Skin and Body Membranes

-Line or cover body surfaces

-Protect body surfaces

-Lubricate body surfaces

body membranes

Type of Epithelial membranes that = skin

-A dry membrane & Outermost protective boundary

Cutaneous membrane

Keratinized stratified squamous epithelium

Superficial epidermis

Mostly dense connective tissue

Underlying dermis

-Surface epithelium (Type depends on site)

-Underlying loose connective tissue (lamina propria)

-Lines all body cavities that open to the exterior body surface

-Often adapted for absorption or secretion

Mucous Membranes

Epithelium, lamina propria and muscularis mucosae Lines passageways that open to the exterior: reproductive, respiratory, urinary and digestive

Mucous Membranes

___(movement of cilia) trap and remove foreign particles and bacteria from internal body surfaces

Mucous

-Surface simple squamous epithelium

-Underlying areolar connective tissue

-Lines open body cavities that are closed to the exterior of the body

-Serous layers separated by serous fluid

Serous Membranes

is a loose connective tissue that consists of a meshwork of collagen, elastic tissue, and reticular fibres - with many connective tissue cells in between the meshwork of fibres.

Areolar Tissue

are strong and form a branching network.

Reticular fibers

are thick, straight or wavy, and often form bundles. They are very strong and resist stretching.

Collagen fibers

are slender, unbranching, and very stretchy. They recoil to their original length after stretching or distortion.

Elastic fibers

is a fixed pigment cell that synthesizes melanin, a brownish-yellow pigment.

melanocyte

fixed macrophage

is a stationary phagocytic cell that engulfs cell debris and pathogens.

re fixed cells that stimulate local inflammation and mobilize tissue defenses.

Mast cells

are fixed cells that synthesize the extracellular fibers of the connective tissue.

Fibroblasts

are fixed cells that store lipid reserves in large intracellular vesicles.

Adipocytes/fat cells

is an active, mobile immune cell that produces antibodies.

plasma cell

are wandering phagocytic cells that patrol the tissue, engulfing debris or pathogens.

Free macrophages

are mobile stem cells that participate in the repair of damaged tissues.

Mesenchymal cells

are small, mobile, phagocytic blood cells that enter tissues during infection or injury.

Neutrophils and eosinophils

are mobile cells of the immune system.

Lymphocytes

Specific serous membranes= Abdominal cavity

Peritoneum

Specific serous membranes= Around the lungs

Pleura

Specific serous membranes= ∙Around the heart

Pericardium

serous membrane layers: in part

visceral serosa

serous membrane layers: the between part

serous cavity

serous membrane layers: the outer part

parietal serosa

Connective tissue only & Lines fibrous capsules surrounding joints

Synovial membrane

Viscous fluid found in the cavities of movable joints

Synovial Fluid

-Inner membrane of synovial joints

-Secretes synovial fluid into the joint cavity

-Contain specialized cells (synoviocytes)

Synovial membrane

specialized cells of Synovial membrane

synoviocytes

Skin derivatives

Sweat glands, Oil glands, Hairs, Nails

Protects deeper tissues from:

-Mechanical damage

-Chemical damage

-Bacterial damage

-Thermal damage

-Ultraviolet radiation

-Desiccation

Skin

-Aids in heat regulation

-Aids in excretion of urea and uric acid ∙

-Synthesizes vitamin D

Skin

-outer layer of skin

-Stratified squamous epithelium

-Often keratinized (hardened by keratin)

Epidermis

Dense connective tissue

Dermis

-Not part of the skin

-Anchors skin to underlying organs -Composed mostly of adipose tissue

hypodermis

Layer of Epidermis:

-Cells undergoing mitosis & Lies next to dermis

Stratum basale

Layer of Epidermis: between the stratum basale and granulosum layers & helps make your skin flexible and strong

Stratum spinosum

Layer of Epidermis: accumulate dense basophilic keratohyalin granules & prevent fluid loss from the body.

Stratum granulosum

Layer of Epidermis: Occurs only in thick skin

Stratum lucidum

Layer of Epidermis: dead cells

Stratum corneum

Pigment produced by melanocytes

Color is yellow to brown to black

Amount of ___produced depends upon genetic and exposure to sunlight

Melanin

___are mostly in the stratum basale

Melanocytes

Dermis layer:

-has Projections called dermal papillae

-Pain receptors & Capillary loops

Papillary layer

Projections of the Papillary layer in the dermis

dermal papillae

Dermis layer:

∙Blood vessels, Glands, & Nerve receptors

Reticular layer

Normal Skin Color Determinants: Yellow, brown or black pigments

Melanin

Normal Skin Color Determinants: ∙Orange-yellow pigment from some vegetables

Carotene

Normal Skin Color Determinants:

-Red coloring from blood cells in dermis capillaries

-Oxygen content determines the extent of red coloring

Hemoglobin

Appendages of the Skin:

-Produce oil

-Lubricant for skin

-Kills bacteria

-Most with ducts that empty into hair follicles

-Glands are activated at puberty

Sebaceous glands

Appendages of the Skin:

-Widely distributed in skin

Sweat glands

Type of Sweat glands:

-Open via duct to pore on skin surface

-most areas of skin

- secretory portion in dermis with duct to surface

- regulate body temperature with perspiration

Eccrine/Merocrine

Type of Sweat glands:

-armpit and pubic region

- secretory portion in dermis with duct that opens onto hair follicle

- secretions more viscous & stinky!

