinosum•stratum basale
cells filled with keratin but allow absorption of water
Contains one columnar layer of undifferentiated cells
Shape changes to polygonal and begins to synthesize keratin
Nuclei are lost, keratin and water-proofing lipids are formed
The Epidermis’ Five LayersThe Epidermis’ Five Layers Cells are shaped like columns at the base and
migrate upward, as dead cells are continuously sloughed off at the surface
•stratum corneum •stratum lucidum•stratum granulosum •stratum spinosum•stratum basale
Contains one columnar layer of undifferentiated cells
Shape changes to polygonal and begins to synthesize keratin
Nuclei are lost, keratin and water-proofing lipids are formed
Only present in thick skin
cells filled with keratin but allow absorption of water
Specialized Epidermal Cells The melanocyte- produces pigment
(melanin) The Langerhans' cell- frontline
defense of the immune system in the skin
Layer Two: The DermisLayer Two: The Dermis This layer varies in
thickness as well, depending on the area of the body. It is a mere 0.3 mm on the eyelid and 3.0 mm on your back.
The dermis is composed primarily of connective tissue, blood vessels, sweat glands, hair follicles, nerves receptors, and oil glands.
What makes these hairs stand on end? Why?
Can you name structures 1-4?
Layer 3: The Layer 3: The SubcutaneousSubcutaneous Also referred to as the “Also referred to as the “hypodermishypodermis,,” ”
this layer of the skin is composed this layer of the skin is composed primarily of primarily of adipose tissueadipose tissue (fat). This (fat). This layer plays a key role in insulating the layer plays a key role in insulating the body and regulating the temperature body and regulating the temperature of the skin. of the skin.
The hypodermis can vary significantly The hypodermis can vary significantly in thickness and incorporates larger in thickness and incorporates larger blood vessels and nerves.blood vessels and nerves.
The NailsThe Nails
Your nails extend from the Your nails extend from the epidermis and contain a epidermis and contain a tough protein called tough protein called keratinkeratin. .
They play an important They play an important role in grasping objects, role in grasping objects, scratching, and protecting scratching, and protecting fingers and toes. fingers and toes.
The HairThe Hair
Also composed of the protein keratin hair acts as an effective insulator between you and the environment.
hair follicles
originate in the dermis.
Did You Know?Did You Know?
Hair can grow as little as 0.1 inches per month or as fast as 0.5 inches per month depending on genetics and your diet.
Aging and the Aging and the integumentary systemintegumentary system
Marked declines in: Cell division in stratum
basale Melanocyte production Glandular activity Hair follicle function Elastic fiber function in
dermis Blood supply to skin Rate of repair
Disorders of the skinDisorders of the skin
•Lesions and tumors•Infections (bacterial, viral, fungal, parasitic)•Inflammatory reactions and allergies•Genetic diseases•Acne
Anatomy of a PimpleAnatomy of a Pimple