Integumentary systems
Mia Cervantes p.5

Major functions of the Integumentary system and Functions.

Regulation of body temperature

sensation; touch, vibration, pain, temperature

Body Membranes (Thin, sheet like structure)

The functions

Excretion; waste in form of urea (sweat)

Synthesis of vitamin D

A. Cover and protect body surfaces

(Parietal Membrane) B. Line body cavities

(Visceral Membrane) C. cover surfaces of the organs

D. Anchor organs

E. Secrete Fluids

2 major categories

Epithelial Membranes:

Cutaneous Membrane: (primary) organ of the integumentary sysem, Membrane covers the body surface.

Serous Membrane: Lines body cavities and covers organ surfaces (closed to the exterior) , double membrane layer, Function: secrete serous (watery) fluid for lubrication.

Mucus Membrane: made in the Epithelial cells. Function: Produces Mucus-think secretion that keeps the membranes soft and moist. Called phlegm in nasal passages.

Connective tissue membrane

Synovial Membrane: the ONLY connective tissue) Soft areolar, No epithelial tissue. Function: produces synovial fluid: lubrication, reduce friction. Line bursae (sacs around joints) like couches for organs moving against each other

Layers of the skin

Dermis (inner layer)

Hypodermis (underlying layer or subcutaneous) Hypo: under

Epidermis (outer layer)

The layers of the.. Epidermis

  1. Stratum Spinosum (prickly cell layer) the cell layers thick of flattened cells with bundles of Keratin. Cells in this layer form Desmosomes causing the cells to pack together and become prickly.
  1. Stratum Granulosum: very thin region around (3-5 layers). The last layer of the epidermis that can obtain nutrients from diffusion. Process of keratinization begins here and cells die.
  1. Stratum Lucidum: (clear layer). around 2-3 clear, flat, and dead cell layers. Visible only in thick skin.
  1. Stratum Corneum: (outermost layer). 20-30 cells thick of all dead cells goes up to about 200. High levels of Keratin. The average person sheds about 40 lbs of dead skin cells in a lifetime.

The two major layers of the..Dermis

Papillary layer: papilla-any small fleshy projection. Thin superficial layer. Areolar connective tissue. Loose connective tissue. Superior surface is called the dermal papilla.
located:under the epidermis. Contains: capillaries, nerve endings, light touch receptors called Mesissners corpuscles

Reticular layer: Deepest layer bottom 2/3 of dermis. Has dense connective tissue. Highly vascular- lots of blood vessels.

The Hypodermis (subcutaneous layer)

The 3rd major skin region of the cutaneous membrane. Compared to ADIPOSE tissue. Function: insulation, cushioning and energy storage.

Skin Appendages (Accessory Organs)

  1. Stratum Basale: (stratum Germanitivum) Is the deepest layer and the closet to the epidermis. Cells are constantly dividing mitosis

Hair: millions of hairs are grown all over the body
except for palms of hands, soles, lips, nipples, and parts of the external genitilla. The flexibility strands are produced by hair follicles, Melanocytes provides pigment for hair color.
The structure of hair: made by cells in the follicle. Hair is fused Keratinized cells. and is divided into 3: bulb, root, shaft.

Nails : are clear, hard derivatives of stratum corneum.
Nail plate: hard part of nail.
Free edge: overhangs the tip of the nail.
Nail body: visible, attached, part of the nail.
Nail root: proximally under the overhanging.
Nail bed: skin under the nail plate.
Nail Matrix: growth zone.
Lunule: white crescent at proximal end of nail.
Eponychium (cuticle): dead skin under that are under the lunule

Glands: Consist of the Sweat (Sudoriferous) Glands. And Oil (Sebacious) Glands.

Sudoriferous (sweat) glands: All over the skin except for nipples, lips, and some genitilla. Two major types: Eccrine sweat glands. and Apocrine sweat glands.
Sweat is secreted into and through the glands duct system to the surface of the skin. Sudor =Sweat
Eccrine sweat glands are found almost everywhere and the most numerous. Duct extends to open in a pore,

Sebacious (oil) glands: Found all over the body except on palms and soles of feet. Secrete an oily substance called sebum. Bactericidal (bacteria-killing) takes action. Stimulated by hormones and activated at puberty.
Blackheads: When the sebaceous glands duct is blocked and the sebum accumulates
Acne: Active inflammation of the sebaceous glands accompanied by "pimples". Caused by bacterial infection.

Skin cancer types

Benign: Most tumors like warts, Does not spread and grows slowly. Least Malignant but most common skin cancer, Stratum basal cells proliferate and invade the dermis and hypodermis.

Malignant: mal=BAD. Grows relentlessly and may become killers. Most deadly, Highly metastatic and resistant to chemotherapy.

Squamous cell carcinoma: Second most common skin cancer, affects males more than women. Grows and metastasizes to lympth nodes quickly. Early removal is a good chance of cure.

Skin disorders

Psoriasis: A chronic condition characterized by reddened epidermal lesions covered with dry, silvery scales

Athletes foot (Fungi): an itchy, red, peeling condition of the sin between the toes resulting from a fungal infection (common)

Cold sores: Small fluid filled blistered that itch and sting, caused by herpes simplex infection (common)

Contract Dermatitis: Itching, redness, and swelling of the skin causing blistering. Caused by exposure of skin to chemicals.

Impetigo: Pink water-filled, raised lesions that develop (mouth and nose) a yellow crust and will rupture. Caused by bacteria infection.

Burns

First- degree burns (epidermis): Skin is red and swollen

Second degree burns (epidermis and upper dermis): skin is red with blisters.

Third degree burns ( entire skin layer) High rise for fluid loss, burn is gray-white cherry red or black. Nerve endings are destroyed so it is not painful at first. Usually skin grafting is required.