Membrane and Layers of the Skin - A&P

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Integumentary System

Sheet like membranes that cover body surfaces and other appendages

What 4 types of membranes are found covering the human body

Serous, mucous, synovial, and cutaneous membranes

Serous Membranes

Lines body cavities that lack openings to the outside

Serous membranes function

Lubrication (secretes serous fluid that lubricates surface of membrane)

What do serous membranes consist of

Simple squamous epithelium and a layer of loose connective tissue

Mucous Membranes

Lines tubes and cavities that have openings to the outside and has various functions depending on location

What do mucous membranes consist of

Epithelium over loose connective tissue

What do mucous membranes secrete

Mucus

Synovial Membranes

Forms inner linings of joint cavities (synovial joints)

Synovial membranes function

Secretes synovial fluid that lubricates the joints

What do synovial membranes consist of

Fibrous connective tissue over loose connective tissue and adipose

Cutaneous Membranes

Found covering outer surface of the body (skin)

Cutan meaning

Skin

What does cutaneous membranes consist of

Epithelium over connective muscle and nervous tissue

What is the largest organ in the body

Skin

What are the 2 layers the skin contains

Epidermis and dermis

Epidermis

Outermost layer of skin that consists of stratified squamous epithelium that has 5 layers

Epidermis 5 layers (outermost to innermost)

Stratum Corneum, Stratum Lucidum, Stratum Granulosum, Stratum Spinosum, Stratum Basale (Germinativum)

Stratum Corneum

Made of dead cells (cells keratinized), exposed to outside

Stratum corneum function

Protect body from invaders, injuries, and keeps water in and out of the body

Stratum Lucidum

Underneath corneum, made of mostly dead cells, not always present (presence determines thickness of skin)

Where is stratum lucidum present/found

Palms of hand and soles of feet (more contacted skin

Stratum Granulosum

Underneath lucidum, made of living and dead cells

Stratum Spinosum

Located underneath granulosum, made of mostly living cells

Stratum Basale (Germinativum)

Attached to dermis by basement membrane, made of living cells

What does Stratum basale/germinativum contain

Basal stem cells that divide to produce melanocytes and Merkel cells

Dermis

Underneath epidermis (connected by basement membrane)

Dermis fibrous connective tissue and elastin fibers

Allows skin to be tough, yet flexible

Dermis blood vessels

Nourishes cells and helps body regulate temperature

Dermis nerve fibers

Controls muscle and gland activity, has sensory receptors to fell touch/pain/temperature/pressure

Dermis accessory organs

Hair, nails, sudoriferous glands, sebaceous glands

Dermis 2 layers

Papillary and reticular layer

Papillary Layer

Upper layer, responsible for fingerprints

Reticular Layer

Bottom layer, thicker layer that contains accessory organs

Hypodermis/Subcutaneous Layer

Adipose layer under skin (some claim it’s the 3rd layer but isn’t), major blood vessels of skin found here

Hypodermis functions

Insulation, cushion, and energy storage

Hair shaft

Pore

Sebaceous Gland

Epidermis

Dermis

Hypodermis

Arrector pili muscle

Hair follicle

Artery

Hair root

Vein

Sweat gland

Pacinian corpuscle

Sensory nerve fiber

Adipose tissue

Reticular layer

Free nerve ending

Papillary layer

Meissner’s corpuscle

Dermal papilla