Exam 2 A&P

Integument and Muscular System

Largest Organ of the Body

Integument

Major Components of the Integument?

The cutaneous membrane and accessory structures

Components of the Cutaneous Membrane (Skin)

Epidermis and Dermis

Accessory Structures

Hair, Nails, and Exocrine glands

Dermis Components

Papillary and Reticular Layer

What accounts for 20% of dermis

Papillary Layer

What accounts for 80% of dermis

Reticular Layer

Sebaceous Glands Produce

Sebum (oil)

Ceruminous Glands Produce

Cerumen (wax)

Types of Sudoriferous Glands

Merocrine (eccrine) and apocrine sweat glands

Sudoriferous Glands Produce

Perspiration (sweat)

Other Term for Hypodermis (Subcutaneous/SubQ)

Superficial Fascia

If Dermal Papilla is the Mound, What is the Valley

Epidermal Ridge

Papillary Region is Composed of

Areolar connective tissue

Reticular Region is Composed of

Dense irregular collagenous connective tissue

Epidermis Composed of

Keratinized stratified squamous epithelium

Keratinocytes

Predominant epithelial cell in epidermis that produces keratin and lamellar granules

Hard Keratin is found in

Hair and nails

Soft Keratin is found in

Skin

Lamellar Granules/Bodies (specialized organelles) produce

Tactile (Merkel) Disc is

a neuron

Tactile (Merkel) Disc + Tactile (Merkel, Tactile Epithelial) Cell (least numerous)

Are sensitive to light touch and superficial pressure

Melanocyte (10%-25% of cells in stratum basale) (reach into stratum granulosum)

Produces the pigment melanin

Intraepidermal Macrophage (Langerhans/Dendritic) Cell

Cells that are part our immunity found in the stratum spinosum

Epidermolysis Bullosa (EB) (“Touch Me Not”)

An inherited condition that results in the skin to be extremely fragile due to the inability of the stratum basale to effectively anchor to the basement membrane

Stratum Basale Cells Divide

Horizontally then vertically from dermal papilla to dermal ridge then up

Eumelanin

Brown-black melanin

Pheomelanin

yellow-brown melanin

Melanosome

packaged melanin transported to keratinocytes

Stratum Spinosum Layers

8-10

Stratum Spinosum (cells appear “spiny” due to coarser bundles of keratin intermediates)

provide flexibility and strength, is where lamellar bodies accumulate

Stratum Granulosum Layers

3-5

Stratum Granulosum “Grainy Layer” (Dying layer)

Marks transition between metabolically active and dead cell layers, keratinocytes stop producing keratin

Keratohyalin Granules (Stratum Granulosum)

Dense granules that cross link keratin fibers and assemble them into final form

Cell envelope (Stratum gruanulosum)

layers of proteins form on the inner leaflet of the plasma membrane

Lamellar bodies in Stratum Granulosumm

Release their lipid rich secretion

Stratum Lucidum (clear layer)

cells are clear, flattened, dead, densely packed together and contain no organelles

Stratum Lucidum Cytoplasm

filled with keratin with a thickened plasma membrane

Stratum Lucidum Layers

4-6

Stratum Corneum layers

15-30 or 50+

Stratum Corneum “horny or cornified layer” (Durable “overcoat”)

resistant to abrasion, protects against microbes and reduces water loss

Lamellar Ichthyosis (autosomal recessive lifelong disorder, scaling of the skin)

results from the inability to form a cell envelope which is needed for lipid layer to adhere to

Keratinization (Cornification)

occurs on all exposed skin surfaces except eyes and takes 4-6 weeks to go from stratum basale to shedding

Thin Skin (Hairy Skin except for lips & external genetalia)

contain hair, sebaceous glands, and sweat glands

Thick Skin (hairless)

found in fingertips, toes, soles, and palms only containing Merocrine (eccrine) sweat glands

Thin Skin Epidermal Ridges

Are lacking and have less well organized dermal papillae resulting in fewer sensory receptors

Skin Coloration Factors

Epidermal pigmentation and dermal circulation

2 pigments

Carotene and melanin

Carotene (can be converted to vitamin A for immune function, vision and other physiological processes)

An orange yellow pigment that normally accumulates in epidermal cells and fatty tissue in subq

Nevus (Mole)

Harmless localized overgrowth of melanocyte that rarely becomes malignant but should be monitored for changes (melanoma)

Freckles (yellowish or brown spots)

Represent localized areas of increased melanocyte activity (degree of pigmentation based on sun exposure and hereditary)

Albinism (inherited autosomal recessive disorder condition)

Enzyme for melanin production is nonfunctional

Vitiligo (autoimmune disorder)

loss of melanocytes and loss of color

Erythema (can be due to) (increased blood flow)

excessive redness due to inflammation, infection excessive heat or allergic reaction