- develop around puberty Release contents by breaking into pieces

Apocrine

Function of Sweat:

-Mostly water

-Some metabolic waste

-Fatty acids and proteins (apocrine only)

Composition

Function of Sweat:

-∙Helps dissipate excess heat

-Excretes waste products

-Acidic nature inhibits bacteria growth

Function

Function of Sweat: Odor is from associated ___

bacteria

-Produced by hair bulb

-Consists of hard keratinized epithelial cells

-Melanocytes provide pigment for hair color

Hair

Middle of the inner part of the hair

Central medulla

surrounds medulla

Cortex

on outside of cortex & Most heavily keratinized

Cuticle

Associated Hair Structures: Dermal and epidermal sheath surround hair root

Hair follicle

Associated Hair Structures: Smooth muscle

Arrector pilli

Associated Hair Structures: produce and secrete sebum, an oily substance that lubricates and protects the skin and hair.

Sebaceous gland

Associated Hair Structures: small structures in the skin that produce and release sweat, a fluid that helps regulate body temperature.

Sweat gland

Appendages of the Skin: Scale-like modifications of the epidermis & Heavily keratinized

-∙Stratum basale extends beneath the nail bed

Responsible for growth & Lack of pigment makes them colorless

Nails

proximal nail fold that projects onto the nail body

Eponychium

Nail: The half-moon at the base of the nail. This is an extension of the nail matrix, where the new cells are formed

Lanula

Nail: The soft tissue that protects the emerging nail plate

Proximal Nail Fold

Nail: The visible part of the proximal nail fold that appears to end at the base of the nail

Eponychium

Nail: Made up of keratin protein

Nail Plate

Nail: An extention of the proximal nail fold, it protects each side of the nail plate

Lateral Fold

Nail: The free edge of the nail (older cells)

The Distal Edge

Nail: The eponychium will shed a thin layer of skin (dead tissue) that piggy-backs on the nail plate. This is the only skin that should be removed, not the eponychium as well.

Cuticle

Caused by fungal infection

Athletes foot

Caused by bacterial infection

Boils and carbuncles

Caused by virus

Cold sores

vesicles on erythematous base. Open to form shallow ulcerations.

HSV

-Contact dermatitis

-Exposures cause allergic reaction

Infections and allergies

Caused by bacterial infection

Impetigo

-Cause is unknown

-Triggered by trauma, infection, stress

Psoriasis

is caused by a substance you're exposed to that irritates your skin or triggers an allergic reaction. The substance could be one of thousands of known allergens and irritants.

Contact dermatitis

Two types of Contact dermatitis

irritant and allergic contact dermatitis

is caused by one of two kinds of bacteria—strep (streptococcus) or staph (staphylococcus). Often these bacteria enter the body when the skin has already been irritated or injured because of other skin problems such as eczema, poison ivy, insect bites, burns, or cuts.

Impetigo

two kinds of bacteria that causes Impetigo

streptococcus and staphylococcus

-Tissue damage and cell death caused by heat, electricity, UV radiation, or chemicals

-Associated dangers ∙Dehydration

-Electrolyte imbalance ∙Circulatory shock

Burns

-Way to determine the extent of burns

-Body is divided into 11 areas for quick estimation

-Each area represents about 9%

Rules of Nines

Severity of Burns:

-Only epidermis is damaged

-Skin is red and swollen

First-degree burns

Severity of Burns:

-Epidermis and upper dermis are damaged ---Skin is red with blisters

Second degree burns

Severity of Burns:

-Destroys entire skin layer

-Burn is gray-white or black

Third-degree burns

Burns are considered critical if:

-Over _% of body has second degree burns

-Over _% of the body has third degree burns

-There are __ degree burns of the face, hands, or feet

25, 10, third

abnormal cell mass

Cancer

Type of cancer: ∙Does not spread (encapsulated)

Benign

Type of cancer: Metastasized (moves) to other parts of the body

Malignant

It is the most common type of cancer

Skin cancer

Skin Cancer Types:

-Least malignant

-Most common type

-Arises from statum basale

Basal cell carcinoma

Skin Cancer Types:

-Arises from stratum spinosum

-Metastasizes to lymph nodes

-Early removal allows a good chance of cure

Squamous cell carcinoma

Skin Cancer Types:

-Most deadly of skin cancers

-Cancer of melanocytes

-Metastasizes rapidly to lymph and blood vessels

-Detection uses ABCD rule

Malignant melanoma