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