Palor (decreased blood flow)

Skin becomes pale can be due to shock, excessive cold and anemia

Cyanosis (severe reduction in blood flow)

skin turns blue or purple can be from extreme cold, or lack of oxygen

Jaundice (yellowish coloration of skin and whites of eyes)

Build up of bile pigment (bilirubin) usually indicative of liver disease

Addison’s Disease (skin darkening, deep tan bronze)

autoimmune disease that causes the destruction of the adrenal gland specifically the adrenal cortex

Metastasis

the spread of cancerous cells to a different area/region of the body from the initial site

Basal Cell Carcinoma (most common type of cancer that originates in the stratum basale)

usually occurs in face and is least dangerous as it seldom metastasizes, can be surgically removed

Squamous Cell Carcinoma (arises in stratum spinosum and may metastasize)

lesion that usually appears on scalp, ears, lower lip, or dorsum of hand, can be treated by early detection and surgical removal

Malignant Melanoma (most dangerous due to aggressive growth and metastasis, advanced cases may be difficult to treat)

arises from melanocytes usually in preexisting mole, early detection and removal is key

ABCDE

Asymmetry, Border, Color, Diameter, Evolving

Diameter

affected are is 6mm (1/4in) or larger

Skin Turgor (indicators of dehydrated or hydrated state)

Properties of flexibility and resilience

Sagging and Wrinkles (reduced skin elasticity) are caused by

dehydration, age, hormonal changes, and uv exposure

Stretch Marks (striae)

Thickened tissue (scar tissue) resulting from excessive stretching of skin due to pregnancy and weight gain

Lines of Cleavage (tension lines)

Collagen and elastic fibers in dermis are arranged in parallel bundles and resist force in a specific direction

Important patterns established by lines of cleavage

a parallel cut remains shut and heals well, a perpendicular cut pulls open and scars

Plexus (blood vessels or nerves)

network

Subcutaneous Plexus (blood vessel network in subq that branches into reticular layer)

supplies both the adipose tissue of the subcutaneous and tissue of the integument

Subpapillary Plexus

give rise to capillary network (capillary loops) in papillary layer (dermal papillae)

Contusion

damage to these blood vessels resulting in blue and black bruising

Nerve Fibers in/of skin

control blood flow and gland secretions

Merkel (tactile epithelial cell) + Merkel Disc (tactile disc) located in the epidermis

Senses steady light touch and superficial pressure

Tactile Corpuscle (Meissner Corpuscle) located in dermis

sensitive to light rubbing

Bulbous Corpuscle (Ruffini Corpuscle) located in the dermis

Sensitive to steady pressure and stretching

Root Hair Plexus (free nerve endings associated with hair)

sensitive to light touch and movement of hair shaft

Free Nerve Endings (located in the epidermis)

sensitive to temperature and pain

Lamellated Corpuscle (Pacinian Corpuscle) (located in the reticular layer and subcutaneous)

sensitive to deep pressure and vibration

Location of Merkle cell and Merkle disc

Epidermis

Location of Tactile Corpuscle

In dermal papillae

Location of Bulbous Corpuscle

Dermis

Location of Free Nerve Endings

Epidermis

Location of Lamellated Corpuscle (Pacinian Corpuscle)

Reticular layer and subcutaneous

Functions of the Skin (Integument)

Thermoregulation, blood reservoir, protection, cutaneous sensation, excretion and absorption, and synthesis of vitamin D

Integument Blood Reservoir

extensive demal blood vessel plexus carry 8-10% of total blood flow

Acidic Mantle of Skin (retards bacterial growth)

composed of secretion of sebaceous and sweat glands

Hypodermis Composition

Consists of areolar connective tissue, elastic and adipose connective tissue

Function of Hypodermis

Stabilized the skin and allows for the separate movement of the integument and the deeper tissue

Subcutaneous Fat (connected to reticular layer of integument) Distribution Patterns

Determined by hormones

Decubitus Ulcers (Bedsores)

results when dermal circulation is restricted affecting both the epidermis and dermis

Functions of Hair

protects and insulates, guards openings against particles and insects and is sensitive to light touch

Dermal Sheath Composition (outermost layer)

Dense fibrous connective tissue

Epithelial Root Sheath (epithelial tissue) Consists of

external epithelial root sheath and internal epithelial root sheath

Hair Follicle Consists of

Dermal root sheath and epithelial root sheath

Lanugo

fine very soft hair that covers the body of the fetus and sometimes the newborn

Where does the hair capillary plexus come from

the cutaneous plexus

Hair Matrix

A layer of dividing basal cells

Growing Hair

firmly attached to the hair matrix